Article

Obesity and risk of hearing loss: A prospective cohort study

Authors:
  • YAMAHA Health Care Center
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Background & aims: The existing yet limited prospective studies reported conflicting results about obesity and hearing loss. We investigated the prospective association between obesity and hearing loss in a large-scale Japanese working population, as well as the association between metabolic phenotype and hearing loss. Methods: The study included 48,549 employees aged 20-64 years and free of hearing loss at baseline. Pure-tone audiometric testing was performed annually to identify hearing loss at 1 and 4 kHz. Cox proportional hazards regression was used to investigate the risk of hearing loss associated with body mass index (BMI) and metabolic phenotype (based on a BMI of ≥25.0/<25.0 kg/m2 and presence/absence of ≥2 components of metabolic syndrome, except waist circumference). Baseline and updated information were obtained from annual health checkups. Results: With a median follow-up of 7 years, 1595 and 3625 individuals developed unilateral hearing loss at 1 and 4 kHz, respectively. The adjusted hazard ratios (HR) for hearing loss at 1 kHz were 1.21 (1.08, 1.36) and 1.66 (1.33, 2.08) for those with BMI 25.0-29.9 kg/m2 and BMI ≥30.0 kg/m2, respectively, compared to individuals with BMI <25.0 kg/m2. For hearing loss at 4 kHz, the corresponding HRs were 1.14 (1.05, 1.23) and 1.29 (1.09, 1.52). Compared with metabolically healthy non-obese individuals, the adjusted HRs for hearing loss at 1 kHz were 1.19 (1.03, 1.39), 1.27 (1.01, 1.61), and 1.48 (1.25, 1.76) for unhealthy non-obese, healthy obese, and unhealthy obese individuals, respectively. For hearing loss at 4 kHz, the corresponding HRs were 1.13 (1.04, 1.25), 1.21 (1.04, 1.41), and 1.26 (1.12, 1.41). Conclusions: Overweight and obesity are associated with an increased risk of hearing loss, and metabolically unhealthy obesity may confer additional risk.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... These associations are biologically plausible because individuals with these conditions are likely to have poor microvascular circulation that can lead to reduced blood supply to the cochlea, resulting in damage to the hair cells and eventually in hearing loss [12,13,18]. In the past few years, the findings of several epidemiological studies [19][20][21][22][23][24][25][26][27][28] have indicated that elevated body mass index (BMI), in the obesity range, and to a lesser extent, in the overweight range, was positively associated with hearing loss. However, the association between excess body weight and hearing loss remained inconclusive, as other studies found no association between both conditions [29][30][31][32]. ...
... Of these excluded articles, 13 studies did not investigate the associations of interest, two studies [43,44] enrolled adolescents, two studies [45,46] were conducted in the same population as the included study [32], one study [47] comparing low versus high BMI (high BMI as reference), one study [48] investigating the association between hearing loss and obesity, and one study [49] did not report the risk estimate. Finally, 14 studies [19][20][21][22][23][24][25][26][27][28][29][30][31][32], with a total of 489,354 participants and 55,410 cases, were included in the final analysis. ...
... Characteristics of the included studies are summarized in Additional file 1 (Table S1). Of the 14 included studies, six were longitudinal studies [19][20][21][27][28][29] and eight were cross-sectional studies [22][23][24][25][26][30][31][32]. Twelve studies [19-22, 24-29, 31, 32] were populationbased and two studies [23,30] were hospital-based. ...
Article
Full-text available
Background: Emerging evidence implicates excess weight as a potential risk factor for hearing loss. However, this association remained inconclusive. Therefore, we aimed to systematically and quantitatively review the published observational study on the association between body mass index (BMI) or waist circumference (WC) and hearing loss. Methods: The odds ratios (ORs) or relative risks (RRs) with their 95% confidence intervals (CIs) were pooled under a random-effects model. Fourteen observational studies were eligible for the inclusion in the final analysis. Results: In the meta-analysis of cross-sectional studies, the ORs for prevalent hearing loss were 1.10 (95% CI 0.88, 1.38) underweight, 1.14 (95% CI 0.99, 1.32) for overweight, OR 1.40 (95% CI 1.14, 1.72) for obesity, 1.14 (95% CI 1.04, 1.24) for each 5 kg/m2 increase in BMI, and 1.22 (95% CO 0.88. 1.68) for higher WC. In the meta-analysis of longitudinal studies, the RRs were 0.96 (95% CI 0.52, 1.79) for underweight, 1.15 (95% CI 1.04, 1.27) for overweight, 1.38 (95% CI 1.07, 1.79) for obesity, 1.15 (95% CI 1.01, 1.30) for each 5 kg/m2 increase in BMI, and 1.11 (95% CI 1.01, 1.22) for higher WC. Conclusions: In summary, our findings add weight to the evidence that elevated BMI and higher WC may be positively associated with the risk of hearing loss.
... In the last few years, epidemiological studies have suggested that a high body mass index (BMI) in the obesity range, and to a lesser extent, in the overweight range, is positively associated with hearing loss [5][6][7][8][9][10][11]. In addition, a diet high in cholesterol is associated with an increased risk of developing sensorineural hearing loss (SNHL) [12,13]. ...
... Large-scale longitudinal studies have provided growing evidence for a chronic HFD as a risk factor for hearing loss due to its association with DIO and metabolic disease [7,10,11,215,217]. For example, Scinicariello and colleagues [10] found that the prevalence of high-frequency hearing loss in obese adolescents was significantly higher compared to normal-weight adolescents [10]. ...
... A cross-sectional study by Hwang et al. [215] was one of the first studies to point out a possible link between SNHL and central obesity in a group of 690 females and males between 35 and 85 years old. It was supported by a prospective cohort study [7], which demonstrated that a high BMI and obesity increase the risk for SNHL. Another retrospective cross-sectional study showed that childhood DIO could be correlated with higher hearing thresholds across all frequencies and an almost two-fold increase in unilateral low-frequency SNHL [216]. ...
Article
Full-text available
This review aims to provide a conceptual and theoretical overview of the association between gut dysbiosis and hearing loss. Hearing loss is a global health issue; the World Health Organisation (WHO) estimates that 2.5 billion people will be living with some degree of hearing loss by 2050. The aetiology of sensorineural hearing loss (SNHL) is complex and multifactorial, arising from congenital and acquired causes. Recent evidence suggests that impaired gut health may also be a risk factor for SNHL. Inflammatory bowel disease (IBD), type 2 diabetes, diet-induced obesity (DIO), and high-fat diet (HFD) all show links to hearing loss. Previous studies have shown that a HFD can result in microangiopathy, impaired insulin signalling, and oxidative stress in the inner ear. A HFD can also induce pathological shifts in gut microbiota and affect intestinal barrier (IB) integrity, leading to a leaky gut. A leaky gut can result in chronic systemic inflammation, which may affect extraintestinal organs. Here, we postulate that changes in gut microbiota resulting from a chronic HFD and DIO may cause a systemic inflammatory response that can compromise the permeability of the blood–labyrinth barrier (BLB) in the inner ear, thus inducing cochlear inflammation and hearing deficits.
... Previous studies have also used this definition. [20][21][22] We used hearing loss in at least one ear as the variable in our primary analysis because few people developed bilateral hearing loss during follow-up. We identified the year that participants developed hearing loss at the annual health examination between April 2002 and March 2008. ...
... We selected these covariates based on previous literature suggesting associations with hearing loss. 20,[23][24][25] Several sensitivity analyses were conducted to check the robustness of the results. Missing exposure and covariate data were imputed via multiple imputation using chained equations 26, 27 with 10 complete datasets. ...
Article
Full-text available
BACKGROUND Several cross-sectional studies have linked higher physical fitness with better hearing sensitivity but have not established a causal relation; none have used a prospective design that is less susceptible to bias. We used a prospective cohort study to investigate the association between muscular and performance fitness and the incidence of hearing loss. METHODS In total, 21,907 participants without hearing loss received physical fitness assessments between April 2001 and March 2002. Muscular and performance fitness index, an age- and sex-specific summed z-score based on grip strength, vertical jump height, single-leg balance, forward bending, and whole-body reaction time was calculated. Participants were classified into quartiles according to the muscular and performance fitness index as well as each physical fitness test. They were followed up for the development of hearing loss, assessed by pure-tone audiometry at annual health examinations between April 2002 and March 2008. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for hearing loss incidence were estimated using Cox proportional hazards regression models. RESULTS During follow-up, 2765 participants developed hearing loss. The HRs (95% CIs) for developing hearing loss across the muscular and performance fitness index quartiles (lowest to highest) were 1.00 (reference), 0.88 (0.79–0.97), 0.83 (0.75–0.93), and 0.79 (0.71–0.88) (Ptrend <.001). Among the various physical fitness components, a clear dose-response association with hearing loss incidence was observed in vertical jump height and single-leg balance (Ptrend <.001 for both). CONCLUSION Higher muscular and performance fitness is associated with a lower incidence of hearing loss.
... Central obesity, increased waist circumference, and increased hearing threshold after BMI correction of the content of visceral adipose tissue were found to be related [20]. Obesity, as determined by BMI, has been associated with an increased risk of hearing loss [26]. Moreover, abdominal lipid-related factors were reported to be associated with hearing loss at specific frequency bands [25]. ...
... For example, one study found that WHR may be a surrogate marker for predicting the risk of hearing loss, [18] whereas another study suggested that FRAs were associated with hearing loss at specific frequencies, as determined by sex and the presence of diabetes, and that visceral adipose tissue (VAT) is particularly important role for hearing [25]. Two studies found relationships between BMI and hearing loss, with one finding that underweight and severe obesity were associated with an increased prevalence of hearing loss in a Korean population, and the other reporting that overweight was associated with an increased risk of hearing loss in a Japanese population [26]. ...
Article
Full-text available
The prevalence of sensorineural hearing loss has increased along with increases in life expectancy and exposure to noisy environments. Metabolic syndrome (MetS) is a cluster of co-occurring conditions that increase the risk of heart disease, stroke and type 2 diabetes, along with other conditions that affect the blood vessels. Components of MetS include insulin resistance, body weight, lipid concentration, blood pressure, and blood glucose concentration, as well as other features of insulin resistance such as microalbuminuria. MetS has become a major public health problem affecting 20-30% of the global population. This study utilized health examination to investigate whether metabolic syndrome was related to hearing loss. Methods: A total of 94,223 people who underwent health check-ups, including hearing tests, from January 2010 to December 2020 were evaluated. Subjects were divided into two groups, with and without metabolic syndrome. In addition, Scopus, Embase, PubMed, and Cochrane libraries were systematically searched, using keywords such as "hearing loss" and "metabolic syndrome", for studies that evaluated the relationship between the two. Results: Of the 94,223 subjects, 11,414 (12.1%) had metabolic syndrome and 82,809 did not. The mean ages of subjects in the two groups were 46.1 and 43.9 years, respectively. A comparison of hearing thresholds by age in subjects with and without metabolic syndrome showed that the average pure tone hearing thresholds were significantly higher in subjects with metabolic syndrome than in subjects without it in all age groups. (p < 0.001) Rates of hearing loss in subjects with 0, 1, 2, 3, 4, and 5 of the components of metabolic syndrome were 7.9%, 12.1%, 13.8%, 13.8%, 15.5% and 16.3%, respectively, indicating a significant association between the number of components of metabolic syndrome and the rate of hearing loss (p < 0.0001). The odds ratio of hearing loss was significantly higher in subjects with four components of metabolic syndrome: waist circumference, blood pressure, and triglyceride and fasting blood sugar concentrations (p < 0.0001). Conclusions: The number of components of the metabolic syndrome is positively correlated with the rate of sensorineural hearing loss.
... Epidemiological studies suggest that a high body mass index (BMI) in the obesity range, and to a lesser extent, in the overweight range, is positively associated with hearing loss [1][2][3][4][5][6][7]. Sensorineural hearing loss (SNHL) has also been reported as an extra-intestinal manifestation of inflammatory bowel disease (IBD) [8][9][10]. ...
Article
Full-text available
There is growing evidence for a relationship between gut dysbiosis and hearing loss. In-flammatory bowel disease, diet-induced obesity (DIO), and type 2 diabetes have all been linked to hearing loss. Here, we investigated the effect of a chronic high-fat diet (HFD) on the development of inner ear inflammation using a rodent model. Three-week-old CD-1 (Swiss) mice were fed an HFD or a control diet for ten weeks. After ten weeks, mouse cochleae were harvested, and markers of cochlear inflammation were assessed at the protein level using immunohistochemistry and at the gene expression level using quantitative real-time RT-PCR. We identified increased immunoexpres-sion of pro-inflammatory biomarkers in animals on an HFD, including intracellular adhesion molecule 1 (ICAM1), interleukin 6 receptor α (IL6Rα), and toll-like-receptor 2 (TLR2). In addition, increased numbers of ionized calcium-binding adapter molecule 1 (Iba1) positive macrophages were found in the cochlear lateral wall in mice on an HFD. In contrast, gene expression levels of inflam-matory markers were not affected by an HFD. The recruitment of macrophages to the cochlea and increased immunoexpression of inflammatory markers in mice fed an HFD provide direct evidence for the association between HFD and cochlear inflammation.
... This is a particularly vulnerable population who also have significant co-existing comorbidities such as incident dementia, and cognitive and physical decline all of which result in social isolation, poor community support and increased risk of falls [2,3]. Furthermore, adults with HL have higher burden of chronic illnesses such as obesity, heart disease and diabetes compared to normal hearing people [4]. Communication of correct information is key for coordinated and effective response to pandemic. ...
... Notch signaling is crucial for cell-cell communication and development, and it has been found important for metabolism that improves glucose tolerance, insulin sensitivity and ameliorates obesity and atherosclerosis [59]. There are also reports of changes in auditory [60][61][62], sight [63,64] and pharyngeal function [65,66] that relate to high BMI or obesity. The top significant probes are all inferred as differentially expressed in response to BMI but not as causing changes in BMI. ...
Article
Aim: Many efforts have been deployed to identify genetic variants associated with BMI. Alternatively, we explore epigenetic contribution to BMI variation by focusing on long noncoding RNAs (lncRNAs) which represents a key layer of epigenetic control. Materials & methods: We analyzed lncRNA expression in whole blood of 229 monozygotic twin pairs in association with BMI using generalized estimating equations. Results & conclusion: Six lncRNA probes were identified as significant (false discovery rate <0.05), with BMI showing causal effects on the expression of the significant lncRNAs. Functional annotation of differential profiles identified Gene ontology biological processes including kidney development, regulations of lipid biosynthetic process, circadian rhythm, notch signaling, etc. Whole blood lncRNAs are significantly expressed in response to BMI variation.
... A study on older adults suggested a positive association between BMI and hearing thresholds in crosssectional analysis that became non-significant in longitudinal analysis, probably due to the small sample size (n ¼ 636) [52]. However, Hu et al. [53], in a prospective cohort study with 48,549 Asian participants aged 20e64 years, found that obese individuals Table 2 Hazard ratios (95% confidence interval) for the association between total coffee consumption and the risk of hearing impairment in the UK Biobank study stratified by sex (N ¼ 36,923). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 YCLNU4577_proof ■ 3 December 2020 ■ 5/7 ...
Article
Background Hearing loss is the fifth leading cause of disability in the world. Coffee consumption might have a beneficial effect on hearing function because of the antioxidant and anti-inflammatory properties of some of its compounds. However, no previous longitudinal study has assessed the association between coffee consumption and the risk of hearing impairment. Objective To assess the prospective association between coffee consumption and risk of disabling hearing impairment in middle and older men and women from the UK Biobank study. Methods Analytical cohort with 36,923 participants (16,142 men and 20,781 women) [mean (SD): 56.6 (7.8) years, 1.6 (1.4) cups/d, and −7.6 (1.3) dB for age, total coffee consumption and speech reception threshold in noise at baseline, respectively]. At baseline, coffee consumption was measured with 3–5 multiple-pass 24-h food records. Hearing function was measured with a digit triplet test, and disabling hearing impairment was defined as a speech reception threshold in noise > -3.5 dB in any physical exam during the follow-up. Analyses were stratified by sex and Cox regression models were used to assess the prospective association proposed. Results Over 10 years of follow-up, 343 men and 345 women developed disabling hearing impairment. Among men, compared with those who consumed <1 cup/d of coffee, those who consumed 1, and ≥2 cups/d had a lower risk of hearing impairment (hazard ratio [95% confidence interval]: 0.72 [0.54–0.97] and 0.72 [0.56–0.92], respectively; P-trend: 0.01). This association was similar for caffeinated and decaffeinated coffee, and for filtered and non-filtered coffee, and was stronger in those with obesity (hazard ratio [95% confidence interval] for consumption of ≥2 vs. <1 cups/d: 0.39 [0.21–0.74]). No association was found between coffee and hearing function among women. Conclusions Coffee consumption was associated with lower risk of disabling hearing impairment in men but not in women. The association appeared to be independent of the coffee type and the preparation method.
... In addition, a prospective cohort study of employees aged 20-64 years in Japan found that the adjusted hazard ratios (HRs) for hearing loss at 1 kHz were 1.21 and 1.66 for those with BMI 25.0-29.9 and ≥30.0 kg/m 2 , respectively, compared to individuals with BMI < 25.0 kg/m 2 [12]. Factors related to obesity that increase the prevalence of sensorineural hearing loss include waist circumference, total cholesterol, triglyceride, BMI, metabolic syndrome, and presence of visceral adipose tissue [13]. ...
Article
Full-text available
This study aimed to explore the relationship between body mass index (BMI) and hearing loss. We analyzed data from the Korean National Health Insurance Service Health Screening Cohort 2009–2019 (291,471 patients with hearing loss and 6,088,979 control participants). Both patient groups were subsequently divided into four groups according to BMI: <18.5 (underweight), 18.5–24.9 (normal), 25–29.9 (obese I), and ≥30 (obese II). To evaluate the relationship between BMI and hearing loss, multivariate logistic regression analysis was used, adjusting for age, sex, smoking, alcohol consumption, blood pressure, triglycerides, total cholesterol, low-density lipoprotein, proteinuria, serum creatinine, aspartate aminotransferase, alanine aminotransferase, and fasting glucose levels. The adjusted odds ratio (OR) of the underweight group for hearing loss was 1.21 (95% CI = 1.19–1.24) compared to the normal BMI group, whereas the adjusted ORs of obese I and obese II groups for hearing loss were 0.95 and 0.87, respectively. Being underweight was generally associated with an increased prevalence of hearing loss in the Korean adult population.
... To the best of our knowledge, this association was not highlighted before. However, Hu et al 26 concluded that increased BMI may carry an increased risk of hearing impairment, especially in cases of morbid obesity. ...
Article
Introduction: Proteasome subunit beta type-8 (PSMB8) is a protein that contributes to the complete assembly of 20S proteasome complexes, which play a role in the pathogenesis of vitiligo. Objective: The study aimed to evaluate the association between PSMB8 gene polymorphisms with vitiligo to assess its clinical significance among a sample of Egyptian patients with vitiligo. Methods: Genomic DNA was isolated from blood samples of 100 patients with vitiligo and 100 control subjects, and detection of PSMB8 polymorphisms was done by real-time PCR. Data analysis was carried out for the entire cohort. Statistics were performed using software. Audiological evaluation was performed, including pure-tone audiometry, extended high-frequency audiometry, transient evoked otoacoustic emissions, and auditory brainstem response. Results: There was a significant difference between PSMB8 genotypes and alleles distribution in patients and control groups. Ten percent of the study sample had sensorineural hearing loss. The patients with hearing loss were significantly older (P=0.0002), had significantly later age of onset (P=0.0007), longer duration (P=0.0021), higher body mass index (BMI) (P=0.045), and higher vitiligo area scoring index (VASI) scores (P=0.0015). All patients had extensive forms of vitiligo (generalized and universal). Regarding the VIT rs2071543 polymorphism, all of the patients with hearing loss were carrying the CA and AA genotypes. None of the patients carried the reference genotype, CC. The A allele of VIT rs2071543 was significantly associated with hearing affection (P=0.024). Conclusion: In our study, PSMB8 polymorphism was associated with the susceptibility to develop vitiligo and appeared to have clinical significance among the studied group of patients. Factors predicting auditory abnormalities should be further studied for early detection and management.
... This definition was used in previous studies. 7,23 Hearing loss was defined as the occurrence of hearing loss in at least one ear because few individuals developed bilateral hearing loss. On health examinations conducted between April 2002 and March 2008, we evaluated the month in which hearing loss was detected. ...
Article
Full-text available
Previous cohort study reported that high physical activity was associated with a low risk of self‐reported hearing loss in women. However, no studies have examined the association between physical activity and the development of hearing loss as measured using an objective assessment of hearing loss in men and women. Here we used cohort data to examine the association between leisure‐time physical activity and incidence of objectively assessed hearing loss in men and women. Participants included 27,537 Japanese adults aged 20–80 years without hearing loss, who completed a self‐administered physical activity questionnaire between April 2001 and March 2002. The participants were followed up for the development of hearing loss as measured by audiometry between April 2002 and March 2008. During follow‐up, 3691 participants developed hearing loss. Compared with the none physical activity group, multivariable adjusted hazard ratios for developing hearing loss were 0.93 (95% confidence interval, 0.86–1.01) and 0.87 (0.81–0.95) for the medium (<525 MET‐min/week) and high (≥525 MET‐min/week) physical activity groups, respectively (P for trend = .001). The magnitude of risk reduction was slightly greater in vigorous‐intensity activity than in moderate‐intensity activity (P for interaction = .01). Analysis by sound frequency showed that the amount of physical activity was inversely associated with high frequency hearing loss development (P for trend <.001), but not with low frequency hearing loss development (P for trend = .19). Higher level of leisure‐time physical activity was associated with lower incidence of hearing loss, particularly for vigorous‐intensity activities and high sound frequencies.
... A puzzling aspect of the results is that heightened auditory sensitivity amongst this cluster of individuals, as such link had not been reported elsewhere. In fact, hearing loss has been shown to increase likelihood of obesity (Hu et al., 2020;Hwang, Wu, Hsu, Liu, & Yang, 2009;Lalwani, Katz, Liu, Kim, & Weitzman, 2013;Üçler et al., 2016). One plausible explanation to our unexpected finding relates to the tested stimuli. ...
Article
Understanding how human senses are linked to eating behaviour and adiposity has been a key topic in sensory science, and a source of substantial controversy. Despite strong correlations in sensitivity across different sensory modalities, the fundamental question of whether individuals possess a ‘generalised sensitivity’ across senses remains unanswered. A better understanding of the relationships between multiple senses and eating behaviour is needed to tackle the current obesity epidemic. The present study synthesises published data regarding sensory sensitivities across modalities and presents new empirical findings. Specifically, we synthesise findings from 115 publications, including meta-analyses of 26 studies. These data reveal strong yet complex links between senses, highlighting the potential of multi-sensory analyses to better characterise sensory variations. In the empirical study, 98 Caucasian males (25.9 ± 5.8 years of age; body mass index: 26.8 ± 5.1 kg∙m⁻²) are tested for their supra-threshold sensory sensitivities (d’) to 11 food-related mono-modal stimuli across olfaction, gustation, vision, and audition. Canonical correlations on d’ for each modality reveal significant positive correlations between olfaction and gustation (p < 0.001), vision and audition (p < 0.001), as well as olfaction and audition (p = 0.008). Additionally, K-means cluster analysis identifies three broad groups of individuals with distinct multi-sensory fingerprints. Intriguingly, individuals in separate clusters are shown to have significantly different adiposity measures (body mass index: p = 0.01; body fat percentages: p = 0.05). Overall, this study sheds important new light on multi-sensory ‘fingerprints’, and their links to obesity.
... We performed separate analyses in women and men, as we found a statistically significant interaction term for sex and intake of PUFA when predicting incident hearing impairment (P = 0.03). Also, and according to the previous literature, we performed analyses stratified by subgroups of age [39], presence of tinnitus [40], being overweight or obese [41], having chronic diseases [42], and diet quality [30]. Additionally, we conducted separate analyses among those with optimal hearing at the start of the study, to understand whether the effect of fatty acids depends on the baseline hearing status. ...
Article
Full-text available
Purpose To examine the associations of specific dietary fats with the risk of disabling hearing impairment in the UK Biobank study. Methods This cohort study investigated 105,592 participants (47,308 men and 58,284 women) aged ≥ 40 years. Participants completed a minimum of one valid 24-h recall (Oxford Web-Q). Dietary intake of total fatty acids, polyunsaturated fatty acids (PUFA), saturated fatty acids (SFA), and monounsaturated fatty acids (MUFA) was assessed at baseline. Functional auditory capacity was measured with a digit triplet test (DTT), and disabling hearing impairment was defined as a speech reception threshold in noise > − 3.5 dB in any physical exam performed during the follow-up. Results Over a median follow-up of 3.2 (SD: 2.1) years, 832 men and 872 women developed disabling hearing impairment. After adjustment for potential confounders, including lifestyles, exposure to high-intensity sounds, ototoxic medication and comorbidity, the hazard ratios (HRs), and 95% confidence interval (CI) of disabling hearing function, comparing extreme quintiles of intakes were 0.91 (0.71–1.17) for total fat, 1.09 (0.83–1.44) for PUFA, 0.85 (0.64–1.13) for SFA and 1.01 (0.74–1.36) for MUFA among men. Among women, HRs comparing extreme intakes were 0.98 (0.78–1.24) for total fat, 0.69 (0.53–0.91) for PUFA, 1.26 (0.96–1.65) for SFA, and 0.91 (0.68–1.23) for MUFA. Replacing 5% of energy intake from SFA with an equivalent energy from PUFA was associated with 25% risk reduction (HR: 0.75; 95% CI: 0.74–0.77) among women. Conclusions PUFA intake was associated with decreased risk of disabling hearing function in women, but not in men.
Article
This article summarizes some of the significant knowledge of interactions between metabolism pathology and hearing, in particular, diabetes mellitus, dyslipidemia, obesity and metabolic syndrome. Knowledge on interactions between metabolism pathology and auditory function is progressing and much of this progress comes from animal model and preclinical studies, as well as clinical research in humans. Since these pathologies are frequently found together, it is important to investigate them individually. The authors made an effort to deepen the topics separately, giving a vision that included epidemiology studies, physiopathological hypotheses, supported, when possible, by anatomopathological observations. In this review, we highlight potential methods and research directions, with the goal of advancing our understanding, prevention, diagnosis, and treatment of ear disturbance influenced by pathology of metabolism.
Article
Full-text available
The aim of this systematic review and meta-analysis study was to clarify the effects of sensorineural hearing loss (SNHL) on the incidence of stroke. In line with this, PubMed, Scopus, Web of Science, and ScienceDirect databases were searched using related keywords and MeSH terms from inception to March 1, 2020. Out of the 1961 initial records, eight cohort studies comprising 4,564,202 participants were included, and their qualities were assessed using the Newcastle-Ottawa Scale (NOS). Then, the random-effects model was used to pool HR (95% CI) for risk of stroke; and heterogeneity was presented with I ² index. Subgroup analysis and publication bias tests were performed, and the pooled HR (95% CI) of stroke in SNHL was estimated as 1.31 (1.08, 1.53) for the unadjusted model and 1.33 (1.18, 1.49) for the adjusted model. Subgroup analysis indicates a significantly higher risk of stroke in patients with sudden SNHL (SSNHL) in comparison to age-related HL (ARHL) both in the unadjusted model, [HR = 1.46; 95% CI (1.08, 1.63)] versus [HR = 1.14; 95% CI (0.64, 1.65)], and in the adjusted model, [HR = 1.44; 95% CI (1.15, 1.74)] versus [HR = 1.29; 95% CI (1.24, 1.34)]. Our study showed that patients with SNHL face a higher risk of stroke than those without SNHL. It is necessary to perform hematologic and neurological examinations to help clinicians detect patients who are potentially at risk for stroke.
Article
Full-text available
There is growing consensus that certain lifestyles can contribute to cognitive impairment and dementia, but the physiological steps that link a harmful lifestyle to its negative impact are not always evident. It is also unclear whether all lifestyles that contribute to dementia do so through the same intermediary steps. This article will focus on three lifestyles known to be risk factors for dementia, namely obesity, sedentary behavior, and insufficient sleep, and offer a unifying hypothesis proposing that lifestyles that negatively impact cognition do so through the same sequence of events: inflammation, small vessel disease, decline in cerebral perfusion, and brain atrophy. The hypothesis will then be tested in a recently identified risk factor for dementia, namely hearing deficit. If further studies confirm this sequence of events leading to dementia, a significant change in our approach to this debilitating and costly condition may be necessary, possible, and beneficial.
Article
Resumen Esta investigación presenta un diagnóstico de seguridad y salud en el trabajo basado en el Modelo Obrero Italiano, para la identificación de riesgos y demandas fisiológicas en trabajadores de una estación de bomberos en Chihuahua, México. Se midieron los niveles de ruido, la pérdida auditiva y las partículas en suspensión. Se empleó el método ergonómico REBA para detectar el riesgo en el ascenso-descenso de la unidad móvil de rescate. Las demandas psicosociales se evaluaron a través del instrumento DAAS 21. El análisis estadístico se realizó utilizando el software SAS 9.0. El ruido excedió el Nivel Máximo Permitido (MLP) establecido por la norma mexicana. Se detectaron bomberos con hipoacusia leve a moderada. Se analizó el nivel de correlación entre umbral de audición (UA), antigüedad, edad e índice de masa corporal (IMC). Las partículas PM2.5 y PM10 fueron medidas y su concentración se encontró dentro del MLP. El método REBA categorizó el riesgo ergonómico como medio y muy alto. Los resultados del DASS 21 estuvieron en un rango normal para ansiedad-depresión-estrés. Los resultados brindan evidencia científica que demuestra la necesidad de equipos y atención médica para los bomberos.
Article
Full-text available
Objectives The aim of this study was to determine whether haemoglobin A1c (HbA1c) level is associated with the incidence of hearing impairment accounting for smoking status and diabetic condition at baseline. Methods Participants were 131 689 men and 71 286 women aged 30–65 years and free of hearing impairment at baseline (2008) who attended Japanese occupational annual health check-ups from 2008 to 2015. We defined low-frequency hearing impairment at a hearing threshold >30 dB at 1 kHz and high frequency at >40 dB at 4 kHz in the better ear in pure-tone audiometric tests. HbA1c was categorised into seven categories. The association between HbA1c and hearing impairment was assessed using the Cox proportional hazards model. Results On 5 years mean follow-up, high HbA1c was associated with high-frequency hearing impairment. In non-smokers, HbA1c≥8.0% was associated with high-frequency hearing impairment, with a multivariable HR (95% CI) compared with HbA1c 5.0%–5.4% of 1.46 (1.10 to 1.94) in men and 2.15 (1.13 to 4.10) in women. There was no significant association between HbA1c and hearing impairment in smokers. A J-shaped association between HbA1c and high-frequency hearing impairment was observed for participants with diabetes at baseline. HbA1c was not associated with low-frequency hearing impairment among any participants. Conclusions HbA1c ≥8.0% of non-smokers and ≥7.3% of participants with diabetes was associated with high-frequency hearing impairment. These findings indicate that appropriate glycaemic control may prevent diabetic-related hearing impairment.
Article
Full-text available
Background: Hearing loss is a disabling condition whose prevalence rises with age. Obesity-a risk factor common to many non-communicable diseases-now appears to be implicated. We aimed to determine: (1) cross-sectional associations of body composition measures with hearing in mid-childhood and mid-life and (2) its longitudinal associations with 10-year body mass index (BMI) trajectories. Methods: Design & Participants: There were 1481 11-12-year-old children and 1266 mothers in the population-based cross-sectional CheckPoint study nested within the Longitudinal Study of Australian Children (LSAC). Anthropometry (CheckPoint): BMI, fat/fat-free mass indices, waist-to-height ratio; LSAC wave 2-6-biennial measured BMI. Audiometry (CheckPoint): Mean hearing threshold across 1, 2 and 4 kHz; hearing loss (threshold > 15 dB HL, better ear). Analysis: Latent class models identifying BMI trajectories; linear/logistic regression quantifying associations of body composition/trajectories with hearing threshold/loss. Results: Measures of adiposity, but not fat-free mass, were cross-sectionally associated with hearing. Fat mass index predicted the hearing threshold and loss in children (β 0.6, 95% confidence interval (CI) 0.3-0.8, P < 0.001;, odds ratio (OR) 1.2, 95% CI 1.0-1.4, P = 0.05) and mothers (β 0.8, 95% CI 0.5-1.2, P < 0.001; OR 1.2, 95% CI 1.1-1.4, P = 0.003). Concurrent obesity (OR 1.5, 95% CI 1.1-2.1, P = 0.02) and waist-to-height ratio (WHtR) ≥ 0.6 (OR 1.6, 95% CI 1.2-2.3, P = 0.01) predicted maternal hearing, with similar but attenuated patterns in children. In longitudinal analyses, mothers', but not children's, BMI trajectories predicted hearing (OR for severely obese 3.0, 95% CI 1.4-6.6, P = 0.01). Conclusions: Concurrent adiposity and decade-long BMI trajectories showed small, but clear, associations with poor hearing in mid-life women, with emergent patterns by mid-childhood. This suggests that obesity may play a role in the rising global burden of hearing loss. Replication and mechanistic and body compositional studies could elucidate possible causal relationships.
Article
Full-text available
Background/objectives Hearing loss (HL) is associated with certain diseases and affects health, resulting in a low quality of life. Some components of the metabolic syndrome (MetS) coincide with the risk factors for sensorineural hearing loss (SNHL). To date, very few studies have examined the link between MetS and HL. The aim of the current study was to try to understand the potential association between MetS and HL. Methods Using Iranian health surveys of professional drivers, we enrolled 11,114 individuals aged 20–60 years, whose main job is to operate a motor vehicle. We examined participants for the presence and absence of SNHL and the components of the MetS. Additionally, we investigated the relationship between MetS and the pure tone air conduction hearing thresholds of participants with SNHL, including low-frequency and high-frequency thresholds. Results This cross-sectional study consisted of 11,114 participants: 3202 (28.81%) diagnosed with MetS and 7911 (71.18%) without and 2772 (24.94%) with SNHL and 8432 (75.86%) without. Participants with SNHL had a higher number of components of MetS (P<0.001 for all components). Conclusion Our results demonstrated that an association possibly exists between different components of MetS (obesity, hypertension, hypertriglyceridemia, high fasting glucose levels, and waist circumference) and SNHL in a population of West Azerbaijan drivers. Therefore, it is important to schedule periodic checkups for drivers to detect and avoid the increase in MetS components at an early stage in this population.
Article
Full-text available
BACKGROUND Although the rising pandemic of obesity has received major attention in many countries, the effects of this attention on trends and the disease burden of obesity remain uncertain. METHODS We analyzed data from 68.5 million persons to assess the trends in the prevalence of overweight and obesity among children and adults between 1980 and 2015. Using the Global Burden of Disease study data and methods, we also quantified the burden of disease related to high body-mass index (BMI), according to age, sex, cause, and BMI in 195 countries between 1990 and 2015. RESULTS In 2015, a total of 107.7 million children and 603.7 million adults were obese. Since 1980, the prevalence of obesity has doubled in more than 70 countries and has continuously increased in most other countries. Although the prevalence of obesity among children has been lower than that among adults, the rate of increase in childhood obesity in many countries has been greater than the rate of increase in adult obesity. High BMI accounted for 4.0 million deaths globally, nearly 40% of which occurred in persons who were not obese. More than two thirds of deaths related to high BMI were due to cardiovascular disease. The disease burden related to high BMI has increased since 1990; however, the rate of this increase has been attenuated owing to decreases in underlying rates of death from cardiovascular disease. CONCLUSIONS The rapid increase in the prevalence and disease burden of elevated BMI highlights the need for continued focus on surveillance of BMI and identification, implementation, and evaluation of evidence-based interventions to address this problem. (Funded by the Bill and Melinda Gates Foundation.)
Article
Full-text available
The reported effects of a metabolically healthy obese (MHO) phenotype on diabetes and cardiovascular disease (CVD) risk are contradictory. Within the context of a population-based cohort study, we aimed to investigate the long-term risk of an MHO status for the development of diabetes and CVD, and whether consistency of this phenotype or age affected cardiometabolic outcomes. We recruited 7588 subjects without diabetes or CVD, aged 40 to 69 years at baseline examination, from the Korean Genome and Epidemiology Study, and followed-up these subjects for 10 years biennially. Participants were divided into 4 groups based on the body mass index and the presence of metabolic syndrome: metabolically healthy normal weight (MHNW), MHO, metabolically unhealthy normal weight (MUNW), and metabolically unhealthy obese (MUO). We defined persistent phenotypes if subjects maintained the same phenotype at every visit from baseline to their last visit. Incident diabetes and CVD morbidity or mortality were identified during 10 years of follow-up. Compared to MHNW controls, MUNW and MUO groups had increased risk for development of diabetes (hazard ratio [HR] 3.0 [95% CI: 2.5–3.6], and 4.0 [3.4–4.7], respectively) and CVD (HR 1.6 [1.3–2.0], and 1.9 [1.5–2.4], respectively). However, the MHO group showed only a marginal increase in risk for diabetes and CVD (HR 1.2 [0.99–1.6], 1.4 [0.99–1.8], respectively). The impact of MHO on the development of diabetes was more prominent in younger individuals (HR 1.9 [1.2–3.1] vs 1.1 [0.8–1.4], <45 years vs ≥45 years at baseline). Only 15.8% of MHO subjects maintained the MHO phenotype at every visit from baseline to the 5th biennial examination (persistent MHO). In subjects with persistent MHO, the risk for diabetes and CVD was significantly higher than those with persistent MHNW (1.9 [1.2–3.1], 2.1 [1.2–3.7], respectively). MHO phenotype, even if maintained for a long time, was associated with a significantly higher risk for the development of diabetes and CVD in Korean subjects.
Article
Full-text available
Summary Background Underweight and severe and morbid obesity are associated with highly elevated risks of adverse health outcomes. We estimated trends in mean body-mass index (BMI), which characterises its population distribution, and in the prevalences of a complete set of BMI categories for adults in all countries. Methods We analysed, with use of a consistent protocol, population-based studies that had measured height and weight in adults aged 18 years and older. We applied a Bayesian hierarchical model to these data to estimate trends from 1975 to 2014 in mean BMI and in the prevalences of BMI categories (<18·5 kg/m2 [underweight], 18·5 kg/m2 to <20 kg/m2, 20 kg/m2 to <25 kg/m2, 25 kg/m2 to <30 kg/m2, 30 kg/m2 to <35 kg/m2, 35 kg/m2 to <40 kg/m2, ≥40 kg/m2 [morbid obesity]), by sex in 200 countries and territories, organised in 21 regions. We calculated the posterior probability of meeting the target of halting by 2025 the rise in obesity at its 2010 levels, if post-2000 trends continue. Findings We used 1698 population-based data sources, with more than 19·2 million adult participants (9·9 million men and 9·3 million women) in 186 of 200 countries for which estimates were made. Global age-standardised mean BMI increased from 21·7 kg/m2 (95% credible interval 21·3–22·1) in 1975 to 24·2 kg/m2 (24·0–24·4) in 2014 in men, and from 22·1 kg/m2 (21·7–22·5) in 1975 to 24·4 kg/m2 (24·2–24·6) in 2014 in women. Regional mean BMIs in 2014 for men ranged from 21·4 kg/m2 in central Africa and south Asia to 29·2 kg/m2 (28·6–29·8) in Polynesia and Micronesia; for women the range was from 21·8 kg/m2 (21·4–22·3) in south Asia to 32·2 kg/m2 (31·5–32·8) in Polynesia and Micronesia. Over these four decades, age-standardised global prevalence of underweight decreased from 13·8% (10·5–17·4) to 8·8% (7·4–10·3) in men and from 14·6% (11·6–17·9) to 9·7% (8·3–11·1) in women. South Asia had the highest prevalence of underweight in 2014, 23·4% (17·8–29·2) in men and 24·0% (18·9–29·3) in women. Age-standardised prevalence of obesity increased from 3·2% (2·4–4·1) in 1975 to 10·8% (9·7–12·0) in 2014 in men, and from 6·4% (5·1–7·8) to 14·9% (13·6–16·1) in women. 2·3% (2·0–2·7) of the world's men and 5·0% (4·4–5·6) of women were severely obese (ie, have BMI ≥35 kg/m2). Globally, prevalence of morbid obesity was 0·64% (0·46–0·86) in men and 1·6% (1·3–1·9) in women. Interpretation If post-2000 trends continue, the probability of meeting the global obesity target is virtually zero. Rather, if these trends continue, by 2025, global obesity prevalence will reach 18% in men and surpass 21% in women; severe obesity will surpass 6% in men and 9% in women. Nonetheless, underweight remains prevalent in the world's poorest regions, especially in south Asia. Funding Wellcome Trust, Grand Challenges Canada
Article
Full-text available
Background We sought to establish the optimal waist circumference (WC) cut-off point for predicting diabetes mellitus (DM) and to compare the predictive ability of the metabolic syndrome (MetS) criteria of the Joint Interim Statement (JIS) and the Japanese Committee of the Criteria for MetS (JCCMS) for DM in Japanese. Methods Participants of the Japan Epidemiology Collaboration on Occupational Health Study, who were aged 20–69 years and free of DM at baseline (n = 54,980), were followed-up for a maximum of 6 years. Time-dependent receiver operating characteristic analysis was used to determine the optimal cut-off points of WC for predicting DM. Time-dependent sensitivity, specificity, and positive and negative predictive values for the prediction of DM were compared between the JIS and JCCMS MetS criteria. Results During 234,926 person-years of follow-up, 3180 individuals developed DM. Receiver operating characteristic analysis suggested that the most suitable cut-off point of WC for predicting incident DM was 85 cm for men and 80 cm for women. MetS was associated with 3–4 times increased hazard for developing DM in men and 7–9 times in women. Of the MetS criteria tested, the JIS criteria using our proposed WC cut-off points (85 cm for men and 80 cm for women) had the highest sensitivity (54.5 % for men and 43.5 % for women) for predicting DM. The sensitivity and specificity of the JCCMS MetS criteria were ~37.7 and 98.9 %, respectively. Conclusion Data from the present large cohort of workers suggest that WC cut-offs of 85 cm for men and 80 cm for women may be appropriate for predicting DM for Japanese. The JIS criteria can detect more people who later develop DM than does the JCCMS criteria. Electronic supplementary material The online version of this article (doi:10.1186/s12889-016-2856-9) contains supplementary material, which is available to authorized users.
Article
Full-text available
An elevation in hearing thresholds and decrease in hearing sensitivity in adults, particularly due to aging, are quite common. Recent studies have shown that, apart from aging, various other factors also play a role in auditory changes. Studies on the association of hearing loss (HL) with obesity are limited in advanced age cases and present contradictions. In this study, the association between obesity and hearing thresholds in women aged 18-40 years has been assessed. Forty women diagnosed with obesity (mean age, 31.8 years) and 40 healthy non-obese female controls (mean age, 30.5 years) were included in this prospective study. Each subject was tested with low (250, 500, 1000 and 2000 Hz) and high (4000, 6000 and 8000 Hz) frequency audiometry. In the case and control groups, the average hearing thresholds at low frequencies were 16.03 ± 4.72 and 16.15 ± 2.72 (p = 0.885) for the right ear, respectively, and 16.15 ± 5.92 and 14.71 ± 3.18 (p = 0.180) for the left ear, respectively. The average hearing threshold levels at high frequencies were 20.70 ± 10.23 and 15.33 ± 3.87 (p = 0.003), respectively, for the right ear, and 22.91 ± 15.54 and 15.87 ± 4.35 (p = 0.007), respectively, for the left ear with statistical significance. This is the first report on the association of obesity with hearing threshold in women aged 18-40 years. We have demonstrated that obesity may affect hearing function, particularly that related to high frequencies. Hearing loss can be prevented by avoidance or control of obesity and its risk factors. Moreover, an auditory screening of obese cases at an early stage may provide early diagnosis of HL and may also contribute to their awareness in the fight against obesity.
Article
Full-text available
Background: Leisure-time physical activity is associated with a lower risk of depression. However, the precise shape of the dose-response relationship remains elusive, and evidence is scarce regarding other domains of activity. We prospectively investigated associations of physical activity during leisure, work, and commuting with risk of depressive symptoms in Japanese workers. Methods: We conducted a cohort study of 29 082 Japanese workers aged 20-64 years without psychiatric disease (including depressive symptoms) at baseline with a maximum 5-year follow-up. Physical activity was self-reported. Depressive symptoms were assessed by 13 self-report questions on subjective symptoms. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for incidence of depressive symptoms were calculated using Cox regression analysis. Results: During a mean follow-up of 4.7 years, 6177 developed depressive symptoms. Leisure exercise showed a U-shaped association with risk of depressive symptoms adjusting for potential confounders. Additional adjustment for baseline depression scores attenuated the association, but it remained statistically significant (P for trend = 0.037). Compared with individuals who engaged in sedentary work, the HR (95 % CI) was 0.86 (0.81, 0.92) for individuals who stand or walk during work and 0.90 (0.82, 0.99) for those who are fairly active at work. However, the association disappeared after adjusting for baseline depression scores. Walking to and from work was not associated with depressive symptoms. Conclusions: The findings suggest that leisure-time exercise has a U-shaped relation with depressive symptoms in Japanese workers. Health-enhancing physical activity intervention may be needed for individuals who engage in sedentary work.
Article
Full-text available
Hearing loss was a common, chronically disabling condition in the general population and had been associated with several inflammatory diseases. Metabolic syndrome, which was associated with insulin resistance and visceral obesity, was considered a chronic inflammatory disease. To date, few attempts had been made to establish a direct relationship between hearing loss and metabolic syndrome. The aim of the present study was to investigate the relationship between metabolic syndrome and hearing loss by analyzing the data in the reports of the National Health and Nutrition Examination Survey 1999-2004. This study included 2100 participants aged ≤ 65 years who enrolled in the National Health and Nutrition Examination Survey (1999-2004). We examined the relationship between the presence of different features of metabolic syndrome in the participants and their pure-tone air-conduction hearing thresholds, including low-frequency and high-frequency thresholds. After adjusting for potential confounders, such as age, medical conditions, and smoking status, the participants with more components of metabolic syndrome were found to have higher hearing thresholds than those with fewer components of metabolic syndrome (p < 0.05 for a trend). The low-frequency hearing threshold was associated with individual components of metabolic syndrome, such as abdominal obesity, high blood pressure, elevated triglycerides, and a low level of high-density lipoprotein cholesterol (HDL-C) (p < 0.05 for all parameters). The results indicated that the presence of a greater number of components of metabolic syndrome was significantly associated with the hearing threshold in the US adult population. Among the components of metabolic syndrome, the most apparent association was observed between low HDL and hearing loss.
Article
Full-text available
Background: The aim of this study was to determine whether metabolic syndrome (MetS) or chronic kidney disease (CKD) is associated with hearing thresholds in the general Korean population. Patients and methods: A total of 16,554 participants were included in this study. MetS was defined using the National Cholesterol Education Program Adult Treatment Panel III guidelines, and CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2 or a dipstick proteinuria result of ≥1+. The hearing thresholds were measured at 0.5, 1, 2, 3, 4, and 6 kHz. Low-frequency (Freq) was defined as pure-tone averages at 0.5 and 1 kHz, while Mid-Freq and High-Freq were defined as the average thresholds at mid-frequency (2 and 3 kHz) and high frequency (4 and 6 kHz), respectively. Results: In men, the hearing thresholds were 15.1 ± 14.5 dB, 22.2 ± 21.3 dB, and 37.3 ± 26.5 dB for Low-, Mid-, and High-Freq, respectively. In women, the hearing thresholds were 14.9 ± 15.3 dB, 16.6 ± 18.0 dB, and 26.1 ± 21.5 dB for Low-, Mid-, and High-Freq, respectively. The hearing thresholds for men were significantly higher than the hearing thresholds for women in all 3 threshold categories. Male and female subjects with MetS or CKD had higher hearing thresholds than the subjects that did not have these disorders. In the multivariate analysis, MetS was associated with increased hearing thresholds in women, and CKD was associated with increased hearing thresholds in men and women. Conclusion: MetS is associated with hearing thresholds in women, and CKD is associated with hearing thresholds in men and women. Therefore, patients with MetS or CKD should be closely monitored for hearing impairment.
Article
Full-text available
Objective: We investigated whether the metabolically healthy obese (MHO) phenotype was associated with an increased risk of the development of diabetes. If so, we aimed to determine what factors could explain this finding. Design, setting, and participants: Studied were 8090 Japanese individuals without diabetes. Metabolic health status was assessed by common clinical markers: blood pressure, triglycerides, high-density lipoprotein-cholesterol, and fasting glucose concentrations. The cutoff value for obesity or normal weight (NW) was a body mass index of 25.0 kg/m(2). Results: The 5-year incidence rate of diabetes was 1.2% (n = 58 of 4749) in metabolically healthy NW (MHNW) individuals, 2.8% (n = 20 of 719) in MHO individuals, 6.0% (n = 102 of 1709) in metabolically abnormal NW individuals, and 10.3% (n = 94 of 913) in metabolically abnormal obese individuals. Although MHO individuals had no or one metabolic factor, 47.8% had ultrasonographic fatty liver (FL). The MHO group had a significantly increased risk of diabetes compared with the MHNW group [multivariate adjusted odds ratio (OR) 2.23 (95% confidence interval [CI] 1.33, 3.75)], but this risk was attenuated after adjustment for FL. Compared with the MHNW/non-FL group, the risk of diabetes in the MHO/non-FL group was not significantly elevated [OR 1.01 (95% CI 0.35, 2.88)]. However, the MHO/FL and MHNW/FL groups had similarly elevated risks of diabetes [OR 4.09 (95% CI 2.20, 7.60) and 3.16 (1.78, 5.62), respectively]. Conclusions: Almost half of the MHO participants had FL, which partially explained the increased risk of diabetes among the obese phenotypes. The presence of FL should be evaluated to assess whether an individual was actually in a metabolically benign state for the prediction of diabetes.
Article
Full-text available
The aim of this study was to investigate the mechanisms of diet-induced obesity on hearing degeneration in CD/1 mice. Sixty 4-week-old male CD/1 mice were randomly and equally divided into 2 groups. For 16 weeks, the diet-induced obesity (DIO) group was fed a high fat diet and the control group was fed a standard diet of 13.43 % kcal fat. The morphometry, biochemistry, auditory brainstem response thresholds, omental fat, and histopathology of the cochlea were compared between the beginning and end of the study (4 vs. 20 weeks old). The results show that the body weight, fasting plasma triglyceride concentrations, and omental fat weight were higher in the DIO group than in the control group at the end of experiment. The auditory brainstem response thresholds at high frequencies were significantly elevated in the DIO group compared to those of the control group. Histology studies showed that, compared to the control group, the DIO group had blood vessels with smaller diameters and thicker walls in the stria vascularis at the middle and basal turns of the cochlea. The cell densities in the spiral ganglion and spiral ligament at the basal turn of the cochlea were significantly lower in the DIO group. Immunohistochemical staining showed that hypoxia-induced factor 1 (HIF-1), tumor necrosis factor alpha (TNF-α), nuclear factor kappa B (NF-κB), caspase 3, poly(ADP-ribose) polymerase-1, and apoptosis inducing factor were all significantly more dense in the spiral ganglion and spiral ligament at the basal turn of cochlea in the DIO group. Our results suggest that diet-induced obesity exacerbates hearing degeneration via increased hypoxia, inflammatory responses, and cell loss in the spiral ganglion and spiral ligament and is associated with the activation of both caspase-dependent and -independent apoptosis signaling pathways in CD/1 mice.
Article
Full-text available
This paper will focus on understanding the role and action of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the molecular and biochemical pathways responsible for the regulation of the survival of hair cells and spiral ganglion neurons in the auditory portion of the inner ear. The pivotal role of ROS/RNS in ototoxicity makes them potentially valuable candidates for effective otoprotective strategies. In this review, we describe the major characteristics of ROS/RNS and the different oxidative processes observed during ototoxic cascades. At each step, we discuss their potential as therapeutic targets because an increasing number of compounds that modulate ROS/RNS processing or targets are being identified.
Article
Full-text available
The prevalence and correlates of obese individuals who are resistant to the development of the adiposity-associated cardiometabolic abnormalities and normal-weight individuals who display cardiometabolic risk factor clustering are not well known. The prevalence and correlates of combined body mass index (normal weight, < 25.0; overweight, 25.0-29.9; and obese, > or = 30.0 [calculated as weight in kilograms divided by height in meters squared]) and cardiometabolic groups (metabolically healthy, 0 or 1 cardiometabolic abnormalities; and metabolically abnormal, > or = 2 cardiometabolic abnormalities) were assessed in a cross-sectional sample of 5440 participants of the National Health and Nutrition Examination Surveys 1999-2004. Cardiometabolic abnormalities included elevated blood pressure; elevated levels of triglycerides, fasting plasma glucose, and C-reactive protein; elevated homeostasis model assessment of insulin resistance value; and low high-density lipoprotein cholesterol level. Among US adults 20 years and older, 23.5% (approximately 16.3 million adults) of normal-weight adults were metabolically abnormal, whereas 51.3% (approximately 35.9 million adults) of overweight adults and 31.7% (approximately 19.5 million adults) of obese adults were metabolically healthy. The independent correlates of clustering of cardiometabolic abnormalities among normal-weight individuals were older age, lower physical activity levels, and larger waist circumference. The independent correlates of 0 or 1 cardiometabolic abnormalities among overweight and obese individuals were younger age, non-Hispanic black race/ethnicity, higher physical activity levels, and smaller waist circumference. Among US adults, there is a high prevalence of clustering of cardiometabolic abnormalities among normal-weight individuals and a high prevalence of overweight and obese individuals who are metabolically healthy. Further study into the physiologic mechanisms underlying these different phenotypes and their impact on health is needed.
Article
Full-text available
A multicenter study was set up to elucidate the environmental and medical risk factors contributing to age-related hearing impairment (ARHI). Nine subsamples, collected by nine audiological centers across Europe, added up to a total of 4,083 subjects between 53 and 67 years. Audiometric data (pure-tone average [PTA]) were collected and the participants filled out a questionnaire on environmental risk factors and medical history. People with a history of disease that could affect hearing were excluded. PTAs were adjusted for age and sex and tested for association with exposure to risk factors. Noise exposure was associated with a significant loss of hearing at high sound frequencies (>1 kHz). Smoking significantly increased high-frequency hearing loss, and the effect was dose-dependent. The effect of smoking remained significant when accounting for cardiovascular disease events. Taller people had better hearing on average with a more pronounced effect at low sound frequencies (<2 kHz). A high body mass index (BMI) correlated with hearing loss across the frequency range tested. Moderate alcohol consumption was inversely correlated with hearing loss. Significant associations were found in the high as well as in the low frequencies. The results suggest that a healthy lifestyle can protect against age-related hearing impairment. Electronic supplementary material The online version of this article (doi: 10.1007/s10162-008-0123-1) contains supplementary material, which is available to authorized users.
Article
Objective: We investigated the hypothesis that childhood obesity is a risk factor for sensorineural hearing loss (SNHL) independent of other metabolic risk factors. Study design: A complex, multistage, stratified geographic area design for collecting representative data from noninstitutionalized US population. Methods: A total of 5,638 adolescents between age 12 and 19 from the NHANES database (2005-2010) were studied. Subjects with body mass index >= 95th percentile were classified as obese. SNHL was defined as average pure-tone greater than 15 dB HL for 0.5, 1, and 2 kHz or 3, 4, 6, and 8 kHz in at least 1 ear. Multivariable logistic regression models assessed incident hearing loss odds across obese patients in comparison with normal weight individuals (5th-85th percentile). Multivariable models included age, sex, socioeconomic status, race, smoke exposure, high density lipoprotein level, triglyceride level, elevated blood pressure measurement, hemoglobin A1C level, and C-reactive protein level. Results: The rate of SNHL was 21.5% in obese and 13.44% in normal weight adolescents (p < 0.0001). In multivariable analyses, obesity was associated with 1.73-fold increase in the odds of SNHL (95% CI: 1.25-2.40, p value = 0.006). Potentially confounding and mediating factors had minimal effect on the odds of SNHL in obese study participants (OR range of 1.69-1.75, all p values <= 0.01). Conclusions: Obesity is associated with higher prevalence of SNHL in adolescents independent of other potential risk factors. Future longitudinal investigations and mechanistic studies are warranted.
Article
Background: Although the association of metabolic syndrome (MetS) and hearing loss has been evaluated, findings are controversial. This study investigated this association in a Chinese population. Methods: A cross-sectional study including a total of 18,824 middle-aged and older participants from the Dongfeng-Tongji Cohort study was conducted. Hearing loss was defined as the pure-tone average (PTA) of frequencies 0.5, 1.0, 2.0, and 4.0 kHz >25 decibels hearing level (dB HL) in the better ear and graded as mild (PTA 26-40 dB HL), moderate (PTA >40 to ≤60 dB HL), and severe (PTA >60 dB HL). MetS was defined according to the International Diabetes Foundation (IDF) criteria of 2005. Association analysis was performed by logistic regression. Results: After adjustment for potential confounders, participants with MetS showed higher OR of hearing loss (OR, 1.11; 95% CI: 1.03-1.19). The MetS components including central obesity (OR, 1.07; 95% CI: 1.01-1.15) and hyperglycemia (OR, 1.12; 95% CI: 1.04-1.20) were also positively associated with hearing loss. Low HDL-C levels were also associated with higher OR of moderate/severe hearing loss (OR, 1.21; 95% CI: 1.07-1.36). Conclusions: The MetS, including its components central obesity, hyperglycemia, and low HDL-C levels were positively associated with hearing loss.
Article
Introduction: We aimed to determine the prospective association of smoking status, smoking intensity, and smoking cessation with the risk of hearing loss in a large Japanese cohort. Methods: The cohort study included 50195 employees, who were aged 20-64 years and free of hearing loss at baseline. Participants were followed up for a maximum of 8 years. Pure-tone audiometric testing was performed annually to identify hearing loss at 1 and 4 kHz. Cox proportional hazards regression models were used to investigate the association between smoking and hearing loss. Results: During follow-up, 3532 individuals developed high-frequency hearing loss, and 1575 developed low-frequency hearing loss. The hazard ratio (HR) associated with current smokers was 1.6 (95% confidence interval [CI] = 1.5 to 1.7) and 1.2 (95% CI = 1.1 to 1.4) for high- and low-frequency hearing loss, respectively, as compared with never smokers. The risk of high- and low-frequency hearing loss increased with the number of cigarettes smoked per day (both p for trend <.001). The HR associated with former smokers was 1.2 (95% CI = 1.1 to 1.3) and 0.9 (95% CI = 0.8 to 1.1) for high- and low-frequency hearing loss, respectively. The analysis by quitting years showed a decline in risk of hearing loss after quitting smoking, even among those who quitted less than 5 years before baseline. Conclusions: Smoking is associated with increased risk of hearing loss, especially at the high frequency, in a dose-response manner. The excess risk of hearing loss associated with smoking disappears in a relatively short period after quitting. Implications: The prospective association between smoking and hearing loss has not been well studied. To the best of our knowledge, our study is the largest to date investigating the association between smoking and incident hearing loss. Our results indicate that smoking is associated with increased risk of hearing loss in a dose-response manner. Quitting smoking virtually eliminates the excess risk of hearing loss, even among quitters with short duration of cessation. These results suggest that smoking may be a causal factor for hearing loss, although further research would be required to confirm this. If so, this would emphasize the need for tobacco control to prevent or delay the development of hearing loss.
Article
Background: Although several observational studies showed a relationship between various conditions of metabolic syndrome (MetS) and hearing threshold, there are no studies about longitudinal audiometric results related MetS. The aim of this study was to investigate the association between MetS and age-related hearing impairment (ARHI) through a large, average 5-year longitudinal follow-up, clinical comparative analysis. Materials and methods: We recruited 1381 women older than 50 years who were enrolled in 2007 and reevaluated in 2012. They had normal or symmetrical sensorineural hearing loss. For the evaluation of the independent impact of MetS on hearing, multivariate analysis was used. Results: The average follow-up period was 5.0 ± 0.2 years. Subjects with MetS had higher hearing thresholds than subjects without MetS. The loss in high-frequency hearing (≥2000 Hz) progressed more rapidly in women with MetS over a 5-year period. Conclusion: Our analysis using longitudinal and large data revealed that MetS is associated with ARHI in women 50 years and older. High-frequency hearing loss tended to be greater in women with MetS than in those without MetS at the 5-year follow-up. Therefore, older women with MetS should be followed up closely for hearing evaluation.
Article
The comorbidities related to obesity are both extensive and established, but as the prevalence of obesity increases globally, so to do the number of its associated conditions. The relationship between hearing impairment and obesity is a relatively recent research interest, but significant as both conditions have the ability to substantially reduce an individual’s quality of life both physically and psychologically. Obesity has a significant effect on vascular function and this may impact highly vascular organs such as the auditory system. This review aims to provide an overview of the existing literature surrounding the association between hearing loss and obesity, in order to emphasise these two highly prevalent conditions, and to identify areas of further investigation. Our literature search identified a total of 298 articles with eleven articles of relevance to the review. The existing literature in this area is sparse with interest ranging from obesity and its links to age-related hearing impairment (ARHI) and sudden sensorineural hearing loss (SSNHL), to animal models and genetic syndromes that incorporate both disorders. A key hypothesis for the underlying mechanism for the relationship between obesity and hearing loss is that of vasoconstriction in the inner ear, whereby strain on the capillary walls due to excess adipose tissue causes damage to the delicate inner ear system. The identified articles in this review have not established a causal relationship between obesity and hearing impairment. Further research is required to examine the emerging association between obesity and hearing impairment, and identify its potential underlying mechanisms.
Article
We prospectively examined diabetes risk in association with a summary measure of degree and duration of weight change. The study participants were 51,777 employees from multiple companies in Japan, who were aged 30-59years, free of diabetes at baseline, and followed up for 7years (2008-2015). Exposure was cumulative body mass index (BMI)-years, which was defined as the area of BMI units above or below baseline BMI during follow-up, and was treated as a time-dependent variable in the Cox proportional hazards regression models. During the 263,539 person-years of follow-up, 3465 participants developed diabetes. The adjusted hazard ratio (HR) of diabetes for a 1-unit increase in cumulative BMI-years was 1.11 (95% confidence interval (CI): 1.09, 1.12). The association was more pronounced among overweight (HR=1.11; 95% CI: 1.08, 1.14) and obese (HR=1.12; 95% CI: 1.08, 1.15) adults compared with normal- and under-weight (HR=1.07; 95% CI: 1.03, 1.11) adults (P for interaction of cumulative BMI-years X baseline BMI-group=0.002). The association of higher cumulative BMI-years with incident diabetes did not substantially differ by metabolic phenotype. The present results emphasize the importance of avoiding additional weight gain over an extended period of time for the prevention of type 2 diabetes, especially among overweight and obese adults, irrespective of metabolic health status.
Article
Purpose of review: This review will provide the reader with an update on our understanding of the adverse effects of fatty acid accumulation in non-adipose tissues, a phenomenon known as lipotoxicity. Recent studies will be reviewed. Cellular mechanisms involved in the lipotoxic response will be discussed. Physiologic responses to lipid overload and therapeutic approaches to decreasing lipid accumulation will be discussed, as they add to our understanding of important pathophysiologic mechanisms. Recent findings: Excess lipid accumulation in non-adipose tissues may arise in the setting of high plasma free fatty acids or triglycerides. Alternatively, lipid overload results from mismatch between free fatty acid import and utilization. Evidence from human studies and animal models suggests that lipid accumulation in the heart, skeletal muscle, pancreas, liver, and kidney play an important role in the pathogenesis of heart failure, obesity and diabetes. Excess free fatty acids may impair normal cell signaling, causing cellular dysfunction. In some circumstances, excess free fatty acids induce apoptotic cell death. Summary: Recent studies provide clues regarding the cellular mechanisms that determine whether excess lipid accumulation is well tolerated or cytotoxic. Critical in this process are physiologic mechanisms for directing excess free fatty acids to specific tissues as well as cellular mechanisms for channeling excess fatty acid to particular metabolic fates. Insight into these mechanisms may contribute to the development of more effective therapies for common human disorders in which lipotoxicity contributes to pathogenesis.
Article
To determine associations between smoking, adiposity, diabetes mellitus, and other risk factors for cardiovascular disease (CVD) and the 15-year incidence of hearing impairment (HI). A longitudinal population-based cohort study (1993-95 to 2009-10), the Epidemiology of Hearing Loss Study (EHLS). Beaver Dam, Wisconsin. Participants in the Beaver Dam Eye Study (1988-90; residents of Beaver Dam, WI, aged 43-84 in 1987-88) were eligible for the EHLS. There were 1,925 participants with normal hearing at baseline. Fifteen-year cumulative incidence of HI (pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz greater than 25 decibels hearing level in either ear). Cigarette smoking, exercise, and other factors were ascertained according to questionnaire. Blood pressure, waist circumference, body mass index, and glycosylated hemoglobin were measured. Follow-up examinations (≥1) were obtained from 87.2% (n = 1,678; mean baseline age 61). The 15-year cumulative incidence of HI was 56.8%. Adjusting for age and sex, current smoking (hazard ratio (HR) = 1.31, P = .048), education (<16 years; HR = 1.35, P = .01), waist circumference (HR = 1.08 per 10 cm, P = .02), and poorly controlled diabetes mellitus (HR = 2.03, P = .048) were associated with greater risk of HI. Former smokers and people with better-controlled diabetes mellitus were not at greater risk. Smoking, central adiposity, and poorly controlled diabetes mellitus predicted incident HI. These well-known risk factors for CVD suggest that vascular changes may contribute to HI in aging. Interventions targeting reductions in smoking and adiposity and better glycemic control in people with diabetes mellitus may help prevent or delay the onset of HI. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.
Article
Acquired hearing loss is highly prevalent, but prospective data on potentially modifiable risk factors are limited. In cross-sectional studies, higher body mass index (BMI), larger waist circumference, and lower physical activity have been associated with poorer hearing, but these have not been examined prospectively. We examined the independent associations between BMI, waist circumference, and physical activity, and self-reported hearing loss in 68,421 women in the Nurses' Health Study II from 1989 to 2009. Baseline and updated information on BMI, waist circumference, and physical activity was obtained from biennial questionnaires. After more than 1.1 million person-years of follow-up, 11,286 cases of hearing loss were reported to have occurred. Higher BMI and larger waist circumference were associated with increased risk of hearing loss. Compared with women with BMI <25 kg/m(2), the multivariate-adjusted relative risk (RR) for women with BMI ≥40 was 1.25 (95% confidence interval [CI], 1.14-1.37). Compared with women with waist circumference <71 cm, the multivariate-adjusted RR for waist circumference >88 cm was 1.27 (95% CI, 1.17-1.38). Higher physical activity was related inversely to risk; compared with women in the lowest quintile of physical activity, the multivariate-adjusted RR for women in the highest quintile was 0.83 (95% CI, 0.78-0.88). Walking 2 hours per week or more was associated inversely with risk. Simultaneous adjustment for BMI, waist circumference, and physical activity slightly attenuated the associations but they remained statistically significant. Higher BMI and larger waist circumference are associated with increased risk, and higher physical activity is associated with reduced risk of hearing loss in women. These findings provide evidence that maintaining healthy weight and staying physically active, potentially modifiable lifestyle factors, may help reduce the risk of hearing loss.
Article
Objectives/HypothesisChildhood obesity, defined as body mass index (BMI)95%, is a significant health problem associated with a variety of disorders, and in adults it has been found to be a risk factor for hearing loss. We investigated the hypothesis that obese children are at increased risk of sensorineural hearing loss (SNHL). Study DesignA complex, multistage, stratified geographic area design for collecting representative data from noninstitutionalized U.S. population. Methods Relevant cross-sectional data from the National Health and Nutrition Examination Survey, 2005 to 2006, for 1,488 participants 12 to 19 years of age was examined. Subjects were classified as obese if their BMI95th percentile. SNHL was defined as average pure-tone level greater than 15 dB for 0.5, 1, and 2 kHz (low frequency) and 3, 4, 6, and 8 kHz (high frequency). ResultsCompared to normal weight participants (BMI 5%-85%), obesity in adolescents was associated with elevated pure tone hearing thresholds and greater prevalence of unilateral low-frequency SNHL (15.2 vs. 8.3%, P=0.01). In multivariate analyses, obesity was associated with a 1.85 fold increase in the odds of unilateral low-frequency SNHL (95% CI: 1.10-3.13) after controlling for multiple hearing-related covariates. Conclusions We demonstrate for the first time that obesity in childhood is associated with higher hearing thresholds across all frequencies and an almost 2-fold increase in the odds of unilateral low-frequency hearing loss. These results add to the growing literature on obesity-related health disturbances and also add to the urgency in instituting public health measures to reduce it. Level of Evidence2b. Laryngoscope, 123:3178-3184, 2013
Article
Objectives/hypothesis: Hearing loss is the most common sensory disorder in the United States, affecting more than 36 million people. Cardiovascular risk factors have been associated with the risk of hearing loss in cross-sectional studies, but prospective data are currently lacking. Study design: Prospective cohort study. Methods: We prospectively evaluated the association between diagnosis of hypertension, diabetes mellitus, hypercholesterolemia, smoking, or body mass index (BMI) and incident hearing loss. Participants were 26,917 men in the Health Professionals Follow-up Study, aged 40 to 74 years at baseline in 1986. Study participants completed questionnaires about lifestyle and medical history every 2 years. Information on self-reported professionally diagnosed hearing loss and year of diagnosis was obtained from the 2004 questionnaire, and cases were defined as hearing loss diagnosed between 1986 and 2004. Multivariable-adjusted hazard ratios (HRs) were calculated using Cox proportional hazards regression models. Results: A total of 3,488 cases of hearing loss were identified. History of hypertension (HR 0.96; 95% confidence interval [CI], 0.88-1.03), diabetes mellitus (HR 0.92; 95% CI, 0.78-1.08), or obesity (HR 1.02; 95% CI, 0.90-1.15 for BMI >or=30 compared to normal range of 19-24.9) was not significantly associated with hearing-loss risk. Hypercholesterolemia (HR 1.10; 95% CI, 1.02-1.18) and past smoking history (HR 1.09; 95% CI, 1.01-1.17) were associated with a significantly increased risk of hearing loss after multivariate adjustment. Conclusions: A history of hypertension, diabetes mellitus, or obesity is not associated with increased risk of hearing loss; a history of past smoking or hypercholesterolemia has a small but statistically significant association with increased risk of hearing loss in adult males.
Article
A WHO expert consultation addressed the debate about interpretation of recommended body-mass index (BMI) cut-off points for determining overweight and obesity in Asian populations, and considered whether population-specific cut-off points for BMI are necessary. They reviewed scientific evidence that suggests that Asian populations have different associations between BMI, percentage of body fat, and health risks than do European populations. The consultation concluded that the proportion of Asian people with a high risk of type 2 diabetes and cardiovascular disease is substantial at BMIs lower than the existing WHO cut-off point for overweight (⩾25 kg/m2). However, available data do not necessarily indicate a clear BMI cut-off point for all Asians for overweight or obesity. The cut-off point for observed risk varies from 22kg/m2 to 25kg/m2 in different Asian populations; for high risk it varies from 26kg/m2 to 31kg/m2. No attempt was made, therefore, to redefine cut-off points for each population separately. The consultation also agreed that the WHO BMI cut-off points should be retained as international classifications. The consultation identified further potential public health action points (23·0, 27·5, 32·5, and 37·5 kg/m2) along the continuum of BMI, and proposed methods by which countries could make decisions about the definitions of increased risk for their population.
Article
Normal blood supply to the cochlea is critically important for establishing the endocochlear potential and sustaining production of endolymph. Abnormal cochlear microcirculation has long been considered an etiologic factor in noise-induced hearing loss, age-related hearing loss (presbycusis), sudden hearing loss or vestibular function, and Meniere's disease. Knowledge of the mechanisms underlying the pathophysiology of cochlear microcirculation is of fundamental clinical importance. A better understanding of cochlear blood flow (CoBF) will enable more effective management of hearing disorders resulting from aberrant blood flow. This review focuses on recent discoveries and findings related to the physiopathology of the cochlear microvasculature.
Article
Hearing loss is the most common sensory disorder in the United States, affecting more than 36 million people. Cardiovascular risk factors have been associated with the risk of hearing loss in cross-sectional studies, but prospective data are currently lacking. Prospective cohort study. We prospectively evaluated the association between diagnosis of hypertension, diabetes mellitus, hypercholesterolemia, smoking, or body mass index (BMI) and incident hearing loss. Participants were 26,917 men in the Health Professionals Follow-up Study, aged 40 to 74 years at baseline in 1986. Study participants completed questionnaires about lifestyle and medical history every 2 years. Information on self-reported professionally diagnosed hearing loss and year of diagnosis was obtained from the 2004 questionnaire, and cases were defined as hearing loss diagnosed between 1986 and 2004. Multivariable-adjusted hazard ratios (HRs) were calculated using Cox proportional hazards regression models. A total of 3,488 cases of hearing loss were identified. History of hypertension (HR 0.96; 95% confidence interval [CI], 0.88-1.03), diabetes mellitus (HR 0.92; 95% CI, 0.78-1.08), or obesity (HR 1.02; 95% CI, 0.90-1.15 for BMI >or=30 compared to normal range of 19-24.9) was not significantly associated with hearing-loss risk. Hypercholesterolemia (HR 1.10; 95% CI, 1.02-1.18) and past smoking history (HR 1.09; 95% CI, 1.01-1.17) were associated with a significantly increased risk of hearing loss after multivariate adjustment. A history of hypertension, diabetes mellitus, or obesity is not associated with increased risk of hearing loss; a history of past smoking or hypercholesterolemia has a small but statistically significant association with increased risk of hearing loss in adult males.
Article
A cluster of risk factors for cardiovascular disease and type 2 diabetes mellitus, which occur together more often than by chance alone, have become known as the metabolic syndrome. The risk factors include raised blood pressure, dyslipidemia (raised triglycerides and lowered high-density lipoprotein cholesterol), raised fasting glucose, and central obesity. Various diagnostic criteria have been proposed by different organizations over the past decade. Most recently, these have come from the International Diabetes Federation and the American Heart Association/National Heart, Lung, and Blood Institute. The main difference concerns the measure for central obesity, with this being an obligatory component in the International Diabetes Federation definition, lower than in the American Heart Association/National Heart, Lung, and Blood Institute criteria, and ethnic specific. The present article represents the outcome of a meeting between several major organizations in an attempt to unify criteria. It was agreed that there should not be an obligatory component, but that waist measurement would continue to be a useful preliminary screening tool. Three abnormal findings out of 5 would qualify a person for the metabolic syndrome. A single set of cut points would be used for all components except waist circumference, for which further work is required. In the interim, national or regional cut points for waist circumference can be used.
Article
To investigate the effect of central obesity on the severity and characteristics of age-related hearing impairment (ARHI), we recruited 690 adult subjects with normal or symmetrical sensorineural hearing loss (SNHL). The effects of age, gender, morphometry, habits, systemic diseases, and environmental noise exposure on average pure tone hearing level at low frequencies (pure tone audiometry (PTA)-low) and high frequencies (PTA-high) were analyzed. After adjusting for age, gender, systemic disease, and other variables, waist circumference (WC) showed a significant positive association with PTA-low and PTA-high. In females, PTA-low and PTA-high only showed significant positive association with age, but not with WC or other variables. However, PTA-high showed a positive association with borderline significance with WC in female subjects older than 55. In males, WC as well as age and noise exposure showed significant positive associations with both PTA-low and PTA-high, primarily in subjects younger than 55. When both WC and BMI were taken into account in a backward stepwise multivariate linear regression analysis, WC, but not BMI, showed a significant positive association with PTA-low and PTA-high in males younger than 55, and with PTA-high with borderline significance in females older than 55. However, the audiogram patterns were not significantly affected by central obesity in either age or gender. Our results suggest that WC was, even after adjustment for BMI, an independent risk factor of ARHI, particularly for low and high frequencies in males younger than 55 and for high frequencies in female subjects older than 55.
Article
Temporal bones, brains, and kidneys of 40 patients over 50 years of age were studied histopathologically, paying special attention to angiosclerotic changes. The histopathologic findings were correlated with audiometric and manometric records obtained while the patients were alive. A close relation existed among the lumen narrowing of the internal auditory artery, spiral ganglion atrophy, and hearing loss. The angiosclerotic changes of the Willis' circle, encephalomalacia, and hearing loss were also related.
Article
The association of cigarette smoking with development of hearing impairment (loss of 30 dB at 1000 Hz and 40 dB at 4000 Hz) over a 5-year follow-up was studied in 1554 non-hearing-impaired Japanese male office workers who ranged in age from 30 to 59 years. After controlling for potential predictors of hearing impairment, the relative risk for low-frequency hearing impairment compared with never smokers was 1.12 (95% confidence interval [CI], 0.57 to 2.17) for ever-smokers, 1.21 (95% CI, 0.65 to 2.25) for current smokers of 1 to 20 cigarettes/day, 1.35 (95% CI, 0.70 to 2.61) for current smokers of 21 to 30 cigarettes/day, and 1.82 (95% CI, 0.98 to 3.38) for current smokers of 31 or more cigarettes/day (P for trend = 0.063). The respective multivariate-adjusted relative risks for high-frequency hearing impairment compared with never smokers were 1.70 (95% CI, 0.85 to 3.40), 1.82 (95% CI, 0.92 to 3.59), 2.00 (95% CI, 0.98 to 4.08), and 2.20 (95% CI, 1.09 to 4.42) (P for trend = 0.025). As the number of pack-years of exposure increased, the risk for high-frequency hearing impairment increased in a dose-dependent manner (P for trend = 0.011), but the risk for low-frequency hearing impairment did not (P for trend = 0.172). Our results indicate that cigarette smoking is highly associated with development of high-frequency hearing impairment in Japanese male office workers.
Article
In order to determine the risk factors for hearing loss in the elderly, a total of 496 subjects with bilateral hearing loss and 2807 age-matched persons without hearing disturbance were recruited from the participants in an automated multiphasic health screening examination, and their lifestyle and medical data were analysed. Current smokers showed a significantly increased risk of hearing loss compared with non-smokers (odds ratio after adjustment for sex, age, and potential confounders=2.10 (1.53-2.89)), while heavy drinkers did not show an increased risk compared to non-drinkers. Our findings might provide some clues for the primary prevention of age-related hearing loss.
Article
This review will provide the reader with an update on our understanding of the adverse effects of fatty acid accumulation in non-adipose tissues, a phenomenon known as lipotoxicity. Recent studies will be reviewed. Cellular mechanisms involved in the lipotoxic response will be discussed. Physiologic responses to lipid overload and therapeutic approaches to decreasing lipid accumulation will be discussed, as they add to our understanding of important pathophysiologic mechanisms. Excess lipid accumulation in non-adipose tissues may arise in the setting of high plasma free fatty acids or triglycerides. Alternatively, lipid overload results from mismatch between free fatty acid import and utilization. Evidence from human studies and animal models suggests that lipid accumulation in the heart, skeletal muscle, pancreas, liver, and kidney play an important role in the pathogenesis of heart failure, obesity and diabetes. Excess free fatty acids may impair normal cell signaling, causing cellular dysfunction. In some circumstances, excess free fatty acids induce apoptotic cell death. Recent studies provide clues regarding the cellular mechanisms that determine whether excess lipid accumulation is well tolerated or cytotoxic. Critical in this process are physiologic mechanisms for directing excess free fatty acids to specific tissues as well as cellular mechanisms for channeling excess fatty acid to particular metabolic fates. Insight into these mechanisms may contribute to the development of more effective therapies for common human disorders in which lipotoxicity contributes to pathogenesis.
Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants.
  • Ncd-Risc
Obesity: preventing and managing the global epidemic. Report of a WHO consultation. WHO technical report series 894.
  • World Health Organization