The common belief that kids who go to daycare have lower rates of asthma and allergy later in life might be nothing more than wishful thinking, according to new research appearing in the American Journal of Respiratory and Critical Care Medicine. "We found no evidence for a protective or harmful effect of daycare on the development of asthma symptoms, allergic sensitization, or airway hyper-responsiveness at the age of eight years," says researcher Johan C de Jongste, of Erasmus University in the Netherlands. "Early daycare was associated with more airway symptoms until the age of four years, and only in children without older siblings, with a transient decrease in symptoms between four and eight years."
For the study, the researchers followed a group of nearly 4,000 Dutch children over the course of eight years. Parents completed questionnaires during pregnancy, at three and 12 months, and then yearly until the child reached the age of eight, and reported their children's airway symptoms annually. At the age of eight, more than 3,500 of the children were also assessed for specific allergies.
The researchers found that children who started daycare early were twice as likely to experience wheezing in the first year of life compared to those who didn't go to daycare. However, as the children aged, there was a shift: by age five, there was a trend for less wheezing among early attendees: they were about 80 percent as likely as non-attendees to wheeze, but this was not statistically significant. What's more, the shift reversed itself by age eight, when there was no association between early daycare attendance and wheezing at all.
Despite the widespread acceptance of the idea that early exposures pay off in later health benefits, the data in this study do not support that belief. If anything, this study suggests that these exposures cause more airway symptoms early in life with no counterbalancing benefit later, noted the study. "Early daycare merely seems to shift the burden of respiratory morbidity to an earlier age where it is more troublesome than at a later age," said Dr. de Jongste. "Early daycare should not be promoted for reasons of preventing asthma and allergy."
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Source: American Thoracic Society
