A new study reports that a low blood vitamin D concentration is common among 6-year-old children in The Netherlands, especially in winter and spring.
The observational study measured the serum 25-hydroxyvitamin D [25(OH)D] concentrations in 4,167 children aged six years (1). The study results showed that 6.2% of the children were severely deficient in vitamin D (below 25 nmol/L), 23.6% were deficient (25 to below 50 nmol/L), while 36.5% had sufficient (50 to below 75 nmol/L) and 33.7% had optimal (75 nmol/L or higher) 25(OH)D concentrations. The prevalence of vitamin D deficiency (below 50 nmol/L) was higher in winter (51.3%) than in summer (10.3%); and higher in African, Asian, Turkish, and Moroccan children (54.5%) than in those with a Dutch or other Western ethnic background (17.6%).
The researchers noted that several factors were associated with vitamin D deficiency, including lower household income, more television watching and playing less outside. In a subgroup with dietary data, vitamin D deficiency was associated with a lower diet quality. Supplementation or lifestyle changes are important to prevent vitamin D deficiency in children, potentially affecting later health, they said.