Pa. Mckinney et al., Early social mixing and childhood Type 1 diabetes mellitus: a case-controlstudy in Yorkshire, UK, DIABET MED, 17(3), 2000, pp. 236-242
Aims Evidence from animal models shows an increased risk of Type 1 diabetes
mellitus associated with the absence of early life exposure to pathogens.
To test this 'hygiene hypothesis', patterns of social mixing and infections
in the first year of life and the risk of developing autoimmune diabetes i
n childhood were examined.
Methods Personal interviews were conducted with the mothers of 220 children
with Type 1 diabetes (0-15 years) and 433 age/sex matched controls from a
population-based case control study in Yorkshire, UK. Social mixing includi
ng attendance at daycare, and infections occurring under 1 year of age were
measures of exposure. Adjusted odds ratios (OR) were derived using conditi
onal logistic regression.
Results Frequency of attendance at daycare during the Ist year of life was
inversely associated with childhood diabetes (OR 0.71, 95% confidence inter
val 0.51-1.00, P = 0.05), a finding not explained by mother's age, level of
education or maternal diabetes. Increasing numbers of children in the dayc
are setting and numbers of sessions attended were significantly associated
with increasing protection from diabetes. The strongest effect was observed
in children with diabetes diagnosed aged 0-4 years.
Conclusions Social mixing through attendance at daycare in early infancy ap
pears to confer protection against the development of childhood diabetes. T
his may be mediated through exposure to infectious agent(s) as a significan
t dose-response effect was evident with increasing numbers of child 'contac
ts'. These findings suggest early infectious exposure may play a role in th
e development of immunoregulatory mechanisms which protect against diabetes
and further work is warranted.