Extreme heat events pose a growing threat to individuals with dementia.A study presented at AAIC 2026 shows that short-term exposure to outdoor heat may exacerbate behavioural and psychological symptoms of dementia (BPSD), including affective and psychotic manifestations.
“Individuals living with dementia are especially vulnerable to heat due to impaired thermoregulation, limited mobility, and reduced adaptive capacity to perceive and respond to thermal stress,” noted Dr Eun Young Choi from the Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, US, and colleagues.
“Sex-specific symptom patterns suggest that males and females living with dementia may express heat-related distress through different behavioural and neuropsychiatric pathways,” said Choi and colleagues.
BPSD prevalence
Compared with males, females were more likely to experience four of the eight proxy-reported distinct BPSD. These include getting lost (35 percent vs 23 percent; p<0.001), wandering (7 percent vs 5 percent; p=0.005), hallucinations (29 percent vs 15 percent; p<0.001), and delusions (14 percent vs 10 percent; p=0.045).
Females also had numerically higher rates of sleep difficulties (57 percent vs 52 percent) and pacing or rocking (15 percent vs 11 percent) than males, but the between-group comparisons failed to achieve statistical significance.
Males were slightly more likely to exhibit anger or hostility than females (36 percent vs 33 percent), but the rates of dangerous behaviours were similar between sexes (12 percent for both). [AAIC 2026, abstract 13751]
Short-term outdoor heat exposure
In males, higher heat exposure was significantly associated with wandering (odds ratio [OR], 1.30, 95 percent confidence interval [CI], 0.99–1.72; p=0.058) and dangerous behaviours (OR, 1.98, 95 percent CI, 1.27–3.08; p=0.002).
In females, the specific BPSD significantly associated with higher heat exposure were hallucinations (OR, 1.15, 95 percent CI, 1.00–1.33; p=0.058) and anger or hostility (OR, 1.28, 95 percent CI, 0.98–1.67; p=0.070).
According to the investigators, the ORs represent an interquartile range increase in the 7-day mean Heat Index (61–87°F).
Sex-specific associations
There are several studies demonstrating the association between high outdoor temperature and hospitalization and mortality risk in individuals living with dementia. [BMC Public Health 2026;26:1488; Lancet Reg Health West Pac 2024:52:101217; J Gerontol A Biol Sci Med Sci 2025;80:glae292]
Moreover, comorbidities in this patient setting may compound the hospitalization and mortality risk associated with extreme temperatures. [Environ Res 2021;195:110762; Int J Environ Res Public Health 2017;14:385]
“BPSD may be an important precursor to these severe outcomes, yet their association with outdoor heat remains understudied,” the investigators said.
To evaluate sex-specific associations between short-term outdoor heat exposure and BPSD among community-dwelling individuals living with dementia in the US, the researchers used data from the US Health and Retirement Study (2000–2020). The data were then linked to census-tract weather data from the Contextual Data Resource. The study sample included 938 males and 1,300 females who completed the proxy-reported interviews.
“[In this study, we found that] heat exposure was more strongly associated with externalizing behavioural dysregulation in males. In females, heat exposure was more strongly associated with neuropsychiatric and affective symptoms,” the investigators said.
“These patterns may reflect sex differences in baseline vulnerability, with frontal or executive dysfunction related to wandering and risky behaviours among males, and limbic or affective vulnerability related to hallucinations and irritability among females,” they added.
Taken together, the study provides important insights into the effects of climate change and heatwaves on individuals with dementia and highlights the need for sex-specific monitoring of BPSD during heat events.