Mortality effects of hypothetical interventions on physical activity and TV viewing

Yang, Yi and Hodge, Allison M. and Dugue, Pierre-Antoine and Williamson, Elizabeth J. and Gardiner, Paul A. ORCID: and Barr, Elizabeth L. M. and Owen, Neville and Dunstan, David W. and Lynch, Brigid M. and English, Dallas R. (2021) Mortality effects of hypothetical interventions on physical activity and TV viewing. Medicine and Science in Sports and Exercise, 53 (2). pp. 316-323. ISSN 0195-9131


Introduction Long-term effects of physical activity and television (TV) viewing on mortality have been inferred from observational studies. The associations observed do not allow for inferences about the effects of population interventions and could be subject to bias due to time-varying confounding.

Methods Using data from the Australian Diabetes, Obesity and Lifestyle Study, collected in 1999-2000 (T0), 2004-2005 (T1), and 2011-2012 (T2), we applied the parametric g-formula to estimate cumulative risks of death under hypothetical interventions on physical activity and/or TV viewing determined from self-report while adjusting for time-varying confounding.

Results In the 6377 participants followed up for 13 yr from 2004 to 2005 to death or censoring in 2017, 781 participants died. The observed cumulative risk of death was 12.2%. The most effective hypothetical intervention was to increase weekly physical activity to >300 min (risk ratio (RR), 0.66 (0.46-0.86) compared with a 'worst-case' scenario; RR, 0.83 (0.73-0.94) compared with no intervention). Reducing daily TV viewing to <2 h in addition to physical activity interventions did not show added survival benefits. Reducing TV viewing alone was least effective in reducing mortality (RR, 0.85 (0.60-1.10) compared with the worst-case scenario; RR, 1.06 (0.93-1.20) compared with no intervention).

Conclusions Our findings suggested that sustained interventions to increase physical activity could lower all-cause mortality over a 13-yr period, and there might be limited gain from intervening to reduce TV viewing time in a relatively healthy population.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 13 Sep 2021 05:06
Last Modified: 03 Nov 2021 02:13
Uncontrolled Keywords: cohort study; g-formula; hypothetical interventions; time-varying confounding
Fields of Research (2008): 11 Medical and Health Sciences > 1117 Public Health and Health Services > 111799 Public Health and Health Services not elsewhere classified
11 Medical and Health Sciences > 1117 Public Health and Health Services > 111706 Epidemiology
Fields of Research (2020): 42 HEALTH SCIENCES > 4202 Epidemiology > 420201 Behavioural epidemiology
42 HEALTH SCIENCES > 4206 Public health > 420699 Public health not elsewhere classified
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