Abdominal obesity and muscle loss increases the risk of death by 83% after age 50

A study by researchers at the Federal University of São Carlos (UFSCar) in Brazil, in partnership with University College London (UCL) in the United Kingdom, has concluded that the combination of abdominal fat and muscle loss increases the risk of death by 83%, compared to people without these conditions.

This combination is so dangerous that it identifies an even greater problem: sarcopenic obesity. This condition is characterised by loss of muscle mass while gaining fat throughout the body. It is a difficult condition to diagnose, and it is related to loss of autonomy and a worsening quality of life in older adults. It is also known as frailty syndrome and is associated with an increased risk of falls and 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 be used to detect sarcopenic obesity. This is important because the lack of consensus on diagnostic criteria for this disease makes it difficult to detect and treat," Tiago da Silva Alexandre, a professor in the Department of Gerontology at UFSCar and one of the authors of the study. Thus, our findings allow older adults to have greater access to early interventions, such as nutritional monitoring and physical exercise, ensuring an improvement in quality of life."

The results were obtained from 12 years of follow-up of 5,440 participants in the English Longitudinal Study of Ageing (ELSA) aged 50 years or older. Abdominal obesity and low muscle mass were respectively defined based on high waist circumference and low skeletal muscle mass index (SMMI) determined by an equation. The sample was divided into four groups: non-low muscle mass/non-abdominal obesity (NLMM/NAO), non-low muscle mass/abdominal obesity (NLMM/AO), low muscle mass/non-abdominal obesity (LMM/NAO), and low muscle mass/abdominal obesity (LMM/AO).

They found LMM/AO increased the risk of death by 83% (HR:1.83; 95%CI: 1.35–2.66) compared to those in the NLMM/NAO group. AO alone was not associated with a greater risk of mortality (HR:1.09; 95%CI: 0.93–1.27), whereas LMM alone increased the risk by 40% (HR:1.40; 95%CI:1.18–1.66).

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

The relationship between muscle mass 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 who didn't have them. We also found that the risk of death was reduced by 40% among those with low muscle mass and no abdominal obesity, a finding that reinforces the potential danger of the coexistence of the conditions.

"Interestingly, individuals with abdominal obesity but adequate muscle mass weren't associated with an increased risk of death," explained Valdete Regina Guandalini, a professor at the Federal University of Espírito Santo (UFES) and researcher in the Department of Gerontology at UFSCar. She is also the first author of the article.

She added 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, fat infiltrates the muscle and takes up its space. This systemic and progressive inflammation directly affects muscle tissue, compromising its metabolic, endocrine, immunological, and functional capabilities," she says.

Since there is no consensus among researchers worldwide on the definition of sarcopenic obesity, the study used simpler measures to define abdominal obesity and muscle mass loss. Thus, to predict the risk of sarcopenic obesity, the researchers identified abdominal obesity as having an abdominal circumference greater than 102cms for men and 88cms for women. At the same time, low muscle mass was defined as a skeletal muscle mass index of less than 9.36 kg/m² for men and less than 6.73 kg/m² for women.

The findings were reported in the paper, ‘Can simple measures from clinical practice serve as a proxy for sarcopenic obesity and identify mortality risk?’ published in Aging Clinical and Experimental Research. To access this paper, please click here