The relationship between changes in sitting time and mortality in post-menopausal US women.
Prolonged sitting is linked to various deleterious health outcomes. The alterability of the sitting time (ST)-health relationship is not fully established however and warrants study within populations susceptible to high ST.



We assessed the mortality rates of post-menopausal women from the Women's Health Initiative (WHI) observational study, a 15-year prospective study of post-menopausal women aged 50-79 years, according to their change in ST between baseline and year six. A total of 77 801 participants had information at both times on which to be cross-classified into the following: (i) high ST at baseline and follow-up; (ii) low ST at baseline and follow-up; (iii) increased ST and (iv) decreased ST. Cox regression was used to assess the relationship between all-cause, CVD and cancer mortality with change in ST.



At the end of follow-up, there were 1855 deaths. Compared with high ST maintainers, low ST maintainers had a 51 and 48% lower risk of all-cause and cancer mortality, respectively. Reducing sitting also resulted in a protective rate of 29% for all-cause and 27% for cancer mortality.



These results highlight not only the benefit of maintaining minimal ST, but also the utility of decreasing ST in older women, if current levels are high.
School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada M3J1P3.
J
J
Lee
School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada M3J1P3.
J L
JL
Kuk
School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada M3J1P3.
C I
CI
Ardern
D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000453:epidemiology; D002423:Cause of Death; D002908:Chronic Disease / Q000401:mortality*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D009369:Neoplasms / Q000401:mortality; D017698:Postmenopause; D011187:Posture; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D057185:Sedentary Behavior; D012907:Smoking / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014481:United States; D016387:Women's Health
chronic disease; cohort study; life expectancy; lifestyle; sedentary