Smoking cessation intervention.

of vitamin D receptors in asthma and allergies. On the other hand, recent epidemiological data from birth cohort studies have shown beneficial associations between maternal vitamin D intake during pregnancy and early childhood asthma symptoms. In Crete, the basic factor affecting vitamin D is probably exposure to sunlight. Margarine is fortified with vitamin D but is not commonly used among children, and olive oil remains the principal source of fat intake. A randomised clinical trial could provide strong evidence on the effect of fortified margarine intake in childhood allergies. We think, however, that there is an increasing need for more observational studies on this controversial field before embarking on a long term intervention study. We have recently started a mother– child cohort in Crete (Rhea study; http:// rhea.med.uoc.gr/) aiming, among other issues, to investigate the role of early life dietary exposures on the development of asthma and allergies. We hope to answer some of the questions on the role of vitamin D in the development of allergic disorders.