Abstract
OBJECTIVES: To investigate the separate and combined effects of caregiver status and high stress on mortality risk over 8 years in elderly women. DESIGN: Prospective cohort study conducted in four U.S. communities followed from 1999/01 (baseline) to December 31, 2007. SETTING: Home-based interviews. PARTICIPANTS: Three hundred seventy-five caregiver and 694 noncaregiver participants from the Caregiver-Study of Osteoporotic Fractures (Caregiver-SOF) who participated in the baseline Caregiver-SOF interview. MEASUREMENTS: Caregiver status was based on SOF respondents' self-report of performing one or more instrumental or basic activities of daily living for a relative or friend with impairments. Two measures of stress were used: Perceived Stress Scale and stress related to caregiving tasks. All-cause mortality was the outcome. RESULTS: Caregivers were more stressed than noncaregivers; 19.7% of caregivers and 27.4% of noncaregivers died. Mortality was lower in caregivers than noncaregivers (adjusted hazard ratio, (AHR)=0.74, 95% confidence interval (CI)=0.56-0.89). High-stress respondents had greater mortality risk than low-stress respondents over the first 3 years of follow-up (AHR=1.81, 95% CI=1.16-2.82) but not in later years. Likewise, high-stress caregivers and noncaregivers had higher mortality risk than low-stress noncaregivers, although low-stress caregivers had significantly lower mortality than did noncaregivers, whether perceived stress or caregiving-related stress was measured (AHR=0.67 and 0.57). Similar results were observed in analyses comparing spouse caregivers with married noncaregivers. CONCLUSION: Short-term effects of stress, not caregiving per se, may increase the risk of health decline in older caregivers.