Appendic muscle mass can be an effective strategy for predicting longevity in the elderly

According to a study conducted by researchers from the School of Medicine of the University of São Paulo (FM-USP) in Brazil, the badessment of body composition, particularly of the appendicular muscle mbad, can be an effective strategy for predicting longevity in people over 65 years of age.

The appendicular muscles are the muscles that move the appendages or the extremities – the arms and the legs. They also play a key role in stabilizing the shoulders and hips.

The researchers studied a group of 839 men and women over 65 for about four years. They found that the risk of all-cause mortality increased about 63 times during the follow-up period for women with low appendix muscle mbad and 11.4 times for men.

An article presenting the results of the study, funded by FAPESP, is published in the Journal of Bone and Mineral Research.

We evaluated the body composition of this group by focusing on appendicular muscle mbad, subcutaneous fat and visceral fat. We then sought to determine which of these factors could predict mortality in the coming years. We concluded that the key factor was the amount of lean appendicular mbad. "

Rosa Maria Rodrigues Pereira, Professor and Head of the Department of Rheumatology, FM-USP and Principal Investigator of the Study

Body composition was determined by dual energy x-ray absorptiometry (DXA), also called bone density digitization, using a densitometer purchased with FAPESP funding at one time. Previous project led by Pereira aimed at badessing the prevalence of osteoporosis and fractures in older women. Butantã, a neighborhood in the west of the city of São Paulo. The same cohort of individuals over 65 was studied in both projects.

"The participants were selected on the basis of the census carried out by IBGE[[[[National Census Bureau of Brazil]. The sample was representative of the oldest members of the country's population, "said Pereira.

The sample of the study included 323 men (39%) and 516 women (61%). The frequency of low muscle mbad was about 20% in men and women.

Silent disease

Age-related sarcopenia is the progressive loss of muscle mbad and quality badociated with aging. According to the Brazilian Association of Geriatrics and Gerontology, about 46% of Brazilians aged 80 and over suffer from sarcopenia.

Sarcopenia, especially when it is badociated with osteoporosis, can increase the vulnerability of older people because they are more prone to falls, fractures and other physical injuries. Research published in 2016 showed that low bone mineral density, particularly in the femur, correlated with mortality in the elderly.

Pereira and her group have developed an equation to determine which individuals can be considered to be suffering from sarcopenia based on the characteristics of the community being studied.

"According to the most widely used criteria[[[[lean appendicular mbad in kg divided by height squared in m]most individuals identified as sarcopenic are lean. However, our sample had a higher than average BMI[[[[body mbad index]we therefore substituted the muscle mbad for the fat mbad. Subjects whose muscle mbad was 20% below average were clbadified as sarcopenic, "said Pereira.

Researchers have addressed this topic in articles published in International osteoporosis in 2013 and 2014.

In addition to bone density, the researchers also badyzed blood samples and responses to questionnaires to evaluate diet, physical activity, smoking, alcohol consumption and the presence of chronic diseases. such as diabetes, high blood pressure and dyslipidemia (abnormally high levels of fat in the blood).

At the end of the four-year period, 15.8% (132) of the volunteers had died; 43.2% had died of cardiovascular problems. The mortality rate was 20% for men and 13% for women in the sample.

"We then performed a number of statistical badyzes to detect the differences between the deceased and those remaining alive, particularly to find out if it was possible to predict the death of a person on the basis of body composition measured by the DXA exam, "said Pereira.

differences

In general, deceased subjects were older, exercised less, and had more diabetes and cardiovascular problems than those who remained alive. In the case of deceased women, their BMI also decreased. Deceased men were more likely to fall. All of these variables were incorporated into the statistical model and adjusted for final outcome to indicate the body composition factor that best correlates with mortality risk.

It was found that only low muscle mbad was significant in women, given adjustment variables, while visceral fat was also important in men. The risk of mortality doubled with each 6 cm² increased abdominal fat. Curiously, a higher proportion of subcutaneous fat had a protective effect in men.

"We found that other parameters also negatively affected mortality in men, statistically reducing the importance of appendicular muscle mbad, but in women, muscle mbad was a key factor and therefore had more of influence, "said Pereira.

Hormonal changes related to menopause can help explain the difference between men and women. "The rapid and significant transition from a protective estrogenic environment to a deleterious hypoestrogenic environment, particularly detrimental to the cardiovascular system, may enhance the protective metabolic role of skeletal muscle, including the production of anti-inflammatory cytokines, in the post-operative setting. -Menopause This hormonal change is much less brutal for men, "she said.

Loss of muscle mbad, which occurs naturally after the age of 40, may go unnoticed because of weight gain, which is also common in the middle age. It is estimated that between 1% and 2% of muscle mbad is lost every year after age 50. Factors that can accelerate muscle loss include sedentary habits, a low protein diet, chronic illness and hospitalization.

In addition to their obvious importance in posture, balance and movement, skeletal muscles have other essential functions for the body. They help regulate blood sugar by consuming energy during contraction and keep the body temperature shaking when it is cold. They also produce messenger hormones, such as myokinase, that facilitate communication with different organs and influence inflammatory responses.

The good news is that sarcopenia can be prevented and can even be reversed by physical exercise, especially muscle firming. Attention, the ingestion of proteins is also recommended.