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International Journal of Environmental
Health Research
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Difficulties of defining the term, “heat
wave”, in public health
a b c
Juan Carlos Montero , Isidro Juan Miron , Juan José Criado ,
d e
Cristina Linares & Julio Díaz
a
Health Sciences Institute, Castile-La Mancha Regional Health &
Social Welfare Authority , Talavera de la Reina, Toledo , Spain
b
Torrijos Health District, Castile-La Mancha Regional Health &
Social Welfare Authority , Torrijos , Spain
c
Castile-La Mancha Health Service (Servicio de Salud de Castilla-
La Mancha - SESCAM), Talavera de la Reina , Toledo , Spain
d
Centro Nacional de Epidemiologia, Area de epidemiología
ambiental y cáncer , Madrid , 28029 , Spain
e
Instituto de Salud Carlos III. Escuela Nacional de Sanidad, Sinesio
Delgado 8 , Madrid , 28029 , Spain
Published online: 16 Oct 2012.
To cite this article: Juan Carlos Montero , Isidro Juan Miron , Juan José Criado , Cristina Linares
& Julio Díaz (2013) Difficulties of defining the term, “heat wave”, in public health, International
Journal of Environmental Health Research, 23:5, 377-379
To link to this article: http://dx.doi.org/10.1080/09603123.2012.733941
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Downloaded by [Inst Salud Carlos Iii] at 02:24 12 November 2013International Journal of Environmental Health Research, 2013
Vol. 23, No. 5, 377–379, http://dx.doi.org/10.1080/09603123.2012.733941
TECHNICAL NOTES
Difficulties of defining the term, ‘‘heat wave’’, in public health
Juan Carlos Monteroa, Isidro Juan Mironb, Juan José Criadoc, Cristina Linaresd
and Julio Dı́aze*
a
Health Sciences Institute, Castile-La Mancha Regional Health & Social Welfare Authority,
Talavera de la Reina (Toledo), Spain; bTorrijos Health District, Castile-La Mancha Regional
Health & Social Welfare Authority, Torrijos, Spain; cCastile-La Mancha Health Service
(Servicio de Salud de Castilla-La Mancha - SESCAM), Talavera de la Reina (Toledo), Spain;
d
Centro Nacional de Epidemiologia, Area de epidemiologı´a ambiental y cáncer, Madrid 28029,
Downloaded by [Inst Salud Carlos Iii] at 02:24 12 November 2013
Spain; eInstituto de Salud Carlos III. Escuela Nacional de Sanidad, Sinesio Delgado 8, Madrid
28029, Spain
(Received 16 July 2012; final version received 22 July 2012)
There can be no question that in any area of science it is important to establish
methodologies and criteria which enable universally comparable and applicable
results to be obtained. In this regard, while the effort made by the EuroHEAT
project to furnish a single definition of ‘‘heat wave’’ for comparison of this
phenomenon’s impact on different European cities is doubtless praiseworthy
(D’Ippoliti et al. 2010), it would also be true to say that an effort of this nature is
confronted by series of limitations which must be considered.
In the first place, the use of any given parameter that synthesizes diverse variables
in a single mathematical algorithm is only advisable if its efficacy has previously been
tested under all possible scenarios. Reliance on apparent temperature implies
assuming that, during any heat wave, there is a positive quadratic relationship
between relative humidity (as measured by a wet-bulb temperature) and mortality,
namely, that an increase in humidity is always associated with an increase in
mortality. Nevertheless, a number of papers report exceptions to this: in the USA,
for instance, the above relationship varies among the different cities analyzed (Braga
et al. 2002); and in Spain, studies which have examined humidity independently show
that the highest mortality is associated with low humidities (Dı́az et al. 2002;
Montero et al. 2012). Failure to take into account the direction of the association
may give rise to erroneous interpretation of results. There can be no doubt that the
extent to which air temperature influences the definition of apparent temperature
makes for this strong association between apparent temperature and mortality,
regardless of any possible impact of relative humidity.
Furthermore, to define heat waves for the purpose of implementing health
actions, using a parameter based solely on the climatological conditions of one city
or region means that a public health decision would be made without any population
*Corresponding author. Email: j.diaz@isciii.es
Ó 2012 Taylor & Francis378
2 J.C. Montero et al.
health indicator being taken into account. Most experts recommend using a
definition based on ‘‘a robust understanding of the cause-and-effect relationships
between the thermal environment and health outcomes at the population level’’
(Kovats and Ebi 2006).
It must be borne in mind that heat waves occur at lower temperatures in colder
places (Curriero et al. 2002), and hence it is recommended to use the percentile of the
temperature series rather than absolute temperatures to define a thermal extreme.
This feature must doubtless be considered when interpreting the higher mortality in
Europe’s northernmost countries during the 2003 heat wave (D’Ippoliti et al. 2010).
Based on this, the 90th percentile of the monthly distribution could be assumed to be
the point at which the health effects of high temperatures were always triggered, and
the requirements described in the preceding paragraph for defining a heat wave
would thus be met.
Downloaded by [Inst Salud Carlos Iii] at 02:24 12 November 2013
The relationship between health and temperature is not immutable, however. On
the contrary, it is regulated by a complex number of economic, social, cultural, and
health variables (Basu 2009). Several studies which have analyzed the trend in the
association between mortality and temperature, in sufficiently long series in the USA
(Davis et al. 2003), UK (Carson et al. 2006) and Spain (Mirón et al. 2010), have
detected that temperature evolves differently, adapting itself to the changes in the
characteristics of each society. There is one variable that has special importance in
the trend in this relationship, i.e. the ageing index. One recent study in Spain
reported that it is in populations that have a larger elderly segment where an increase
in mortality at lower temperatures is detected (Montero et al. 2012). In such a case, it
would seem that, from a health standpoint, it could be said that the greater the
ageing of the population, the lower the temperature at which the effects of a heat
wave appear.
In our opinion, these results amount to a change of paradigm when it comes to
defining a heat wave. Such a definition cannot be a fixed one: not only is it impossible
to establish a temperature that would serve for all latitudes, but it is also impossible
to fix a percentile of the temperature series to which a population would be exposed,
since the temperature–mortality relationship varies over time. In contrast, efforts – in
the form of consistent epidemiological studies – should be directed at searching for
the threshold temperature for defining a heat wave, i.e. for defining, by reference to
the target area, from which temperature the effects of heat on the health variables
considered are to be deemed unacceptable.
Needless to say, a threshold temperature determined in this way will be a
consequence of the social, economic, and demographic characteristics of a specific
society. One would thus be sure that implementation of prevention plans based on
the surpassing of these types of thresholds would result in a reduction of the impact
of high temperatures on the health of the population.
References
Basu R. 2009. High ambient temperature and mortality: a review of epidemiologic studies
from 2001 to 2008. Environ Health. 8:40.
Braga AI, Zanobetti A, Schwartz J. 2002. The effect of weather on respiratory and
cardiovascular deaths in 12 U.S. cities. Environ Health Perspect. 110:859–863.
Carson C, Hajat Sh, Armstrong B, Wilkinson P. 2006. Declining vulnerability to temperature-
related mortality in London over the 20th century. Am J Epidemiol. 164:77–84.
Curriero FC, Heiner KS, Samet JM, Zeger SL, Strug L, Patz JA. 2002. Temperature and
mortality in 11 cities of the Eastern United States. Am J Epidemiol. 155:80–87.International Journal of Environmental Health Research 3793
Davis RE, Knappenberger PC, Novicoff WM, Michaels PJ. 2003. Decadal changes in summer
mortality in US cities. Int J Biometeorol. 47:166–175.
Dı́az J, López C, Jordán A, Alberdi JC, Garcı́a R, Hernández E, Otero A. 2002. Heat waves in
Madrid 1986–1997: effects on the health of the elderly. Int Arch Occup Environ Health.
75:163–170.
D’Ippoliti D, Michelozzi P, Marino C, Menne B, Katsouyanni K, Kirchmayer U, Analitis A,
Medina-Ramón M, Paldy A, Atkinson R, et al. 2010. The impact of heat waves on
mortality in 9 European cities: results from the EuroHEAT project. Environ Health 9:37.
Kovats RS, Ebi KL. 2006. Heat waves and public health in Europe. Eur J Public Health.
16:592–599.
Mirón IJ, Montero JC, Criado-Álvarez JJ, Linares C, Dı́az J. 2010. Effects of temperature
extremes on daily mortality in Castile-La Mancha (Spain): trends from 1975 to 2003. Gac
Sanit. 24(2):117–122.
Montero JC, Mirón IJ, Criado-Álvarez JJ, Linares C, Dı́az J. 2012. Influence of local factors
in the relationship between mortality and heat waves: Castile-La Mancha (1975–2003). Sci
Total Environ. 414:73–80.
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