Background: The modest clothing that Orthodox Jewish women wear exposes very little of their skin to sunlight. Under these conditions they may develop vitamin D deficiency, even in sunny Israel.
Objectives: To determine and compare the vitamin D nutritional status in Jewish orthodox mothers to that of non-orthodox mothers who live in the same metropolitan area in Israel.
Methods: 25-Hydroxyvitamin D was measured by competitive protein-binding radioassay in the sera of 341 Jewish Israeli mothers (156 orthodox and 185 non-orthodox). The sera were obtained 48-72 hours after childbirth during the late summer of 1998 and the spring of 1999.
Results: The mean (SD) serum concentration of 25-OHD was significantly (P < 0.002) lower (13.5 +/- 7.5 ng/ml) in the orthodox than in the non-orthodox mothers (18.6 +/- 9.6 ng/ml). Vitamin D deficiency (< 5 ng/ml) and insufficiency (< 10 ng/ml) were more common in the orthodox mothers (5.1% and 32.7% respectively) than in the non-orthodox mothers (2.7% and 13%, respectively). In subgroups of mothers supplemented with 400 units of vitamin D daily during pregnancy, vitamin D deficiency and insufficiency were less common (2.2% and 13%, respectively) in orthodox and non-orthodox mothers (0% and 8.1%, respectively). Vitamin D insufficiency was more common in the winter than in the summer only among non-orthodox mothers.
Conclusions: The high prevalence of vitamin D deficiency and insufficiency in Israeli mothers raises the question whether vitamin D supplements should be given to pregnant women in Israel, at least to orthodox mothers.