January 19 (HealthDay News) -- Women appear to have less access than their male counterparts to kidney transplants as they age, a new study shows.

The report, published in the March edition of the Journal of the American Society of Nephrology, found that a woman's access to donated kidneys seems to decrease starting in those aged 46 to 55. That group had only a 3 percent lower chance of moving from the waiting list for a kidney to the actual transplant list but the disparity grew much greater in older groups -- 15 percent less access for those aged 56 to 65, 29 percent for 66- to 75-year-olds, and 59 percent for women over age 75.

Once on the list for a transplant, though, a woman's odds of getting a new kidney were equal to a man's. The researchers found that women in this study had an equal to slightly better survival benefit from a kidney transplant than men in all age groups, a finding that showed no reason to limit a woman's access to a transplant because of age.

"Knowing that the gender disparity is limited to older women indicates that efforts should be made to identify specific differences between older men and older women rather than general differences between all men and women in an effort to minimize the gender disparity in access to transplantation," study leader Dr. Dorry Segev, of the Johns Hopkins Medical Institutions in Baltimore, said in a news release issued by the journal.

The findings were based on national data from 563,197 patients with end-stage kidney disease diagnosed between 2000 and 2005.

SOURCE: American Society of Nephrology, news release, Jan. 7, 2009