The effect of menopause on body composition

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Dr. Greendale

During the menopause transition, defined as the 4 years bracketing the final menstrual period, women gain fat mass and lose lean body mass. These alterations in body composition plateau 2 years after the final menstrual period, according to a prospective study.

The longitudinal study published in JCI Insight concluded that both fat and lean body mass increase a small amount prior to the menopause transition.  However, at the start of the transition, the rate of fat gain doubles and lean mass begins to fall.  

“We found that weight gain did not accelerate during the menopause transition, although gain in fat mass did accelerate,” said lead author Gail Greendale, MD, a professor of medicine and ob/gyn at David Geffen School of Medicine at the University of California, Los Angeles (UCLA). “How can a woman accumulate more fat but not weigh more? The answer is by simultaneously losing lean body mass, so the overall weight value breaks even, despite the individual having more body fat.”

Dr. Greendale said the trade-off between fat gain and lean loss is what occurs during the menopause transition. 

All 1,246 study participants were from the Study of Women’s Health Across the Nation (SWAN), with a mean baseline age of 47.1 years and an average age at final menstrual period of 52.2 years.

Body composition was determined by dual energy x-ray absorptiometry over 18 years (spanning roughly 9 years prior to the final menstrual period to 10 years after).  

“The bottom line is that simply measuring body weight does not illustrate what is happening ‘under the skin,’” Dr. Greendale told Contemporary OB/GYN. “Gains in fat and losses of lean are not captured by total weight on the scale during the menopause transition.”

Dr. Greendale said other researchers have reported that the ability of body mass index (BMI) to forecast risk of conditions such as diabetes or cardiovascular disease declines in older women.

“The menopause-related shifts in fat and lean mass that we uncovered in SWAN may be one reason for the decline in the predictive capacity of body mass index in older women,” said Dr. Greendale, theSWAN principal investigator at UCLA.

One of the strengths of SWAN is its multi-racial study sample. “This allows us to identify variation in how women from different backgrounds experience the menopause transition,” Dr. Greendale said. 

In SWAN, black and white women had similar patterns of change in body composition and weight. But Japanese women lost some lean mass during the menopause transition but did not gain fat mass, whereas Chinese women gained lean mass and lost fat mass during postmenopause. 

To reduce a gain in fat mass and retain lean mass, Dr. Greendale advocates that midlife women watch their diet and establish or maintain a good physical activity regimen. 

“However, no one can guarantee that exercise and diet alone will counter the effects of menopause on fat and lean tissue,” she said. “We do not know how powerful the drivers are for the fat gain and lean loss, nor how they operate. Therefore, we cannot be sure that the usual recommendations of workout more and eat less will operate in the same way and to the same degree as they do at other times in the life course.”

Nonetheless, as long as there is full disclosure about this uncertainty, Dr. Greendale believes it is reasonable to recommend a healthy diet and physical activity plan, as well as a healthy dose of honesty about such advice “being our best guess about what to do. After all, optimizing diet and physical activity are good things to do, for a multitude of physical and mental health reasons.”

Dr. Greendale and her colleagues will be undertaking additional investigations to explore the next set of questions that follow from their study: What are the reasons for the fat/lean shift at menopause? And can physical activity minimize these unfavorable alterations in body composition?   

Disclosures:

Dr. Greendale reports no relevant financial disclosures.