What is the common age range for the onset of atrial fibrillation?

The onset of atrial fibrillation commonly occurs in older adults, particularly those over 65 years of age. This condition is linked to age-related changes in the heart, such as fibrosis and structural remodeling, which increase the risk of electrical conduction abnormalities. As people age, the prevalence of various cardiovascular diseases also rises, leading to a higher incidence of atrial fibrillation. Research consistently shows that older adults are more likely to experience episodes of this arrhythmia compared to younger populations, making age over 65 a critical factor in understanding its onset.

The other choices, while representing different age groups, do not align with the established clinical observations regarding the epidemiology of atrial fibrillation. Atrial fibrillation is rare in children, and while it can occur in middle-aged adults, the incidence significantly increases with age, especially post-65. Young adults are also less frequently affected, as the cumulative risk factors associated with atrial fibrillation typically accumulate over decades. Thus, the distribution of atrial fibrillation incidence clearly illustrates that older adults are the demographic most commonly impacted.