Middle-Aged Muscle Mass Tied to Future CVD Risk in Men

Higher levels of lean muscle mass in middle age may be linked to lower 10-year cardiovascular disease (CVD) risk, regardless of traditional risk factors such as diet, income, smoking, obesity, diabetes, high blood pressure, and abnormal cholesterol levels, a study found.

Stefanos Tyrovolas, PhD, of the Centre for Biomedical Research in Mental Health in Barcelona, Spain, and colleagues with the ATTICA study published their findings online today in the Journal of Epidemiology and Community Health.

"The present study reports an inverse association between skeletal muscle mass [SMM] preservation and the 10 year CVD incidence in a large community-based cohort of CVD-free adults 45+ years old," the authors explain.

Lean muscle mass accounts for approximately half of body mass and plays an important role in metabolism and control of blood sugar levels. Starting at around age 30 years, lean muscle mass starts to decrease, and this decline may continue at a rate of approximately 3% per decade.

Until now, most studies have examined the association between muscle mass and CVD in people with existing CVD. The new study looked at people without CVD at baseline. The findings have implications for prevention of heart attack and stroke, at least in men.

"These results point to the importance of skeletal muscle mass preservation in relation to CVD risk and the public health actions that need to be taken to  improve CVD health in middle aged and older populations," the authors add.

Decreased lean muscle mass has been linked to a number of health problems, including disability, poor mental health, diabetes, CVD, and death; therefore, interventions that target the decline in lean muscle mass may have further reaching implications for CV and overall health.

The authors suggest that health campaigns aimed at improving nutrition and protein intake, as well as exercise with resistance training, may prevent age-related deterioration in muscle mass. However, more study is needed about the impact of these strategies on CVD.

The prospective study included 1019 participants who did not have CVD at baseline and were aged 45 years and older (485 women, 534 men). At baseline, participants reported physical activity, how closely they followed the Mediterranean diet, and smoking.  Researchers also measured CVD risk factors, including blood pressure, body mass index, fasting lipids and glucose, and markers of inflammation. They calculated lean muscle mass using a previously published equation and adjusted these values for body mass index to obtain a skeletal muscle mass index.

The cohort had a 10-year incidence of fatal or non-fatal CVD of 26.7%.  Compared with individuals with the lowest levels of lean muscle, those with the highest levels had 81% lower 10-year risk for a CVD event such as stroke or heart attack (hazard ratio [HR], 0.19). Rates of these events were also lower among those with the highest levels of lean muscle (14% vs 31.7%).  

Further analyses adjusted for gender, education, socioeconomic level, smoking, physical activity, Mediterranean diet, hypertension, diabetes, hypercholesterolemia, and obesity showed that higher levels of smooth muscle mass at baseline were linked to significantly lower 10-year CVD risk (HR, 0.06).  

In general, those with the highest levels of lean muscle mass were younger, male, smokers, physically active, educated, with a high socioeconomic level, and high adherence to the Mediterranean diet. They were also less likely to be obese, have diabetes or high blood pressure, compared with those with the lowest levels of lean muscle mass (all P < .07).

Men had almost four times higher 10-year CVD risk compared with women (HR, 3.7).

Further analyses that looked at women and men separately showed that 10-year CVD incidence was significantly linked to lean muscle mass in men but not in women (HR, 0.03 and HR, 0.18, respectively).

Although increased muscle mass was significantly linked to lower markers of inflammation (CRP, IL-6, fibrinogen all P < 0.001), these factors did not influence the relationship between lean muscle and CVD risk.

Hormonal differences between women and men play a role in how the two sexes age differently and could explain the different results for men and women. In general, men often have higher lean muscle mass than women, which could also play a role, according to the authors. 

The researchers measured lean muscle mass at baseline only; therefore, the study could not evaluate how changes in lean muscle over time affect CVD risk. Also, the observational nature of the study means that results cannot prove higher levels of lean muscle mass in middle age protect against CVD events. 

The study was funded by the Hellenic Cardiovascular Society, Hellenic Atherosclerosis Society, and the European Union's Horizon 2020 research and innovation program. The authors have disclosed no relevant financial relationships.

J Epidemiol Community Health. Published online November 11, 2019. Full text

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Cite this: Middle-Aged Muscle Mass Tied to Future CVD Risk in Men - Medscape - Nov 11, 2019.