Parental age and birth order in Alzheimer's disease: a case-control study in the Saguenay-Lac-St-Jean area (Quebec, Canada).

Parental age at the time of birth of 133 clinically diagnosed Alzheimer patients from the Saguenay-Lac-St-Jean area (Quebec, Canada) were compared with those of 6 control groups formed out a population registry. The birth order of the Alzheimer patients was also analyzed. The results did not show any parental age or birth order effect, which is in agreement with previous reports. The importance of control selection in such studies is stressed.