Women who gain weight in the early decades of adulthood dramatically reduce their chances of reaching old age in good health compared with lean counterparts, a study published on Wednesday said.
More than 17,000 American women were monitored for health every two years from around the age of 50 until they reached at least 70, according to the paper released online by the British Medical Journal (BMJ).
The more weight that women gained, the less their chance of "healthy survival," a term meaning that they had no history of 11 major chronic diseases or substantial mental or physical decline at 70 and beyond.
Of the volunteers who survived to at least 70, 1,686 (9.8 percent) met the criteria for "healthy survival".
The overwhelming majority in this group had kept a stable and moderate weight, as determined by body mass index (BMI), investigators found.
Three-quarters of them had either never smoked or had given up smoking by middle age.
After taking several factors into count, the researchers found that every one unit increase in BMI from the start of the study in middle age was linked to a reduction of 12 percent in the odds of "healthy survival."
Even more striking, though, was the impact of weight gain in early adulthood.
For every kilo (2.2 pounds) increase in weight gain after the age of 18, the chance of "health survival" fell by five percent.
Women who were overweight at 18 and gained 10 kilos (22 pounds) or more by middle age were 82 percent less likely to have problem-free health as septuagenarians.
"These data provide evidence that adiposity in mid-life is strongly related to reduced probability of healthy survival among women who live to older ages, and emphasize the importance of maintaining a healthy weight from early adulthood," the authors said.
A Swedish study published in February, also by the BMJ, found that simply being overweight, as opposed to obese, from an early age boosted the risk of premature death by a third, an impact equivalent to smoking up to 10 cigarettes a day.
People who were clinically obese by the age of 18 ran more than double this risk of fatality, and the odds worsened proportionately if they also smoked.