Abstract 76: Consistency of Meeting Physical Activity Guidelines and Long-term Risk of Cardiovascular Disease

Abstract

Background: The long-term consistency of meeting physical activity guidelines may be critical for cardiovascular health, yet its independent contribution beyond total physical activity amount remains unclear. Methods: A total of 225,264 adults from 3 large prospective cohorts (Health Professionals Follow-up Study, 1988-16; Nurses’ Health Study, 1988-2018; Nurses’ Health Study II, 1991-2017) were included. Leisure-time physical activity was assessed biennially using validated questionnaires and expressed in metabolic equivalent (MET)-hours per week. Consistency was defined as the percentage of follow-up years meeting the recommended level (≥7.5 MET-hours/week) and was updated at each questionnaire cycle across three decades of follow-up. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident cardiovascular disease (CVD), myocardial infarction (MI), and stroke. Results: Over up to 30 years of follow-up, 24,766 CVD cases were documented. In traditional dose–response analyses, the lowest CVD risk was observed at 50.7 MET-hours/week (HR = 0.73; 95% CI, 0.70–0.77). After considering long-term consistency, consistently maintaining the guideline-recommended level at moderate intensity (median = 11.6 MET-hours/week) was associated with a 23% lower CVD risk (HR = 0.77; 95% CI, 0.72–0.84) compared with individuals with low activity (<7.5 MET-hours/week) and very low consistency. Consistently maintaining higher levels of physical activity was not associated with additional risk reduction (HRs [95% CIs]: 0.78 [0.73–0.83], 0.80 [0.75–0.85], 0.77 [0.73–0.82], and 0.77 [0.73–0.82] for median levels of 18.7, 26.0, 36.3, and 60.7 MET-hours/week, respectively). Similar associations were observed for MI and stroke and were consistent after adjustment for body mass index and across subgroups defined by age, gender, smoking status, and dietary quality. Conclusions: Traditional dose-response analysis suggested that 50.7 MET-hours/week was needed for optimal mortality benefit. After incorporating long-term consistency, we found that maintaining a moderate level around 11.6 MET-hours/week over three decades was sufficient to achieve the optimal benefit in CVD risk reduction.