The purpose of the present study is to examine the difference in kidney function for replacing long-bout sedentary with short-bout sedentary or light intensity physical activity (LPA) time without increasing in moderate-to-vigorous intensity physical activity (MVPA) time in community-dwelling adults.
This cross-sectional study included participants aged 20 years or older from the physical activity measurement sub-cohort of the Tohoku Medical Megabank Project Community-Based Cohort Study and Birth and Three-Generation Cohort Study. A total of 6,142 participants (mean age: 61.2 years, 70.2% women) were included, excluding those with moderate or severe CKD. Kidney function was assessed using estimated glomerular filtration rate (eGFR), calculated based on blood cystatin C levels. Participants were asked to wear a tri-axial accelerometer on their waist for 10 consecutive days, except for sleeping and bathing time, to measure their daily time spent in physical activity (LPA and MVPA) and SB time. SB time was categorized into long (30 min ≥) and short (30 min ) bouts, according to their consecutive duration. Physical activity and SB time were processed via compositional data analysis approach. We estimated eGFR difference between actual SB time and the theoretical replacement of long-bout SB time with short-bout SB or LPA time using parametric g-formula. Long-bout SB time was replaced it to be within 120 minutes.
The mean eGFR value was 100.1 (±12.3) mL/min/1.73 m2. The daily mean LPA, MVPA, long-bout SB, and short-bout SB, and accelerometer wearing time were 384.7 (±94.8), 60.7 (±35.1), 226.9 (±109.6), 236.2 (±54.9), and 908.5 (±94.9) minutes. Mean proportion of long-bout SB time among whole SB time was 46.8 (±14.4) %. Compared with actual distribution, kidney function was significantly higher when long-bout SB time was isotemporally replaced with short-bout SB time (Kidney function difference: 1.36 mL/min/1.73 m2, 95% confidence intervals[CIs]: 0.44-2.28, P=0.004), or with LPA time (Kidney function difference: 1.45 mL/min/1.73 m2, 95%CIs: 0.80-2.03, P0.001).
Reducing short-bout SB time by increasing short-bout SB or LPA time, without increasing MVPA, was associated with better kidney function. Further longitudinal studies are needed to determine whether reducing long-bout SB lowers the incidence of CKD.
These results may be valuable for population-based strategies aimed at reducing the harmful impacts of SB.
Kidney Function
Physical Activity