Hypogonadism, quadriceps weakness, and exercise intolerance in chronic obstructive pulmonary disease

Abstract

Rationale: Circulating levels of testosterone and gonadotrophins of patients with chronic obstructive pulmonary disease (COPD) have never been compared with those of elderly men with normal pulmonary function. Moreover, the relationship of hypogonadism with quadriceps muscle weakness and exercise intolerance has been studied scarcely in men with COPD.

Objectives: To compare circulating levels of hormones of the pituitary-gonadotrophic axis of men with COPD with those of age-matched control subjects. Moreover, to study the relationship of hypogonadism with quadriceps muscle force, 6-min walking distance, and systemic markers of inflammation in the patients.

Methods and measurements: Circulating levels of follicle-stimulating hormone, luteinizing hormone, testosterone, and sex hormone-binding globulin were determined, and free testosterone was calculated in 78 patients (FEV1: 44 +/- 17% of the predicted values) and 21 control subjects. Moreover, quadriceps muscle force, 6-min walking distance, number of pack-yr, and systemic inflammation were determined.

Main results: Follicle-stimulating hormone and luteinizing hormone were higher in the patients, whereas testosterone was lower (p < or = 0.05). The latter finding was also present in 48 non-steroid-using patients with normal blood gases. Low androgen status was significantly related to quadriceps muscle weakness (r = 0.48) and C-reactive protein (r = -0.39) in the patients, but not to exercise intolerance, the number of pack-yr, or increased circulating levels of interleukin 8 or soluble receptors of tumor necrosis factor alpha.

Conclusions: In contrast to exercise intolerance, quadriceps muscle weakness is related to low circulating levels of testosterone in men with COPD.