Table 2.

Summary of selected studies.

Author and Year	Country	Objectives	Subjects	Study Design	Intervention or Factors	Outcomes	Recommendations
Hansen et al. 2011 [43]	Australia	Investigate heat-susceptibility in older people and perceived adaptation barriers during heatwaves in Adelaide	n = 35 four groups of health providers, managers and policy makers	Telephone interviews and focus groups	Questioning respondents knowledge of risks to older people and barriers to adaptive behaviours	Respondents identified physiological (poor health, chronic conditions, functional disabilities), socioeconomic issues (costs associated with running air-conditioners), psychological issues (anxieties, cognitive dysfunction), and barriers/enablers to adaptive strategies	Clear instructions on operation of air-conditioners Energy rebates for older people Specific strategies for specific medical conditions
Hansen et al. 2015 [44]		Investigate prevention behaviours (PB) of independently living residents in South Australia and Victoria	n = 1000 ≥65	Cross-sectional Telephone survey	Demographics, social contacts, self-evaluated health status, coping strategies, medications, air conditioning, and heat warnings	Most demonstrated PB; More heat warnings recall and AC in South Australia vs. Victoria; Female sex, chronic illness sufferers reported increased morbidity	Review current policies Disseminate heat warnings via media and SMS
Ibrahim et al. 2012 [45]		Investigate healthcare providers current practices to care for older people living independently in Victoria	n = 327 Six groups	Cross-sectional electronic survey	32 questions - demographic, professional characteristics, heatwave impacts, heat health knowledge, current practices to treat heat-related illness	Most aware of danger to older people; Gaps in knowledge: thermo-regulation, electric fans use and most critical time to offer help; Few emergency plans in place; Reactive and opportunistic in practices	Emergency response plans needed Improvement required in knowledge Call for a more proactive approach
McInnes et al. 2010 [46]		Investigate roles of community organisations and health providers in reducing harm to older people living independently in Victoria	n = 12 Four groups	Cross-sectional study, face-to-face and telephone survey	Semi-structured interviews exploring their roles in an heatwave emergency and issues such as coordination, identification of high-risk persons and training/education	No formal heat action plans (HAPs); At-risk individuals identified prior to summer; Good communication networks available, potentially able to provide appropriate care but lacking coordination and training; Mainly reactive and opportunistic activities	Need formalised heat action plans More proactive strategies and practices More resources and training needed Develop ’buddy’ system of volunteers
Nitschke et al. 2013 [47]		Investigate resilience, prevention behaviours, risk factors and health outcomes of independently living residents in South Australia	n = 499 ≥65	Cross-sectional computer assisted telephone survey	Survey explored demographics, housing, social connectedness, self-reported health status and vulnerability, heat health knowledge and resilience	Majority are resilient; Variety of prevention behaviours reported; High medication usage for chronic diseases, female sex, mobility aids, chronic diseases, mental health increased risk and poorer outcomes; Less social contact for those <75	Targeted intervention required to address medication use, co-morbidities, knowledge improvement and social isolation Policy development required
Nitschke et al. 2016 [48]		Investigate effectiveness of heatwave warning system in Adelaide	Residents of all ages	Comparing morbidity–mortality data ecological design	Incidence rate ratios (IRRs) of daily ambulance call-outs, emergency presentations and mortality data from 2009 and 2014 heatwaves	Significant reduction in morbidity especially emergency presentations in 75+ group; No reduction in mortality rate	In-depth assessment of services provided during heatwave including reach and behaviour change More studies into mortality risks factors
Nitschke et al. 2017 [49]		Investigate effectiveness of targeted information in preventing adverse health outcomes during heatwave	n = 637 ≥65	RCT	Intervention group provided with specific instructions on heat protective measures; Control group advised to follow media and seek own medical assistance as needed	Higher use of AC, wet cloth on face/body and significant heat stress reduction in intervention group; Control group also demonstrated protective behaviours through media	Results generalizable to other older people population in SA Further studies on built environment thermal comfort, social services, GPs active involvement
Liotta et al. 2018 [50]	Italy	Assess effectiveness of long live the elderly (LLE) program in reducing heat-related mortality from social isolation of independently living residents	n = 12207 ≥75	Quasi- experimental retrospective cohort study	Intervention group given social support and all health needs via both formal institutions and volunteers; No extra support for control group; Mean property tax evaluation determined SES	Mortality rate reduced 13% under LLE with 25 deaths averted; LLE indirectly reduced impact of low SES and mortality	Routine assessments of older people and provision of case-specific social services could improve health outcomes during heatwaves
Michelozzi et al. 2010 [51]		Analyse current practices and methodologies of the Italian national heat prevention program	93% residents ≥65 across 34 cities	Examine dose– response relationship between mortality and maximum apparent temperature (MAT)	Assessing strengths and limitations of different methods to monitor daily summer mortality in 2008, 2003 and reference period 1995–2002, using Rome and Milan as examples	Mortality (MAT) differed across cities; City-specific warning systems, coordinated central information network, constant modulation of preventative measures major strengths; Specific prevention programs ensured timely mitigation measures; Reduction in mortality rate attributable to prevention strategies	Implement local registries to identify vulnerable individuals - ensures uniform identification At-risk individuals require specific home-care plans Further assessment of heat mitigation plans required
Schifano et al. 2012 [52]		Investigating effectiveness of heatwave prevention plans post-2003	Residents ≥65 across 16 cities	Multi-centre time series (1998–2002) vs. (2006–2010) random effect multi-variate meta-analysis	Comparing 16 city-specific daily mortality rates pre and post heat prevention measures, by studying relationships between mortality and maximum apparent temperature	Observable reduction in effects of high temperature on mortality rates attributable to mitigation plans	More attention needed at beginning of summer when populations yet to adapt to heat and prevention activities not yet fully functional, and end of summer when the effect of heat is stronger
Benmarhnia et al. 2016 [53]	America/Canada	Investigating causal effects heat action plans (HAP) and association with different subgroups	Male vs. Female; ≥65 vs. <65; Education first vs. third tertile	Quasi-experimental retrospective - difference-in-differences approach	Comparing daily mortality rates (2000–2003) and post-HAP introduction (2004–2007)	A reduction in 2.52 deaths per day overall with 2.44 deaths per day less for older people ≥ 65; A 2.48 deaths per day less for low SES group; No differences between genders	Specifically targeting vulnerable population may reduce inequalities between populations More frequent home visits and daily phone calls to more at-risk individuals
Sheridan 2007 [54]		Investigate efficacy - four heat warning systems in Dayton, Philadelphia Phoenix, Arizona, Toronto	n = 908 ≥65	Cross-sectional telephone survey	Perception of own vulnerability, knowledge of prevention behaviour and course of action during heatwaves	Most aware of heat warnings but few understood what to do; Only ~ half changed behaviour; Main source of warnings from television and radio	Broadcast specific/easy to understand heat health advisories Address warnings ’blocking out’/confusion Explain safe use of electric fans
White-Newsome et al. 2011 [55]		Investigate behaviours and adaptability to increased indoor temperatures and environment in Detroit	n = 29 Aged >65	Cross-sectional survey of volunteered residents	Data collection via hourly activity logs of eight heat-adaptive behaviours	Indoor temperature significantly influenced behaviour; More adaptive behaviours in high-rises and highly impervious areas; Changing clothes, taking additional showers and going outside rarely used	Public health interventions outreach to this vulnerable group to encourage full range of prevention behaviours
Abrahamson et al. 2009 [56]	UK	Explore frontline healthcare professionals’ risks awareness and support for older people at risk of heatwaves adverse effects and perceived barriers to effective implementation of HAP	n = 109 covering three different socio-economic areas	Semi-structured interviews and focus groups	Awareness of details of HAP; opinions of self and organizations’ ability to identify and prioritize high-risk individuals; barriers and facilitators to effective implementation of HAP	Poor awareness of HAP from health professionals; Summer workloads not prioritised with older people in mind citing complexities and classification of vulnerability and infrequency of heatwaves as barriers	Multidisciplinary approach to interventions recommended Further evaluation of existing practices
Abrahamson et al. 2009 [57]		Investigate knowledge, perceptions of heat health risks, and protective behaviours of older people living independently	n = 73 Aged 72–94	Semi-structured interviews	Face-to-face interviews with subjects recommended by GPs	Few respondents considered themselves old or vulnerable or at risk of heat related illness, despite being aware of comorbidities; Most respondents disliked ’nanny state’ approach of intervention	Imbed warnings into favourite TV programs Clear/easy to understand instructions Focus on most ’at-risk’ individuals by health professionals Warn community rather than targeting individuals
Wolf et al. 2010 [58]		Investigate older people self-reported vulnerability and subsequent influence on adaptive behaviour	n = 105 Aged 72–94 in Norwich and London	Semi-structured interviews and open-ended questions. Respondents (A) and nominated people (B) to whom they turned to for assistance also interviewed	Perceptions and knowledge of heat risks explored including daily routine, socialisation habits, physical activity, actual/hypothetical behavioural changes in response to heatwaves, barriers to do so, medical conditions and medications, and type of housing.	Most (A) did not think they were vulnerable nor perceive heatwaves as a threat to themselves; They did not understand the increased risks associated with certain medical conditions and medications; Reported behaviours more towards coping rather than mitigation; (B) respondents displayed inconsistent and limited knowledge of heat risks; Also (B) did not want to impinge on (A) independence; Potentially exacerbate (A) vulnerability	Further research into the role of bonding social capital and climate change adaptation Definite need to address barriers in mitigating behaviours Call for government initiatives to finance local social development such as community groups in providing support thus empowering the older people Re-evaluation of adaptation strategies and policy effectiveness
Herrman et al. 2018 [59]	Germany	Investigate GPs perceptions on susceptibility and nursing care of older people during heatwaves in Baden-Württemberg	n = 24 over four districts	Face-to-face semi-structured interviews, Qualitative software analysed	Exploring knowledge of heatwaves, perceptions of older people morbidity and mortality risks factors and impact levels of future climate change to their well-being	Inconsistent knowledge of heatwaves amongst GPs; Variable levels of concern for older people heat–health based on varied perceptions of risks; Demonstrable uncertainties on impact of climate change on health	More training for GPs on climate change and heatwaves impacts on older people’s health Increase social support and nursing care for older people in extreme weather and heatwaves
Takahashi et al. 2015 [60]	Japan	Investigate improvement in prevention behaviours and heat health knowledge of older people in Nagasaki	n = 1524 aged 65–84 selected via stratified random sampling	Randomised controlled community trial	Three groups: 1. Heat health warnings + pamphlets 2. Heat health warnings + water bottles + pamphlets 3. Control group	Group 1 took more breaks, reduced activities, wore hats and sun block; Group 2 improved protective behaviours significantly - increased water intake and body cooling; All—poor knowledge of fans usage	Both individual and community based approaches are required for optimal improvement in heat health knowledge and prevention behaviours

HAP: Heat action plan.