Researchers at Leeds University discovered links between nitrate levels in water and diabetes even though, in all cases, the nitrate levels were below the EU recommended maximum levels. In rural areas, where water nitrate levels can be up to four times as high as in urban areas, the incidence of diabetes can be 25% higher. The researchers agree that further work is required but, given that only one in ten of the children in the study had relatives with diabetes, suspect an environmental rather than a genetic cause.

Another US study found that Vietnam war veterans exposed to Agent Orange (an organochloride) have three times the risk of developing diabetes.