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 NHANES 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). Higher sitting time was associated with greater all-cause and heart disease mortality risk in inactive (MVPA<10 min/week) or insufficiently active adults with diabetes (10≤MVPA<150 min/week), but not in active adults (MVPA≥150 min/week) (all-cause mortality: P-interaction=0.003; heart disease mortality: P-interaction=0.008).

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.