25-Hydroxycholecalciferol levels in a representative sample of children and young adolescents from the Ikwerre-speaking Local Government Areas of Rivers State, Nigeria

Abstract

Adequate vitamin D status is important for bone growth and mineralization and has been implicated in the regulation of autoimmunity, metabolic function and cancer prevention. There are no reports of population-based studies on the vitamin D status of Rivers State youth in Nigeria, a population where mandatory fortification of foods is currently advocated. We measured 25-hydroxycholecalciferol [25(OH)D], the best indicator of vitamin D status, in a postprimary school-based cross-sectional sample of representative Rivers State youth (n=1120) ages 10, 15, and 20 living in the Ikwerre-speaking local government areas (LGAs). Blood samples were collected from February to July 2009. We defined 25(OH)D deficiency as ≤ 27.5nmol/'L, hypovitaminosis as ≤ 37.5nmol/L, and optimal as > 75nmol/L. More than 95% of youth in each age and sex group had suboptimal 25(OH)D concentrations. The prevalence of 25(OH)D deficiency increased with age in both sexes (P< 0.001). It was 2%, 4% and 13% in 10,-15,and 20-year-old boys and 2%, 9% and 12% in 10-, 15-, and 20-year-old girls. Girls with higher body mass index and girls from households with lower income had lower 25(OH)D concentrations. These effects were not found in boys. Inadequate vitamin D status is a potentially serious public health problem among children and young adolescents in Rivers State. This result calls for renewed efforts to ensure adequate vitamin D intake among growing children and adolescents.