Walsh & Hoyt: Epidemiology

Autoimmune MG affects all races and ages, with an incidence of 45 per 100,000. There is a female predominance overall, but the sex predilection is age-dependent, with women predominating among younger patients and men among those who are older at diagnosis. The prevalence of MG has been increasing slowly in most epidemiologic studies over the past 50 years, in part due to improved treatment and reduced mortality of the disease. Patients with thymomas are more likely to be over 30 years old, with a mean age at diagnosis of 50 years in one large series, and about equally male and female.