Prospective Associations of Accelerometer-Measured Physical Activity and Sedentary Time With Incident Cardiovascular Disease, Cancer, and All-Cause Mortality
Authors: Paddy C. Dempsey, Tessa Strain, Kay-Tee Khaw, Nicholas J. Wareham, Søren Brage, Katrien Wijndaele
Journal: Circulation (2020)

mortality ◼ neoplasms ◼ public health ◼ sedentary behavior B oth insufficient moderate-to-vigorous intensity physical activity (MVPA) and high volumes of sedentary time (ST) have been associated with increased risk of all-cause mortality, cardiovascular disease (CVD), and some cancers. 1 However, epidemiological evidence has relied mostly on self-reported physical activity (PA) and ST measures, which are prone to reporting bias and measurement error.Cohort studies incorporating more objective assessments are emerging, 2-4 but few investigate relationships of accelerometer-measured PA and ST with clinical end points, particularly incident CVD, and include both men and women. 5In addition, the relevance of light intensity PA (LIPA) in this context, which is an important contributor to total PA and may be a more feasible behavioral target for middle to older aged adults, remains unclear.Here, we examine the prospective associations of accelerometer-measured PA and ST with incident CVD (primary outcome), incident cancer, and all-cause mortality.Participants were from the European Prospective Investigation Into Cancer and Nutrition-Norfolk study, a population-based cohort of 25 639 adults 40 to 79 years of age residing in Norfolk, UK.Between 2004 and 2016, 7820 participants attending in-clinic assessments wore an accelerometer (ActiGraph GT1M/GT3X+) on their right hip for 7 days during waking hours.We excluded those with <4 days of sufficient wear time (>10 hours/day; n=134) or missing covariate data (n=19).Those with prevalent CVD (n=2083), cancer (n=629), or either CVD or cancer (n=2488) were excluded from the CVD, cancer, and all-cause mortality analyses, respectively.Cox proportional hazards regression was used to model nonlinear associations (using splines) of total PA volume (average accelerometer counts per minute/day), MVPA (minutes/day; ≥2020 counts/min), LIPA (hours/day; 100-2019 counts/min), and ST (hours/day; <100 counts/min) with total (nonfatal or fatal) incident CVD (International Classification of Diseases, 9th Revision codes 401-448 or 10th Revision codes I10-I79), cancer (International Classification of Diseases, 9th Revision codes 140-280 or 10th Revision codes C00-C97), and all-cause mortality.Outcome status was ascertained via hospital admissions and death certificates through March 31, 2016, for incident CVD and cancer and through March 31, 2018, for all-cause mortality.The Norwich District Ethics Committee provided ethics approval, and all participants gave written informed consent.Key findings are summarized in the Figure .A total of 1106 incident CVD, 516 incident cancer, and 339 all-cause mortality events occurred for 5585, 7052, and 5249 participants, respectively.Mean age at baseline was 68.9 years (SD, 7.2 years); mean body mass index was 26.5 kg/m 2 (SD, 4.1 kg/m 2 ); and 58.5% were female.After adjustment for sex and wear time (model 1, Figure), higher levels of total PA and MVPA were associated with lower incident CVD risk in a nonlinear manner; after an initially steeper decrease in hazard ratios, there was a flattening of the relationships.Associations persisted for total PA and MVPA (model 2) after