Day-Care Attendance Reduces The Risk of Wheeze At Age Five Years

Asthma and wheeze have been on the rise over the past few decades. There are many hypotheses to explain why they have become more common. One of the most common theories is the hygiene hypothesis, which suggests that the decrease in exposure to infections and microbial products in early childhood may alter the maturation of the immune system resulting in an increase in allergic disease. In a study published in the Journal of Allergy and Clinical Immunology, Nicolaou et al hypothesized that children who attended day-care and/or had older siblings might have a lower prevalence of asthma and wheezing as a result of an increased contact with other children and exposures to infectious agents. The authors studied a group of 922 children who have been followed since birth and, at age 5, collected information about wheezing and allergic symptoms, physician-diagnosed illnesses, treatments received, exposure to environmental tobacco smoke, socio-economic status, and pet ownership and contact. Data were also collected about the number of siblings and position within sibship and childcare arrangements, with focus on the type of care setting and age of entry into day-care. The authors found that day-care attendance at any age was associated with a reduced risk of current wheeze at age 5, compared to children who did not attend day-care. No association was observed between the presence and number of older siblings and wheezing, indicating that day-care attendance and position in sibship are the markers of different exposures.

The protective effect for day-care attendance may be strongest for children who enter day-care between 6 and 12 months of age. For example there was a 75% reduction in the odds of having wheeze at age 5 years for those children who entered day-care between ages of 6-12 months, and a 35% reduction for those entering day-care after 12 months of age, compared with those children who did not attend day-care at all. These data suggest that the timing of exposure to the day-care environment may play an important role in the development of childhood wheeze.

Although this study has shown the possible benefit of attending day-care to children in the reduction of wheezy symptoms, further studies will need to be carried out to ascertain whether the protective effect afforded by the day-care attendance in early life applies to all children, or just a susceptible sub-group within the population. The results of this study alone should not influence parent’s decision making with regard to day-care. Day-care attendance has other benefits and disadvantages, and parents need to weigh up the pros and cons of day-care for their individual child and family.

Press Release Reproduced With the Kind Permission of Professor Adnan Custovic, University of Manchester

Page created: 20 September 2008