Vitamin D Deficiency among South Asians
- Vitamin D deficiency is known to impair insulin synthesis and secretion in human and animal models of diabetes, suggesting a possible role in the development of diabetes, a condition highly prevalent south Asians.
- Vitamin D deficiency has been found in some UK south Asian populations.1 Vitamin D replacement therapy in South Asian patients with diabetes has been shown to decrease in both HbA1c and weight.2
- Asian Indians in the US have been shown to have markedly low serum vitamin D and 25(OH)D levels. Besides, altered vitamin D metabolism is only partially reversed by supplementation. Thus, Asian Indians residing in the U.S. are at risk for developing vitamin D deficiency, rickets, and osteomalacia.3
- Vitamin D deficiency is a major public health issue in the Asian population in the US. More than 80% South Asians have low vitamin D (< 50 nmol/l) and was more common among diabetic subjects.4
- Low vitamin D level was associated with an enhanced risk for incident CAD. Vitamin D receptor genotypes did not show any association with either vitamin D levels or CAD.5
- In the Indian Atherosclerosis study (n=521), vitamin D levels were extremely low in people with (11ng/ml) and without CAD (12ng/ml) ─both in the vitamin D deficiency range (<20 ng/ml). Despite these very low levels, patients in the first vitamin D quartile showed 3 fold greater risk for CAD than those in the fourth quartile.5
- Vitamin D levels were significantly lower in vegetarians than in nonvegetarians and showed inverse association with body weight, triglyceride, and body mass index.5
- The lower vitamin D in South Asian newborns has been reported and may explain their increased prevalence of neonatal hypocalcaemia and rickets.6
- The potential role of low Vitamin D levels in the high prevalence of metabolic syndrome, diabetes and CAD deserves greater scientific scrutiny.
Sources
1. Boucher BJ, Mannan N, Noonan K, Hales CN, Evans SJ. Glucose intolerance and impairment of insulin secretion in relation to vitamin D deficiency in east London Asians. Diabetologia. Oct 1995;38(10):1239-1245.
2. Sabherwal S, Bravis V, Devendra D. Effect of oral vitamin D and calcium replacement on glycaemic control in South Asian patients with type 2 diabetes. Int J Clin Pract. Jul 2010;64(8):1084-1089.
3. Awumey EM, Mitra DA, Hollis BW, Kumar R, Bell NH. Vitamin D metabolism is altered in Asian Indians in the southern United States: a clinical research center study. J Clin Endocrinol Metab. Jan 1998;83(1):169-173.
4. Tahrani AA, Ball A, Shepherd L, Rahim A, Jones AF, Bates A. The prevalence of vitamin D abnormalities in South Asians with type 2 diabetes mellitus in the UK. Int J Clin Pract. Feb 2010;64(3):351-355.
5. Shanker J, Maitra A, Arvind P, et al. Role of vitamin D levels and vitamin D receptor polymorphisms in relation to coronary artery disease: the Indian atherosclerosis research study. Coron Artery Dis. Aug 2011;22(5):324-332.
6. Sulaiman R A, Sharratt CL, Lee PW, et al. Ethnic differences in umbilical cord blood vitamin D and parathyroid hormone–South Asians compared to Whites born in the UK. J Matern Fetal Neonatal Med. Nov 2010;23(11):1315-1317.