The accumulation of fat in the abdominal region, especially visceral fat (fat that accumulates between organs), significantly increases the risk of stress urinary incontinence in women. A study conducted at the Federal University of São Carlos (UFSCar) in the state of São Paulo, Brazil, and supported by FAPESP (projects 13/00798-2 and 22/16910-5 ), identified this region as the one most strongly associated with involuntary urine leakage, surpassing total body fat. The results were published in the European Journal of Obstetrics & Gynecology and Reproductive Biology and indicate that body fat distribution may be a more decisive factor than weight itself in explaining the condition.
Stress urinary incontinence is characterized by involuntary urine leakage during everyday activities such as coughing, laughing, lifting heavy objects, or exercising. "It's that urinary leakage that occurs when pressure inside the abdomen increases and the pelvic floor can't hold it in," explains Patricia Driusso , a professor of physical therapy in women's health at UFSCar and the advisor for the study. Although the condition is often associated solely with aging, it is not exclusive to older women. "It happens to women of all ages, including very young women. These pelvic floor muscles are rarely exercised throughout life, and without proper training, they can become weak and lose function," she states.
The study is part of a broader line of research on pelvic floor dysfunctions, which include urinary incontinence, fecal incontinence, pelvic organ prolapse (when structures such as the uterus and bladder descend through the vaginal canal), sexual dysfunction, and chronic pelvic pain. In this phase, the researchers decided to specifically investigate the relationship between body fat distribution and urinary leakage. Physical therapist Ana Jéssica dos Santos Sousa , the first author of the study, conducted the research in partnership with Western Michigan University in the United States.
The results were obtained by evaluating 99 women between the ages of 18 and 49 who were recruited in the city of São Carlos. The study focused exclusively on women because urinary incontinence is significantly more prevalent in this population. In men, the problem is usually associated with prostate surgery. In women, multiple factors are involved, including anatomical characteristics, pregnancy, menopause, and greater strain on the pelvic floor.
The participants did not need to have a prior incontinence diagnosis and had varying BMIs (body mass index) to allow for comparison of different profiles. The women underwent a test called Dual-Energy X-ray Absorptiometry (DXA), which is considered the gold standard for body composition analysis. DXA can measure not only the total amount of fat, but also its distribution in specific regions of the body.
The researchers analyzed total fat, abdominal fat (android), fat in the pelvic region (gynoid), and visceral fat, which lies between the organs. Additionally, they administered validated questionnaires to identify incontinence and assess its impact on the women's quality of life. About 39.4% of the participants reported episodes of urinary leakage, a figure consistent with international estimates.
"The problem is often underreported, but even a few episodes of urinary leakage indicate that the continence mechanism is not functioning properly," the professor warns, noting that many women normalize minor leaks, thinking they are isolated incidents.
Impact of visceral fat
The results showed that women with higher amounts of body fat were more likely to experience incontinence. However, the main finding was the role of visceral fat. The presence of this type of fat increased the likelihood of stress urinary incontinence by about 51%. "That was the most strongly associated factor. We had imagined that fat in the gynecological region, being closer to the pelvic floor, would have a greater influence, but what emerged was visceral fat," says Driusso.
According to her, there are two possible explanations. The first is mechanical. As visceral fat accumulates within the abdominal cavity, it increases pressure on the internal organs and overloads the pelvic floor, which is the structure responsible for supporting the bladder and controlling urine flow. "Excess weight in this region creates constant strain. Over time, these muscles can become more fatigued and less efficient," the researcher explains.
The second mechanism is metabolic. Visceral fat does not merely function as an energy store; it is metabolically active and releases inflammatory substances that circulate throughout the body. This process can compromise muscle quality and reduce contractile capacity, including that of the pelvic floor muscles. "We're talking about low-grade chronic inflammation, which affects different tissues in the body. That can also contribute to muscle weakness," says the professor.
Obesity is already recognized as a risk factor for urinary incontinence, along with aging, menopause, the number of pregnancies, and delivery conditions. Regarding childbirth, Driusso issues a warning: "The problem isn't childbirth itself, but obstetric care. Inappropriate interventions, such as episiotomy [a surgical incision made in the perineum, the muscular region between the vagina and the anus, during vaginal delivery to widen the vaginal opening], can increase the risk of pelvic floor dysfunction," she states.
Prevention and treatment
According to Driusso, the study is important because it shows that excess weight and the way fat is distributed in the body can influence the development of the problem, even in women with a normal BMI. However, since this is a cross-sectional study, which analyzes participants at a single point in time, the researchers cannot establish a cause-and-effect relationship; they can only conclude that there is an association between the factors. Nevertheless, the findings help guide prevention and care strategies.
One of the main forms of treatment is strengthening the pelvic floor muscles through women's health physical therapy. "Today, we have a high level of evidence that training these muscles is effective. It's the gold standard for treating stress urinary incontinence," says Driusso.
According to her, professional supervision is essential since many women cannot correctly contract these muscles on their own. "About 30% of women can't contract them properly without guidance. Some perform the opposite movement, which can worsen the condition," she explains. With proper guidance, training can lead to significant improvement in about three months. However, like any other muscle group, the pelvic floor needs continuous exercise. "If you stop, you lose strength. It's a practice that must be maintained throughout life," she says.
The researchers are planning the next steps in their investigation, which will include using MRIs to directly assess the presence of fat infiltrating the muscles, a phenomenon known as myosteatosis. They are also studying whether obese women can benefit from specific training protocols.
For Driusso, the results underscore the importance of expanding the conversation around this still-taboo topic. "Urinary incontinence impacts quality of life, limits activities, and is often overlooked. But it can be treated and prevented. The most important thing is for women to know that they don't have to live with it."
About São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.
