Replacement of sedentary behavior with various physical activities and the risk of all-cause and cause-specific mortality

Abstract

Background: Sedentary behavior (SB) has emerged as a significant health concern that deserves attention. This study aimed to examine the associations between prolonged sedentary behavior and the risk of all-cause and cause-specific mortality as well as to explore desirable alternatives to sitting in terms of physical activity (PA).

Methods: Two prospective cohort investigations were conducted using the UK Biobank and NHANES datasets, with a total of 490,659 and 33,534 participants, respectively. Cox proportional hazards regression models were used to estimate the associations between SB and the risk of all-cause and cause-specific mortality due to cancer, cardiovascular disease (CVD), respiratory diseases, and digestive diseases. In addition, we employed isotemporal substitution models to examine the protective effect of replacing sitting with various forms of PA.

Results: During the average follow-up times of 13.5 and 6.7 years, 36,109 and 3057 deaths were documented in the UK Biobank and NHANES, respectively. Both cohorts demonstrated that, compared with individuals sitting less than 5 h per day, individuals with longer periods of sitting had higher risks of all-cause and cause-specific mortality due to cancer, CVD, and respiratory diseases but not digestive diseases. Moreover, replacing SB per day with PA, even substituting 30 min of walking for pleasure, reduced the risk of all-cause mortality by 3.5% (hazard ratio [HR] 0.965, 95% confidence interval [CI] 0.954-0.977), whereas cause-specific mortality from cancer, CVD, and respiratory diseases was reduced by 1.6% (HR 0.984, 95% CI 0.968-1.000), 4.4% (HR 0.956, 95% CI 0.930-0.982), and 15.5% (HR 0.845, 95% CI 0.795-0.899), respectively. Furthermore, the protective effects of substitution became more pronounced as the intensity of exercise increased or the alternative duration was extended to 1 h.

Conclusions: SB was significantly correlated with substantially increased risks of all-cause mortality and cause-specific mortality from cancer, CVD, and respiratory diseases. However, substituting sitting with various forms of PA, even for short periods involving relatively light and relaxing physical activity, effectively reduced the risk of both overall and cause-specific mortality.

Keywords: Mortality; NHANES; Physical activity; Sedentary behavior; UK Biobank.

Fig. 1

Flowchart of the participants

Fig. 2

Associations of the sedentary behavior time with all-cause and cause-specific mortality. The solid line represents the hazard ratio modeled via a restricted cubic spline with 4 knots, and the dashed lines represent the 95% confidence intervals for the hazard ratios. The hazard ratios are adjusted for age, sex, race (white, nonwhite, missing), Townsend deprivation index (continuous), education level (college or university degree, professional qualifications, A levels/AS levels or equivalent, O levels/GCSEs or equivalent, missing), employment status (working, retired, others, missing), BMI (normal, overweight, obese), smoking status (current smoker, never smoker, previous smoker), ideal drinking (yes, no, missing), vegetable and fruit intake (continuous), processed meat intake (never, less than once a week, once a week, 2–4 times a week, 5–6 times a week, once or more daily, missing), overall health rating (excellent or good, fair or poor, missing), and sleep duration (continuous). In the NHANES cohort, the model was adjusted for age, sex, race (Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black, other race), income level (< $25 k, $25 k to < $75 k, ≥ $75 k, missing), education level (less than high school, high school, college or above, missing), employment status (working, unemployed, missing), BMI (normal, overweight, obese), smoking status (current or previous smoker, never smoker), alcohol consumption frequency (more than once a week, more than once a month, less than once a month, never, missing), healthy diet (quartiles), overall health rating (excellent or good, fair or poor, missing), and sleep duration (continuous)

Fig. 3

Thirty minutes/day of sedentary behavior was replaced with different types of physical activity. In the UK Biobank, the model was adjusted for age, sex, race (white, nonwhite, missing), Townsend deprivation index (continuous), education level (college or university degree, professional qualifications, A levels/AS levels or equivalent, O levels/GCSEs or equivalent, missing), employment status (working, retired, others, missing), BMI (normal, overweight, obese), smoking status (current smoker, never smoker, previous smoker), ideal drinking (yes, no, missing), vegetable and fruit intake (continuous), processed meat intake (never, less than once a week, once a week, 2–4 times a week, 5–6 times a week, once or more daily, missing), overall health rating (excellent or good, fair or poor, missing), and sleep duration (continuous). In the NHANES cohort, the model was adjusted for age, sex, race (Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black, other race), income level (< $25 k, $25 k to < $75 k, ≥ $75 k, missing), education level (less than high school, high school, college or above, missing), employment status (working, unemployed, missing), BMI (normal, overweight, obese), smoking status (current or previous smoker, never smoker), alcohol consumption frequency (more than once a week, more than once a month, less than once a month, never, missing), healthy diet (quartiles), overall health rating (excellent or good, fair or poor, missing), and sleep duration (continuous). Abbreviations: HR, hazard ratio; CI, confidence interval; BMI, body mass index