Vasomotor symptoms and sarcopenia assessed by skeletal muscle

Vasomotor symptoms (VMS) are significantly less common in menopausal women with sarcopenia than in those without, according to a study conducted in the Republic of Korea.

The study in the journal Menopause also found that VMS is linked to paraspinal muscle mass via the skeletal muscle index (SMI).1

The study comprised 295 Korean menopausal women, aged 40 to 65 (mean age 54.93 years), who were self-referred for a routine health check, including abdominal computed tomography (CT), at Korea University Anam Hospital in Seoul between January 2014 and May 2016.

The decision to undergo CT was at the sole discretion of the patient.

The cross-sectional areas of adipose and skeletal muscles were measured at the third lumbar spine vertebra (L3) level via CT.

The SMI is defined as the sum of the skeletal muscle area: cm2/height2 (m2), whereas sarcopenia was identified by an SMI of <34.9 cm2/m2. VMS was assessed via the Menopause Rating Scale (MRS).

Among the cohort, 54.2% (n = 160) reported VMS: 86 mild, 48 moderate, 18 severe, and 8 very severe cases.

Sarcopenia was more likely in women without VMS than in those with VMS: 18.5% vs. 6.9%, respectively.

In addition, the frequency of sarcopenia was inversely connected to the prevalence of VMS: odds ratio (OR) 0.32; 95% confidence interval (CI): 0.15 to 0.67.

The paraspinal muscle index was also positively associated with the prevalence of VMS: OR 1.06; 95% CI = 1.01-1.11.

This muscle index finding was calculated after adjusting for age, body mass index (BMI), waist circumference, adipose tissue area, history of hormone therapy, systolic and diastolic blood pressures, total cholesterol, insulin resistance, alcohol intake, and exercise.

Skeletal muscle mass was independently linked to VMS. According to the authors, most previous studies gauging the association between VMS and being overweight/obese have evaluated anthropometric measures like BMI, “which are limited in assessing body composition.”

The paraspinal muscles are an intermediate layer of the intrinsic back muscles that run lengthwise along the spinal column and are implicated in low back pain. But the authors were unable to precisely explain why the paraspinal muscle index was independently connected to VMS in their study.

Some studies have proposed that subcutaneous adipose tissue provides an insulating effect and induces malfunction in response to core temperature changes; however, it is unknown whether trunk muscle masses could alter the core temperature and VMS severity.

Because some recent studies show increased fatty infiltration in the paraspinal muscles in women with low back pain, future studies might need to assess intramuscular adipose tissue content, along with muscle mass.

Due to the reported higher ratio of androgens to estrogens in middle-aged women with VMS, the authors hypothesize that androgen levels or the androgen-to-estrogen ratio may contribute to the association between VMS and muscle mass changes; yet they were unable to confirm this finding because of the lack of laboratory data on sex hormone levels in their study.

“Considering that VMS are some of the major reasons that middle-aged women visit hospitals, healthcare providers should consider that menopausal women without VMS also need to be screened carefully given the high risk of sarcopenia observed in this study,” wrote the authors.

The authors said additional longitudinal studies are needed to investigate the causal relationships between VMS, skeletal muscle indices, fat and muscle distribution, and sarcopenia, plus the underlying mechanisms.

References:

1. Ryn KJ, Kim HK, Lee YJ, et al. Association between vasomotor symptoms and sarcopenia assessed by L3 skeletal muscle index among Korean menopausal women. Menopause. Published online November 8, 2021. doi:10.1097/GME.0000000000001879