Sitting Time Reduction and Blood Pressure in Older Adults

Key Points Question Is sitting time reduction an effective strategy for improving blood pressure? Findings In this randomized clinical trial of 283 older adults, there were greater reductions in sitting time and systolic blood pressure during 6 months in the intervention arm compared with the control condition. Meaning Reducing sitting time could be a practical strategy for promoting cardiometabolic health in older populations.


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The interventions included 10 health coaching sessions in both arms a Percentage of sessions reviewed that met the indicated criteria.
b Session-rating scale: 0 = did not follow content; 1 = addressed some content but skipped key concepts; 2 = mainly followed content with minor changes; 3 = followed content as directed in health coach training and materials b Difference in adjusted mean change: Difference between adjusted mean change in I-STAND intervention minus adjusted mean change in attention control at the stated timepoint for those randomized pre COVID-19 pandemic or those randomized in March 2020.Results were calculated fitting a linear regression model with generalized estimating equations on the outcome change from baseline including timepoints 3 and 6 months in the same model with indicators for 6-month timepoint, I-STAND intervention, post-COVID randomization, and interactions between indicators adjusting for baseline outcome, baseline outcome and post-COVID randomization interaction, county, age, gender, race, body mass index, arthritis, physical function, diabetes, hypertension, retirement status and number of hypertensive medication classes.To obtain the adjustment mean change, we assumed the mean baseline covariate response for all randomized.For SBP and DBP only 6-month outcomes were included in the analyses.CI, confidence interval; SBP, systolic blood pressure; DBP, diastolic blood pressure *6 months is the primary outcome timepoint of the trial ** Blood pressure outcomes pre COVID were only collected only at the 6-month timepoint Adjusted mean change and difference: Calculated fitting a separate model for the subgroup with PRE-COVID all measurements and the subgroup with POST-COVID all measurements.Model fit was a linear regression model with generalized estimating equations on the outcome change from baseline, including timepoints 3 and 6 months in the same model with indicators for 6-month timepoint, I-STAND intervention, and interactions between these indictors adjusting for baseline outcome, county (for POST-COVID subgroup only), age, gender, race, body mass index, arthritis, physical function, diabetes, hypertension, retirement status and number of hypertensive medication classes.To obtain the adjustment mean change we assumed the mean baseline covariate response for all randomized.For SBP and DBP PRE-COVID models, only 6-month outcomes were included in analyses.CI, confidence interval; SBP, systolic blood pressure; DBP, diastolic blood pressure * 6 months is the primary timepoint of the trial ** Blood pressure for participants randomized before the COVID-19 pandemic was measured at only the 6-month timepoint

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Difference in adjusted mean change: This is the difference between the adjusted mean change in I-STAND intervention minus the adjusted mean change in the attention control within a given moderator category.We fit a linear regression model with GEE on the outcome change from baseline including only 6 months outcome data with an indicator for the moderator, indicator for I-STAND intervention, and interactions between these indicators adjusting for baseline outcome, baseline outcome and Post-COVID randomization interaction, county, age, gender, race, BMI, arthritis, physical function, diabetes, hypertension, retirement status and number of hypertensive classes.b Interaction p-value tests if the interaction effect between the moderator indicator and intervention indicator are statistically significant

eTable 1 .
Adherence to Health Coaching Sessions and Fidelity to the Interventions Coprimary Outcome Secondary Analysis at 3 and 6 Months by Intervention Group and Randomization Pre or Post COVID-19 Pandemic a eTable 2.

eTable 3 .
Coprimary Outcomes Results by Intervention Group at 3 and 6 Months by Whether All Measurements Were Completed Before or After the COVID-19 Pandemic Onset

eTable 4 .
Moderator Analyses at 6 Months to Assess Differential Intervention Effects Mo, months; CI, confidence interval; SBP, systolic blood pressure; DBP, diastolic blood pressure