Effect of Demographic Variables on 25(OH)D Level and on the Risk of Vitamin D Insufficiency in SEANUTS Countries

Abstract

Objectives: Vitamin D insufficiency is endemic in western countries. Emerging evidence suggests this may be true also for countries with abundant sunshine. This study aimed to evaluate the vitamin D status and associated risk factors in a sub-sample of children from the South East Asian Nutrition Surveys (SEANUTS). Methods: SEANUTS was conducted in Indonesia, Malaysia, Thailand and Vietnam in a country representative sample of 16744 children aged 0.5 to 12 years. Information on socio-demographic variables, lifestyle habits and anthropometric measures were collected. In a sub-sample of 2016 children, serum 25-hydroxyvitamin D [25(OH)D] levels were determined. Data were analysed using SPSS complex sample with weight factors to report population representative data. Results: In Malaysia and Thailand, urban children had lower 25(OH)D levels than rural children. Except Vietnam, boys in all countries had higher 25(OH)D levels and older children had lower 25(OH)D levels. Regional differences persisted in all countries even after correcting for age, sex and area of residence. In Malaysia and Thailand, 25(OH)D status was also associated with religion. The percentage of children with adequate 25(OH)D levels (>75nmol/L) ranged from as low as 5% (Indonesia) to 20% (Vietnam). Vitamin D insufficiency (<50nmol/L) was noted in nearly 40% to 50% of children in all countries. Girls, urban area, region and religion significantly increased the odds of being vitamin D insufficient. Conclusions: The high prevalence of vitamin D insufficiency in SEANUTS countries suggests a need for a tailored approach to successfully combat this problem. Promoting active and outdoor lifestyle along with food fortification can be feasible options.