Portugal, Summer 2003 Mortality: the Heat Waves Influence 9

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9

Portugal, Summer 2003 Mortality:

the Heat Waves Influence

Rui Manuel D. Calado · Jaime da Silveira Botelho · Judite Catarino · Mário Carreira

Introduction

In Portugal, during both June 1981 and July 1991, the air temperature rose above 32 °C during 2 or more consecutive days. Studies aft er these periods concluded that these heat incidents were associated with excess deaths.

Th is events justifi ed the development, by the National Observatory of Health, of a heat wave vigilance and alert system, using data and information from the Meteorological Institute.

On a regular basis, since 1999, from 15th of May until the end of September, the “Civil Protection” and the General Directorate of Health receive the Ícaro Index daily. Th is index helps to predict the possibility of a heat occurrence which would be intense enough to aff ect mortality 3 days in advance.

Th is short article describes the eff ects of the summer heat-waves 2003 in Portugal.

Summer 2003 occurrence

In Summer 2003 the alert was given three times. It corresponded to the heat waves of 18 – 20 June, 29 of July to 13th August and 11 – 14 September ( > Fig. 1).

Th rough the “Alert and Appropriate Response System” the alerts were immediately communicated to the “Health Authorities” at regional and local levels.

Th e alerts given on 19th of June and 29th of July led to technical recommendations sent to the “Regional Health Authorities” on 20th June and 30th July, respectively.

During the fi rst week of August, the technical recommendations were published through the General Directorate of Health web site and were complemented with more technical data considered pertinent.

Th e “Civil Protection” formal reports through the media informed the population of the possibility of receiving additional information about prevention measures on the heat problem, using the Public Health Call Center. During the fi rst two weeks of August, this phone line received more than 1400 calls. Th e daily frequency of the calls followed the “Civil Protection” alerts and the Ícaro Index variations ( > Fig. 2 and 3).

Summer 2003 mortality

In the second week of August, the population was alerted through the media with news about the mortality increase in France and the incapacity of French authorities to identify a large number of corpses and to conduct their funerals.

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90 9 Portugal, Summer 2003 Mortality: the Heat Waves Inﬂ uence

⊡ Fig. 2

Heat Wave 2: ÍCARO alerts, Civil Protection official reports and Public Health Call Center activity. Source:

General Directorate of Health (DGS)

⊡ Fig. 1

Ícaro Index between 15.05 and 30.09.2003 Source: National Observatory of Health (ONSA)

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91 Portugal, Summer 2003 Mortality: the Heat Waves Inﬂ uence 9

⊡ Fig. 3

Heat Wave 2: relationship between Ícaro Índex and use of the Public Health Call Center. Source: General Directorate of Health (DGS)

In Portugal between 30 July and 14 August, our central department received no formal or informal com- munication about hospital problems related to the heat waves. But the analysis of “people movement” at the Hospital Emergency Services between 1 June and 31 August revealed an increase in its use of 11,6 % in relation to the “people movement” average verifi ed in the previous 2 years. Th ere is an increase in percentage to 27,2 % for people over 74 years of age and this percentage increases to 40,5 % if we consider the search for health care by aged people in the South of Portugal alone ( > Tab. 1).

⊡ Tab. 1

Hospital emergency consultations between June 1 and August 31. Source: General Directorate of Health (DGS)

Regions Age group 2001/02 2003 Variation ∆ %

Portugal All ages 1289916 1439875 149959 11,6

75E+ 99445 126506 27062 27,2

North All ages 527603 553414 25812 4.9

75E+ 40735 48089 7355 18.1

Centre All ages 300765 306494 5729 1.9

75E+ 14090 15777 1687 12.0

South All ages 461549 579967 118419 25.7

75E+ 44620 62640 18020 40.4

At the end of August, a “National Observatory of Health” study alerted to an eventual increase of deaths during the fi rst two weeks of August related to the “heat wave.” Th e estimation predicted an excess of

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1316 deaths, distributed over “all ages” but with a predominance in people of over 74 years (58 % of the total excess).

It was thus necessary to confi rm the conclusions of that study. Th e General Directorate of Health requested of the “Death Registration Department” immediate access to the death certifi cate copies of the Summer months registers, to compare its number with equivalent periods (it was used the 5 years average of 1997 – 2001), and to study not only the cause of death described, but also the co-morbidities.

Th e data was obtained from 32778 death certifi cates, of which 16563 pertained to males (50,5 %).

During the 4 months analyzed (1 June to 30 September) the daily mortality incidence represented a strong increase in 2 periods, coincident with the fi rst and the second heat waves. But whilst in the fi rst period we can see the anomalous increase during just 4 days, in the second period the increased number of deaths is much higher, the adverse eff ects present during 17 days and with 3 acute moments (2, 8, 13 August), immediately aft er worsening weather conditions that occurred respectively in the 1, 6 and 12 August ( > Fig. 1 and 4).

⊡ Fig. 4

Heat Waves: daily deaths between June 1 and September 30. Source: General Directorate of Health (DGS)

Th e increase of mortality during the fi rst heat wave occurred among both genders, but during the second it was predominant in females (69 % of the death excess over the fi rst two weeks of August). During the third heat wave, the mortality numbers didn’t show any important change, with the numbers by gender maintaining them usual pattern, which means higher values for males ( > Fig. 5).

Th e analysis of weekly incidence reveal that only the eff ects of the second heat wave were of enough magnitude to infl uence in a signifi cant way this indicator, during the week 9th,10th and 11th of the con- sidered period ( > Fig. 6).

Th e comparison of death by age group registered between 1997 – 2001 and 2003, for equivalent periods during Summer time, revealed that the “heat wave” adverse eff ects aff ect in particular persons over 74 years of age. During August 2003 the excess was of 2131 deaths, with 2055 (96,6 %) belonging to this age group ( > Tab. 2).

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⊡ Fig. 5

Heat Waves: weekly deaths by sex, between June 1 and September 30. Note: The week 1 begin in 01.06.2003 and the week 17 end in 27.09.2003. Source: General Directorate of Health (DGS)

⊡ Fig. 6

Heat Waves: weekly deaths, between June 1 and September 30 and last 5 years average. Source: General Directorate of Health (DGS)

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⊡ Tab. 2

Heat Waves: total deaths by age group, during August 2003. Source: General Directorate of Health (DGS) Age group Last 5 years

average

2003 Difference %-difference

< 15 years 103 94 –9 –8 %

15 – 64 years 1849 1795 –54 –3 %

65 – 74 years 1688 1827 +139 +8 %

75E+ 4338 6393 +2055 +47 %

Total 7978 10109 +2131 +27 %

Curiously, in the other Summer 2003 months (June, July and September) the death number was always lower than that expected for this period. So the deaths excess for the period between 1 June and 30 Sep- tember 2003 was 1802 ( > Tab. 3).

⊡ Tab. 3

Heat Waves: total deaths by age group, between June 1 and September 30. Source: General Directorate of Health (DGS)

Age group Last 5 years average

2003 Difference %-difference

< 15 years 385 314 –71 –18 %

15–64 years 7026 6393 –633 –9 %

65–74 years 6607 6330 –277 –5 %

75E+ 16962 19746 +2784 +16 %

Total 30981 32783 +1802 +6 %

In the fi rst 2 weeks of August and in the same period for 1997 – 2001, the percentage diff erence between deaths was +159 % for endocrine diseases, +83 % for respiratory diseases, +51 % for cerebrovascular diseases and +47 % for ischemic heart diseases. Th e death excess that result from these 4 causes was 1029, which represents 45 % of its total. It is also important to note the existence of 14 deaths with “exposure to excessive natural heat” like basic cause (X30 in the International Classifi cation of Diseases – ICD10).

Th e rise in adverse deaths during “heat waves” did not appear to infl uence the place of occurrence of death. So the data comparison of the fi rst fortnight of 2003 August (54 % hospital deaths and 32 % at home) with the deaths observed during the summer of previous years, reveals an evident maintenance of the distribution of home versus hospital deaths ( > Fig. 7).

Identification of risk population

Given current demographics, it is easy to understand that the major risk group is elderly women, with some diseases that make them more vulnerable to heat adverse eff ects.

Th e ageing of the Portuguese population, where between 1960 and 2000 there was a gain of 12,2 years in life expectancy, in clear convergence with the EU, has strong implications for the population health situation. Th e process has created favourable conditions in the increase in vulnerability of the aged population, which is becoming more and more numerous.

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Th e increase of the susceptible population could also be the consequence of a small number of winter deaths in Portugal between November 2002 and March 2003. Th e number was lower than that expected (comparing with the homologous 1997 – 2001 period), with the enormous diff erence of –4746 deaths ( > Fig. 8).

⊡ Fig. 8

Heat Waves: deaths in the last winter and summer months, and in the same periods of the last 5 years.

Source: General Directorate of Health (DGS) and National Statistics Institute (INE)

⊡ Fig. 7

Deaths during the first fortnight in August: occurrence place. Source: General Directorate of Health (DGS)

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It is also possible to observe that, between January and September 2003, the global number of deaths cor- respond to an intermediate value in relation to the same period of 2001 and 2002. As that number was infl uenced by excess related to the “heat waves”, it is possible to think that it is the consequence of mortality decrease and a concomitant ageing of the population ( > Fig. 9).

⊡ Fig. 9

Heat Waves: 3 periods 2003 total deaths and last 2 years similar periods. Source: National Institute of Statistics (INE)

Civil measures for the future

To combat the adverse eff ects of predictable “heat waves” eff ects in future and considering the necessity to minimize avoidable mortality, it is important to reinforce resources and improve intervention strategy.

Th e education of health professionals, social services and populations, the active involvement of social institutions and the timely alerts to take all necessary and adequate measures to eliminate the undesirable eff ects of heat excess, will be considered and applied in a near future.

As a follow-up of its proved usefulness, the Ícaro Index can help to respond to the vigilance and alert necessities of all country regions.

Portugal will elaborate a Contingency Plan for Heat Waves, in consideration of the results of WHO meetings in Madrid (14 – 15 December 2003) and Bratislava (9 – 10 February 2004) which were organized to discuss the problem and to propose all suitable recommendations to prevent its eff ects effi ciently.

References

Calado R, Nogueira PJ, Catarino J, Paixão EJ, Botelho J, Carreira M, Falcão JM (2003) Onda de calor de Agosto de 2003: os seus efeitos sobre a mortalidade da população portuguesa (aceite para publicação na Revista Portuguesa de Saúde Pú- blica)

Falcão JM, Nogueira PJ, Contreiras MT, Paixão EJ, Brandão J, Batista I (2003) Onda de calor de Agosto de 2003: efeito sobre a mortalidade da população. Estimativas provisórias (até 12.08.2003). Observatório Nacional de Saúde

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Garcia CP, Nogueira P, Falcão JM (1999) Onda de calor de Junho de 1981: efeitos na mortalidade. Clima e Saúde. Revista Por- tuguesa de Saúde Pública. Volume temático:I

Nogueira P (2003) Como fazemos as estimativas do excesso de óbitos numa onda de calor. Observações Nº 20; Ob- servatório Nacional de Saúde

Paixão EJ, Nogueira PJ (2003) Efeitos de uma onda de calor na mortalidade. Revista Portuguesa de Saúde Pública 21;1:41–

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