Gaining just 5-22 pounds in the first half of adulthood significantly increases the risk of chronic disease in the second half, especially the likelihood of type 2 diabetes, gallstones, and hypertension, according to investigators.
They looked at how much 92,837 women in the Nurses’ Health Study remembered weighing when they were 18 years old, and how much 25,303 men in the Health Professionals Follow-Up Study recalled weighing at age 21. The Harvard team matched those weights to how much their subjects actually weighed at age 55, and then followed the women out to a median of 73 years and the men out to a median of 69 years to see how their weight changes in early adulthood affected their health later on (JAMA. 2017;318:255-269. doi: 10.1001/jama.2017.7092).
The women gained a mean of 12.6 kg and the men a mean of 9.7 kg by age 55; about 23% of the women and 13% of men gained 20 kg or more. The magnitude of weight gain was comparable with the U.S. general population.
The investigators found that even a moderate gain of up to 10 kg increased the risk of major chronic diseases and early death. “Maintaining a healthy weight throughout early and middle adulthood is associated with overall health ... These findings may help counsel patients regarding the risks of weight gain,” wrote the investigators, led by Yan Zheng, MD, PhD, of the department of nutrition, Harvard T. H. Chan School of Public Health, Boston.
It’s not news that packing on a few pounds with age isn’t healthy, but quantifying the effects of early adulthood weight gain is novel. “The advantage of focusing on weight gain throughout” the first half of adult life “is that it primarily reflects the accumulation of excess adiposity from early to middle adulthood, which is often ignored by individuals and their physicians because the consequences of modest weight accumulation may not yet be apparent,” the investigators noted.
Specifically, they found that compared to participants who maintained a stable weight – no more than 2.5 kg either way – people who gained up to 10 kg had an increased incidence of not only type 2 diabetes, gallstones, and hypertension, but also cardiovascular disease, cataracts, severe osteoarthritis, and death, and added weight increased health risks in a dose-dependent manner. People who gained more than 10 kg from their high school years fared worse, even if they started out as obese.
The adjusted incidence per 100,000 person-years for type 2 diabetes rose from 110 cases to 207 cases per 100,000 person-years among women 55 years old who weighed up to 22 pounds more than they did in high school; it was similar for men, with a rise from 147 cases to 258 cases per 100,000 person-years. Weight gain up to 10 kg boosted the incidence of hypertension from 2,754 cases to 3,415 cases per 100,000 person-years for women and from 2,366 cases to 2,861 cases for men.
Results were similar for cardiovascular disease and obesity-related cancers, particularly breast cancer among women and colorectal and prostate cancer among men. Higher amounts of weight gain were also associated with a lower likelihood of healthy aging, a composite score of the absence of multiple chronic diseases, cognitive decline, and physical limitations.
However, the investigators noted that “considering that individuals tend to underreport their weight, it is possible that our findings might have exaggerated the true risks associated with the measured weight change from early to middle adulthood.”
Also, “participants were all health professionals and were mostly white ... the results might not be generalizable to all populations,” they said.