Evaluation of muscle and bone composition and function in aging women with polycystic ovary syndrome

Objective

The potential effects of polycystic ovary syndrome (PCOS) on the musculoskeletal system are not well established. We examined the musculoskeletal system in women with PCOS in their late reproductive years.

Study-design

This cross-sectional study included 34 women with PCOS and 32 control women matched for age and body mass index (BMI).

Main outcome measures

Dual-energy x-ray absorptiometry (DXA) was used for body composition analysis and cross-sectional areas and fat fraction of muscles were assessed by magnetic resonance imaging-proton density fat fraction (MRI-PDFF) of the abdomen and thigh. Muscle strength was measured using an isokinetic dynamometer.

Results

The mean age of the PCOS group was 43 ± 3.7 years and of the control group 42.2 ± 3.5 years. Testosterone, free androgen index, and fasting insulin were higher in PCOS patients than controls (p < 0.001, p = 0.001 and p = 0.032, respectively). Patients and controls had similar values for total abdominal muscle area (TAMA), paraspinal muscle area, thigh muscle area, vertebral MRI-PDFF, thigh and paraspinal muscle MRI-PDFF. There was no difference in DXA-derived muscle and bone composition between the two groups. Body composition parameters measured by MRI and DXA were correlated with BMI and fasting insulin levels, but not with androgen levels in both groups. Subgroup analyses showed that PCOS women with obesity had higher TAMA than controls with obesity (p = 0.012). Apart than higher 60°/sec knee extensor average power in nonobese PCOS (p = 0.049), no difference in muscle mechanical function was detected between PCOS patients and controls.

Conclusion

Musculoskeletal composition and function are similar in PCOS patients and healthy women in late reproductive years. Body composition is linked with obesity and insulin resistance rather than hyperandrogenemia.