THURSDAY, April 4 (HealthDay News) -- Overweight young adults are much more likely than those who are not overweight to develop kidney disease by the time they are seniors, according to a new study.
Researchers analyzed data from a long-term study of nearly 4,600 people in the United Kingdom who were born in March 1946. The data included the participants' body-mass index at ages 20, 26, 36, 43, 53 and 60 to 64. Body-mass index is a measurement of body fat based on height and weight.
Participants who were overweight in early adulthood -- ages 26 or 36 -- were twice as likely to have chronic kidney disease at ages 60 to 64, compared with those who were never overweight or did not become overweight until ages 60 to 64.
Having a larger waist-to-hip ratio (called an apple-shaped body) during middle age also was associated with chronic kidney disease at ages 60 to 64, according to the study, which was published online April 4 in the Journal of the American Society of Nephrology.
The researchers calculated that 36 percent of chronic kidney disease cases in people aged 60 to 64 could be prevented if nobody became overweight until at least that age.
"To our knowledge we are the first to report how age of exposure to overweight ... may affect kidney disease risk," study author Dr. Dorothea Nitsch, of the London School of Hygiene & Tropical Medicine, said in a journal news release.
It isn't clear whether being overweight in early adulthood or the length of time people are overweight is behind the increased risk of chronic kidney disease at ages 60 to 64. Either explanation suggests that preventing excess weight gain in early adulthood could greatly reduce a person's risk of developing chronic kidney disease, the researchers said.
They added that preventing excess weight gain in early adulthood appears to have a larger effect than any known treatment for chronic kidney disease.
Although the study tied being overweight in young adulthood to kidney disease later in life, it did not establish a cause-and-effect relationship.
More than 1.4 billion adults worldwide were overweight in 2008, including about 500 million who were obese, according to the World Health Organization.
The National Kidney Foundation has more about chronic kidney disease.