Dairy food, calcium and vitamin D intake and prevalence of allergic disorders in pregnant Japanese women.

SETTING: Epidemiological evidence for the associations between intake of dairy products, calcium and vitamin D and allergic disorders has been inconsistent.

OBJECTIVES: To examine such associations in Japan.

DESIGN: This cross-sectional study enrolled 1745 pregnant women. The definitions of wheeze and asthma were based on European Community Respiratory Health Survey criteria, whereas those of eczema and rhinoconjunctivitis were based on International Study of Asthma and Allergies in Childhood criteria. Information on dietary factors was collected using a validated self-administered diet history questionnaire.

RESULTS: Intake of total dairy products, milk, yoghurt, cheese and calcium was not related to the prevalence of wheeze, asthma, eczema or rhinoconjunctivitis. After adjustment for potential confounders, vitamin D intake was found to be independently positively associated with the prevalence of asthma: the adjusted ORs for asthma in the first, second, third and fourth quartiles were respectively 1.00 (reference), 1.26 (95%CI 0.65-2.50), 2.08 (95%CI 1.13-3.94), and 1.82 (95%CI 0.97-3.51, P for trend = 0.03). There were no relationships between vitamin D consumption and the prevalence of wheeze, eczema or rhinoconjunctivitis.

CONCLUSIONS: These findings suggest that vitamin D intake may be positively related to the prevalence of asthma in young adult Japanese women.