Scientists with the National Institutes of Health National Institute of Environmental Health Sciences and the National Cancer Institute say the associations between specific pesticides and incident diabetes ranged from a 20 percent to a 200 percent increase in risk.

"The results suggest that pesticides may be a contributing factor for diabetes along with known risk factors such as obesity, lack of exercise and having a family history of diabetes," study co-author Dale Sandler of the NIEHS said in a statement. "Although the amount of diabetes explained by pesticides is small, these new findings may extend beyond the pesticide applicators in the study."

The study, published in the American Journal of Epidemiology, found pesticide applicators in the highest category of lifetime days of use of any pesticide had an increase in risk for diabetes of 17 percent compared with those in the lowest pesticide use category of zero to 64 lifetime days.

The researchers analyzed data from 31,787 licensed pesticide applicators in North Carolina and Iowa. The study found that 1,171 reported a diagnosis of diabetes in the five-year follow-up interview.