The association of exercise and sedentary behaviours with incident end-stage renal disease: the Southern Community Cohort Study

Abstract

Objective: To examine whether lifestyle factors, including sedentary time and physical activity, could independently contribute to risk of end-stage renal disease (ESRD).

Study design: Case-cohort study.

Setting: South-eastern USA.

Participants: The Southern Community Cohort Study recruited ~86 000 black and white participants from 2002 to 2009. We assembled a case cohort of 692 incident ESRD cases and a probability sample of 4113 participants.

Predictors: Sedentary time was calculated as hours/day from daily sitting activities. Physical activity was calculated as metabolic equivalent (MET)-hours/day from engagement in light, moderate and vigorous activities.

Outcomes: Incident ESRD.

Results: At baseline, among the subcohort, mean (SD) age was 52 (8.6) years, and median (25th, 75th centile) estimated glomerular filtration rate (eGFR) was 102.8 (85.9-117.9) mL/min/1.73 m². Medians (25th-75th centile) for sedentary time and physical activity were 8.0 (5.5-12.0) hours/day and 17.2 (8.7-31.9) MET-hours/day, respectively. Median follow-up was 9.4 years. We observed significant interactions between eGFR and both physical activity and sedentary behaviour (p<0.001). The partial effect plot of the association between physical activity and log relative hazard of ESRD suggests that ESRD risk decreases as physical activity increases when eGFR is 90 mL/min/1.73 m². The inverse association is most pronounced at physical activity levels >27 MET-hours/day. High levels of sitting time were associated with increased ESRD risk only among those with reduced kidney function (eGFR ≤30 mL/min/1.73 m²); this association was attenuated after excluding the first 2 years of follow-up.

Conclusions: In a population with a high prevalence of chronic kidney disease risk factors such as hypertension and diabetes, physical activity appears to be associated with reduced risk of ESRD among those with preserved kidney function. A positive association between sitting time and ESRD observed among those with advanced kidney disease is likely due to reverse causation.

Keywords: end stage renal disease; physical activity; sedentary time.

Figure 1

Study selection of the SCCS case-cohort. eGFR, estimated glomerular filtration rate; SCCS, Southern Community Cohort Study.

Figure 2

Partial effect plots of (A) Physical activity (MET-hours/day) (B) Total sitting time (hours/day) and log relative hazard of ESRD by baseline levels of eGFR. The plot is based on the multivariable Cox model that includes terms for physical activity, sedentary time, BMI, smoking status, age, sex, race, education, income, diabetes, hypertension, high cholesterol, eGFR, and the interactions between physical activity and eGFR and sedentary time and eGFR. BMI, body mass index; eGFR, estimated glomerular filtration rate; ESRD, end-stage renal disease; MET, metabolic equivalent.

Figure 3

Plots of continuous HRs of (A) Physical activity (MET-hours/day) (B) Total sitting time (hours/day) and ESRD by baseline levels of eGFR. The plot is based on the multivariable Cox model that includes terms for physical activity, sedentary time, BMI, smoking status, age, sex, race, education, income, diabetes, hypertension, high cholesterol, eGFR, and the interactions between physical activity and eGFR and sedentary time and eGFR. The CIs in the HR plot were generated using bootstrap resampling methods. BMI, body mass index; eGFR, estimated glomerular filtration rate; ESRD, end-stage renal disease; MET, metabolic equivalent.