The Impact of Temperature on Mortality …
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census regions (Fig. 2), and age group and gender (Fig. 3). Figure 2 shows that for
all regions, colder than (the national) average temperatures have at same point of the
curve a positive and statistically significant impact on mortality rates. For instance,
one additional day in a month with a mean daily temperature of 9.4
◦ C increases
annual mortality by 4.6 pp (95% CI: 3.38–5.79) in Buenos Aires metropolitan area
(Panel A). In the same fashion, an additional day of 5.6
◦ C rises annual mortality risks
by 5.2 (95% CI: 2.37–8.08) in the Pampean region (Panel B). In the northeast (Panel
C), a day of 8.33
◦ C increases mortality by 8.3 pp (95% CI: 0.54–16.05), while in
the northwest region (Panel D) a day with mean daily temperature of 10.55
◦ C raises
mortality by 7.83 pp (95% CI: 3.81–11.87). Finally, in the western region of Cuyo
(Panel E) an additional day of temperature around 2
◦ C raises local mortality rates
by 10.02 pp (95% CI: 2.47–17.57). Again, the estimated impacts are relative to a one
less day in a month with mean daily temperature of 18.9
◦ C, which is the national
average temperature.
Figure 3 provides evidence of heterogeneous impacts by age group (females in
Panel A and males in Panel B). Only the elderly are affected by extreme temperatures, but colder than average temperatures seem to be more likely to be statistically
significantly different from a day with 18.9
◦ C. Also, cold temperatures have a greater
impact on male mortality risks, with no apparent difference between sexes for hotter
than normal temperatures.
Discussion
Environmental factors are important determinants of human health. Recently, due to
global warming and the recurrence of heat waves, the attention has been placed on
how weather affects health outcomes, among which mortality has captured the most
attention.
The existing literature, mainly for developed countries, has pointed to a U-shaped
type of relationship between temperature and mortality risks. Using flexible regression models over longitudinal monthly weather and mortality data for 322 municipalities spanning January 2004 and December 2010, this study has confirmed this
relationship from a countrywide perspective.
We found a significant impact of both cold and hot days on mortality risks; however, colder than average temperatures have a greater effect on mortality. This finding
holds irrespective of using the daily mean, maximum, or minimum temperatures.
Using a comparable methodology applied for US counties, Barreca and Shimshack
(2012) also reported a similar association between colder temperatures and influenza
mortality, although their work concerned mainly with the impact of absolute humidity. Almeira et al. (2016) also report a higher susceptibility to colder extremes than to
hotter temperatures in the cities of Buenos Aires and Rosario. An additional interesting result is that hotter than average temperatures have no impact when splitting the
data by regions. In particular, we found no significant impact of hotter than average
temperatures in Buenos Aires metropolitan area. In contrasts, De Garín and Bejarán
11
census regions (Fig. 2), and age group and gender (Fig. 3). Figure 2 shows that for
all regions, colder than (the national) average temperatures have at same point of the
curve a positive and statistically significant impact on mortality rates. For instance,
one additional day in a month with a mean daily temperature of 9.4
◦ C increases
annual mortality by 4.6 pp (95% CI: 3.38–5.79) in Buenos Aires metropolitan area
(Panel A). In the same fashion, an additional day of 5.6
◦ C rises annual mortality risks
by 5.2 (95% CI: 2.37–8.08) in the Pampean region (Panel B). In the northeast (Panel
C), a day of 8.33
◦ C increases mortality by 8.3 pp (95% CI: 0.54–16.05), while in
the northwest region (Panel D) a day with mean daily temperature of 10.55
◦ C raises
mortality by 7.83 pp (95% CI: 3.81–11.87). Finally, in the western region of Cuyo
(Panel E) an additional day of temperature around 2
◦ C raises local mortality rates
by 10.02 pp (95% CI: 2.47–17.57). Again, the estimated impacts are relative to a one
less day in a month with mean daily temperature of 18.9
◦ C, which is the national
average temperature.
Figure 3 provides evidence of heterogeneous impacts by age group (females in
Panel A and males in Panel B). Only the elderly are affected by extreme temperatures, but colder than average temperatures seem to be more likely to be statistically
significantly different from a day with 18.9
◦ C. Also, cold temperatures have a greater
impact on male mortality risks, with no apparent difference between sexes for hotter
than normal temperatures.
Discussion
Environmental factors are important determinants of human health. Recently, due to
global warming and the recurrence of heat waves, the attention has been placed on
how weather affects health outcomes, among which mortality has captured the most
attention.
The existing literature, mainly for developed countries, has pointed to a U-shaped
type of relationship between temperature and mortality risks. Using flexible regression models over longitudinal monthly weather and mortality data for 322 municipalities spanning January 2004 and December 2010, this study has confirmed this
relationship from a countrywide perspective.
We found a significant impact of both cold and hot days on mortality risks; however, colder than average temperatures have a greater effect on mortality. This finding
holds irrespective of using the daily mean, maximum, or minimum temperatures.
Using a comparable methodology applied for US counties, Barreca and Shimshack
(2012) also reported a similar association between colder temperatures and influenza
mortality, although their work concerned mainly with the impact of absolute humidity. Almeira et al. (2016) also report a higher susceptibility to colder extremes than to
hotter temperatures in the cities of Buenos Aires and Rosario. An additional interesting result is that hotter than average temperatures have no impact when splitting the
data by regions. In particular, we found no significant impact of hotter than average
temperatures in Buenos Aires metropolitan area. In contrasts, De Garín and Bejarán