[Show abstract][Hide abstract] ABSTRACT: Background Several recessive Mendelian disorders are common in Europeans, including cystic fibrosis (CFTR), medium-chain-acyl-Co-A-dehydrogenase deficiency (ACADM), phenylketonuria (PAH) and alpha 1-antitrypsin deficiency (SERPINA1).
Methods In a multicohort study of >19 000 older individuals, we investigated the relevant phenotypes in heterozygotes for these genes: lung function (forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC)) for CFTR and SERPINA1; cognitive measures for ACADM and PAH; and physical capability for ACADM, PAH and SERPINA1.
Results Findings were mostly negative but lung function in SERPINA1 (protease inhibitor (PI) Z allele, rs28929474) showed enhanced FEV1 and FVC (0.13 z-score increase in FEV1 (p=1.7×10−5) and 0.16 z-score increase in FVC (p=5.2×10−8)) in PI-MZ individuals. Height adjustment (a known, strong correlate of FEV1 and FVC) revealed strong positive height associations of the Z allele (1.50 cm increase in height (p=3.6×10−10)).
Conclusions The PI-MZ rare (2%) SNP effect is nearly four times greater than the ‘top’ common height SNP in HMGA2. However, height only partially attenuates the SERPINA1-FEV1 or FVC association (around 50%) and vice versa. Height SNP variants have recently been shown to be positively selected collectively in North versus South Europeans, while the Z allele high frequency is localised to North Europe. Although PI-ZZ is clinically disadvantageous to lung function, PI-MZ increases both height and respiratory function; potentially a balanced polymorphism. Partial blockade of PI could conceivably form part of a future poly-therapeutic approach in very short children. The notion that elastase inhibition should benefit patients with chronic obstructive pulmonary disease may also merit re-evaluation. PI is already a therapeutic target: our findings invite a reconsideration of the optimum level in respiratory care and novel pathway potential for development of agents for the management of growth disorders.
Preview · Article · Feb 2016 · Journal of Medical Genetics
[Show abstract][Hide abstract] ABSTRACT: Increased circulating plasma urate concentration is associated with an increased risk of coronary heart disease, but the extent of any causative effect of urate on risk of coronary heart disease is still unclear. In this study, we aimed to clarify any causal role of urate on coronary heart disease risk using Mendelian randomisation analysis.
Full-text · Article · Jan 2016 · The Lancet Diabetes & Endocrinology
[Show abstract][Hide abstract] ABSTRACT: Objectives The observed associations between smoking and functional measures at older ages are vulnerable to bias and confounding. Mendelian randomisation (MR) uses genotype as an instrumental variable to estimate unconfounded causal associations. We conducted a meta-analysis of the observational associations and implemented an MR approach using the smoking-related single nucleotide polymorphism rs16969968 to explore their causal nature.
Setting 9 British cohorts belonging to the HALCyon collaboration.
Participants Individual participant data on N=26 692 individuals of European ancestry (N from earliest phase analysed per study) of mean ages 50–79 years were available for inclusion in observational meta-analyses of the primary outcomes.
Primary outcomes Physical capability, cognitive capability and cognitive decline. The smoking exposures were cigarettes per day, current versus ex-smoker, current versus never smoker and ever versus never smoker.
Results In observational analyses current and ever smoking were generally associated with poorer physical and cognitive capability. For example, current smokers had a general fluid cognition score which was 0.17 z-score units (95% CI −0.221 to −0.124) lower than ex-smokers in cross-sectional analyses. Current smokers had a walk speed which was 0.25 z-score units lower than never smokers (95% CI −0.338 to −0.170). An MR instrumental variable approach for current versus ex-smoker and number of cigarettes smoked per day produced CIs which neither confirmed nor refuted the observational estimates. The number of genetic associations stratified by smoking status were consistent with type I error.
Conclusions Our observational analysis supports the hypothesis that smoking is detrimental to physical and cognitive capability. Further studies are needed for a suitably powered MR approach.
[Show abstract][Hide abstract] ABSTRACT: Aim:
Obesity is a well-established risk factor for developing Type 2 diabetes. Evidence suggests that sarcopenia, the age-related decline in muscle mass and strength, may exacerbate diabetes risk in obese individuals. The aim of this study was to determine the combined effect of obesity and low muscle strength, dynapenia, on the risk of incident Type 2 diabetes in older adults.
Participants were 5953 (1670 obese) men and women from the English Longitudinal Study of Ageing without known Type 2 diabetes at baseline and for whom handgrip strength, biochemical and other clinical data were collected. A diagnosis of Type 2 diabetes was recorded from self-reported physician diagnosis over 6 years.
For each unit increase in grip strength, there was a reduction in diabetes risk (age and sex, BMI adjusted HR; 0.98; 95% CI 0.96-0.99). The risk of Type 2 diabetes was elevated in all obese participants, but was greatest in those with low handgrip strength (HR = 4.93, 95% CI 2.85, 8.53) compared with non-obese individuals with high handgrip strength. Eleven per cent of the sample met the threshold for weakness (handgrip strength: men < 26 kg; women < 16 kg) that was associated with elevated Type 2 diabetes risk in obese (HR = 3.57, 95% CI 2.04, 6.24) but not in non-obese (HR = 0.86, 95% CI, 0.44, 1.68) compared with normal/non-obese participants.
Dynapenic obesity, determined by high BMI and low handgrip strength, is associated with increased risk of incident Type 2 diabetes in older people. This article is protected by copyright. All rights reserved.
Full-text · Article · Oct 2015 · Diabetic Medicine
[Show abstract][Hide abstract] ABSTRACT: Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHRadjBMI in four strata (men ≤50y, men >50y, women ≤50y, women >50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR<5%) age-specific effects, of which 11 had larger effects in younger (<50y) than in older adults (≥50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.
[Show abstract][Hide abstract] ABSTRACT: Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHRadjBMI in four strata (men 50y, men >50y, women 50y, women >50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed signifi- cant (FDR<5%) age-specific effects, of which 11 had larger effects in younger (<50y) than in older adults (!50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analy- sis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimor- phism of body shape.
[Show abstract][Hide abstract] ABSTRACT: We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 x 10(-11) to 5.0 x 10(-21)). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 x 10(-6)). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.
[Show abstract][Hide abstract] ABSTRACT: Aims:
Among employees with diabetes, comorbidity may considerably deteriorate working capacity. We examined how socioeconomic status, lifestyle factors and job strain were related to work disability in individuals with diabetes with and without comorbidity.
In this pooled analysis of individual-participant data from occupational cohorts from Finland (Finnish Public Sector Study FPS), UK (Whitehall II) and France (GAZEL), 1925 employees with diabetes were followed on average for 4 years. Participants were categorized into four groups, according to their baseline comorbidity status and subsequent work disability, as: non-comorbid diabetes with no/low work disability; comorbid diabetes with no/low work disability; non-comorbid diabetes with moderate/high work disability; and comorbid diabetes with moderate/high work disability. The risk of work disability was assessed with multinomial regression, using Group 1 (the first listed above) as the reference group.
Participants with low socioeconomic status had increased odds for higher work disability, irrespective of comorbidity (OR = 3.12; 95% CI 2.25-4.33, among participants with no comorbidity, and OR = 2.61; 95% CI 1.93-3.51 among those with comorbidity). Obesity was cross-sectionally associated with comorbidity (OR = 1.95; 95% CI 1.35-2.83 for comorbidity without disability), and this association was particularly pronounced among those whom became work disabled (OR = 2.61; 95% CI 1.89-3.60 for comorbidity with disability). Job strain was associated with high/moderate work disability, only among participants with comorbidity (OR = 1.63; 95% CI 1.14-2.34).
Pooled data from three cohort studies showed that low socioeconomic status, obesity, and job strain are linked to both comorbidity and increased work disability in employees with diabetes.
No preview · Article · Sep 2015 · Scandinavian Journal of Public Health
[Show abstract][Hide abstract] ABSTRACT: Low-grade inflammation appears to play an etiological role in cognitive decline. However the association between an inflammatory dietary pattern and cognitive decline has not been investigated. We aimed to investigate dietary patterns associated with inflammation and whether such diet is associated with cognitive decline.
[Show abstract][Hide abstract] ABSTRACT: Metabolically healthy obesity possibly reflects a transitional stage before the onset of metabolic dysfunction, but few studies have characterised this transition. We examined the behavioural and biological characteristics of healthy obese adults that progressed to an unhealthy state over 8 years follow up.
Participants were 2422 men and women (aged 63.3 ± 7.7 years, 44.2% men) from the English Longitudinal Study of Ageing. Obesity was defined as body mass index ≥ 30 kg/m2. Based on blood pressure, HDL-cholesterol, triglycerides, glycated haemoglobin, and C-reactive protein participants were classified as 'healthy' (0 or 1 metabolic abnormality) or 'unhealthy' (≥ 2 metabolic abnormalities).
Over eight years follow-up, 44.5% of healthy obese had transitioned into an unhealthy state, compared to only 16.6% and 26.2% of healthy normal weight and overweight adults, respectively. Compared with healthy obese adults who remained stable, those who progressed to an unhealthy state were more likely to have high blood pressure (75.0% vs 37.0%, age- and sex-adjusted odds ratio [OR] 8.9, 95% confidence interval [CI] 4.7-17.0), high C-reactive protein (53.7% vs 17.0%, OR=8.6, 95% CI 4.1-18.0), high glycated haemoglobin (46.3% vs 5.9%, OR=13.8, 95% CI 6.1-31.2) and high triglycerides (45.4% vs 11.9%, OR=5.9, 95% CI 2.9-12.0) at follow-up, with excess risk remaining independent of lifestyle factors including self-reported physical activity. Progression to an unhealthy state was also linked with significant gains in waist circumference (B=2.7, 95% CI, 0.5 - 4.9 cm).
These data show that a healthy obesity phenotype is relatively unstable. Transition to an unhealthy state is characterised by multiple biological changes which are not fully explained by lifestyle risk factors.
No preview · Article · Aug 2015 · European Journal of Endocrinology
[Show abstract][Hide abstract] ABSTRACT: There is growing evidence that obese adults without metabolic risk factor clustering (the so-called "healthy obese") progress to unhealthy obesity over time (1). However, the pathophysiological changes underlying the long-term transition into an unhealthy obese state have not been well characterized. To inform the clinical management of healthy obesity, we aimed to identify the metabolic risk factors responsible for this transition, as well as the timing of their onset.
Full-text · Article · Aug 2015 · Journal of the American College of Cardiology
[Show abstract][Hide abstract] ABSTRACT: Background:
Plasma adiponectin levels have previously been inversely associated with carotid intima-media thickness (IMT), a marker of subclinical atherosclerosis. In this study, we used a sex-stratified Mendelian randomization approach to investigate whether adiponectin has a causal protective influence on IMT.
Methods and results:
Baseline plasma adiponectin concentration was tested for association with baseline IMT, IMT progression over 30 months, and occurrence of cardiovascular events within 3 years in 3430 participants (women, n=1777; men, n=1653) with high cardiovascular risk but no prevalent disease. Plasma adiponectin levels were inversely associated with baseline mean bifurcation IMT after adjustment for established risk factors (β=-0.018, P<0.001) in men but not in women (β=-0.006, P=0.185; P for interaction=0.061). Adiponectin levels were inversely associated with progression of mean common carotid IMT in men (β=-0.0022, P=0.047), whereas no association was seen in women (0.0007, P=0.475; P for interaction=0.018). Moreover, we observed that adiponectin levels were inversely associated with coronary events in women (hazard ratio 0.57, 95% CI 0.37 to 0.87) but not in men (hazard ratio 0.82, 95% CI 0.54 to 1.25). A gene score of adiponectin-raising alleles in 6 loci, reported recently in a large multi-ethnic meta-analysis, was inversely associated with baseline mean bifurcation IMT in men (β=-0.0008, P=0.004) but not in women (β=-0.0003, P=0.522; P for interaction=0.007).
This report provides some evidence for adiponectin protecting against atherosclerosis, with effects being confined to men; however, compared with established cardiovascular risk factors, the effect of plasma adiponectin was modest. Further investigation involving mechanistic studies is warranted.
Full-text · Article · Aug 2015 · Journal of the American Heart Association
[Show abstract][Hide abstract] ABSTRACT: To investigate, using a Mendelian randomisation approach, whether heavier smoking is associated with a range of regional adiposity phenotypes, in particular those related to abdominal adiposity.
Mendelian randomisation meta-analyses using a genetic variant (rs16969968/rs1051730 in the CHRNA5-CHRNA3-CHRNB4 gene region) as a proxy for smoking heaviness, of the associations of smoking heaviness with a range of adiposity phenotypes.
148 731 current, former and never-smokers of European ancestry aged ≥16 years from 29 studies in the consortium for Causal Analysis Research in Tobacco and Alcohol (CARTA).
Waist and hip circumferences, and waist-hip ratio.
The data included up to 66 809 never-smokers, 43 009 former smokers and 38 913 current daily cigarette smokers. Among current smokers, for each extra minor allele, the geometric mean was lower for waist circumference by -0.40% (95% CI -0.57% to -0.22%), with effects on hip circumference, waist-hip ratio and body mass index (BMI) being -0.31% (95% CI -0.42% to -0.19), -0.08% (-0.19% to 0.03%) and -0.74% (-0.96% to -0.51%), respectively. In contrast, among never-smokers, these effects were higher by 0.23% (0.09% to 0.36%), 0.17% (0.08% to 0.26%), 0.07% (-0.01% to 0.15%) and 0.35% (0.18% to 0.52%), respectively. When adjusting the three central adiposity measures for BMI, the effects among current smokers changed direction and were higher by 0.14% (0.05% to 0.22%) for waist circumference, 0.02% (-0.05% to 0.08%) for hip circumference and 0.10% (0.02% to 0.19%) for waist-hip ratio, for each extra minor allele.
For a given BMI, a gene variant associated with increased cigarette consumption was associated with increased waist circumference. Smoking in an effort to control weight may lead to accumulation of central adiposity.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
[Show abstract][Hide abstract] ABSTRACT: Participants' non adherence to protocol affects data quality. In longitudinal studies, this leads to outliers that can be present at the level of the population or the individual. The purpose of the present study is to elaborate a method for detection of outliers in a study of cognitive ageing.
In the Whitehall II study, data on a cognitive test battery have been collected in 1997-99, 2002-04, 2007-09 and 2012-13. Outliers at the 2012-13 wave were identified using a 4-step procedure: (1) identify cognitive tests with potential non-adherence to protocol, (2) choose a prediction model between a simple model with socio-demographic covariates and one that also includes health behaviours and health measures, (3) define an outlier using a studentized residual, and (4) study the impact of exclusion of outliers by estimating the effect of age and diabetes on cognitive decline.
5516 participants provided cognitive data in 2012-13. Comparisons of rates of annual decline over the first three and all four waves of data suggested outliers in three of the 5 tests. Mean residuals for the 2012-13 wave were larger for the basic compared to the more complex prediction model (all p<0.001), leading us to use the latter for the identification of outliers. Residuals greater than two standard deviation of residuals identified approximately 7% of observations as being outliers. Removal of these observations from the analyses showed that both age and diabetes had associations with cognitive decline similar to that observed with the first three waves of data; these associations were weaker or absent in non-cleaned data.
Identification of outliers is important as they obscure the effects of known risk factor and introduce bias in the estimates of cognitive decline. We showed that an informed approach, using the range of data collected in a longitudinal study, may be able to identify outliers.
[Show abstract][Hide abstract] ABSTRACT: Disease risk is lower in metabolically healthy obese adults than in their unhealthy obese counterparts. Studies considering physical activity as a modifiable determinant of healthy obesity have relied on self-reported measures, which are prone to inaccuracies and do not capture all movements that contribute to health.
We aimed to examine differences in total and moderate-to-vigorous physical activity between healthy and unhealthy obese groups by using both self-report and wrist-worn accelerometer assessments.
Cross-sectional analyses were based on 3457 adults aged 60-82 y (77% male) participating in the British Whitehall II cohort study in 2012-2013. Normal-weight, overweight, and obese adults were considered "healthy" if they had <2 of the following risk factors: low HDL cholesterol, hypertension, high blood glucose, high triacylglycerol, and insulin resistance. Differences across groups in total physical activity, based on questionnaire and wrist-worn triaxial accelerometer assessments (GENEActiv), were examined by using linear regression. The likelihood of meeting 2010 World Health Organization recommendations for moderate-to-vigorous activity (≥2.5 h/wk) was compared by using prevalence ratios.
Of 3457 adults, 616 were obese [body mass index (in kg/m(2)) ≥30]; 161 (26%) of those were healthy obese. Obese adults were less physically active than were normal-weight adults, regardless of metabolic health status or method of physical activity assessment. Healthy obese adults had higher total physical activity than did unhealthy obese adults only when assessed by accelerometer (P = 0.002). Healthy obese adults were less likely to meet recommendations for moderate-to-vigorous physical activity than were healthy normal-weight adults based on accelerometer assessment (prevalence ratio: 0.59; 95% CI: 0.43, 0.79) but were not more likely to meet these recommendations than were unhealthy obese adults (prevalence ratio: 1.26; 95% CI: 0.89, 1.80).
Higher total physical activity in healthy than in unhealthy obese adults is evident only when measured objectively, which suggests that physical activity has a greater role in promoting health among obese populations than previously thought.
Full-text · Article · Jul 2015 · American Journal of Clinical Nutrition
[Show abstract][Hide abstract] ABSTRACT: We examined the role of sarcopenic obesity as a risk factor for new-onset depressive symptoms over 6 years follow up in a large sample of older adults.
The sample comprised 3862 community dwelling participants (1779 men, 2083 women; mean age 64.6±8.3 yrs) without depressive symptoms at baseline, recruited from the English Longitudinal Study of Ageing (ELSA). At baseline and 4 years follow up, handgrip strength (kg) of the dominant hand was assessed using a hand-held dynamometer, as a measure of sarcopenia. The outcome was new onset depressive symptoms at 6 years follow-up, defined as a score of ≥4 on the 8-item Centre of Epidemiological Studies Depression (CES-D) scale. Sarcopenic obesity was defined as obese individuals (BMI≥30 kg/m(2)) in the lowest tertile of sex specific grip strength (<35.3 kg men;<19.6 kg women).
Using a multivariable logistic regression model, the risk of depressive symptoms was greatest in obese adults in the lowest tertile of handgrip strength (Odds ratio, 1.79, 95% CI, 1.10, 2.89) compared to non-obese individuals with high handgrip strength. Participants who were obese at baseline and had a decrease of more than 1 standard deviation in grip strength over 4 years follow up were at greatest risk of depressive symptoms (OR=1.97, 95% CI, 1.22, 3.17) compared to non-obese with stable grip strength.
A reduction in grip strength was associated with higher risk of depressive symptoms in obese participants only, suggesting that sarcopenic obesity is a risk factor for depressive symptoms.International Journal of Obesity accepted article preview online, 30 June 2015. doi:10.1038/ijo.2015.124.
No preview · Article · Jun 2015 · International journal of obesity (2005)