Adverse events in older adults and the risk of dementia and cognitive decline.

Background: Increasing evidence suggests that stress could be a risk factor for dementia but this might vary by gender. This study investigated whether adverse life events were associated with cognitive decline and dementia in later-life, separately in men and women.

Methods: Participants were 12,789 community-dwelling Australians aged ≥ 70 years. Ten common adverse events in later-life were self-reported. Cognitive decline was defined as a 1.5 SD decline from participants' baseline score in tests of global cognition, psychomotor speed, episodic memory, and executive functioning, which were assessed regularly over a maximum of 10.3 years. Dementia was diagnosed according to DSM-IV criteria.

Results: An increased risk of dementia was observed in participants who experienced the death of a spouse/partner (HR: 1.72, 95% CI: 1.17 - 2.52) and for individuals who experienced major financial problems (HR: 1.53, 95% CI: 1.05 - 2.23). The latter also increased the risk of cognitive decline in men specifically (HR: 1.43, 95% CI: 1.10 - 1.86). In contrast, some events for women were associated with a reduced risk of dementia (e.g. close family or friends lost their job/retired (HR: 0.62, 95% CI: 0.40-0.95)).

Limitations: Events including major money problems may result from prodromal dementia symptoms, thus reverse causation needs to be considered.

Conclusions: Adverse life events may influence dementia risk in older adults, but associations vary depending on the nature of the event, and across genders. These findings support the need for early interventions in older people who have experienced adversities, particularly for the death of a loved one.