New study quantifies benefits of being thin

It should come as no surprise that maintaining a healthy weight throughout adulthood significantly boosts the odds of enjoying a healthy old age. A study published Tuesday by the British Medical Journal quantifies just how helpful a trim body can be.

Women who were obese at midlife were 79 percent less likely to be healthy at age 70 compared with women who were lean in their 40s and 50s. Even worse were those women who were obese at age 18 and then gained more than 22 pounds by middle age; their odds were reduced by 82 percent.

The results were calculated by examining data from American women who participated in the Nurses’ Health Study. Researchers from Harvard and the University of Warwick in England looked at the 17,065 nurses who made it to age 70 and compared the weight trends of the 9.9 percent who were considered “healthy” with those of the rest of the group.
 
What did it mean to be healthy? In this study the researchers gave the designation to women who did not suffer from any of 11 major health problems, including diabetes, lung disease and cancer (except melanoma). They also had to be in good mental health and be free of major limitations in physical or cognitive function.

The healthiest nurses were those who had a body mass index between 18.5 and 22.9 at age 18 and didn’t gain weight over the next 30 or so years. For every one-unit increase in BMI (about 5 or 6 pounds for a person of healthy weight), the odds of being healthy at age 70 fell by 12 percent.

In addition, women who maintained a stable weight regardless of initial BMI fared better than women who accumulated pounds over the years. For every 2.2 pounds gained, the odds of being healthy at age 70 fell by 5 percent, the researchers found.

Though BMIs as high as 25 are considered healthy, the researchers found that women who had BMIs of 23 to 24.9 at midlife were 15 percent less likely to reach age 70 in prime condition compared with their leaner counterparts.

by Karen Kaplan – Sept. 30, 2009 12:00 AM
Los Angeles Times