Leisure-time sedentary behaviour and kidney function decline over 12 years in Australian adults with and without type 2 diabetes

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A common leisure-time sedentary behaviour – television (TV)-viewing time – has been associated with kidney dysfunction; however, the longitudinal associations and moderating roles of type 2 diabetes remain underexplored. We examined relationships of 12-year declines in estimated glomerular filtration rate (eGFR: kidney function) with changes in TV-viewing time (and explored potential joint associations with physical inactivity and gender differences) in adult Australians with and without type 2 diabetes. Australian Diabetes, Obesity and Lifestyle Study (AusDiab) data from 6220 baseline participants [mean (standard deviation): age = 50.7 (12.7) years; waist circumference = 90.3 (13.7) cm; 54.2% women] with five-year or 12-year follow-up data, or both, were analysed; eGFR, TV-viewing time, physical inactivity (<150 min/week self-reported physical activity), and glucose metabolism status (normal glucose metabolism, prediabetes, and type 2 diabetes) were assessed at each observation time point. Multilevel modelling used age (centred at 50 years) as the time metric to estimate the rate of eGFR decline and the association with TV-viewing time, as well as the potential moderation by the presence of type 2 diabetes, physical inactivity, and gender, adjusting for potential sociodemographic and clinical confounders. Participants’ mean eGFR decreased, and mean TV-viewing time increased during the 12-year study period. Those with type 2 diabetes had lower eGFR and higher TV-viewing time at each time point compared to those without type 2 diabetes (prediabetes and normal glucose metabolism). At age 50, the mean eGFR was approximately 98 mL/min/1.73m 2 [Main: 97.6 (95% CI: 97.2 to 98.0); Sensitivity (analysis excluded those with chronic kidney disease at baseline, N = 5782): 98.0 (95% CI: 97.6 to 98.4)], which declined by about 0.80 mL/min/1.73m 2 /year [Main: -0.78 (95% CI: -0.80 to -0.77); Sensitivity: -0.79 (95% CI: -0.81 to -0.78)]. Increasing TV-viewing time was significantly associated with eGFR decline [Main: -0.022 (95% CI: -0.031 to -0.013); Sensitivity: -0.024 (95% CI: -0.033 to -0.015)] and was more pronounced in those with type 2 diabetes [Main: -0.037 (95% CI: -0.068 to -0.006); Sensitivity: -0.041 (95% CI: -0.073 to -0.009)]. The association was potentially stronger in those physically inactive at any given time compared to those physically active [Main: -0.015 (95% CI: -0.031 to 0.000), Sensitivity: -0.018 (95% CI: -0.034 to -0.001)], and was also stronger in women than in men [Main: -0.020 (95% CI: -0.039 to -0.002); Sensitivity: -0.029 (95% CI: -0.048 to -0.010)]. Among community-dwelling Australian adults, increasing TV-viewing time was associated with a greater rate of kidney function decline, which was heightened in the presence of type 2 diabetes. The relationship may also be stronger in those who were physically inactive and in women. These longitudinal relationships strengthen the evidence base for kidney health on the detrimental effects of excessive sedentary behaviour, particularly in those living with type 2 diabetes, those physically inactive, and in women. They further reinforce the clinical and public health importance of meeting recommended sedentary behaviour and physical activity guidelines.