Association between caregiving duration and hypertension among family caregivers: the TMM CommCohort study

With the global increase in elderly individuals requiring long-term care, family caregivers face significant physical and psychosocial burdens. This study examined the association between caregiving duration and hypertension using three indices: morning and evening home blood pressure (HBP) and research blood pressure (BP). This cross-sectional study included 13,518 participants from the Tohoku Medical Megabank Community-Based Cohort Study. Caregiving time was categorized via questionnaire. Hypertension was defined according to the Japanese Society of Hypertension Guidelines for the Management of Elevated Blood Pressure and Hypertension 2025 (HBP ≥ 135/85 mmHg, research BP ≥ 140/90 mmHg, or medication use). Multivariable robust Poisson regression estimated prevalence ratios (PRs), adjusted for demographics, lifestyle and social psychological factors. Participants providing care "almost all day" had significantly higher PRs for morning (PR: 1.26; 95% CI: 1.07-1.48) and evening hypertension (PR: 1.27; 95% CI: 1.03-1.56) than non-caregivers. Notably, no significant association was observed with research BP-defined hypertension. Stratified analyses revealed that these associations were particularly prominent among caregivers aged <65 years (P-interaction for morning hypertension = 0.003). The interaction between sex and caregiving time was not significant. Prolonged caregiving burden is associated with a higher prevalence of hypertension in the morning and evening, particularly among working-age caregivers. Because these risks were not captured by research BP, HBP monitoring is essential for cardiovascular risk management in caregivers. Social policies and clinical interventions should target younger caregivers to mitigate the physiological strain of 24-h caregiving responsibilities.