To select the age- and gender-matched subsample of ALC subjects, all ALC subjects less than the mean age (25.6 years) of the HC group were included. The remainder of the ALC subjects who were younger than the maximum age (53.3 years) of the HC group were assigned random numbers and sequentially added to the ALC subsample until the two groups, (ALC, n=255; HC, n=87) did not differ by age or gender.
