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.