Background: Hypogonadism has been described in patients with myotonic muscular dystrophy type 1 but has not been evaluated in other myopathies.
Methods: We measured total and free serum testosterone levels in 59 men with myotonic muscular dystrophy type 1 (N = 12), facioscapulohumeral muscular dystrophy (N = 11), dystrophinopathy (N = 12), metabolic myopathy (N = 7), and inclusion body myositis (N = 17) and compared these with the normal reference interval.
Results: Thirty-two of the 59 (54%) participants had low total testosterone, 23 (39%) had low total and free values, and 5 (8%) had low free with normal total levels. There were no significant differences in the prevalence of hypogonadism between those with myotonic muscular dystrophy type 1 and the other groups even after considering age as a confounder.
Conclusions: Hypogonadism is common in men with myopathies, and with the importance of testosterone in the maintenance of muscle mass, treatment of hypogonadism should be considered.