Table 1.

Baseline characteristics of patients with Alzheimer disease

Variable (n = 641)	Value	Range
Age, years	73 (8.50)	43-93
Female	68%
Education, years	14 (3.56)	0-29
Early exposure index, years	0.5 (0.27)	0-1
Duration of symptoms before initial visit, years	3.7 (2.29)	0.5-13
Follow-up time, years	3.0 (1.94)	0.8-13.4
Total number of visits	3.4 (1.64)	2-11

For all continuous variables, values are presented as mean (standard deviation).