Vitamin D₃ and the risk of CVD in overweight and obese women: a randomised controlled trial

Abstract

Evidence indicates that vitamin D deficiency contributes to CVD. We investigated the effect of vitamin D 3 supplementation on cardiovascular risk factors in women. Healthy premenopausal overweight and obese women (n 77; mean age 38 (SD 8·1) years) were randomly allocated to the vitamin D (25 mg/d as cholecalciferol) or the placebo group in a double-blind manner for 12 weeks. Blood pressure, serum lipoproteins, apolipoproteins and anthropometric parameters were recorded. Dietary intake was recorded using 24 h food recall and FFQ. Physical activity was assessed by the International Physical Activity Questionnaire. Mean total cholesterol concentrations increased in the vitamin D group (0·08 (SD 0·56) mmol/l) but declined in the placebo group (0·47 (SD 0·58) mmol/l), and a significant effect was observed (P#0·001). In the vitamin D group, mean HDL-cholesterol concentration increased, whereas it decreased in the placebo group (0·07 (SD 0·2) v. 20·03 (SD 0·2) mmol/l; P¼ 0·037). Mean apoA-I concentration increased in the vitamin D group, although it decreased in the placebo group (0·04 (SD 0·39) v. 20·25 (SD 0·2) g/l; P# 0·001). Mean LDL-cholesterol:apoB-100 ratio augmented in the vitamin D group, while this ratio declined in the placebo group (0·11 (SD 0·6) v. 2 0·19 (SD 0·3); P¼0·014). Body fat mass was significantly decreased in the vitamin D group more than the placebo group (22·7 (SD 2) v. 20·4 (SD 2) kg; P# 0·001). The findings showed that supplementation with vitamin D 3 can significantly improve HDL-cholesterol, apoA-I concentrations and LDL-cholesterol:apoB-100 ratio, which remained significant in the multivariate model including anthropometric, dietary and physical activity measures. Key words: Vitamin D: CVD: ObesityVitamin D is recognised as the vitamin of sunshine (1) .A relationship between vitamin D and CVD has been proposed by observing more incidence of CVD in winter compared with summer in many countries (2,3) , which might be attributable to the protective effect of vitamin D on CVD (4) .Ecological studies have indicated the higher rate of CHD and high blood pressure increment with more distance from the equator, which is also related to low sun exposure and higher prevalence of vitamin D deficiency (5,6) . It has beenshown that a range of markers including geographic latitude, altitude and season affect vitamin D status which are negatively correlated with cardiovascular morbidity and mortality. Evidence suggests that low levels of vitamin D may contribute to the development of CVD (7) .On the other hand, a range of CVD risk factors including dyslipoproteinaemia, high blood pressure, reduced glucose tolerance, diabetes and increased inflammatory markers are related to obesity, which has been increasing dramatically during recent decades (8 -10) . Serum 25-hydroxyvitamin D (25(OH)D) levels negatively correlate with BMI (11) . It is likely that alteration in vitamin D homeostasis affects CVD development in obese individuals (12)

Long-Term High-Dose Vitamin D 3 Supplementation and Blood Pressure in Healthy Adults

“…27 However, other short-term studies of nonwhite populations found no effect of vitamin D on BP, although this could be a result of their low statistical power because of their small sample sizes (n≤100). 10,21,25 In summary, we have found that long-term vitamin D supplementation, which increased mean serum 25(OH)D concentrations >100 nmol/L for 18 months, had no effect on systolic or diastolic BP. These results, when combined with other studies that gave similarly high vitamin D doses for 12 months, indicate that high-dose long-term vitamin D supplementation does not lower BP in predominantly white, healthy adults without severe vitamin D deficiency.…”

“…Most randomized controlled trials gave vitamin D for periods <1 year (most <6 months) [10][11][12][13][16][17][18][19][20][21][22][23][24][25][26][27] and, therefore, are of limited use for addressing the efficacy of long-term vitamin D supplementation in preventing and treating hypertension. Only 7 trials of long-term (≥1 year) supplementation have been Abstract-Previous randomized controlled trials of vitamin D supplementation and blood pressure (BP) mainly have given vitamin D for short periods (<6 months) or at low doses (400 IU per day).…”

- Treatment of Metabolic Syndrome by Combination of Physical Activity and Diet Needs an Optimal Protein Intake: A Randomized Controlled Trial

“…In vitro experiments in rats have also shown that large doses of vitamin D 2 lead to increases in energy expenditure due to uncoupling of oxidative phosphorylation in adipose tissues [12]. However, randomized controlled trials (RCTs) testing the effect of vitamin D supplementation on weight loss in obese or overweight individuals have provided inconsistent findings [13][14][15]. It has also been suggested that obesity could result from an excessive adaptive winter response, and that the decline in vitamin D skin synthesis due to reduced sunlight exposure contributes to the tendency to increase fat mass during the colder periods of the year [16,17].…”

Comment on Ryan et al., an investigation of association between chronic musculoskeletal pain and cardiovascular disease in the Health Survey for England (2008)

“…The risk of CVD for 18 nmol/L was 2.2 (95% confidence interval, 1.7-2.7) compared with 1.0 (95% CI, 0.85-1.15) at 75 nmol/L. A study in Iran found that treating premenopausal overweight and obese women 1000 IU/day for 12 weeks resulted in significantly improved high-density lipoprotein-cholesterol, apoA-I concentrations and low-density lipoproteincholesterol:apoB-100 ratio (Salehpour et al, 2012). Serum 25(OH)D levels also impact proinflammatory cytokine levels.…”