Vitamin D deficiency in rural girls and pregnant women despite abundant sunshine in northern India

CONTEXT: Vitamin D deficiency is common in urban Indians despite living in the tropics and its public health consequences are enormous. However, 70% of India is rural, and data from rural subjects, who are expected to have good sun exposure, are scant. OBJECTIVES: To determine the population prevalence of vitamin D deficiency in rural pregnant women and adolescent girls, compare serum 25-hydroxyvitamin D (25OHD) status in adolescent boys from the same families, and determine seasonal differences in serum 25OHD. DESIGN: A cross-sectional study conducted over 18 months. SUBJECTS: A random selection of 121 adolescent girls from a survey of a population of 8270 in a rural low socioeconomic community; 139 pregnant women in the second trimester; and a subset of 28 adolescent girls compared with 34 brothers. MEASUREMENTS: Serum 25OHD, serum alkaline phosphatase (AP), sun exposure, and dietary calcium intake. RESULTS: The age-adjusted community prevalence of vitamin D deficiency (25OHD < 50 nmol/l) in adolescent girls was 88.6%. Seventy-four per cent of pregnant women had vitamin D deficiency. Mean +/- SD 25OHD in girls and women in summer was 55.5 +/- 19.8 nmol/l compared to 27.3 +/- 12.3 nmol/l in winter (P < 0.001). Winter serum 25OHD in boys (67.5 +/- 29.0 nmol/l) was higher than that in their sisters (31.3 +/- 13.5 nmol/l, P < 0.001). CONCLUSION: We report a high prevalence of vitamin D deficiency among pregnant women and adolescent girls from a rural Indian community. Boys are relatively protected. Seasonal variation in serum 25OHD is significant at latitude 26 degrees N.