Older women who maintain a stable weight may be nearly twice as likely to live to 90 to 100 years old, although unintentional weight loss was linked to a decrease in the chances of making it to 90, found a large US analysis.
Scientists from the University of California San Diego (UCSD) studied data from thousands of women to determine the likelihood of reaching 90, 95, or 100, which they called “exceptional longevity”, finding that older women who kept a stable weight after 60 might be be 1.2 to two times more likely to reach 90 to 100, reports MedicalNewsToday.
The study involved 54 437 women from the Women’s Health Initiative (WHI), with the researchers looking at short-term and long-term weight changes in women and comparing that to the age they reached.
Women who experienced unintentional weight loss had 51% lower odds of reaching 90, they found.
They said that while while weight loss was associated with decreased longevity, a weight gain of 5% or more did not contribute to exceptional longevity, which points toward the importance of maintaining a stable weight.
Weight loss vs. weight gain vs. stable weight
The authors said earlier studies have analysed the effects of weight loss in early to middle adulthood, such as shifting from being obese to being overweight, but that those studies had not considered whether the weight loss was intentional.
The UCSD study, published in the Journal of Gerontology: Medical Sciences, included nearly 55 000 postmenopausal women who participated in the Women’s Health Initiative study, which began in 1991. The WHI study focused on health issues in postmenopausal women, like heart disease and cancer.
The authors chose to use data from women aged 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 enrolment and later at the three-year and 10-year marks, categorising the women into 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 team also classified the women into “intentional weight loss” or “unintentional weight loss groups” at the three-year weigh-in, depending on whether they reported losing more than 2.2kg on purpose.
Unintentional weight loss dents chances of making 90
After excluding any women who died within the first year of the three-year weigh-in (to avoid pre-existing health conditions affecting results), the researchers found that 56.3% of women who maintained a stable weight lived to be at least 90 years old.
Those who experienced unintentional weight loss of 5% or more were less likely to reach 90.
The women who had weight loss (for any reason) of more than 5% at the three-year check-up had 33% lower odds of reaching 90, 35% lower odds of reaching 95, and 38% lower odds of reaching 100.
The researchers also looked at whether the weight loss was intentional or unintentional –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 three-year weigh-in was not associated with increased chances of survival.
“It is very common for older women in the US to be overweight or obese, with a body mass index range of 25 to 35. Our findings support stable weight as a goal for longevity in older women,” said Professor Aladdin Shadyab, lead author and professor at UCSD’s School of Public Health and Human Longevity Science.
“If ageing women are losing weight when they are not trying to lose weight, this could be a warning sign of ill health and a predictor of decreased longevity.”
Why weight maintenance is important
Dr Jessica Lee, associate professor of geriatrics with McGovern Medical School at UTHealth Houston (University of Texas), said over the years, there have been some questions regarding whether weight changes have more or less benefit with regards to longevity.
“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.
“This research potentially changes the advice for weight loss in older women. Rather than focus on weight loss or gain beyond 60, it will be more important to emphasise maintenance of weight in those who are generally healthy otherwise.”
Katie Lounsberry, a registered dietician at Providence Mission Hospital, said while she found the study helpful, the findings might 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 emphasised the importance of taking the individual into consideration.
“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.
“This study presents interesting considerations when making recommendations regarding weight changes for older adults, as it shows that weight loss may not help women live longer.”
Study details
Association of Later-Life Weight Changes With Survival to Ages 90, 95, and 100: The Women’s Health Initiative
Aladdin Shadyab, JoAnn Manson, Matthew Allison, et al.
Published in The Journals of Gerontology on 29 August 2023
Abstract
Background
Associations of weight changes and intentionality of weight loss with longevity are not well described.
Methods
Using longitudinal data from the Women’s Health Initiative (N = 54 437; 61–81 years), we examined associations of weight changes and intentionality of weight loss with survival to ages 90, 95, and 100. Weight was measured at baseline, year 3, and year 10, and participants were classified as having weight loss (≥5% decrease from baseline), weight gain (≥5% increase from baseline), or stable weight (<5% change from baseline). Participants reported intentionality of weight loss at year 3.
Results
A total of 30 647 (56.3%) women survived to ≥90 years. After adjustment for relevant covariates, 3-year weight loss of ≥5% vs stable weight was associated with lower odds of survival to ages 90 (OR, 0.67; 95% CI, 0.64–0.71), 95 (OR, 0.65; 95% CI, 0.60–0.71), and 100 (OR, 0.62; 95% CI, 0.49–0.78). Compared to intentional weight loss, unintentional weight loss was more strongly associated with lower odds of survival to age 90 (OR, 0.83; 95% CI, 0.74–0.94 and OR, 0.49; 95% CI, 0.44–0.55, respectively). Three-year weight gain of ≥5% vs stable weight was not associated with survival to age 90, 95, or 100. The pattern of results was similar among normal weight, overweight, and obese women in body mass index (BMI)-stratified analyses.
Conclusions
Weight loss of ≥5% vs stable weight was associated with lower odds of longevity, more strongly for unintentional weight loss than for intentional weight loss. Potential inaccuracy of self-reported intentionality of weight loss and residual confounding were limitations.
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