Sitting Time and Its Interaction With Physical Activity in Relation to All-Cause and Heart Disease Mortality in U.S. Adults With Diabetes

OBJECTIVE To evaluate whether associations between sitting time and all-cause and heart disease mortality are modified by physical activity in adults with diabetes. RESEARCH DESIGN AND METHODS Data came from 6,335 U.S. adults with diabetes from National Health and Nutrition Examination Survey 2007–2018 (baseline), with mortality follow-up through 2019. Sitting time and moderate to vigorous physical activity (MVPA) were self-reported. Cox models were adjusted for sociodemographics, lifestyle factors, and medical conditions. RESULTS Over a median follow-up of 5.9 years, 1,278 all-cause and 354 heart disease deaths were documented (mean age, 59.6 years; 48.3% female). Longer sitting time was associated with greater all-cause and heart disease mortality risk in inactive (MVPA 10 min/week) or insufficiently active (MVPA 10 to 150 min/week) adults with diabetes, but not in active adults (MVPA ≥150 min/week) (all-cause mortality: P = 0.003 for interaction; heart disease mortality: P = 0.008 for interaction). CONCLUSIONS In adults with diabetes, meeting guideline-recommended physical activity may offset the elevated all-cause and heart disease mortality risk associated with excessive sitting time.