The researchers analyzed information from the Medical Research Council National Survey of Health and Development, a sample of children born in one week in March 1946 in England, Scotland, and Wales.
A total of 4,584 participants had available data, including body mass index at ages 20, 26, 36, 43, 53, and 60–64 years.
The researchers found that participants who were overweight beginning early in adulthood (ages 26–36) were twice as likely to have CKD at age 60–64 compared with those who first became overweight at age 60–64 years or never became overweight. The link between overweight and CKD was only in part explained by taking diabetes and hypertension into account. Larger waist-to-hip ratios ("apple-shaped" bodies) at ages 43 and 53 years were also linked with CKD at age 60–64 years.
"We estimated that 36% of CKD cases at age 60–64 in the current U.S. population could be avoided if nobody became overweight until at least that age, assuming the same associations as in the analysis sample," said Dorothea Nitsch, London School of Hygiene & Tropical Medicine. "To our knowledge we are the first to report how age of exposure to overweight across adulthood may affect kidney disease risk."
It is unclear whether the timing of overweight onset or the duration of being overweight drives the link with CKD seen in the study. Either explanation suggests that preventing excess weight gain in early adulthood could have a considerable effect on the prevalence of CKD. Doing so appears to have a larger effect than any treatment for CKD known to date, the researchers said.