People who live in sunny climates are less likely to develop inflammatory bowel disease.

A large long-term study of 238,000 nurses in the United States, published by the journal Gut, found those who lived in northern states were more likely to develop the condition, which includes Crohn's disease and ulcerative colitis, by their 30th birthday.

Nurses living in southern states were 52 per cent less likely to develop Crohn's disease compared to those who lived further north and 38 per cent less likely to have ulcerative colitis.

The study's authors said the differences could be explained by the nurses' exposure to sunlight or UVB radiation, which is generally greater in southern latitudes.