Vitamin D status in Andhra Pradesh : a population based study.

BACKGROUND & OBJECTIVE: Data on the vitamin D status of the population in a tropical country like India have seldom been documented. Vitamin D deficiency is presumed to be rare. We carried out this study to document the dietary habits, serum calcium, 25(OH)vitamin D [25(OH)D], and parathyroid hormone levels of urban and rural population in a State in south India. METHODS: A total of 943 healthy urban and 205 rural adult subjects and 76 urban and 70 rural healthy children were studied for their dietary pattern, serum calcium, phosphorus, alkaline phosphatase, 25(OH)D, and N-tact parathyroid hormone levels (N-tact PTH). RESULTS: The daily dietary calcium intake of both the urban and rural population was low compared to that of recommended daily/dietary allowances (RDA) issued by Indian Council of Medical Research (ICMR). Dietary calcium and phosphorus were significantly lower(P<0.0001) in both the rural adult and children compared to that of the urban adult and children. The dietary phytate to calcium ratio was significantly (P<0.0001) higher in rural adult and children compared to that of urban adult and children. N-tact PTH levels negatively correlated with 25(OH)D in rural (r=-0.24; P<0.002), in urban adult subjects (r=-0.12; P<0.0001) and in rural and urban children (r=-0.2; P<0.05). The 25(OH)D levels of rural adult subjects were significantly higher (P<0.001) than that of urban adult subjects in both males and female groups. The 25(OH)D levels of both the urban and rural children were low. INTERPRETATION & CONCLUSION: Low dietary calcium intake and 25(OH)D levels were associated with deleterious effect on bone mineral homeostasis. Prospective longitudinal studies are required to assess the effect on bone mineral density, a surrogate marker for fracture risk and fracture rates.

High prevalence of low dietary calcium and low vitamin D status in healthy south Indians.

Calcium and vitamin D under nutrition can adversely affect the bone mineral metabolism. There is no population-based study from India documenting dietary habits, serum calcium and vitamin D levels. Our study investigated the dietary habits of rural and urban societies in and around Tirupati and their relationship with serum calcium, phosphorous and vitamin D [25(OH)D] levels. Four hundred and seven subjects from 5 villages around Tirupati, (rural population) and 125 asymptomatic staff of our hospital (urban population) were studied. Dietary intakes of calcium, phosphorous and phytates were documented by diet history. Serum calcium, phosphorus and 25 (OH) D levels were estimated in 191 rural subjects and 125 urban subjects. Compared to urban subjects, rural subjects had a significantly lower intake of dietary calcium (P <0.0001) and a significantly higher dietary phytate/calcium ratio and serum calcium and 25 (OH) D levels (P <0.0001). Dietary calcium intake was inadequate in both rural and urban subjects compared to the recommended daily allowances (RDA) for our country. About 31% of the population had normal vitamin D levels, 54% had vitamin D insufficiency and 15% vitamin D deficiency. About two-thirds of the population had low levels of vitamin D. Inadequate dietary calcium intake associated with high phytate/calcium ratio reduces the bioavailable calcium in the gut. Hence, there is a need to fortify food with calcium and to propose new guidelines for 25 (OH) D in Indian subjects. Multicentric studies with large sample populations are required to generate normal standards and nationally relevant guidelines.