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Disparities by Race in Heat-Related Mortality in Four US Cities: The Role of Air Conditioning Prevalence

DOI:10.1093/jurban/jti043
Authors:
Marie O'Neill at University of Michigan
Marie O'Neill
Antonella Zanobetti at Harvard University
Antonella Zanobetti
Joel Schwartz at Harvard University
Joel Schwartz
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Abstract

Daily mortality is typically higher on hot days in urban areas, and certain population groups experience disproportionate risk. Air conditioning (AC) has been recommended to mitigate heat-related illness and death. We examined whether AC prevalence explained differing heat-related mortality effects by race. Poisson regression was used to model daily mortality in Chicago, Detroit, Minneapolis, and Pittsburgh. Predictors included natural splines of time (to control seasonal patterns); mean daily apparent temperature on the day of death, and averaged over lags 1-3; barometric pressure; day of week; and a linear term for airborne particles. Separate, city-specific models were fit to death counts stratified by race (Black or White) to derive the percent change in mortality at 29 degrees C, relative to 15 degrees C (lag 0). Next, city-specific effects were regressed on city- and race-specific AC prevalence. Combined effect estimates across all cities were calculated using inverse variance-weighted averages. Prevalence of central AC among Black households was less than half that among White households in all four cities, and deaths among Blacks were more strongly associated with hot temperatures. Central AC prevalence explained some of the differences in heat effects by race, but room-unit AC did not. Efforts to reduce disparities in heat-related mortality should consider access to AC.
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Journal of Urban Health: Bulletin of the New York Academy of Medicine,
doi:10.1093/jurban/jti043
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Disparities by Race in Heat-Related Mortality in
Four US Cities: The Role of Air Conditioning
Prevalence
Marie S. O’Neill, Antonella Zanobetti, and Joel Schwartz
ABSTRACT Daily mortality is typically higher on hot days in urban areas, and certain
population groups experience disproportionate risk. Air conditioning (AC) has been
recommended to mitigate heat-related illness and death. We examined whether AC
prevalence explained differing heat-related mortality effects by race. Poisson regression
was used to model daily mortality in Chicago, Detroit, Minneapolis, and Pittsburgh.
Predictors included natural splines of time (to control seasonal patterns); mean daily
apparent temperature on the day of death, and averaged over lags 1–3; barometric
pressure; day of week; and a linear term for airborne particles. Separate, city-specific
models were fit to death counts stratified by race (Black or White) to derive the percent
change in mortality at 29 ºC, relative to 15 ºC (lag 0). Next, city-specific effects were
regressed on city- and race-specific AC prevalence. Combined effect estimates across all
cities were calculated using inverse variance-weighted averages. Prevalence of central
AC among Black households was less than half that among White households in all
four cities, and deaths among Blacks were more strongly associated with hot tempera-
tures. Central AC prevalence explained some of the differences in heat effects by race,
but room-unit AC did not. Efforts to reduce disparities in heat-related mortality should
consider access to AC.
KEYWORDS Air conditioning, Climate, Ethnic groups, Heat, Mortality, Socioeconomic
factors, Weather.
INTRODUCTION
Black race, lower educational attainment, age, death outside a hospital, and lack of
access to air conditioning (AC) modify associations between ambient temperatures
and daily mortality.
1–5
Because AC can protect people from heat-related
mortality
1,6
and access to AC and resources to use it may differ by race, we evalu-
ated whether AC played a role in previously reported racial disparities in heat-
related mortality.
5
Dr. O’Neill is with The Robert Wood Johnson Health & Society Scholars Program, Center for Social
Epidemiology and Population Health, University of Michigan, Ann Arbor, Michigan; Drs. Zanobetti and
Schwartz are with the Department of Environmental Health, Harvard School of Public Health, Boston,
Massachusetts; and Dr. Schwartz is with the Department of Epidemiology, Harvard School of Public
Health, Boston, Massachusetts.
Correspondence: Marie S. O’Neill, PhD, The Robert Wood Johnson Health & Society Scholars
Program, Center for Social Epidemiology and Population Health, University of Michigan, 1214 South
University Avenue, Room 249, Ann Arbor, MI 48104-2548. (E-mail: marieo@umich.edu)
2 of 7 O’NEILL ET AL.
METHODS
Data Sources
Mortality and environmental data were described previously.
5
Briefly, daily, nonin-
jury mortality counts were obtained for 1986–1993 and stratified by race (Blacks
and Whites). This analysis used data for the metropolitan area (defined by county)
of four cities: Chicago, Illinois; Detroit, Michigan; Minneapolis and St. Paul,
Minneapolis (“Minneapolis” in this article); and Pittsburgh, Pennsylvania. Here,
the term city refers to these metropolitan areas. We chose these cities because they
had an adequate number of hot days for estimating heat–mortality associations,
daily information on air pollution (which has been associated with daily
mortality
7
), and AC prevalence data. Between 1986 and 1993, 684,847 people died
in the four areas.
Weather data were from the airport station closest to each city. Apparent tem-
perature, an index of human discomfort, was calculated from ambient temperature
and dew point, as described previously.
5
Barometric pressure and concentrations of
particulate matter less than 10 microns in aerodynamic diameter (PM
10
) were also
covariates for this analysis. PM
10
can be inhaled into the lungs and has been linked
with several adverse health outcomes.
8
The American Housing Survey collects data on AC prevalence (central and one;
two; three or more room units) about every 4 years, sampling 4,800 or more housing
units per metropolitan area.
9
Between 1986 and 1993, two surveys were adminis-
tered in each of the four cities. City-specific AC prevalence was averaged from those
two surveys and applied over the entire study period. Prevalence was reported by
race/ethnicity (Black, Hispanic, and total). Because we lacked Hispanic mortality
data for the whole study period, we report AC prevalence statistics by Black house-
holds and “White/Other” (i.e., households not reported as being Black or Hispanic).
Statistical Methods
Robust Poisson regression was used to model daily death counts as the dependent
variable in models fit individually for each city. Independent variables included a
linear term for mean PM
10
on the day of death and the previous day and natural
cubic splines of mean daily barometric pressure, day of week, and day of study.
Because of the nonlinear dependence of mortality on temperature and previous
research showing differing lag structures for hot- and cold-weather mortality,
10
we
used two cubic splines to model temperature. The cold term was temperature aver-
aged over lags 1–3, and the heat term was temperature at lag 0. Other details of
model fitting criteria are described elsewhere.
5
City-specific regressions were fit to
daily death counts among Blacks and Whites, and a combined four-city effect esti-
mate was calculated for each race by using inverse variance-weighted averages.
To evaluate the effects of AC prevalence, we performed a meta-regression with
a model of the following form:
β
ij
=C
0
+
γ
Z
ij
+ε
ij
where
β
ij
is the coefficient for the effect of 29°C heat, at lag 0 in city i, stratum j
(Blacks or Whites), and
γ
Z
ij
is the AC prevalence in city i, stratum j. The expected
value of
ε
ij
is assumed zero, and the variance of
ε
ij
is represented as σ
ij
2
+σ, where σ
ij
2
is the estimated standard error of
β
ij
within city and stratum, and σ is the heterogeneity
DISPARITIES BY RACE IN HEAT-RELATED MORTALITY 3 of 7
in the β
ij
not explained by AC prevalence. The C
0
and γ are estimated with inverse
variance-weighted least squares regression, and between-city variance σs were esti-
mated with iterative maximum likelihood estimation.
11
A random effect for city
accounted for heterogeneity among the four cities.
RESULTS
Environmental variables for the four cities were reported previously.
5
They all had
comparable maximum mean daily apparent temperatures (range =34.3–36.9 °C).
Mean levels of particles and other meteorological variables were also similar. About
40% of those who died in Detroit during the study period were Black; the corre-
sponding percentages were 28 in Chicago; 11 in Pittsburgh; and 4 in Minneapolis,
consistent with city demographics (Table 1).
In all four cities, central AC prevalence in the “White/Other” households
was more than double the central AC prevalence in Black households (Table 2).
Pittsburgh had the lowest overall prevalence of central AC, at 25%, and Minneapolis
the highest, at 47%. There was less variation by race in room-unit AC prevalence
and no consistent pattern of differences by race.
Table 3 summarizes city-specific heat effects by race (also reported in O’Neill
et al.
5
) and the pooled effect across the four cities. In each city, heat-associated mor-
tality was higher among Blacks, and the pooled effect showed an effect among
Blacks over twice that among Whites.
TABLE 1. Demographics of four metropolitan areas, 1986–1993
Chicago Detroit Minneapolis Pittsburgh
Total population (million) 5.11 2.11 1.52 1.34
Black (%) 26 40 5 11
TABLE 2. Air conditioning (AC) prevalence by household race
9
Prevalence statistics are means of the two survey years.
*Reporting one or more room-unit air conditioners.
†All households in the survey not reported as Black or Hispanic.
AC (%)
City Years Population Central Room unit*
Chicago 1987, 1991 Total 41 35
Blacks 16 32
Whites/Other† 49 35
Detroit 1989, 1993 Total 35 26
Blacks 17 30
Whites/Other 39 25
Minneapolis 1989, 1993 Total 47 26
Blacks 21 19
Whites/Other 48 27
Pittsburgh 1986, 1990 Total 25 33
Blacks 10 46
Whites/Other 26 33
4 of 7 O’NEILL ET AL.
In the meta-regression, for each 10% increase in central AC prevalence, heat-
associated mortality, pooled across all four cities, dropped by 1.4% (95% CI =−0.1
to 2.9), a marginally significant result. The overall effect of heat on mortality (the
effect of heat in a city with a 0% prevalence of central AC) was a 10.2% increase
(95% CI =4.5–16.2). Applying the 1.4% estimated drop in mortality to the average
difference in AC prevalence between Blacks and White/Other across all four cities
(24%) suggests that differences in central AC prevalence explain no more than a
3.4% difference in heat-related mortality. Blacks had 5.3% higher heat-related
mortality than Whites (Table 2); therefore, as much as 64% of this disparity is
potentially attributable to central AC prevalence.
Excess heat-related mortality with 0% room-unit AC prevalence was estimated
with meta-regression at 2.5% (95% CI=−13.6 to 21.7). Each 10% increase in
room-unit AC prevalence was associated with a 0.95% increase in heat-associated
mortality (95% CI =−4.4 to 6.5).
Because there was less of a gradient in room-unit AC prevalence and no consis-
tent pattern of disparities by race, this variable had limited utility in this analysis.
Figure shows central AC prevalence plotted against the coefficients reflecting the
size of the association between heat and mortality by city and race. Higher heat and
mortality associations and lower central AC prevalence were seen for Blacks. Cen-
tral AC prevalence varied little among Black households across the cities.
DISCUSSION
Heat-related mortality in four US cities was reduced with increasing central AC
prevalence, and substantially higher effects of heat on mortality were observed
among Blacks compared with Whites. A large proportion of the disparity in heat-
related mortality may be due to differences in central AC prevalence. Room-unit
AC prevalence showed little effect on heat-related mortality and no consistent pat-
tern of disparities by race.
Several previous studies showed both Black race and lack of AC as indicating
vulnerability to heat-related health effects.
1–6
Heat-related mortality associations
were higher in areas with lower AC prevalence, even after adjusting for latitude.
4
Access to AC has been recommended as a key component of efforts to prevent heat-
related deaths.
12–14
Among 72,420 US residents, hot-weather death rates from 1980
to 1985 were 42% lower among people with central AC compared with people
with no AC, and AC benefits were highest for women, the elderly, people not in the
labor force, and those in dwellings of less than six rooms.
6
Comparing room-unit
AC with no AC, the effect was not significantly different from zero, except among
TABLE 3. Percent change in daily mortality and 95% confidence intervals (CIs) associated with
29 °C apparent temperature, pooled and city specific (1988–1993 for Chicago, 1986–1993 for
other cities)
Estimates are relative to 15 °C apparent temperature and control for barometric pressure, PM
10
, time trend,
day of week, and apparent temperature averaged over lags 1, 2, and 3 (heat effect is expressed for apparent
temperature lag 0).
Pooled Chicago Detroit Minneapolis Pittsburgh
Total mortality 4.6 (2.6–6.7) 4.5 (2.3–6.7) 7.5 (4.2–10.8) 2.4 (−2.1 to 7.1) 3.1 (−0.5 to 6.9)
Black 9.0 (5.3–12.8) 5.9 (2.0–9.9) 12.0 (6.8–17.4) 17.0 (−7.8 to 48.4) 12.5 (1.4–24.8)
White 3.7 (1.9–5.4) 4.1 (1.5–6.7) 5.5 (1.4–9.7) 2.3 (−2.4 to 7.1) 2.0 (−1.7 to 6.0)
DISPARITIES BY RACE IN HEAT-RELATED MORTALITY 5 of 7
people whose dwellings had one to three rooms, where room-unit AC was benefi-
cial.
6
An inverse association between expected risk of death at 30 °C and prevalence
of central AC, with 33% of the variation in heat-associated mortality explained by
AC prevalence, was seen in 12 US cities.
10
Central AC prevalence is likely correlated with other area socioeconomic char-
acteristics indicating vulnerability to mortality on extreme temperature days
15
;
therefore, the explanatory power of this variable probably reflects influences of
these other factors. During a 1995 heat wave in Chicago, social contacts, mobility,
affordability of electricity, and sense of personal security affected whether people
had adequate ventilation and cooling in their homes.
16
These factors differed across
small-scale geographic areas (neighborhoods). The AC prevalence statistics used for
this study were aggregated by city, limiting conclusions about smaller-scale neigh-
borhood characteristics. Because room-unit AC prevalence patterns differed by city
and race, this study design was not able to provide insights into whether these units
are beneficial at the population level, though intuition would suggest that they
would be. Studies examining individual-level data on AC use and ownership would
be required to further evaluate this question.
Although the number of deaths occurring in the four cities was substantial, con-
fidence intervals for the meta-regression results were wide. Additionally, Figure
shows substantial scatter in the relationship between central AC prevalence and
the heat and mortality effect. For heat-related mortality among Whites, Pittsburgh
10 20 30 40 50
5
1.001.050
.
00.0
10 20 30 40 50
5
1.001.050
.
00.0
Percent AC prevalence
tneiciffeocytilatrom/taeH
Pittsburgh
Chicago
Detroit
Minneapolis
Pittsburgh
Detroit
Chicago
Minneapolis
FIGURE. Coefficients for the relative risk of mortality on days at 29 °C apparent temperature com-
pared with days at 15 °C, by prevalence of central air conditioning (AC), race, and city. ▲, Whites
(and Whites/Others, for AC prevalence); ■, Blacks. Coefficients are from Poisson regression models
with covariates including barometric pressure, PM
10
, time trend, day of week, and apparent tem-
perature averaged over lags 1, 2, and 3 (heat effect is expressed for apparent temperature lag 0).
Data cover the period 1986–1993.
6 of 7 O’NEILL ET AL.
represented the greatest outlier in the group. The other three cities may be represen-
tative of US cities. Future analyses with more cities would help increase confidence
in the results.
In spite of these limitations, the findings of this study are consistent with previous
observations that central AC use is protective against heat-related mortality. They
also suggest that the strong racial disparities in heat-related mortality are partially
explained by central AC prevalence or other socioeconomic factors correlated with
central AC prevalence that differ by race. Outreach programs to reduce heat-
related mortality, which commonly include ensuring access to cool environments,
17
should take into account demographic patterns in AC prevalence to ensure equita-
ble protection.
ACKNOWLEDGEMENT
This work was supported in part by the National Institute of Environmental Health
Sciences (NIEHS), National Institutes of Health (NIH) (grant 2 T32 ES07069-24).
Its contents are solely the responsibility of the authors and do not necessarily repre-
sent the official views of NIEHS, NIH. (Additional funding sources include grants
NIEHS ES00002 and EPAR827353.)
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Studies on the relationship between temperature and local, small scale mobility are limited, and sensitive to the region and time period of interest. We contribute to the growing mobility literature through a detailed characterization of the observed temperature‐mobility relationship in the San Francisco Bay Area at fine spatial and temporal scale across two summers (2020–2021). We used anonymized cellphone data from SafeGraph's neighborhood patterns data set and gridded temperature data from gridMET, and analyzed the influence of incremental changes in temperature on mobility rate (i.e., visits per capita) using a panel regression with fixed effects. This strategy enabled us to control for spatial and temporal variability across the studied region. Our analysis suggested that all areas exhibited lower mobility rate in response to higher summer temperatures. We then explored how several additional variables altered these results. Extremely hot days resulted in faster mobility declines with increasing temperatures. Weekdays were often more resistant to temperature changes when compared to the weekend. In addition, the rate of decrease in mobility in response to high temperature was significantly greater among the wealthiest census block groups compared with the least wealthy. Further, the least mobile locations experienced significant differences in mobility response compared to the rest of the data set. Given the fundamental differences in the mobility response to temperature across most of our additive variables, our results are relevant for future mobility studies in the region.
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... The underlying factors for this vulnerability include agerelated impairments in body thermoregulation [3,4]; diminished thermal sensitivity that leads to hindered behavioral adaptations [5,6]; decline in cognitive functions [7][8][9] associated with increased risk of fall injury [10]; and adverse effects of certain chronic diseases [11] or medications [12]. The risk of extreme thermal conditions on elderly from low-income groups is even higher [2,[13][14][15][16], because they may not have access to cooling or heating, and even if they do, many may not be able to afford the cost of energy [17][18][19]. On the other hand, the proportion of elderly in societies is rising at unprecedented rates due to the increase in life expectancy and the decrease in human fertility [20]. ...
Enhancing sustainability and resilience of elderly dwellings: Optimized refurbishing parameters and air conditioning operation
Article
Refurbishing buildings to minimize lifecycle costs and increase reliance on natural ventilation may reduce building resilience to extreme weather. This is critical for elderly whose health is affected by exposure to thermally stressful conditions. This study proposes a novel approach for refurbishing elderly houses to enhance their sustainability and heatwave resilience with the aim of supporting low-income groups. This approach involves using multi-objective optimization to identify refurbishment parameters and an autonomous control strategy to provide thermoneutral indoor conditions at a low cost. The optimization procedure and control strategy were applied to a case study for a representative apartment in the Mediterranean climate using a validated building model. The strategy led to substantial reduction (61%) in cooling energy, while the optimization yielded Pareto solutions that showed trade-offs between lifecycle cost and resilience. A selected solution resulted in reduced electrical usage for heating (37%) and cooling (45%) and decreased indoor overheating during heatwaves. The study recommends design features for cost-effective and resilient elderly housing in the Mediterranean climate, such as limited window area, enhanced thermal properties, and a modest air conditioning system for low-income populations. Larger windows and AC systems are recommended for high income populations seeking reduced operational expenses and improved sustainability.
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... Poor housing characteristics have been shown to increase psychological distress [13] and increased air pollutant exposure for lower socioeconomic households [14]. Correspondingly, households comprised of members of historically underserved racial groups face disparities in air conditioning access, likely contributing to higher heat-related mortality in these populations [15]. Energy poverty is a public health issue [16,17] that is not formally recognized nationally despite state and local responses [2]. ...
Fleeting energy protections: State and utility level policy responses to energy poverty in the United States during COVID-19
Article
  • Mar 2023
Millions of American households suffer from energy poverty, threatening their continued access to electricity. The COVID-19 pandemic of 2020 has unveiled the entrenched environmental and energy injustices that threaten public health at the household level and has inspired energy protection responses to address pandemic-caused economic hardship. While policies supporting energy protections have been in place for years, they vary spatially. Moreover, the scholarly research that explores energy protection responses during the pandemic is limited. This paper explores energy protection responses to the pandemic implemented in 25 major metropolitan areas in the United States. We employ a content analysis of policy language to examine the response time, authorization level, and type of energy protections deployed during the initial months of the pandemic. We demarcate authorization level as either mandatory or voluntary measures and characterize 'energy resiliency responses' as a suite of residential energy protections required to reduce vulnerability to energy poverty and build resilience during the pandemic. We examine the total number and type of responses relative to household energy burden. We find differences in residential consumer energy protections among low-income and highly energy burdened households and conclude that protections are unevenly deployed across the country. Our findings motivate contemporary national, state, and local energy poverty recognition and responses that center personal and economic wellbeing during and after crises.
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... AC is the best protection against the adverse health effects of extreme heat. Cities with a higher AC prevalence experience fewer heat-related deaths [6][7][8]. Among New Yorkers who died of heat stress (i.e. the death was recognized and coded as caused by heat) from 2010 to 2019, 71% died in un-air-conditioned homes [2]. ...
Extreme Heat and COVID-19 in New York City: An Evaluation of a Large Air Conditioner Distribution Program to Address Compounded Public Health Risks in Summer 2020
Article
Full-text available
In summer 2020, New York City (NYC) implemented a free air conditioner (AC) distribution program in response to the threats of extreme heat and COVID-19. The program distributed and installed ACs in the homes of nearly 73,000 older, low-income residents of public and private housing. To evaluate the program's impact, survey data were collected from October 2020 to February 2021 via mail and online from 1447 program participants and 902 non-participating low-income NYC adults without AC as a comparison group. Data were examined by calculating frequencies, proportions, and logistic regression models. Participants were 3 times more likely to report staying home during hot weather in summer 2020 compared to non-participants (adjusted odds ratio [AOR] = 3.0, 95% confidence interval [CI] = 2.2, 4.1), with no difference between groups in summer 2019 (AOR = 1.0, CI = 0.8, 1.3). Participants were less likely to report that 2020 hot weather made them feel sick in their homes compared to non-participants (AOR = 0.2, CI = 0.2, 0.3). The program helped participants-low-income residents and primarily people of color-stay home safely during hot weather. These results are relevant for climate change health-adaptation efforts and heat-health interventions.
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The contribution of demographic changes to future heat-related health burdens under climate change scenarios
Article
Anthropogenic climate change will have a detrimental impact on global health, including the direct impact of higher ambient temperatures. Existing projections of heat-related health outcomes in a changing climate often consider increasing ambient temperatures alone. Population growth and structure has been identified as a key source of uncertainty in future projections. Age acts as a modifier of heat risk, with heat-risk generally increasing in older age-groups. In many countries the population is ageing as lower birth rates and increasing life expectancy alter the population structure. Preparing for an older population, in particular in the context of a warmer climate should therefore be a priority in public health research and policy. We assess the level of inclusion of population growth and demographic changes in research projecting exposure to heat and heat-related health outcomes. To assess the level of inclusion of population changes in the literature, keyword searches of two databases were implemented, followed by reference and citation scans to identify any missed papers. Relevant papers, those including a projection of the heat health burden under climate change, were then checked for inclusion of population scenarios. Where sensitivity to population change was studied the impact of this on projections was extracted. Our analysis suggests that projecting the heat health burden is a growing area of research, however, some areas remain understudied including Africa and the Middle East and morbidity is rarely explored with most studies focusing on mortality. Of the studies pairing projections of population and climate, specifically SSPs and RCPs, many used pairing considered to be unfeasible. We find that not including any projected changes in population or demographics leads to underestimation of health burdens of on average 64 %. Inclusion of population changes increased the heat health burden across all but two studies.
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A random-effects regression model for meta-analysis
Article
Full-text available
  • Feb 1995
Many meta-analyses use a random-effects model to account for heterogeneity among study results, beyond the variation associated with fixed effects. A random-effects regression approach for the synthesis of 2 x 2 tables allows the inclusion of covariates that may explain heterogeneity. A simulation study found that the random-effects regression method performs well in the context of a meta-analysis of the efficacy of a vaccine for the prevention of tuberculosis, where certain factors are thought to modify vaccine efficacy. A smoothed estimator of the within-study variances produced less bias in the estimated regression coefficients. The method provided very good power for detecting a non-zero intercept term (representing overall treatment efficacy) but low power for detecting a weak covariate in a meta-analysis of 10 studies. We illustrate the model by exploring the relationship between vaccine efficacy and one factor thought to modify efficacy. The model also applies to the meta-analysis of continuous outcomes when covariates are present.
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Air-conditioning and Mortality in Hot Weather
Article
A cohort of 72,740 persons for whom information on household air-conditioning was available was monitored for mortality via the National Death Index from April 1980 through December 1985. A total of 2, 275 deaths occurred among the members of this cohort. The basic question addressed was whether persons in households with air-conditioning experienced lower death rates during hot weather than persons in households without air-conditioning. This question was examined for both central and room air-conditioning. The analysis was based on a state-by-state approach, that cross-tabulated deaths by air-conditioning status (yes or no) and average temperature during the month of death (<21.2°C (<70°F) or >21.2°C (>70°F)). The Mantel-Haenszel and sign tests were used to summarize the data. For central air-conditioning versus no air-conditioning, statistically significant benefits (p < 0.05, Mantel-Haenszel test) were observed for the overall total, for females, for persons not in the labor force, and for persons living in fewer than six rooms. These groups had more exposure to air-conditioning. The relative risk for the total group was 0.58, implying that in hot weather, the death rate for persons who had central air-conditioning was 42 percent lower than the rate for persons who did not have air-conditioning, after confounding variables had been controlled for. For room air-conditioning versus no air-conditioning, the odds ratio for the total group was 0.96, which was not significantly different from 1.0, suggesting that no real benefit was derived from room air-conditioning. Some reasons for the lack of a demonstrable benefit for room air-conditioning are given.
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Heat Wave: A Social Autopsy of Disaster in Chicago
Article
  • Jan 2003
On Thursday, July 13, 1995, Chicagoans awoke to a blistering day in which the temperature would reach 106 degrees. The heat index, which measures how the temperature actually feels on the body, would hit 126 degrees by the time the day was over. Meteorologists had been warning residents about a two-day heat wave, but these temperatures did not end that soon. When the heat wave broke a week later, city streets had buckled; the records for electrical use were shattered; and power grids had failed, leaving residents without electricity for up to two days. And by July 20, over seven hundred people had perished-more than twice the number that died in the Chicago Fire of 1871, twenty times the number of those struck by Hurricane Andrew in 1992—in the great Chicago heat wave, one of the deadliest in American history. Heat waves in the United States kill more people during a typical year than all other natural disasters combined. Until now, no one could explain either the overwhelming number or the heartbreaking manner of the deaths resulting from the 1995 Chicago heat wave. Meteorologists and medical scientists have been unable to account for the scale of the trauma, and political officials have puzzled over the sources of the city's vulnerability. In Heat Wave, Eric Klinenberg takes us inside the anatomy of the metropolis to conduct what he calls a "social autopsy," examining the social, political, and institutional organs of the city that made this urban disaster so much worse than it ought to have been. Starting with the question of why so many people died at home alone, Klinenberg investigates why some neighborhoods experienced greater mortality than others, how the city government responded to the crisis, and how journalists, scientists, and public officials reported on and explained these events. Through a combination of years of fieldwork, extensive interviews, and archival research, Klinenberg uncovers how a number of surprising and unsettling forms of social breakdown—including the literal and social isolation of seniors, the institutional abandonment of poor neighborhoods, and the retrenchment of public assistance programs—contributed to the high fatality rates. The human catastrophe, he argues, cannot simply be blamed on the failures of any particular individuals or organizations. For when hundreds of people die behind locked doors and sealed windows, out of contact with friends, family, community groups, and public agencies, everyone is implicated in their demise. As Klinenberg demonstrates in this incisive and gripping account of the contemporary urban condition, the widening cracks in the social foundations of American cities that the 1995 Chicago heat wave made visible have by no means subsided as the temperatures returned to normal. The forces that affected Chicago so disastrously remain in play in America's cities, and we ignore them at our peril.
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Rogot E, Sorlie PD, Backlund E. Air-conditioning and mortality in hot weather
Article
A cohort of 72,740 persons for whom information on household air-conditioning was available was monitored for mortality via the National Death Index from April 1980 through December 1985. A total of 2,275 deaths occurred among the members of this cohort. The basic question addressed was whether persons in households with air-conditioning experienced lower death rates during hot weather than persons in households without air-conditioning. This question was examined for both central and room air-conditioning. The analysis was based on a state-by-state approach, that cross-tabulated deaths by air-conditioning status (yes or no) and average temperature during the month of death (less than 21.2 degrees C (less than 70 degrees F) or greater than or equal to 21.2 degrees C (greater than or equal to 70 degrees F)). The Mantel-Haenszel and sign tests were used to summarize the data. For central air-conditioning versus no air-conditioning, statistically significant benefits (p less than 0.05, Mantel-Haenszel test) were observed for the overall total, for females, for persons not in the labor force, and for persons living in fewer than six rooms. These groups had more exposure to air-conditioning. The relative risk for the total group was 0.58, implying that in hot weather, the death rate for persons who had central air-conditioning was 42 percent lower than the rate for persons who did not have air-conditioning, after confounding variables had been controlled for. For room air-conditioning versus no air-conditioning, the odds ratio for the total group was 0.96, which was not significantly different from 1.0, suggesting that no real benefit was derived from room air-conditioning. Some reasons for the lack of a demonstrable benefit for room air-conditioning are given.
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The epidemiology of heat-related deaths, Texas--1950, 1970-79, and 1980
Article
  • Aug 1983
A study of the deaths during a 1980 heat wave in Texas revealed death rates that were highest in males, the elderly, Blacks and those engaged in heavy labor, the latter two factors perhaps reflecting socioeconomic status. The data suggest that persistent high temperatures were related to death to a greater degree than the temperature peaks reached. Higher heat death rates in earlier years are believed to be attributable to the limited availability of air conditioning in those years.
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Heat-Related Deaths During the July 1995 Heat Wave in Chicago
Article
  • Aug 1996
During a record-setting heat wave in Chicago in July 1995, there were at least 700 excess deaths, most of which were classified as heat-related. We sought to determine who was at greatest risk for heat-related death. We conducted a case-control study in Chicago to identify risk factors associated with heat-related death and death from cardiovascular causes from July 14 through July 17, 1995. Beginning on July 21, we interviewed 339 relatives, neighbors, or friends of those who died and 339 controls matched to the case subjects according to neighborhood and age. The risk of heat-related death was increased for people with known medical problems who were confined to bed (odds ratio as compared with those who were not confined to bed, 5.5) or who were unable to care for themselves (odds ratio, 4.1). Also at increased risk were those who did not leave home each day (odds ratio, 6.7), who lived alone (odds ratio, 2.3), or who lived on the top floor of a building (odds ratio, 4.7). Having social contacts such as group activities or friends in the area was protective. In a multivariate analysis, the strongest risk factors for heat-related death were being confined to bed (odds ratio, 8.2) and living alone (odds ratio, 2.3); the risk of death was reduced for people with working air conditioners (odds ratio, 0.3) and those with access to transportation (odds ratio, 0.3). Deaths classified as due to cardiovascular causes had risk factors similar to those for heat-related death. In this study of the 1995 Chicago heat wave, those at greatest risk of dying from the heat were people with medical illnesses who were socially isolated and did not have access to air conditioning. In future heat emergencies, interventions directed to such persons should reduce deaths related to the heat.
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