December 15, 2016
By Lisa Rapaport
(Reuters Health) - Women who have more lean muscle mass or better grip strength may be less likely to experience stress urinary incontinence, a study suggests.
In the study, researchers examined data on 1,475 elderly women, including 212 who experienced stress incontinence at least once a month and another 223 who had overactive bladder, or urge incontinence, at least monthly.
Women were less likely to develop or continue experiencing stress incontinence by the end of the three-year study when they didn't have much decline in muscle strength, as assessed by grip strength. Women also had lower odds of stress incontinence when they lost substantial amounts of weight and fat mass.
"Our study found that changes in body composition and grip strength are associated with changes in stress urinary incontinence frequency over time, but not with changes in urgency urinary incontinence frequency over time," said lead study author Dr. Anne Suskind of the University of California, San Francisco.
"This finding may be explained by the anatomic underpinnings of stress versus urgency incontinence," Suskind added by email.
High body mass index (BMI) is a risk factor for incontinence in young and middle-aged adults, researchers note in the Journal of the American Geriatrics Society, online December 5th.
As people age, however, the relationship between BMI and incontinence gets more complicated because of change in body composition and the amount of fat versus lean muscle mass, the researchers point out.
For the current study, researchers asked participants to complete questionnaires about incontinence and also examined data on their BMI, grip strength, leg power in the quadriceps and walking speed.
All of the women were between 70 and 79 years old at the start of the study.
Women who experienced at least a 5 percent decrease in grip strength during the study were 60 percent more likely to have new or persistent stress incontinence by the end.
In addition, women who had a 5 percent or greater drop in BMI during the study were 54 percent less likely to have stress incontinence three years later.
After accounting for BMI, a 5 percent or greater increase in lean muscle mass was associated with 83 percent lower odds of stress incontinence, while at least a 5 percent decrease in fat mass was tied to 47 percent lower odds of stress incontinence.
One limitation of the study is its reliance on women to accurately recall and report on the frequency and type of incontinence they experienced, the authors note. The women didn't have exams to verify the details about incontinence they reported on questionnaires.
Even so, the findings suggest that weight loss and exercise aimed at muscle strength may help prevent stress incontinence, Dr. Blayne Welk, a researcher at Western University and St. Joseph's Hospital in London, Ontario, who wasn't involved in the study, said by email.
"By reducing weight and abdominal fat there is less pressure on the bladder resulting in less stress urinary incontinence," said Dr. Cindy Amundsen of Duke University in Durham, North Carolina. "Better muscle strength may be associated with higher pelvic floor muscle strength and function, decreasing the susceptibility to urine leakage."
Women can work when they're younger to lower their odds of incontinence as they age, Amundsen, who wasn't involved in the study, added by email.
"Women should optimize their body composition by achieving a normal BMI and improve their muscle strength, and they should continue to do so well into their 70s," Amundsen said.
J Am Geriatr Soc 2016.
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