And boosts risks of diabetes, potentially fatal blood clots, and heart attacks
Young men who are obese in their early 20s are significantly more likely to develop serious ill health by the time they reach middle age, or not even make it that far, suggests research published in the online journal BMJ Open.
It's well known that obesity in adulthood poses a risk for diabetes and cardiovascular disease, but it's not been clear whether obesity in early adulthood strengthens that risk.
The authors tracked the health of 6500 Danish 22 year old men for 33 years up to the age of 55. All of them had been born in 1955, and had registered with the Military Board for a fitness test to gauge their suitability for military service.
All potential conscripts in Denmark are subjected to a battery of psychological and physical tests, including weight. Most (83%; 5407) were within the normal range and 5% were underweight (353). One in 10 (639) were overweight and 1.5% (97) were obese.
Normal weight is classified as a body mass index (BMI) of between 18.5 and 25; obesity is classified as a BMI of 30 or more.
Almost half of those classified as obese at the age of 22 were diagnosed with diabetes, high blood pressure, heart attack, stroke, blood clots in the legs or lungs, or had died before reaching the age of 55.
They were eight times as likely to get diabetes as their normal weight peers and four times as likely to get a potentially fatal blood clot (venous thromboembolism). They were also more than twice as likely to develop high blood pressure, have had a heart attack, or to have died.
Every unit increase in BMI corresponded to an increased heart attack rate of 5%, high blood pressure and blood clot rates of 10%, and an increased diabetes rate of 20%.
In all, obese young men were three times as likely to get any of these serious conditions as their normal weight peers by middle age, conferring an absolute risk of almost 50% compared with only 20% among their normal weight peers.
The findings prompt the authors to warn that the continuing rise in obesity may counteract the fall in deaths from heart disease.
"Thus, obesity related morbidity and mortality will, in decades to come, place an unprecedented burden on healthcare systems worldwide," they suggest.