Community-dwelling older persons’ level of functional ability and heat-related vulnerability: results from the Heat-Health Action Plan study in Cologne, Germany

BACKGROUND: Climate change has intensified significantly across the globe in recent decades. Among others, the 65 + age group and those with certain pre-existing illnesses are at risk. To date, functional ability, as proposed in the WHO framework on Ageing and Health, is not addressed in Heat-Health Action Plans (HHAP). Our study aimed to explore the significance of considering the functional ability to identify individuals at risk during episodes of heat in the 65 + age group. METHODS: Two hundred fifty-eight community-dwelling older adults aged 65 + from the Cologne HHAP Study Group (mean age: 74.1, 50.8% female) were assessed in four carefully selected locations representing the city's range in both socioeconomic status (affluent vs. deprived) and objective thermic exposure (less vs. highly heat-impacted). Questionnaire-based, face-to-face interviews were performed covering heat-related areas. Levels of functional ability were assessed using the LUCAS Functional Ability Index (robust, post-robust, pre-frail, frail); care levels (disability) were determined according to the German Medical Advisory Services. RESULTS: The distinction between functionally robust (62%) and functionally disadvantaged (38%) participants has a significant impact on identifying heat-related vulnerability which cannot be identified using chronological age groups (65-74: 55%, 75 + : 45%). During heat events, functionally disadvantaged persons perceived higher levels of heat strain (p = 0.005), were more worried about their health (p < 0.001) and perceived significantly more symptoms such as tiredness, headaches or dizziness. Functionally robust participants changed their outdoor mobility significantly less during heat events (p = 0.025) and more often used the internet as an information source about heat warnings (p = 0.005). CONCLUSIONS: This study shows that considering healthy ageing from the perspective of functional ability rather than focusing on chronological age has the potential to more precisely address those community-dwelling older people living with functional decline, frailty or disability who are most vulnerable in heat situations. The measurement of functional ability by screening community-dwelling older people with a self-administered questionnaire on functional resources and risks proved to be a good asset in evaluating persons with high heat-related vulnerability in the heterogeneous older population.