Low serum 25-hydroxyvitamin D is associated with increased risk of the development of the metabolic syndrome at five years: results from a national, population-based prospective study (The Australian Diabetes, Obesity and Lifestyle Study: AusDiab).
ABSTRACT Serum 25-hydroxyvitamin D [25(OH)D] concentration has been inversely associated with the prevalence of metabolic syndrome (MetS), but the relationship between 25(OH)D and incident MetS remains unclear.
We evaluated the prospective association between 25(OH)D, MetS, and its components in a large population-based cohort of adults aged 25 yr or older.
We used baseline (1999-2000) and 5-yr follow-up data of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab).
Of the 11,247 adults evaluated at baseline, 6,537 returned for follow-up. We studied those without MetS at baseline and with complete data (n = 4164; mean age 50 yr; 58% women; 92% Europids).
We report the associations between baseline 25(OH)D and 5-yr MetS incidence and its components, adjusted for age, sex, ethnicity, season, latitude, smoking, family history of type 2 diabetes, physical activity, education, kidney function, waist circumference (WC), and baseline MetS components.
A total of 528 incident cases (12.7%) of MetS developed over 5 yr. Compared with those in the highest quintile of 25(OH)D (≥34 ng/ml), MetS risk was significantly higher in people with 25(OH)D in the first (<18 ng/ml) and second (18-23 ng/ml) quintiles; odds ratio (95% confidence interval) = 1.41 (1.02-1.95) and 1.74 (1.28-2.37), respectively. Serum 25(OH)D was inversely associated with 5-yr WC (P < 0.001), triglycerides (P < 0.01), fasting glucose (P < 0.01), and homeostasis model assessment for insulin resistance (P < 0.001) but not with 2-h plasma glucose (P = 0.29), high-density lipoprotein cholesterol (P = 0.70), or blood pressure (P = 0.46).
In Australian adults, lower 25(OH)D concentrations were associated with increased MetS risk and higher WC, serum triglyceride, fasting glucose, and insulin resistance at 5 yr. Vitamin D supplementation studies are required to establish whether the link between vitamin D deficiency and MetS is causal.
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ABSTRACT: Although a high serum low-density lipoprotein cholesterol (LDL-C) level is an established risk factor for atherosclerosis, it is unclear whether it is associated with osteoporosis. In this study, the associations between the serum LDL-C level and bone mineral density (BMD), bone metabolic markers, and the presence of prevalent vertebral or non-vertebral fractures were examined. A total of 211 healthy postmenopausal women (age range, 46-80 years) who visited a community health center were recruited consecutively. Their radiographic and biochemical characteristics were collected. Prevalent vertebral and non-vertebral fractures were found in 49 (23.2 %) and 36 (17.1 %) subjects, respectively. Simple regression analyses showed that the serum LDL-C level was not significantly correlated with lumbar or femoral BMD or serum levels of total amino-terminal propeptide of type I collagen (PINP) or carboxy-terminal telopeptide of type I collagen (CTX). Logistic regression analyses adjusted for age and BMI showed that the increased serum LDL-C level was selected as an index affecting the presence of prevalent non-vertebral fractures, but not vertebral fractures. This result was still significant after additional adjustments for years since menopause, physical activity, previous cardiovascular events, bone markers, BMD, serum Ca, P, Cr, 25(OH)D, grip strength, tandem gait test, and use of drugs for hyperlipidemia [odds ratio 1.76 (1.13-2.73), p = 0.012]. These findings suggest that a high serum LDL-C level may be a risk factor for prevalent non-vertebral fragility fractures independent of bone turnover, bone mass, vitamin D insufficiency, or frail status in postmenopausal women, and that it may be detrimental to bone, as well as blood vessels.Endocrine 05/2014; · 1.42 Impact Factor
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ABSTRACT: Context: The last decades have provided insights into vitamin D physiology linked to glucose homeostasis. Uncertainties remain in obesity due to its intrinsic effects on vitamin D and glucose tolerance.Objectives: To assess the relationship between vitamin D and glucose abnormalities in severely obese individuals previously unknown to suffer from abnormal glucose metabolism.Setting: Tertiary care centre.Patients: 524 obese patients (50.3 +/- 14.9 yrs; BMI, 47.7 +/- 7.3 kg/m2) screened by OGTT, HbA1c and the lipid profile. Vitamin D status was assessed by 25(OH)D3, PTH and electrolyte levels. 25(OH)D3 deficiency/insufficiency were set at 20 and 30 ng/ml, respectively. All comparative and regression analyses were controlled for age, BMI and gender. The prevalence of vitamin D deficiency/insufficiency and secondary hyperparathyroidism were 95% and 50.8%, respectively. Normal glucose tolerance (NGT), impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) were found in 37.8%, 40.5% and 21.7% of cases, respectively. Large variations in metabolic parameters were seen across categories of vitamin D status, but the only significant differences were found for C-peptide, tryglicerides, LDL- and HDL-cholesterol levels (p < 0.05 for all). The prevalence of vitamin D deficiency was documented to be slightly but significantly more frequent in glucose-intolerant patients (IFG + IGT + T2DM) compared to the -normotolerant counterpart (87% vs. 80%, p < 0.05). In partial correlation analyses, there was no association between vitamin D levels and glucose-related markers but for HbA1c (r = -0.091, p < 0.05), and both basal and OGTT-stimulated insulin levels (r = 0.097 and r = 0.099; p < 0.05 for all). Vitamin D levels were also correlated to HDL-cholesterol (r = 0.13, p = 0.002). Multivariate regression analysis inclusive of vitamin D, age, BMI, gender and fat mass as independent variables, showed that vitamin D was capable of predicting HbA1c levels (beta = -0.101, p < 0.05). Given the inherent effect of obesity on vitamin D and glucose homeostasis, current data suggest a potential independent role for vitamin D in the regulation of glucose metabolism in a setting of obese patients previously unknown to harbour glucose metabolism abnormalities.Cardiovascular Diabetology 03/2014; 13(1):57. · 4.21 Impact Factor
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ABSTRACT: Vitamin D (Vit D) deficiency may be linked to the development of obesity-associated complications such as insulin resistance and type 2 diabetes. We therefore evaluated the relationship of Vit D serum concentrations with metabolic parameters and type 2 diabetes in middle-aged Caucasian men and women. One thousand six hundred and thirty-one Caucasians (832 males, 58.8 ± 9.7 years; 799 females, 59.7 ± 10.7 years) were evaluated in a cross-sectional study. Vit D status was assessed by measuring the serum concentration of 25-hydroxyvitamin D3 [25(OH)D3]. Type 2 diabetes prevalence was ascertained by medical history, fasting plasma glucose concentrations, oral glucose tolerance testing and/or glycosylated hemoglobin. Men displayed higher crude or seasonally adjusted 25(OH)D3 serum concentrations than women (24.64 ± 10.98 vs. 22.88 ± 11.6 ng/ml; P < 0.001). Strong associations between body mass index (BMI) and 25(OH)D3 were observed in both genders (P < 0.001). Seasonally adjusted levels of 25(OH)D3 revealed stronger associations with type 2 diabetes in women than men (P < 0.001). However, adjustment for BMI and other confounding variables revealed an independent inverse association of 25(OH)D3 with diabetes only in women (P < 0.001), whereas the association was abrogated in men. Using a 15 ng/ml 25(OH)D3 cutoff for binary comparison, adjusted odds ratios for having newly diagnosed or known type 2 diabetes more than doubled (2.95 [95 % CI 1.37-4.89] and 3.26 [1.59-6.68], respectively), in women below the cutoff. We conclude that in women, but not in men, low 25(OH)D3 serum levels are independently associated with type 2 diabetes. These findings suggest sex-specific effects of Vit D in the pathogenesis of type 2 diabetes.Acta Diabetologica 05/2014; · 4.63 Impact Factor