Cold comfort for parents as child diabetes 'more likely over winter'

Published on Sunday 23 August 2009 20:12

CHILDREN may be more likely to develop diabetes in the winter than the summer, according to new findings which have puzzled scientists.

The trend was uncovered by a worldwide study looking at data on 31,000 children under the age of 15 in 53 countries.

It had a significant effect in 42 out of 105 centres, 28 of which saw new cases of insulin-dependent diabetes peak between October and January.

In 33 centres, incidence rates dipped to their lowest level during the summer months between June and August.

Centres further away from the equator were likely to encounter the greatest number of new cases in winter. The trend was most noticeable among boys and older children of both sexes.

Insulin-dependent – or type 1 diabetes – usually appears before the age of 40 and most often strikes children. It occurs when the body's immune system destroys insulin-producing cells in the pancreas.

Without the presence of natural insulin to regulate blood sugar levels, the vital hormone has to be administered with regular injections.

Around 300,000 people in the UK have Type 1 diabetes. Far more suffer from the Type 2 form of the disease which is not caused by an auto-immune reaction and is linked to obesity.

Previous studies have hinted at seasonal variation in the development of Type 1 diabetes, but the evidence has not been clear.

Study leader Dr Elena Molchanova, from the National Institute for Health and Welfare in Helsinki, Finland, said: "Numerous reasons have been suggested for the apparent seasonality of the onset of Type 1 diabetes.

"These include a seasonal variation in people's levels of blood glucose and insulin, seasonal viral infections, the fact that young people tend to eat more and do less physical activity during winter months and, similarly, that summer holidays provide a rest from school stress and more opportunity to play outdoors."

The findings have been reported in the journal Diabetic Medicine.

Victoria King, research manager at the charity Diabetes UK, said: "Results from previous studies in this area have been conflicting but this larger study shows a stronger correlation which is interesting, especially as we still don't know exactly why Type 1 diabetes develops.

"Investigating why we might be seeing this pattern could tell us more about what may be triggering the development of Type 1 diabetes."

Ms King also pointed out that not all the centres' studies showed a seasonal pattern and the research was conducted over a relatively short, nine-year period. And she added: "More data are needed before definite conclusions can be drawn."