Birth order and maternal age effect in dementia of the Alzheimer type.

Birth order and maternal age were unrelated to dementia of the Alzheimer type (DAT) in a study of 42 probands with clinically diagnosed DAT and 42 age-matched control subjects. Mean birth order in both groups did not differ significantly from the general population. The mean maternal age for the DAT probands was neither significantly different from that for the controls nor from that for the 1920 U.S. Caucasian population. Since the diagnostic criteria for the DAT group were only clinical, an additional 14 probands with DAT confirmed by autopsy were studied. Mean maternal age did not differ significantly in this group from the controls, the general population, or the clinically diagnosed DAT group. It was concluded that maternal age and birth order bear no special relationship to DAT in this sample.