The Effect of Day Care Exposure on the Risk of Developing Type 1 Diabetes

Abstract

OBJECTIVE -Exposure to infections in infancy or childhood may be important in the pathogenesis of type 1 diabetes, but a protective role has also been suggested. We tested the hypothesis that increased early contact with infectious agents, measured by day care exposure, would decrease the risk of type 1 diabetes in childhood.RESEARCH DESIGN AND METHODS -We conducted a systematic review of casecontrol studies. Meta-analysis was performed to combine results, assess for heterogeneity, and explore variation in study design.RESULTS -Several generally well-designed case-control studies show a statistically significant protective effect of day care on type 1 diabetes. However, meta-analysis revealed too much heterogeneity to accept the overall synthesis results and none of the studies used prerecorded data. Day care does seem to have a protective effect in the subgroup of children who will be diagnosed with type 1 diabetes before the age of 5 years (odds ratio ϭ 0.6, 95% CI 0.5-0.8); however, this result is based on only two studies.CONCLUSIONS -Recall bias is one alternate explanation for these data; confirmation using prerecorded data is required. Such data could be prospectively measured in cohort studies of children at risk. We also suggest that information about day care attendance be measured in randomized trials of agents for the prevention of type 1 diabetes, as day care exposure could potentially modify the effect of the preventive agent.

Symptoms of Common Maternal Infections in Pregnancy and Risk of Islet Autoimmunity in Early Childhood

“…Indicators of general exposure to microbial and infectious agents, such as daycare attendance and exposure to pets, have been extensively studied in relation to atopic disorders (4) but relatively rarely in relation to type 1 diabetes. A recent metaanalysis concluded that there is some evidence for a lower risk of type 1 diabetes among children who attended daycare centers early in life, although the amount of heterogeneity between studies makes it difficult to draw strong conclusions (24). The present study does not support a role of early daycare attendance in protecting against islet autoimmunity.…”

Relationship between the incidence of type 1 diabetes and maternal enterovirus antibodies: time trends and geographical variation

“…In Finland, a strong inverse correlation has been reported between population density and the incidence of type 1 diabetes [33,34]. A number of reports have suggested that day-care protects against diabetes, but larger studies are needed to confirm this association [35]. Thus, these epidemiological findings support a possible protective role of such an environment where infections are readily transmissible.…”

A missing link in the hygiene hypothesis?

“…Atopic disorders and childhood diabetes seem to be relatively infrequent in those with a traditional lifestyle but can be acquired by immigrants to more affluent or westernised areas [5,6]. There is strong evidence that atopic disorders are less likely to arise within large sibships or in children receiving day care [7] and day care could also be protective against the development of Type I diabetes, although evidence for this is not strong [8]. Children from East Germany were three times less likely to report asthma or to show positive skin tests than children in West Germany [9] and the prevalence of positive skin tests and hay fever, but not asthma, rose sharply after reunification [10].…”