Prevalence of vitamin B 12 deficiency in healthy Indian school-going adolescents from rural and urban localities and its relationship with various anthropometric indices: a cross-sectional study.

BACKGROUND: Micronutrient deficiency is a global health burden, especially among developing countries. The present cross-sectional study aimed to determine the prevalence of vitamin B12 deficiency in healthy Indian school-going adolescents, based on area of residence, sex and body mass index (BMI). Furthermore, the relationship of serum B12 concentration with dietary vitamin B12 intake and anthropometric indices was assessed among adolescents from rural and urban India.

METHODS: A total of 2403 school-going adolescents (11-17 years) from National Capital Region and rural areas of Haryana, India were selected. Serum B12 concentrations were estimated using an electrochemiluminescence immunoassay. Dietary assessments were conducted on 65% of total participants (n = 1556) by two 24-h diet recalls.

RESULTS: The prevalence of vitamin B12 deficiency in the total study population was 32.4% (rural: 43.9% versus urban: 30.1%, P < 0.001; male: 34.4% versus female: 31.0%, P < 0.05; normal weight: 28.1%, versus overweight: 39.8%, versus obese: 51.2%, P < 0.001). More than half (51.2%) of obese adolescents were vitamin B12 deficient. On multiple linear regression analysis, serum B12 in rural adolescents was associated with age (β = -0.12, P < 0.05). Among urban adolescents, serum B12 was associated with BMI (β = -0.08, P < 0.05) and adjusted dietary vitamin B12 intake (β = 0.14, P < 0.001). Serum vitamin B12 levels were found to be lower in rural females (β = -0.12, P = 0.030) and urban males (β: 0.11, P < 0.001) compared to their respective contemporaries.

CONCLUSIONS: Vitamin B12 deficiency was higher among rural school-going adolescents. Boys had a higher B12 deficiency than girls. Inverse associations of serum B12 with adiposity indices were observed. Serum B12 levels were positively associated with dietary vitamin B12 intake.