City-level impact of extreme temperatures and mortality in Latin America

Abstract

Climate change and urbanization are rapidly increasing human exposure to extreme ambient temperatures, yet few studies have examined temperature and mortality in Latin America. We conducted a nonlinear, distributed-lag, longitudinal analysis of daily ambient temperatures and mortality among 326 Latin American cities between 2002 and 2015. We observed 15,431,532 deaths among ≈2.9 billion person-years of risk. The excess death fraction of total deaths was 0.67% (95% confidence interval (CI) 0.58–0.74%) for heat-related deaths and 5.09% (95% CI 4.64–5.47%) for cold-related deaths. The relative risk of death was 1.057 (95% CI 1.046–1.067%) per 1 °C higher temperature during extreme heat and 1.034 (95% CI 1.028–1.040%) per 1 °C lower temperature during extreme cold. In Latin American cities, a substantial proportion of deaths is attributable to nonoptimal ambient temperatures. Marginal increases in observed hot temperatures are associated with steep increases in mortality risk. These risks were strongest among older adults and for cardiovascular and respiratory deaths.

Heating up

“…An attribution study showed that climate change increased heat-related mortality risk during the 2003 European heatwave -with the highest increase of approximately 70% occurring in central Paris 2 . Alongside the risks associated with heatwaves themselves, a recent study showed that higher ambient temperatures in Latin America increased the risk of premature death by 5.7% per 1 °C increase 3 . Another study considering data covering 43 countries and the period 1991-2018 showed that 37% of heat-related deaths in the warm seasons could be attributed to climate change 4 .…”

Increased risk of cardiovascular disease in cold temperatures

“…The intricate relationships between environmental, lifestyle and genetic factors and their respective and collective involvements in the risk development of CVD poses a colossal challenge to decreasing global burdens [2][3] . Despite difficulties in pinpointing underlying causes for exacerbating CVD, multiple studies have clearly illuminated the impact that climate and temperature, especially cold weather [4][5] and the winter season [6][7] , impose on the incidence of cardiovascular events.…”

Global Population Exposure to Extreme Temperatures and Disease Burden

“…The frequency, intensity, and duration of extreme temperature events are expected to rise worldwide, prompting a sharp increase in population exposure to extreme temperatures in the coming decades [ 1 , 2 , 3 , 4 ]. Although several studies have documented the health risks associated with extremely cold and extremely hot temperatures, a globally comprehensive understanding of population exposure to extreme temperatures is lacking [ 5 , 6 , 7 , 8 , 9 ], and the scale of population exposure and its quantitative relationship with health risks remain unknown. This restricts our ability to identify how to distribute resources to deal with emerging health risks (reducing population-wide exposure versus increasing the resistance of vulnerable populations) [ 1 , 3 , 10 ].…”

“…Furthermore, the effects of extreme temperature have been found to be heterogeneous [ 1 , 9 , 11 , 20 ]. Despite there being several studies in low-income and middle-income countries (LMICs), an increasing number of studies are reporting that low socioeconomic status (SES) is associated with stronger temperature-related mortality, because LMICs lack the human and financial resources to deal with extreme temperatures [ 7 , 21 ].…”