FRIDAY, July 27, 2012 (HealthDay News) -- Women who have their last child after age 30 have a reduced risk of endometrial cancer, according to a new study.
Endometrial cancer occurs in the tissue lining the uterus (womb) and is the most common gynecological cancer in the United States.
Researchers examined data from more than 8,600 women with endometrial cancer and more than 16,500 without the disease. The analysis revealed that the risk of endometrial cancer decreased after age 30 by about 13 percent for each five-year delay in last births.
Compared to women who had their last child before age 25, those who had their last child between ages 30 and 34 had a 17 percent reduced risk of endometrial cancer, those who gave birth to their last child between ages 35 and 39 had a 32 percent lower risk, and those who gave birth at age 40 or older had a 44 percent lower risk.
This protection persisted for many years and was the same for both types of endometrial cancer: the more common type 1 endometrial cancer and the more rare and aggressive type 2.
"While childbearing at an older age previously has been associated with a lower risk of endometrial cancer, the size of this study definitively shows that late age at last birth is a significant protective factor after taking into account other factors known to influence the disease -- body weight, number of kids and oral contraceptive use," principal investigator Veronica Setiawan, an assistant professor of preventive medicine at the Keck School of Medicine at the University of Southern California, said in a Keck news release.
However, when the researchers looked at the women by race/ethnicity, they found that association between older age at last birth and protection against endometrial cancer was evident among white and Hispanic women, but not among the small number of black women in the study. This finding warrants further research with larger groups of black women, Setiawan said.
The study was published online July 23 in the American Journal of Epidemiology.
Endometrial cancer is the fourth most common cancer diagnosed in American women. In 2012, more than 47,000 U.S. women will be diagnosed with uterine cancers and more than 8,000 will die of such cancers, according to the American Cancer Society.
The American Cancer Society has more about endometrial cancer.