This study aimed to analyze any associations between weight changes (intentional or unintentional) and exceptional longevity in older women.

The authors noted that prior studies analyzed the effects of weight loss in early to middle adulthood, such as shifting from being a person with obesity to being overweight, but that these studies had not considered whether the weight loss was intentional.

The UCSD study included nearly 55,000 postmenopausal women who participated in the Women’s Health Initiative (WHI) study, which began in 1991. The WHI study focused on health issues in postmenopausal women, such as heart disease and cancer.

The authors chose to use data from women who were ages 61 to 81 at the time of enrolling in the study. The women provided information, including their weight, medical conditions, alcohol consumption, and smoking status.

The researchers looked at weight changes from the beginning of each participant’s enrollment and later at the 3-year and 10-year marks. They categorized the women into one of three groups:

• Stable weight (less than 5% change from starting weight)
• Weight loss (more than 5% decrease from starting weight)
• Weight gain (more than 5% increase from starting weight)

The authors also classified the women into “intentional weight loss” or “unintentional weight loss groups” at the 3-year weigh-in, depending on whether they reported losing more than 5 pounds on purpose.

After excluding any women who died within the first year of the 3-year weigh-in (to avoid pre-existing health conditions impacting results), the researchers found that 56.3% of women who maintained a stable weight lived to be at least 90 years old.

Women who experienced unintentional weight loss of 5% or more were less likely to reach the age of 90.

According to the authors, women who had weight loss (for any reason) of more than 5% at the 3-year checkup had 33% lower odds of reaching 90, 35% lower odds of reaching 95, and 38% lower odds of reaching 100.

They also looked at whether the weight loss was intentional or unintentional, and the women who tried to lose weight had 17% reduced odds of reaching 90. Some reasons for intentionally losing weight included diet changes and an increase in exercise.

The women who did not lose weight on purpose had 51% reduced odds of reaching 90. Some reasons the women reported for unintentionally losing weight include illness and stress.

Alternatively, a weight gain of more than 5% at the 3-year weigh-in was not associated with increased chances of survival.

“It is very common for older women in the United States to experience [being overweight or having obesity] with a body mass index range of 25 to 35. Our findings support stable weight as a goal for longevity in older women,” says Professor Aladdin H. Shadyab, the study’s lead author and professor at UCSD’s School of Public Health and Human Longevity Science.

Dr. Jessica Lee, associate professor of geriatrics with McGovern Medical School at UTHealth Houston, spoke with Medical News Today about the study.

“Over the years, there have been some questions as to whether weight changes have more or less benefit with regards to longevity,” she said.

“The results of this study indicate that in older women, survival to exceptional longevity is more likely in those who maintain their weight (<5% from baseline) rather than gain or lose weight,” she noted.

Dr. Lee noted that the study could impact the advice doctors give to patients in a clinical setting.

Katie Lounsberry, a registered dietitian at Providence Mission Hospital, in Mission Viejo, CA, also spoke with MNT about the study and said she was impressed with the size of the participant group the researchers analyzed.

“This is seemingly the first sizable study that assesses the relationship between weight changes later in life and exceptional longevity. Prior research has been limited due to small participant numbers and limited follow-up as participants reach advanced ages,” she said.

While Dr. Lee found the study helpful, she did note a potential weakness. She said the findings may not apply to everyone.

“Observational studies are good for examining groups as a whole but are not necessarily applicable to individual patients. For example, an older woman who [has morbid obesity] may still benefit from weight loss to help with other conditions such as heart disease or diabetes that have high mortality risk,” she said.

Lounsberry also emphasized the importance of taking the individual into consideration in matters of weight management.

“Given the abundance of past research regarding the benefits of weight loss for certain disease states and health outcomes, it’s important to assess overall health goals on an individual basis when forming weight goals,” she said.