A wife's high body mass index (BMI) can increase the husband's risk of developing Type-2 diabetes -- a condition that affects over 400 million people worldwide, a study has found.

The findings showed that a man, whose wife had a BMI of 30 kg/m2, had a 21-per cent higher risk of developing diabetes than men whose wives had a BMI of 25 kg/m2 - regardless of the man's own BMI. However, the same was not found in women. "If we adjusted for the women's own weight, they did not have a heightened risk of developing Type-2 diabetes as a result of their husband's BMI. But even when we adjusted for the weight in men, they had a heightened risk," said lead author Jannie Nielsen, post-doctoral student at the University of Copenhagen, Denmark.

The researchers believe that it is so because women are largely in charge of the household and diets. "We believe it is because women generally decide what we eat at home. That is, women have greater influence on their spouse's dietary habits than men do," Nielsen added, in a paper published in the journal Diabetologia. For the study, the team examined data from 3,649 men and 3,478 women.

Based on the results, Nielsen believes that early detection of Type-2 diabetes can be improved if we change our approach to the disease. "Our approach to Type-2 diabetes should not focus on the individual, but instead on, for example, the entire household. If a woman has a heightened risk, there is a strong probability that it is shared by her husband," Nielsen said.