Waist-to-hip ratio, body mass index, and subsequent kidney disease and death

Abstract

Background: Chronic kidney disease (CKD) and obesity are important public health concerns. We examined the association between anthropomorphic measures and incident CKD and mortality.

Study design: Cohort study.

Setting & participants: Individual patient data pooled from the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study.

Predictors: Waist-to-hip ratio (WHR), body mass index (BMI).

Outcomes & measurements: Incident CKD defined as serum creatinine level increase greater than 0.4 mg/dL with baseline creatinine level of 1.4 mg/dL or less in men and 1.2 mg/dL or less in women and final creatinine level greater than these levels, and, in separate analyses, estimated glomerular filtration rate (eGFR) decrease of 15 mL/min/1.73 m(2) or greater with baseline eGFR of 60 mL/min/1.73 m(2) or greater and final eGFR less than 60 mL/min/1.73 m(2). Multivariable logistic regression to determine the association between WHR, BMI, and outcomes. Cox models to evaluate a secondary composite outcome of all-cause mortality and incident CKD.

Results: Of 13,324 individuals, mean WHR was 0.96 in men and 0.89 in women and mean BMI was 27.2 kg/m(2) in both men and women. During 9.3 years, 300 patients (2.3%) in creatinine-based models and 710 patients (5.5%) in eGFR-based models developed CKD. In creatinine-based models, each SD increase in WHR was associated with increased risk of incident CKD (odds ratio, 1.22; 95% confidence interval [CI], 1.05 to 1.43) and the composite outcome (hazard ratio, 1.12; 95% CI, 1.06 to 1.18), whereas each SD increase in BMI was not associated with CKD (odds ratio, 1.05; 95% CI, 0.93 to 1.20) and appeared protective for the composite outcome (hazard ratio, 0.94; 95% CI, 0.90 to 0.99). Results of eGFR-based models were similar.

Limitations: Single measures of creatinine, no albuminuria data.

Conclusions: WHR, but not BMI, is associated with incident CKD and mortality. Assessment of CKD risk should use WHR rather than BMI as an anthropomorphic measure of obesity.

Figure 1

Derivation of the study cohorts.

Figure 2

Log-transformed adjusted odds and 95% confidence interval (dashed line) for developing kidney disease associated with (a) waist to hip ratio and (b) body mass index (based on serum creatinine models). Hatch marks represent the relative proportion of individuals at any given waist to hip ratio or body mass index. Models are plotted as restricted cubic splines with 4 knots and are adjusted for age, sex, race, education, cardiovascular disease, diabetes, hypertension, smoking, alcohol, systolic blood pressure, HDL and total cholesterol, albumin, hematocrit, baseline kidney function, and study of origin. P-values for linearity are 0.6 and 0.9 respectively.

Figure 2

Log-transformed adjusted odds and 95% confidence interval (dashed line) for developing kidney disease associated with (a) waist to hip ratio and (b) body mass index (based on serum creatinine models). Hatch marks represent the relative proportion of individuals at any given waist to hip ratio or body mass index. Models are plotted as restricted cubic splines with 4 knots and are adjusted for age, sex, race, education, cardiovascular disease, diabetes, hypertension, smoking, alcohol, systolic blood pressure, HDL and total cholesterol, albumin, hematocrit, baseline kidney function, and study of origin. P-values for linearity are 0.6 and 0.9 respectively.