Researchers at Johns Hopkins University School of Medicine have found that the APOE-4 gene may shorten the lifespan of men -- but not women -- who develop Alzheimer's disease.

Past studies have found that the gene is more frequent in patients with the disease than in the general public, but researchers have been unclear on whether it affects the rate of Alzheimer's progression or survival.

The researchers examined 125 men and women with probable Alzheimer's disease who were enrolled in the Johns Hopkins Alzheimer's Disease Research Center between November 1984 and March 1987.

Patients were followed at six-month intervals, and grouped according to whether or not they carried the APOE-4 gene.

Results of the study, appearing in Neurology, found that men who did not carry the gene lived an average of 15 years after diagnosis, while men who carried the gene survived for about 11 years.

Although the gene appeared to shorten the overall life span in men, the average rate of survival after the actual onset of the disease did not differ by sex. Results of the study also showed no differences between subgroups in education, duration of the disease upon entering the study, or the severity of dementia.

Men were diagnosed with the disease at a younger age than women, the researchers said, but both men and women with the APOE-4 gene were "approximately three years older at onset of (Alzheimer's disease) and at entry to the study than the (APOE-4) negative group."

Other Sources: Neurology