Life expectancy for women who live to age 50 is going up around the world, but poor and middle-income countries could easily make greater gains, according to a new World Health Organization report.

Heart disease, stroke and cancer kill most women over 50, said Dr. John R. Beard, director of the W.H.O.'s department of aging, so countries should focus on lowering blood pressure with inexpensive drugs and screening for cervical and breast cancer. Those diseases can be prevented or treated, said Dr. Beard, who was also an author of the study, which was published in the Bulletin of the World Health Organization.

Getting women to avoid smoking, excessive drinking and being obese is also crucial, he said.

Japanese women live the longest on average. But women in most countries now live longer than they did 40 years ago, thanks to progress against infectious diseases like flu, tuberculosis and pneumonia. Some countries have improved less than others: South Africa has an AIDS epidemic, Russian women suffered when the Soviet health system collapsed, and growing prosperity in Mexico has led to more lung cancer and obesity-related diabetes.

The bulletin also included a report on older women’s right to protected sex, also co-authored by Dr. Beard.