Middle-aged men with obese wives are significantly more likely to develop type two diabetes than those with slimmer partners, scientists discovered.
A study of more than 3 500 couples reveals a direct correlation between the weight of a woman and her husband’s health.
The reverse is not true, however, with overweight husbands having no impact on their wives’ chance of developing the condition.
Scientists interviewed English couples over the age of 50 between 1998 and 2015, tracking their weight and health for about 11 years.
They found that each woman’s weight at the beginning of the study was a strong predictor of her husband’s chances of developing type two diabetes.
For every five additional points a woman scored on the body mass index scale, her husband was 21% more likely to develop type two diabetes, regardless of his weight to begin with.
Scientists suspect shared lifestyle such as poor diet and lack of exercise is to blame, with obese women influencing their husband’s eating and activity patterns.
But the fact men do not impact their wives’ health suggest women have a much bigger influence on their husband’s lifestyle than men do on their wives.
This may be because women are more likely to cook their husbands’ meals, although experts stress the people assessed were middle-aged couples, so the same may not be true of younger groups.
Others said women may simply be more conscious of their appearance - making them more resistant to following their husbands’ lead.
Presenting their results to the annual meeting of the European Association for the Study of Diabetes in Portugal, the Danish researchers said men with overweight wives should be screened for diabetes.
Led by Adam Hulman of Aarhus University, they said: “This is the first study investigating the sex-specific effect of spousal obesity on diabetes risk.
“Having an obese wife increases a man’s risk of diabetes over and above the effect of his own obesity level, while among women, having an obese husband gives no additional diabetes risk beyond that of her own obesity level.
"Our results indicate that, on finding obesity in a person, screening of their spouse for diabetes may be justified.
“Recognising shared risk between spouses may improve diabetes detection and motivate couples to increase collaborative efforts to eat more healthily and boost their activity levels.
“Obesity or type two diabetes in one spouse may serve as a prompt for diabetes screening and regular weight checks in the other.”
More than 3.5 million people in the UK are thought to have type two diabetes and the rates have soared by 60% in a decade, largely because of obesity.
And while in the past, type two was seen as a predominantly elderly issue, NHS figures show that more than 50 000 people under 40 in England and Wales have the disease.
Tam Fry, who is chairman of the National Obesity Forum, said: “The husband puts the blame for his increasing bulk on the wife’s cooking but she, canny woman, doesn’t gain weight at the same rate.
“She frets about a socially embarrassing increase in dress size and that does the trick. Dress size is not uppermost in a man’s mind.”
But Dr Emily Burns of Diabetes UK said the findings might be out of date because family set-ups have changed.
“The data we’re looking at relates to the nineties, so there’s a question around how relevant the results might be today,” she said.