Race and Medicine

Race and Medicine

Disclosures: The authors report no relevant financial disclosures.
September 30, 2020
2 min read

Midlife obesity shows varying impacts on kidney disease risk based on sex, race

Disclosures: The authors report no relevant financial disclosures.
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Researchers from Johns Hopkins found both Black and white women who were obese at midlife had increased risks for eGFR decline and end-stage kidney disease after 30 years of follow-up.

These results differed for men, however, with only Black men who were obese at midlife having an increased risk for ESKD later in life.

Midlife obesity and kidney disease risk

According to Zhi Yu, BM, MS, and colleagues, obesity is a factor that can be targeted to prevent kidney function decline, potentially decreasing the risk for future kidney disease.

“Higher body-mass index has been associated with increased risk of incident chronic kidney disease (CKD), including greater kidney function decline among healthy, young adults,” the researchers wrote. “However, BMI may not be the best marker of obesity-related risk, and associations may differ across sex and race. Much less is known about the relationship between other obesity indicators, such as waist-to-hip ratio and the recently developed predicted percent fat, and long-term kidney function decline.”

Using data from the Atherosclerosis Risk in Communities study, Yu and colleagues evaluated the associations between the three aforementioned measurements of obesity and eGFR trajectories, while also estimating the associations between obesity and ESKD risk (total of 10,222 white and 3,274 Black participants; mean age at baseline, 53 years; median eGFR, 103 mL/min/1.73m2; median BMI, 26 kg/m2). Adjustments were made for age, center, smoking and coronary heart disease; patients with diabetes were excluded.

In 30 years of follow-up, researchers found all midlife obesity measures were associated with eGFR decline in white and Black women, but that these associations were not consistent in men. More specifically, only waist-to-hip ratio and predicted percent fat were associated with eGFR decline in Black men, while no measures of obesity were associated with eGFR decline in white men.

They further observed that obesity indicators were independently associated with risk for ESKD in all sex-race groups, with the exception of white men.

“The lack of association in white men may be due to the combination of lower obesity and lower kidney disease progression among whites reducing power,” the researchers suggested of the findings. “Alternatively, there may be greater variation in muscle mass as a non-GFR influence of creatinine among men compared to women.”

According to Yu and colleagues, further research is required to more precisely determine the reasons for the observed lack of association between obesity and kidney disease risk in white men.

“Existing research on kidney function trajectories has been more focused on individuals with kidney diseases rather than those with preserved kidney function,” the researchers concluded. “Our study addressed this gap by evaluating baseline obesity categories as a predictor of kidney function decline among individuals with preserved kidney function.”