Vitamin D, body mass composition and metabolic risk factors in healthy young Indians.

BACKGROUND: Studies have linked vitamin D to risk factors for cardiovascular disease. Obesity is a potential confounder in these studies. This study examined the relationship of 25 (OH) cholecalciferol (25[OH] D3) with insulin resistance, blood glucose, and lipid profile in lean male adults. METHOD: We enrolled two hundred and thirty four military recruits before beginning of military training. Demographic and anthropometric data were collected from them. The participants underwent body mass composition analysis by dual energy X ray absorptiometry. Fasting samples were collected for measurement of blood glucose, lipid profile, 25(OH) D3, serum parathormone (PTH) and insulin. RESULTS: Vitamin D deficiency and insufficiency was found in 47.7% (107/224) and 31.6% (71/224) of participants, respectively. Using Pearson's correlation coefficient 25(OH) cholecalciferol and fasting blood glucose (FBG) were inversely correlated (p = 0.023). However, similar relation was not found between 25(OH) D3 and total cholesterol, triglycerides, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, homeostatic model assessment of insulin resistance and levels of PTH. On body composition analysis, there was no correlation of 25(OH) cholecalciferol with body mass index or fat mass index. CONCLUSION: This study showed that in lean young male population, 25(OH) cholecalciferol and FBG are inversely correlated but no association of 25(OH) D3 with other cardiometabolic risk factors could be demonstrated.

The effect of vitamin D supplementation on cardiorespiratory fitness and muscle strength in male adults undergoing basic military training.

BACKGROUND: Vitamin D deficiency (VDD) is ubiquitous in the Indian subcontinent. VDD has been shown to impair muscle functions. However, the association of VDD with cardiorespiratory endurance is uncertain. Hence, we enrolled and supplemented vitamin D in military recruits with VDD with an aim to evaluate effect of supplementation on cardiorespiratory endurance and muscle strength. METHOD: We enrolled 90 military recruits with VDD and randomly allotted them to two groups equally. The group I received cholecalciferol granules 60,000 IU every fortnight for twelve weeks (cases), and the group II was observed as control. Muscle strength and cardiorespiratory endurance was assessed with a battery of tests (standing broad jump, bent arm hang test, 20 m shuttle run) at baseline and repeated at the end of training (nineteen weeks). Blood samples were collected for measurement of serum 25(OH)D and parathyroid hormone. RESULTS: In Group I and Group II, there was significant increase in 25(OH) D levels (25.8 ± 7.1 and 17.3 ± 3.5 ng/ml, respectively), and in VO2 max (9.8 ± 8.8 and 12.7 ± 8.6 ml/kg/min, respectively) compared with the baseline values. However, no significant change was observed in muscle strength after supplementation. There was no difference between the groups in VO2 max and muscle strength at baseline and at the end of training. CONCLUSION: Vitamin D supplementation did not improve muscle strength and cardiorespiratory endurance in military recruits with VDD. A significant rise in 25(OH) D was observed even in those not supplemented with vitamin D.