For most people, excess body adiposity tends to accrue during early and middle adulthood. The average weight gain is 0.5 to 1.0 kg per year during this period among US adults. Although modest, accumulation at this rate can eventually lead to obesity. Additionally, adulthood weight gain has been associated with virtually all metabolic conditions, explains Yan Zheng, MD, PhD. However, it is unclear how such weight gain relates to subsequent health consequences. With recommendations on preventing adulthood weight gain lacking in public health guidelines, Dr. Zheng and colleagues conducted a study to estimate the comprehensive effect of weight gain throughout adulthood on health and disease and published their findings in JAMA.

 

Uncovering the Link

Study participants were female registered nurses from the Nurses’ Health Study and male healthcare professionals from the Health Professionals Follow-up Study. “These participants recalled weight at early adulthood and reported current weight in middle adulthood,” explains Dr. Zheng. “And we prospectively followed participants from 55 years old for incident cases of major health outcomes, including type 2 diabetes, hypertension, cardiovascular disease, cancers, cholelithiasis, severe osteoarthritis, cataract, and mortality.”

Dr. Zheng and colleagues assessed data covering 18 years of follow-up in nearly 93,000 women and covering 15 years in more than 25,000 men. When compared with participants who maintained a stable weight (weight loss ≤2.5 kg or gain <2.5kg), those with a moderate weight gain (≥2.5 kg to <10.0 kg) had increased incidence of type 2 diabetes (absolute rate difference per 100,000 person-years of 98 in women and 111 in men), cardiovascular disease (61 in women), obesity-related cancer (37 in women and 42 in men), and mortality (51 among women who never smoked) (Table). “The key takeaways are that weight change from early to middle adulthood, even moderate weight gain, was associated with subsequent development of these diseases as well as hypertension, cataract, cholelithiasis, and severe osteoarthritis, as well as decreased odds of healthy aging, in both women and men,” says Dr. Zheng. “These findings may help counsel patients regarding the risks of weight gain.”

 

Explaining Differences

The incidence rates per 100,000 person-years among those who gained a moderate amount of weight were 207 in women and 258 in men for diabetes; 3,415 in women and 2,861 in men for hypertension; and 309 in women and 382 in men for cardiovascular disease, says Dr. Zheng. “Although we did not conduct a statistical analysis of the difference in incidence rate between genders, these numbers may not reach a significant difference level,” she adds.

The incidence rates per 100,000 person-years among those who gained a moderate amount of weight were 452 in women and 208 in men for obesity-related cancer. “The impact of adiposity may vary according to characteristics of cancer, including stage, tumor characteristics, subsite, or histology,” notes Dr. Zheng. “Obesity-related cancers include cancers of breast, endometrium, colorectal, kidney, pancreas, esophagus, gallbladder, ovaries, thyroid, and possibly prostate. In women, breast cancer is the main obesity-related cancer, and in men, colorectal cancer is the main contributor. The incidence rate of obesity-related cancer varies because the main component of obesity-related cancer is different between women and men.”

 

Important Implications

Dr. Zheng and colleagues’ study is the first to estimate the association of weight change through adulthood with the risk of major chronic disease in later life. The findings that even a weight gain of 5kg during this period of life was associated with decreased odds of achieving the composite healthy aging outcome—defined as being free of 11 chronic diseases and major cognitive or physical impairment—as well as elevated incidence of a composite measure of major chronic diseases—consisting of type 2 diabetes, cardiovascular disease, cancer, and non-traumatic death—can help physicians provide new information during consultations with patients about the risk of weight gain.

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