Women who are obese in middle age may live to be at least 70 but they are nowhere near as healthy as women who kept in good shape, U.S. researchers reported on Tuesday.

An ongoing giant study of American nurses showed that only about 10 percent who made it to age 70 could be considered in top shape. Women who steadily gained weight from age 18 on ended up in the worst shape, the researchers said.

Most had some kind of physical or mental limitation, and more than a third had both chronic diseases and also mental or physical limitations.

Given that more and more Americans are surviving to older ages and, at the same time, gaining weight, our results might be particularly important with respect to clinical or public health policies and deserve further investigation and confirmation in additional studies, the researchers wrote in the British Medical Journal.

Qi Sun and colleagues at the Harvard School of Public Health and at Brigham and Women's Hospital in Boston studied more than 17,000 women who have been taking part in the ongoing Nurses Health Study.

These women were on average 50 and healthy in 1976. The researchers looked at various aspects of their lives and lifestyles, including smoking and weight.

Of the women who survived until at least age 70, 1,686 (9.9 percent) met our criteria for healthy survival, the researchers wrote.

The fatter the women were at 50, the more likely they were to have a range of diseases and conditions later in life, the researchers found.

Obese women in middle age were 79 percent less likely be healthy at age 70, the researchers found.

Nearly 60 percent of the women had cognitive, physical or mental health limitations but no diagnosed major diseases; and 37 percent had both chronic diseases and cognitive, physical and mental health limitations, the researchers said.

In addition, the more weight gained from age 18 until mid-life, the less likely was healthy survival after the age of 70, the researchers wrote.

The women least likely to end up healthy in old age were already overweight at 18 and gained as little as 10 kg, or just 22 pounds, by age 50 compared to women who stayed lean all their lives.

The findings emphasize the importance of maintaining a healthy weight from early adulthood, the researchers wrote.

Medicine