Objective

Vitamin D deficiency and insufficiency are global public health problems, which must first be identified before they can be appropriately addressed, and yet information is strikingly lacking in most parts of the Asia and Pacific region. The study aimed to document and account for the actual situation in Wenzhou on the southeastern coast of China.

Subjects and methods

Serum 25-hydroxyvitamin D levels among a total of 5845 infants, preschool children, school children, and adolescents aged 1–18 years were examined between March 2014 and February 2015.

Results

Their mean levels were (110.2±26.8), (77.5±25.7), (55.6±15.4), and (47.2±13.9) nmol/L, respectively. Older age groups were involved in increasing risk of vitamin D deficiency and insufficiency. There were significant seasonal differences in its median level and prevalence of deficiency and insufficiency among school children and adolescents, but there was no significant sex difference in mean level and prevalence in any age group.

Conclusions

Vitamin D deficiency and insufficiency were prevalent among infants, preschool children, school children, and adolescents in Wenzhou. A vitamin D-rich diet and outdoor activities for 1–2 h per day under the natural conditions favorable to its endogeous synthesis do not suffice. The vitamin D status in Wenzhounese infants excelling over that in the US was the result of its supplementation thanks to the Chinese Medical Association recommendations, which should be consequently extended to more age groups. Life style shaped by socio-economic environments affects vitamin D status. Knowledge on the importance of vitamin D for healthy growth should be popularized.