25-hydroxyvitamin D is associated with adiposity and cardiometabolic risk factors in a predominantly vitamin D-deficient and overweight/obese but otherwise healthy cohort. Issue 173 (October 2017)

• Record Type: Journal Article
• Authors: Mousa, Aya; Naderpoor, Negar; de Courten, Maximilian P.J.; Scragg, Robert; de Courten, Barbora
• Is Part Of: Journal of steroid biochemistry and molecular biology. Issue 173(2017)
• Page Start: 258
• Page End: 264
• Publication Date: 2017-10
• Subjects: 25(OH)D 25, hydroxyvitamin D -- BMI body mass index -- WHR waist-to-hip ratio -- DEXA dual energy x-ray absorptiometry -- CT computed tomography -- OGTT oral glucose tolerance test -- IPAQ international physical activity questionnaire -- BP blood pressure -- SBP systolic blood pressure -- DBP diastolic blood pressure -- PP pulse pressure -- MAP mean arterial pressure -- HDL high-density lipoprotein -- LDL low-density lipoprotein -- WBC white blood cell -- hsCRP high-sensitivity C-reactive protein -- IQR interquartile range -- UV ultraviolet -- CLIA chemiluminescent immunoassay -- VDR vitamin D receptor -- PTH parathyroid hormone -- RAAS renin-angiotensin-aldosterone system -- NFkB nuclear factor-kappa B -- GLUT glucose transporter -- QUICKI quantitative insulin-sensitivity index -- HOMA-IR homeostatic model assessment of insulin resistance -- ISI insulin sensitivity index -- NHANES III third National Health and Nutrition Examination Survey -- VITAL vitamin D and omega-3 trial -- FIND finnish vitamin D trial -- ViDA vitamin D assessment study -- WHO World Health Organization -- NHMRC National Health and Medical Research Council of Australia -- MCHRI Monash Centre for Health Research and Implementation -- ICMJE International Committee of Medical Journal Editors; Vitamin D -- 25-Hydroxyvitamin D -- Diabetes -- Cardiovascular disease -- Cardiometabolic risk -- Obesity; Steroid hormones -- Periodicals; Biochemistry -- Periodicals; Hormones -- Periodicals; Molecular Biology -- Periodicals; Hormones stéroïdes -- Périodiques; Steroid hormones; Periodicals; 572.579
• DOI: 10.1016/j.jsbmb.2016.12.008
• Languages: English
• ISSNs: 0960-0760

Abstract

Highlights: 25-hydroxyvitamin D levels were associated with cardiometabolic risk factors including adiposity, glucose intolerance, insulin resistance, and inflammation in predominantly overweight/obese but otherwise healthy adults. Most associations between 25-hydroxyvitamin D levels and cardiometabolic risk factors were mediated by adiposity. The mediating effect of adiposity on the relationship between 25-hydroxyvitamin D and cardiometabolic risk was only observed when using direct adiposity measures such as percent body fat, but not when using indirect measures such as body mass index. Abstract: Vitamin D deficiency has reached epidemic proportions worldwide and has recently been linked to cardiometabolic risk factors including obesity, insulin resistance, hypertension, dyslipidemia, as well as type 2 diabetes and cardiovascular disease. The objective of this study was to examine the associations between circulating 25-hydrovitamin D (25(OH)D) levels and cardiometabolic risk factors using direct measures of adiposity, glucose intolerance, and insulin resistance, as well as lipids, blood pressure, and plasma markers of inflammation. We measured circulating 25(OH)D, physical activity (International Physical Activity Questionnaire- IPAQ), anthropometry (body mass index (BMI), waist-to-hip ratio (WHR), % body fat (dual energy X-ray absorptiometry)), metabolic parameters (fasting and 2-h plasma glucose levels during oral glucose tolerance test; insulin sensitivity (M, hyperinsulinaemic-euglycaemic clamp), and cardiovascular and inflammatory profiles (blood pressure (BP), pulse pressure (PP), mean arterial pressure (MAP), plasma lipid levels, white blood cell count (WBC), and plasma high-sensitivity C-reactive protein levels (hsCRP)) in 111 healthy, non-diabetic adults (66 males/45 females; age 31.1 ± 9.2 years; % body fat 36.0 ± 10.2%). Mean 25(OH)D was 39.8 ± 19.8 nmol/L with no difference between genders (p = 0.4). On univariate analysis, 25(OH)D was associated with% body fat (r = −0.27; p = 0.005), 2-h glucose (r = −0.21; p = 0.03), PP (r = 0.26; p = 0.006), and insulin sensitivity (r = 0.20, p = 0.04), but not with age, BMI, WHR, fasting glucose, BP, MAP, lipids, or inflammatory markers (all p > 0.05). After adjusting for age and sex, 25(OH)D remained associated with% body fat (β = −0.12%; p = 0.003), 2-h glucose (β = −0.13 mmol/L; p = 0.02), PP (β = 0.12 mmHg; p = 0.009), and insulin sensitivity (β = 0.22 mg/kg/min; p = 0.03), and became associated with fasting glucose (β = −0.04 mmol/L; p = 0.04) and hsCRP (β = −0.51 mg/L; p = 0.04). After adjusting for age, sex, and % body fat, 25(OH)D was no longer associated with insulin sensitivity, 2-h glucose, or hsCRP, but remained associated with fasting glucose (β = −0.05 mmol/L; p = 0.03) and PP (β = 0.10 mmHg; p = 0.03). 25(OH)D remained associated with fasting glucose (β = −0.06 mmol/L; p = 0.02) after hsCRP and physical activity were added to the model with % body fat, age, and sex. ​These cross-sectional data suggest that associations between vitamin D and cardiometabolic risk among healthy, non-diabetic adults are largely mediated by adiposity. Large-scale intervention and mechanistic studies are needed to further investigate whether vitamin D has an independent role in the prevention and/or management of cardiometabolic risk and disease.