Older people with abdominal fat and weak muscles face an increased risk of suffering a deadly fall, according to a according to a new study.
The work, published in the journal Age and Ageing, said that, while a slower gait is a natural part of growing older, if walking speed decreases too quickly, everyday activities — such as crossing a busy street at a crosswalk — can become a significant problem. If the risk of falling increases, a loss of independence is usually not far behind.
“Our comparative analysis showed loss of gait speed occurring mainly when abdominal fat and weak muscles were associated,” said Tiago da Silva Alexandre, last author of the study and a professor at the department of gerontology at the Centre for Biological and Health Sciences, Federal University of São Carlos (UFSCar). “Gait speed didn’t decline so sharply in older people who had only abdominal fat or only weak muscles.”
The study relied on data from 2,294 adults aged 60 or older who enrolled in the English Longitudinal Study of Ageing (ELSA). Subjects were split into four groups based on gait speed and dynapenia (the age-related loss of muscle strength and power): Dynapenic and abdominally obese; dynapenic only; abdominally obese only; and neither dynapenic nor abdominally obese. For the purposes of the study, abdominal obesity was considered to be a waist circumference greater than 102 cm for men and 88 cm for women; dynapenia was grip strength below 26 kg for men and 16 kg for women.
While none of the participants had issues with mobility or gait speed at the outset of the study, many did over the eight-year course of observation — compared to a baseline speed of 0.8 m/s (2.88 km/h) among people without mobility issues — with the greatest decline occurring in those who were both obese and dynapenic. “In the participants with abdominal obesity and muscle weakness, we observed a loss of 0.15 m/s in the eight-year period,” said Roberta de Oliveira Máximo, first author of the paper and a PhD candidate at UFSCar. “At this rate there may come a time when they can’t cross the street in the time allowed by traffic lights.”
According to researchers, the accumulation of abdominal fat can trigger an intense inflammatory cascade that depletes muscle mass and decreases strength. “Hence the concept of dynapenic abdominal obesity, which we’ve been studying in our research group for several years,” Alexandre said. “In previous studies, we found a correlation between these traits, which are very common in the population, and a heightened risk of falls, alterations to the lipid, carbohydrate, glucose and cholesterol metabolism, incapacity and even death. But this is the first study to associate them with mobility.”
The conditions leading to this loss of mobility only increase with age and affect both genders. “Abdominal fat is more common in men,” Alexandre said. “In women, fat tends to accumulate around the thighs and hips but more fat also accumulates in the belly after the menopausal hormone drop. That’s when the inflammatory cascade occurs. The buildup of abdominal fat fuels the inflammation, which consumes muscle mass and reduces muscle strength, while also impairing neural control of the muscles. The outcome is a steady loss of strength and accumulation of fat.”
Health workers need to focus on these factors as precursors to a loss of mobility and, eventually, independence, he said. “Declining gait speed is an important indicator. It suggests mobility problems, a heightened risk of falls and potential incapacity in older people. Our aim in this study was to show the usefulness of this predictor for medical teams. A sizable number of elderly people have weak muscles and accumulated belly fat.
“Both can be corrected by exercise training and diet.”
Dave Yasvinski is a writer with Healthing.ca