Abstract
A high incidence of rickets among infants in the Peoples Republic of China has been reported, etiology unclear. The vit. D status of infants in China has not been investigated. The specific effect of sunshine (UV) exposure on D status in any infant is unstudied. We hypothesized that breast-fed infants in China have low vit. D status and UV exposure increases serum 25OH vit. D into the normal range. 54 breast-fed term infants 1 to 8 mos. without D supplements were randomly assigned into 2 grps. in a 2 mo. study, Sept. and Oct. (mos. of high UV exposure): controls with "usual" sun exposure; and experimental with 2 hr. sun/d. Infants received only human milk, rice soup, fruit juice and mashed vegetables and exposed mostly face and forearms. A 20 nurse team monitored UV exposure with diaries and a unique infant UV dosimeter. Only 100 μl blood samples were permissible in infants. Serum 25OHD was measured by protein binding assay after chromatography. (N 11 to 68 ng/ml). Mean maternal 25OHD was 22 ng/ml. Infant 25OHD correlated with mother's (r=0.48). Infant 25OHD ranged 3 to 61 ng/ml at entry with 20% <11 ng/ml. Mean ± SE 25OHD did not change for controls (21 ± 3 vs 18 ± 3 ng/ml, pre- vs. post- 2 mo.sun exposure 83 min./d) but increased significantly for experimental (28 ± 4 vs 40 ± 5 ng/ml, p<0.01, sun 144 min./d). Thus, infant 25OHD correlated with maternal 25OHD; although infants in Beijing may receive moderate sun exposure in fall, 20% of 25OHD are low and additional sun exposure for 2 mos. increases serum 25OHD towards normal.
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Ho, M., Tsang, R., Shui, QM. et al. ULTRAVIOLET EXPOSURE AND 250H VITAMIN D IN BREAST-FED INFANTS IN BEIJING, CHINA. Pediatr Res 18 (Suppl 4), 184 (1984). https://doi.org/10.1203/00006450-198404001-00544
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DOI: https://doi.org/10.1203/00006450-198404001-00544