Determining the extent of the damage that bodybuilders inflict on themselves is difficult, in part because there is little interest in financing studies on such an extreme group, and because bodybuilders are not always honest about what they take. That is why a case study published last month by a top kidney journal is generating interest in the nephrology and bodybuilding communities. It is among the first to assert a direct link between long-term steroid use and kidney disease.

Image Patrick Antonecchia, a powerlifter and strong man competitor, ended his steroid use and career about a year ago. Credit... Joyce Dopkeen for The New York Times

The study began 10 years ago when a kidney pathologist at Columbia University Medical Center in New York noticed that a bodybuilder had an advanced form of kidney disease. Curious, she started looking for similar cases and eventually studied 10 men with serious kidney damage who acknowledged using steroids. Nine were bodybuilders and one was a competitive powerlifter with a similar training routine.

All 10 men in the case series, published in November by the Journal of the American Society of Nephrology, showed damage to the filters of the kidney. Nine had an irreversible disease known as focal segmental glomerulosclerosis  the same disease contracted by Wheeler  even though the men in the study did not have other apparent risk factors. Their disease was worse than in obese patients with a higher body-mass index, suggesting that steroids  combined with the other practices  might be harming the kidneys.

Among the study’s most persuasive details is the story of a man, 30 years old at the time, who damaged his kidneys after more than a decade of bodybuilding. The patient’s condition improved after he stopped using the drugs, discontinued his regimen and lost 80 pounds. But it worsened after the man, who became depressed, returned to bodybuilding and steroids.

“These patients are likely the tip of the iceberg,” said Vivette D. D’Agati, the lead researcher. “It’s a risk. A significant risk.”