A study conducted by researchers from the Federal University of São Carlos (UFSCar) in partnership with University College London, in the United Kingdom, concluded that the accumulation of abdominal fat associated with muscle mass loss represents an 83% increase in the risk of death compared to people who do not have either of these conditions.

The combination is so dangerous that, according to the study, it identifies an even greater problem, known as sarcopenic obesity, characterized by the loss of muscle mass while fat gain occurs throughout the body. This is a difficult condition to diagnose and is related to loss of autonomy and a decline in the quality of life of the elderly person, the so-called frailty syndrome, and an increased risk of falls, among other comorbidities.

“In addition to assessing the risk of death associated with abdominal obesity and low muscle mass, we were able to prove that simple methods can detect sarcopenic obesity. This is important because the lack of consensus on diagnostic criteria for this disease hinders its detection and treatment,” says Tiago da Silva Alexandre , professor in the Department of Gerontology at UFSCar and one of the authors of the study, supported by FAPESP. “In this way, our findings allow for greater access for older people to early interventions, such as nutritional monitoring and physical exercise, ensuring an improvement in their quality of life.”

The results, published in the journal Aging Clinical and Experimental Research, were obtained from a 12-year follow-up of 5,440 participants aged 50 or older from the English Longitudinal Study of Ageing ( ELSA ).

Eliminating expensive diagnoses

Sarcopenic obesity is usually diagnosed through complex examinations, such as magnetic resonance imaging (MRI), computed tomography (CT) scans, bioelectrical impedance analysis (BIA), or densitometry, which identify excess body fat and reduced muscle mass and function. However, despite their high accuracy, these tests are expensive and limited to a few healthcare services, making diagnosis a major challenge in clinical practice.

“By correlating the data from the ELSA Study participants, we found that simple measures, such as measuring abdominal circumference and estimating lean mass [using a consolidated equation that utilizes clinical variables such as age, sex, weight, race, and height], showed for the first time that it is possible to screen these individuals early,” celebrates Alexandre.

The relationship between muscle loss and abdominal obesity has an amplified effect on metabolism. “The study revealed that individuals with both conditions had an 83% higher risk of death compared to those without them. We also found that the risk of death was reduced by 40% among those with low muscle mass and no abdominal obesity, a fact that reinforces the potential danger of the coexistence of these conditions. Interestingly, individuals with abdominal obesity but adequate muscle mass were not associated with a higher risk of death,” details Valdete Regina Guandalini , professor at the Federal University of Espírito Santo (Ufes), researcher at the Department of Gerontology at UFSCar, and first author of the article.

Guandalini explains that excess fat intensifies inflammatory processes that trigger metabolic and catabolic changes, further aggravating muscle loss. “In addition to one condition interfering with the other, the fat infiltrates the muscle, occupying its space. This is a systemic and progressive inflammation that directly affects muscle tissue, compromising its metabolic, endocrine, immunological, and functional functions,” he states.

Since the definition of sarcopenic obesity is not yet a consensus among researchers in the field worldwide, the study used simpler measures to define abdominal obesity and muscle loss. Thus, to predict the risk of sarcopenic obesity, the researchers identified abdominal obesity as a waist circumference greater than 102 centimeters for men and 88 centimeters for women. Simultaneously, low muscle mass was defined by a skeletal muscle mass index (obtained by the equation) of less than 9.36 kg/m2 for men and less than 6.73 kg/m2 for women.

The article  Can simple measures from clinical practice serve as a proxy for sarcopenic obesity and identify mortality risk?  can be read at:  https://link.springer.com/article/10.1007/s40520-024-02866-9 .