A sedentary behaviour threshold for multimorbidity in older adults: Analyses from the Canadian health measures survey

The present study aimed to establish a relative sedentary behavior time (RSBT)-i.e. proportion of wake time spent in SB-threshold above which the risks of multimorbidity significantly increase in older adults (OA).

Cross-sectional observational study using secondary data analysis from the Canadian Health Measures Survey.

A total of 2641 OA (aged 65-79) participated in the Canadian Health Measures Survey (2007-2017) and wore an accelerometer for at least four valid days, including one weekend day. Multimorbidity was defined as the presence of two or more of these six health conditions: cancer, cardiovascular, metabolic, musculoskeletal, psychological, and pulmonary. Covariates are age, sex, body mass index, physical activity level, relationship status, type of lodging, education level, income, alcohol consumption and smoking status.

Receiver Operating Characteristic curves were used to determine cut-off points, while odds ratios were calculated using multivariate logistic regressions. Optimal threshold for identifying multimorbidity was established at >79.4 % of RSBT (AUC = 0.579 [0.557-0.601]) while OA exceeding this threshold exhibited 1.58 (95 % CI: 1.35-1.84) increased odds of having multimorbidity. After controlling for all covariates, the risk remained at 1.29 (95 % CI: 1.09-1.53).

These results contribute to establishing future clinical guidelines regarding SB in the OA population.