Television viewing, computer use, time driving and all-cause mortality: the SUN cohort

Abstract

Background: Sedentary behaviors have been directly associated with all-cause mortality. However, little is known about different types of sedentary behaviors in relation to overall mortality. Our objective was to assess the association between different sedentary behaviors and all-cause mortality.

Methods and results: In this prospective, dynamic cohort study (the SUN Project) 13 284 Spanish university graduates with a mean age of 37 years were followed-up for a median of 8.2 years. Television, computer, and driving time were assessed at baseline. Poisson regression models were fitted to examine the association between each sedentary behavior and total mortality. All-cause mortality incidence rate ratios (IRRs) per 2 hours per day were 1.40 (95% confidence interval (CI): 1.06 to 1.84) for television viewing, 0.96 (95% CI: 0.79 to 1.18) for computer use, and 1.14 (95% CI: 0.90 to 1.44) for driving, after adjustment for age, sex, smoking status, total energy intake, Mediterranean diet adherence, body mass index, and physical activity. The risk of mortality was twofold higher for participants reporting ≥ 3 h/day of television viewing than for those reporting <1 h/d (IRR: 2.04 [95% CI 1.16 to 3.57]).

Conclusions: Television viewing was directly associated with all-cause mortality. However, computer use and time spent driving were not significantly associated with higher mortality. Further cohort studies and trials designed to assess whether reductions in television viewing are able to reduce mortality are warranted. The lack of association between computer use or time spent driving and mortality needs further confirmation.

Keywords: death; prospective cohort study; sedentary behavior; sedentary time; sitting time.

Figure 1.

Nelson‐Aalen estimates of total mortality according to categories of baseline television viewing. Adjusted for age (continuous), sex, smoking history (never, current, quit), total energy intake (continuous), Mediterranean diet adherence (continuous), baseline body mass index (continuous), physical activity (quartiles), computer use (continuous), time driving (continuous), using inverse probability weighting.

Figure 2.

Results of subgroup analyses of television viewing and mortality. Adjusted incidence risk ratios per 2 hours of TV (television) viewing per day for mortality within specific subgroups. Squares denote incidence risk ratios; horizontal lines represent 95% confidence intervals. Incidence risk ratios were adjusted for age (continuous), sex, smoking history (never, current, quit), total energy intake (continuous), Mediterranean diet adherence (continuous), baseline body mass index (continuous), physical activity (continuous), computer use (continuous), time driving (continuous). BMI indicates body mass index; IRR, incidence risk ratio; MET, metabolic equivalent task; TV, television.