The Effectiveness of Intervening on Social Isolation to Reduce Mortality during Heat Waves in Aged Population: A Retrospective Ecological Study

Abstract

Background: Heat waves are correlated with increased mortality in the aged population. Social isolation is known as a vulnerability factor. This study aims at evaluating the correlation between an intervention to reduce social isolation and the increase in mortality in the population over 80 during heat waves. Methods: This study adopted a retrospective ecologic design. We compared the excess mortality rate (EMR) in the over-80 population during heat waves in urban areas of Rome (Italy) where a program to reduce social isolation was implemented, to others where it was not implemented. We measured the mortality of the summer periods from 2015 to 2019 compared with 2014 (a year without heat waves). Winter mortality, cadastral income, and the proportion of people over 90 were included in the multivariate Poisson regression. Results: The EMR in the intervention and controls was 2.70% and 3.81%, respectively. The rate ratio was 0.70 (c.i. 0.54–0.92, p-value 0.01). The incidence rate ratio (IRR) of the interventions, with respect to the controls, was 0.76 (c.i. 0.59–0.98). After adjusting for other variables, the IRR was 0.44 (c.i. 0.32–0.60). Conclusions: Reducing social isolation could limit the impact of heat waves on the mortality of the elderly population.

Heat related health inequalities are rising

“…Currently, people with manual and casual occupations are nearly three times as likely to be without a garden, and individuals from some Black and ethnic minority communities are twice as likely to have minimal access to green spaces 2526. Older people in socially deprived communities are more vulnerable to heatwave related mortality—but community based interventions designed to reduce social isolation have been shown to help 27…”

“…25 26 Older people in socially deprived communities are more vulnerable to heatwave related mortality-but community based interventions designed to reduce social isolation have been shown to help. 27 We need to continue to invest in ways to minimise air pollution, a problem disproportionately affecting the most socioeconomically deprived. 28 High pollution and high temperatures have a synergistic effect that leads to increased respiratory, circulatory, and other health problems.…”

Changement climatique et santé des populations : vers un agenda de recherche interdisciplinaire

“…Plus largement, des études mettent en évidence des effets plus forts des températures élevées sur la mortalité parmi les populations socialement défavorisées [12][13][14], même si certains travaux ont au contraire plutôt documenté une majoration de l'effet dans des groupes socialement avantagés [15,16]. Par ailleurs, l'isolement social, mesuré de façons différentes selon les études, est associé à un effet plus fort des températures élevées sur la mortalité [17][18][19].…”

Measuring heat vulnerability with models, maps, and workshops

“…In addition, elderly individuals may also have limited mobility, making accessing cooler environments more challenging. Studies also suggest that elderly individuals are isolated and have limited social support, which can make it difficult to receive aid during EHEs, further increasing their vulnerability to EHEs [79], [80].…”