Too Much Sitting Increases Risk of Death.
Question: Is daily sitting time associated with mortality and cardiovascular disease (CVD) in countries of different economic levels?
Findings: In this cohort study including 105 677 participants from 21 countries, higher sitting time was associated with an increased risk of all-cause mortality and major CVD, and the association was more pronounced in low-income and lower-middle–income countries. Meeting the World Health Organization recommendations for physical activity could effectively attenuate the risk of high sitting time.
Meaning: Reducing sedentary time along with increasing physical activity may be an important strategy for easing the global burden of premature deaths and CVD.
Design, Setting, and Participants: This population-based cohort study included participants aged 35 to 70 years recruited from January 1, 2003, and followed up until August 31, 2021, in 21 high-income, middle-income, and low-income countries with a median follow-up of 11.1 years.
Those who sit for more than 8 hours per day have elevated risk for death and major cardiovascular events compared with those who sit for less than 4 hours per day, according to new data from the PURE cohort study.
The association between longer sitting time and higher death/Cardiovascular disease (CVD) risk was present across all socioeconomic levels, but was most pronounced in low- and lower-middle-income countries, the researchers wrote in JAMA Cardiology.
Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts.
Sidong Li, BM, from the National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, and colleagues analyzed 105,677 participants from the PURE cohort (mean age, 50 years; 59% women). The primary outcome was a composite of all-cause death and major CVD, defined as CV death, MI, stroke or HF. Median follow-up was 11.1 years.
During the study period, there were 6,233 deaths and 5,696 major CV events, the researchers wrote.
Compared with those who sat for less than 4 hours per day, those who sat for 8 hours per day or more had elevated risk for the primary outcome (HR = 1.19; 95% CI, 1.11-1.28; P for trend < .001), all-cause death (HR = 1.2; 95% CI, 1.1-1.31; P for trend < .001) and major CVD (HR = 1.21; 95% CI, 1.1-1.34; P for trend < .001), according to the researchers.
The association between longer sitting time and the primary outcome was higher in low- and lower-middle-income countries (HR for 8 hours or more per day = 1.29; 95% CI, 1.16-1.44) than in high- and upper-middle-income countries (HR for 8 hours or more per day = 1.08; 95% CI, 0.98-1.19; P for interaction = .02), Li and colleagues wrote.
The risk of death/CVD was reduced in people who sat for 8 hours or more per day but had high levels of physical activity, according to the researchers, who noted that the increase in risk ranged from 17% in those with high activity levels to 50% in those with low activity levels.
“By including diverse populations from countries at varying income levels, our study adds to the accumulating evidence on the risk of sitting time,” Li and colleagues wrote. “Our findings support the WHO 2020 global guidelines for sedentary behavior and indicate that physical activity above the recommended level could attenuate the increased risk owing to sedentariness, and sedentary individuals may benefit from replacing sitting time with physical activity.”