STUDY OBJECTIVES:To examine whether change in caregiving status and intensity among community-dwelling older women was associated with sleep characteristics at follow-up, and whether perceived stress modified these associations. METHODS:The sample included 800 women aged 65 years or older who completed baseline and second follow-up interviews in the Caregiver-Study of Osteoporotic Fractures (Caregiver-SOF). Respondents were categorized into four groups based on change in caregiving status and intensity between the two time points: continuous noncaregivers, ceased caregivers, low-intensity caregivers (continuous caregivers with low/decreased intensity), and high-intensity caregivers (continuous caregivers with high/increased intensity or new caregivers). Perceived Stress Scale scores at the second follow-up were dichotomized into high versus low stress. Sleep outcomes at SOF Visit 8 (which overlapped with Caregiver-SOF second follow-up) included the Pittsburgh Sleep Quality Index total score; and actigraphy-measured total sleep time, sleep efficiency, wake after sleep onset, and sleep latency. RESULTS:Multivariate-adjusted sleep characteristics did not differ significantly across caregiving groups. Among high-intensity caregivers, however, those with high stress levels had significantly longer wake after sleep onset (mean 82.3 minutes, 95% confidence interval = 70.9-93.7) than those with low stress levels (mean 65.4 minutes, 95% confidence interval = 55.2-75.7). No other sleep outcomes were modified by stress levels. Further, higher stress was significantly associated with worse Pittsburgh Sleep Quality Index scores, regardless of the caregiving group. CONCLUSIONS:Overall, sleep characteristics did not differ among noncaregivers, ceased caregivers, or those with high-/low-intensity caregiving among older women. However, subgroups of caregivers may be vulnerable to developing sleep problems, particularly those with high stress levels.