In MG, which statement about epidemiology is most accurate?

• A. Incidence increases with age and onset is younger in women
• B. Incidence decreases with age and onset is later in women
• C. Incidence is constant across ages with no sex difference
• D. Only occurs in elderly men

Answer: (A)

Myasthenia gravis shows a distinct age–sex pattern: there are two common onset groups, with younger onset in women and a later onset more typical in men. This means that while younger women are disproportionately affected in earlier decades, there are increasing cases as people age due to late-onset MG, causing overall incidence to rise with age. So the statement that incidence increases with age and onset is younger in women best fits what we know about MG’s epidemiology: women tend to become affected earlier, and older ages bring more new cases. The other ideas—that incidence is constant across ages with no sex differences, that it occurs only in elderly men, or that onset in women is later—don’t match the known pattern of MG.