The weight that Americans typically gain between ages 20 and 50 may raise their risk of developing cancer, heart disease and other major illnesses, according to a new study. Even those who only gained 10 pounds faced a higher risk of major chronic diseases and aging poorly, the study authors report in JAMA.
"In the past, most focus has been put on people who are already obese and how they should lose weight. The problem is that people don't become obese overnight," said senior study author Dr Frank Hu of the Harvard T.H Chan School of Public Health in Boston. "Americans start to gain weight in early adulthood and put on a small amount each year, such as a half pound or pound, which adds up in the long-term," Hu told Reuters Health in a phone interview. "Then it's difficult to lose weight and maintain that lost weight. That's why prevention is extremely important."
The researchers analyzed data from two large studies that followed nearly 93,000 U.S. women and more than 25,000 U.S. men over decades. Participants reported what their weights had been in young adulthood - at age 18 for women and age 21 for men - and again at age 55. The study team then tracked health changes after age 55, including the development of various diseases, cognitive decline and physical limitations associated with aging.
Women gained an average of 28 pounds over 37 years, and men put on an average 21 pounds over 34 years. Consistently across both genders, those who gained more weight were more likely to be physically inactive, non-smokers, have unhealthy diets and have more chronic diseases by the time they were in their 50s. About one in five women and one in three men were considered to be aging healthily in their 70s.
Compared to people who stayed close to their youthful weight, those who gained just 5.5 to 22 pounds (2.5 kg to 10 kg) had nearly double the risk of type 2 diabetes, as well as 38 percent higher risk of gallstones and 9 percent to 25 percent increased risk for hypertension, heart disease and cancer.
People who gained 22 to 44 pounds (10 kg to 20 kg) had a quadrupled risk of developing type 2 diabetes, doubled risk of developing gallstones and 30 percent to 60 percent increased risk of hypertension, heart disease and an obesity-related cancer. Gaining more than 44 pounds (20 kg) was tied to 10 times the odds of hypertension, three times the odds of gallstones and twice the heart disease risk of people who had stayed at the same weight.