At the very end of August, while many of us were heading to the beach or mountains or lake for a last hurrah before fall, and while others of us were frantically finishing up syllabi or purchasing back-to-school supplies and clothing, a big study came out, looking at associations between longevity and weight changes in women over 60.
What did they find? Well, it depends on what you happened to read.
If you looked at news stories, you’d see only this:
The headlines are true. But the headlines aren’t the main result.
Let’s look at the details of the study itself (I’m paraphrasing from the paper abstract below):
- The study used data from the Women’s Health Initiative of 54,437 women, aged 61–81 years.
- It 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.
- Participants were classified as having 1) weight loss (≥5% decrease from baseline); 2) weight gain (≥5% increase from baseline); or 3) stable weight (<5% change from baseline).
- Participants reported intentionality of weight loss at year 3.
So the researchers are really looking at the issue of weight loss after age 60 vs. maintaining a stable weight. Why? Because many studies suggest a relationship between unintentional weight loss and mortality risk in older people. The researchers wanted to see if weight loss in general (including intentional) was associated with reduced chance of survival to age 90 or older.
Here’s what the news stories said:
[The researchers] found that the women whose body weight stayed stable over the years had 1.2 and 2 times the odds of surviving to 90 and beyond than those who lost weight.
Women who lost 5 percent or more of their body weight over the first three years studied had 33 percent lower odds of surviving to 90, 35 percent lower odds of surviving to 95 and 38 percent lower odds of surviving to 100 than their counterparts whose weight remained stable.
One factor associated with longer lives was whether a woman had intentionally lost weight. Those who unintentionally dropped pounds had 51 percent lower odds of survival to age 90 compared with others in the study. The researchers write that gaining weight over the study period “was not significantly associated with survival” to an extended age.
As the news folks say, this story buried the lede. The main result wasn’t that stable weights after 60 increase longevity, but rather than weight loss after 60 is associated with reduced longevity. And, unintentional weight loss was 3X more strongly associated with reduced longevity than intentional weight loss. Their study didn’t find any association between weight gain and reduced longevity. And finally, this pattern of results was similar across all BMI categories.
So, no matter the starting weight at age 60, losing weight was associated with reduced longevity to 90 or older.
One more important thing: these results are about associations found in large data sets. They’re not translatable into clinical advice for individuals. What the results do suggest is that prescribing weight loss for older women may not be productive for longevity. This news story did say that. Yay, Neuroscience News!
There’s a lot of science being done about aging bodies, weight and health. Some of it goes against standard clinical practice, so it’s important to keep up with new results and talk about them with friends, family and our healthcare providers. And we’ll keep you informed as best we can.
