Obesity, Weight Distribution and Risk of Acute Kidney Injury in the Atherosclerosis Risk in Communities (ARIC) Study
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Date
2015-05-01
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Johns Hopkins University
Abstract
Background: Elevated body mass index (BMI) has been associated with acute kidney injury (AKI) in surgical and critically ill patients. Less is known about the relationship between obesity and AKI in the population-based setting.
Study Design: Prospective cohort study.
Setting & Participants: Participants of the Atherosclerosis Risk in Communities (ARIC) study who attended a study visit between 1996 and 1998.
Predictors: BMI and waist-to-hip ratio (WHR) at baseline.
Outcome: AKI occurring during subsequent hospitalizations.
Measurements: Cox proportional hazards models included the following variables: BMI (modeled as a linear spline, with knot at 30 kg/m2), WHR, age, sex, race, hypertension, diabetes, coronary artery disease, estimated glomerular filtration rate, and albuminuria. Participants were censored at 12/31/2010, death, or end-stage renal disease.
Results: At baseline, participants’ mean age was 63.3 years, mean BMI was 28.8 kg/m2, and mean WHR was 0.92 for women and 0.98 for men. Over 12 years of follow-up, 824 participants developed AKI. There was a U-shaped relationship between BMI and AKI. For BMI > 30 kg/m2, a 1 kg/m2 increase was associated with a 7% increase in risk of AKI (adjusted hazard ratio (aHR) 1.07, 95% CI: 1.06, 1.09, p < 0.001); for BMI < 30 kg/m2, a 1 kg/m2 increase was associated with a 3% decrease in AKI risk (aHR 0.97, 95% CI: 0.94, 0.99, p = 0.04). Elevated WHR was linearly associated with AKI. A 0.01 increase in WHR was associated with a 3% increase in risk of AKI (aHR 1.03, 95% CI: 1.01, 1.04; p < 0.001). There was no statistically significant interaction between WHR and BMI.
Limitations: BMI and WHR were measured only at baseline.
Conclusions: In a population-based cohort, higher BMI over 30 kg/m2 and higher WHR were independently associated with increased risk of hospitalized AKI. Obese individuals may benefit from strategies to prevent AKI.
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Keywords
Acute kidney injury, obesity, epidemiology