Cristina Ortiz

Short term effect of air pollution, noise and heat waves on preterm births in Madrid (Spain)

BACKGROUND Preterm birth (PTB) refers to delivery before 37 weeks of gestation and represents the leading cause of early-life mortality and morbidity in developed countries. PTB can lead to serious infant health outcomes. The etiology of PTB remains uncertain, but epidemiologic studies have consistently shown elevated risks with different environmental variables as traffic-related air pollution (TRAP). The aim of the study was to evaluate with time series methodology the short-term effect of air pollutants, noise levels and ambient temperature on the number of births and preterm births occurred in Madrid City during the 2001-2009 period. METHODS A time-series analysis was performed to assess the short term impact of daily mean concentrations (µg/m(3)) of PM2.5 and PM10, O3 and NO2. Measurements of Acoustic Pollution in dB(A) analyzed were: Leqd, equivalent diurnal noise level and Leqn, equivalent nocturnal noise level. Maximum and Minimum daily temperature (°C), mean Humidity in the air (%) and Atmospheric Pressure (HPa), were included too. Linear trends, seasonality, as well as the autoregressive nature of the series itself were controlled. We added as covariate the day of the week too. Autoregressive over-dispersed Poisson regression models were performed and the environmental variables were included with short-term lags (from 0 to 7 days) in reference to the date of birth. Firstly, simple models for the total number of births and preterm births were done separately. In a second stage, a model for total births adjusted for preterm births was performed. RESULTS A total of 298,705 births were analyzed. The results of the final models were expressed in relative risks (RRs) for interquartile increase. We observed evidence of a short term effect at Lag 0, for the following environmental variables analyzed, PM2.5 (RR: 1.020; 95% CI:(1.008 1.032)) and O3 (RR: 1.012; 95% CI:(1.002 1.022)) concentrations and Leqd (RR: 1.139; 95% CI:( (1.124 1.154)) for the total number of births, and besides these, heat temperatures at Lag 1 (RR: 1.055; 95% CI:( (1.018 1.092)) on preterm births in Madrid City during the studied period. In the model adjusted for preterm births, similar RR was obtained for the same environmental variables. CONCLUSIONS Especially PM2.5, diurnal noise levels and O3 have a short-term impact on total births and heat temperatures on preterm births in Madrid City during the studied period. Our results suggest that, given the widespread exposure of the population to the environmental factors analyzed and the possible effects on long-term health associated to low birth weight. There is a clear need to minimize this exposure through the decrease of air pollution and noise levels and through the behavior modification of the mothers.

Comparison of the effects of extreme temperatures on daily mortality in Madrid (Spain), by age group: The need for a cold wave prevention plan

A number of studies have shown that there is a time trend towards a reduction in the effects of heat on mortality. In the case of cold, however, there is practically no research of this type and so there is no clearly defined time trend of the impact of cold on mortality. Furthermore, no other specific studies have yet analysed the time trend of the impact of both thermal extremes by age group. We analysed data on daily mortality due to natural causes (ICD-10: A00-R99) in the city of Madrid across the period 2001-2009 and calculated the impact of extreme temperatures on mortality using Poisson regression models for specific age groups. The groups of age selected coinciding with the pre-existing age-groups analyzed in previous papers. For heat waves the groups of age used were: <10 years, 10-17 years, 18-44 years, 45-64 years, 65-74 years and over-75 years. For cold waves the groups of age used were: <1 year; 1-5 years, 6-17 years, 18-44 years, 45-64 years, 65-74 years and over-75 years. <1, 1-17, 18-44, 45-66, 65-74 and over-75 years. We controlled for confounding variables, such as air pollution, noise, influenza, pollen, pressure and relative humidity, trend of the series, as well as seasonalities and autoregressive components of the series. The results of these models were compared to those obtained for the same city during the period 1986-1997 and published in different studies. Our results show a lightly reduction in the effects of heat, especially in the over-45-year age group. In the case of cold, the behaviour pattern was the opposite, with an increase in its effect. Heat adaptation and socio-economic and public-health prevention and action measures may be behind this amelioration in the effects of heat, whereas the absence of such actions in respect of low temperatures may account for the increase in the effects of cold on mortality. From a public health point of view, the implementation of cold wave prevention plans covering all age groups is thus called for.

Short-term association between environmental factors and hospital admissions due to dementia in Madrid

Background Spain has one of the highest proportions of dementia in the world among the population aged 60 years or over. Recent studies link various environmental factors to neurocognitive‐type diseases. This study sought to analyse whether urban risk factors such as traffic noise, pollutants and heat waves might have a short‐term impact on exacerbation of symptoms of dementia, leading to emergency hospital admission. Material and methods We conducted a longitudinal ecological time‐series study, with the dependent variable being the number of daily dementia‐related emergency (DDE) hospital admissions to Madrid municipal hospitals (ICD‐10 codes 290.0–290.2, 290.4–290.9, 294.1–294) from 01 to 01‐2001 to 31‐12‐2009, as obtained from the Hospital Morbidity Survey (National Statistics Institute). The measures used were as follows: for noise pollution, Leqd, equivalent diurnal noise level (from 8 to 22 h), and Leqn, equivalent nocturnal noise level (from 22 to 8 h) in dB(A); for chemical pollution, mean daily NO2, PM2.5, PM1 as provided by the Madrid Municipal Air Quality Monitoring Grid; and lastly, maximum daily temperature (°C), as supplied by the State Meteorological Agency. Scatterplot diagrams were plotted to assess the type of functional relationship existing between the main variable of analysis and the environmental variables. The lags of the environmental variables were calculated to analyse the timing of the effect. Poisson regression models were fitted, controlling for trends and seasonalities, to quantify relative risk (RR). Results During the study period, there were 1175 DDE hospital admissions. These admissions displayed a linear functional relationship without a threshold in the case of Leqd. The RR of DDE admissions was 1.15 (1.11–1.20) for an increase of 1 dB in Leqd, with impact at lag 0. In the case of maximum daily temperature, there was a threshold temperature of 34 °C, with an increase of 1 °C over this threshold posing an RR of 1.19 (1.09–1.30) at lag 1. The only pollutant to show an association with DDE hospital admissions was O3 at lag 5, with an RR of 1.09 (1.04–1.15) for an increase of 10 &mgr;g/m3 Conclusions Diurnal traffic noise, heat waves and tropospheric ozone may exacerbate the symptoms of dementia to the point of requiring emergency admission to hospital. Lowering exposure levels to these environmental factors could reduce dementia‐related admissions in Madrid. HighlightsSpain has one of the highest proportions of dementia in the world.The RR of DDE admissions was 1.15 (1.11–1.20) for an increase of 1 dB in Leqd.The RR of DDE admissions was 1.19 (1.09–1.30) for an increase of 1 °C above 34 °C in Tmax.The RR of DDE admissions was 1.09 (1.04–1.15) for an increase of 10 &mgr;g/m3 in O3a concentrations.Diurnal traffic noise, heat waves and tropospheric ozone can exacerbate the symptoms of dementia.

Evaluation of short-term mortality attributable to particulate matter pollution in Spain

According to the WHO, 3 million deaths are attributable to air pollution due to particulate matter (PM) world-wide. However, there are no specific updated studies which calculate short-term PM-related cause specific mortality in Spain. The objective is to quantify the relative risks (RRs) and attributable risks (ARs) of daily mortality associated with PM10 concentrations, registered in Spanish provinces and to calculate the number of PM-related deaths. We calculated daily mortality due to natural (ICD-10: A00 R99), circulatory (ICD-10: I00 I99) and respiratory causes (ICD-10: J00 J99) for each province across the period 2000-2009. Mean daily concentrations of PM10, NO2 and O3 was used. For the estimate of RRs and ARs, we used generalised linear models with a Poisson link. A meta-analysis was used to estimate RRs and ARs in the provinces with statically significant results. The overall RRs obtained for these provinces, corresponding to increases of 10 μ g/m3 in PM10 concentrations were 1.009 (95% CI: 1.006 1011) for natural, 1.026 (95% CI: 1.019 1033) for respiratory, and 1.009 (95% CI: 1.006 1012) for circulatory-cause mortality. This amounted to an annual overall total of 2683 deaths (95% CI: 852 4354) due to natural, 651 (95% CI: 359 1026) due to respiratory, and 556 (95% CI: 116 1012) due to circulatory causes, with 90% of this mortality lying below the WHO guideline values. This study provides an updated estimate of the effect had by this type of pollutant on causes of mortality, and constitutes an important basis for reinforcing public health measures.

Effect of Environmental Factors on Low Weight in Non-Premature Births: A Time Series Analysis

Objective Exposure to pollutants during pregnancy has been related to adverse birth outcomes. LBW can give rise to lifelong impairments. Prematurity is the leading cause of LBW, yet few studies have attempted to analyse how environmental factors can influence LBW in infants who are not premature. This study therefore sought to analyse the influence of air pollution, noise levels and temperature on LBW in non-premature births in Madrid during the period 2001–2009. Methods Ecological time-series study to assess the impact of PM2.5, NO2 and O3 concentrations, noise levels, and temperatures on LBW among non-premature infants across the period 2001–2009. Our analysis extended to infants having birth weights of 1,500 g to 2,500 g (VLBW) and less than 1,500 g (ELBW). Environmental variables were lagged until 37 weeks with respect to the date of birth, and cross-correlation functions were used to identify explaining lags. Results were quantified using Poisson regression models. Results Across the study period 298,705 births were registered in Madrid, 3,290 of which had LBW; of this latter total, 1,492 were non-premature. PM2.5 was the only pollutant to show an association with the three variables of LBW in non-premature births. This association occurred at around the third month of gestation for LBW and VLBW (LBW: lag 23 and VLBW: lag 25), and at around the eighth month of gestation for ELBW (lag 6). Leqd was linked to LBW at lag zero. The RR of PM2.5 on LBW was 1.01 (1.00 1.03). The RR of Leqd on LBW was 1.09 (0.99 1.19)(p<0.1). Conclusions The results obtained indicate that PM2.5 had influence on LBW. The adoption of measures aimed at reducing the number of vehicles would serve to lower pregnant womens exposure. In the case of noise should be limited the exposure to high levels during the final weeks of pregnancy.

Geographical variation in relative risks associated with cold waves in Spain: the need for a cold wave prevention plan

In general, there are few studies that analyse the impact of low temperatures on mortality and fewer still that use cold-wave-definition thresholds based on epidemiological and non-climatological criteria. Such a threshold definition, which took into account population features such as socio-economic and demographic characteristics, made it possible for a specific threshold temperature to be obtained for each of Spains 52 provincial capitals in this study. Using generalised linear models with the Poisson regression link, and controlling for trend, autocorrelations and seasonalities of the series, and influenza epidemics, we obtained the impact of low temperatures on mortality in each provincial capital by calculating the relative risks (RRs) and attributable risks (ARs) for natural as well as circulatory and respiratory causes. The study showed higher minimum temperature thresholds in coastal areas, and an overall impact of cold on mortality in Spain due to natural causes RR=1.13 (95% CI: 1.11-1.16), circulatory causes RR=1.18 (95% CI: 1.15-1.22) and respiratory causes RR=1.24 (95% CI: 1.20-1.29) slightly greater than that obtained to date for heat. From a public health standpoint, there is a need for specific cold wave prevention plans at a regional level which would enable mortality attributable to low temperatures to be reduced. These plans have shown themselves to be effective in decreasing heat-related mortality, and we feel that they are essential for reducing cold-related effects on morbidity and mortality.

Saharan dust intrusions in Spain: Health impacts and associated synoptic conditions

Background: A lot of papers have been published about the impact on mortality of Sahara dust intrusions in individual cities. However, there is a lack of studies that analyse the impact on a country and scarcer if in addition the analysis takes into account the meteorological conditions that favour these intrusions. Objectives: The main aim is to examine the effect of Saharan dust intrusions on daily mortality in different Spanish regions and to characterize the large‐scale atmospheric circulation anomalies associated with such dust intrusions. Methods: For determination of days with Saharan dust intrusions, we used information supplied by the Ministry of Agriculture, Food & Environment, it divides Spain into 9 main areas. In each of these regions, a representative province was selected. A time series analysis has been performed to analyse the relationship between daily mortality and PM10 levels in the period from 01.01.04 to 31.12.09, using Poisson regression and stratifying the analysis by the presence or absence of Saharan dust advections. Results: The proportion of days on which there are Saharan dust intrusions rises to 30% of days. The synoptic pattern is characterised by an anticyclonic ridge extending from northern Africa to the Iberian Peninsula. Particulate matter (PM) on days with intrusions are associated with daily mortality, something that does not occur on days without intrusions, indicating that Saharan dust may be a risk factor for daily mortality. In other cases, what Saharan dust intrusions do is to change the PM‐related mortality behaviour pattern, going from PM2.5. Conclusions: A study such as the one conducted here, in which meteorological analysis of synoptic situations which favour Saharan dust intrusions, is combined with the effect on health at a city level, would seem to be crucial when it comes to analysing the differentiated mortality pattern in situations of Saharan dust intrusions. Graphical abstract Figure. No Caption available. HighlightsThe proportion of days on which there are Saharan dust intrusions rises to 30% of days.An intrusion is accompanied by an increase in particle levels in all regions.The synoptic pattern is characterised by an anticyclonic ridge.PM on days with intrusions are associated with daily mortality.Saharan dust may be a risk factor for daily mortality.

Smoke-Free Legislation in Spain and Prematurity

This study evaluates changes in preterm birth and low birth weight rates after the implementation of 2 consecutive smoking bans in Spain. BACKGROUND AND OBJECTIVE: Spain implemented a partial smoking ban in 2006 followed by a comprehensive ban in 2011. The objective was to examine the association between these smoke-free policies and different perinatal complications. METHODS: Cross-sectional study including all live births between 2000 and 2013. Selected adverse birth outcomes were: preterm births (<37 gestational weeks), small for gestational age (SGA; <10th weight percentile according to Spanish reference tables), and low birth weight (<2500 g). We estimated immediate and gradual rate changes after smoking bans by using overdispersed Poisson models with different linear trends for 2000 to 2005 (preban), 2006 to 2010 (partial ban), and 2011 to 2013 (comprehensive ban). Models were adjusted for maternal sociodemographics, health care during the delivery, and smoking prevalence during pregnancy. RESULTS: The comprehensive ban was associated with preterm birth rate reductions of 4.5% (95% confidence interval [CI]: 2.9%–6.1%) and 4.1% (95% CI: 2.5%–5.6%) immediately and 1 year after implementation, respectively. The low birth weight rate also dropped immediately (2.3%; 95% CI: 0.7%–3.8%) and 1 year after the comprehensive ban implementation (3.5%; 95% CI: 2.1%–5.0%). There was an immediate reduction in the SGA rate at the onset of the partial ban (4.9%; 95% CI: 3.5%–6.2%), which was sustained 1 year postimplementation. Although not associated with the comprehensive ban at the onset, the SGA rate declined by 1.7% (95% CI: 0.3%–3.1%) 1 year postimplementation. CONCLUSIONS: The implementation of the Spanish smoke-free policies was associated with a risk reduction for preterm births and low birth weight infants, especially with the introduction of the more restrictive ban.

Assessing the effects of the Spanish partial smoking ban on cardiovascular and respiratory diseases: methodological issues

Objective Recent research has assessed the impact of tobacco laws on cardiovascular and respiratory morbidity. In this study, we also examined whether the association between the implementation of the 2005 Spanish smoking ban and hospital admissions for cardiovascular and respiratory diseases varies according to the adjustment for potential confounders. Design Ecological time series analysis. Setting Residents of Madrid and Barcelona cities (Spain). Outcome Data on daily emergency room admissions for acute myocardial infarction, cerebrovascular disease, chronic obstructive pulmonary disease (COPD), and asthma derived from the 2003–2006 Spanish hospital admissions registry. Methods Changes in admission rates between 2006 and the 2003–2005 period were estimated using additive Poisson models allowing for overdispersion adjusted for secular trend in admission, seasonality, day of the week, temperature, number of flu and acute respiratory infection cases, pollution levels, tobacco consumption prevalence and, for asthma cases, pollen count. Results In Madrid, fully adjusted models failed to detect significant changes in hospital admission rates for any disease during the study period. In Barcelona, however, hospital admissions decreased by 10.2% (95% CI 3.8% to 16.1%) for cerebrovascular diseases and by 16.0% (95% CI 7.0% to 24.1%) for COPD. Substantial changes in effect estimates were observed on adjustment for linear or quadratic trend. Effect estimates for asthma-related admissions varied substantially when adjusting for pollen count in Madrid, and for seasonality and tobacco consumption in Barcelona. Conclusions Our results confirm that the potential impact of a smoking ban must be adjusted for the underlying secular trend. In asthma-related admissions, pollen count, seasonality and tobacco consumption must be specified in the model. The substantial variability in effects detected between the two cities of Madrid and Barcelona lends strong support for a nationwide study to assess the overall effect of a smoking ban in Spain and identify the causes of the observed heterogeneity.

Effect of cardiovascular prevention strategies on incident coronary disease hospitalisation rates in Spain; an ecological time series analysis.

Objective To assess the overall population impact of primary prevention strategies (promotion of healthy lifestyles, prevention of smoking and use of vascular risk drug therapy) of coronary disease in Spain. Design Ecological time series analysis, 1982–2009. Setting All public and private hospitals in Spain. Participants General population. Outcome Incident coronary disease hospitalisation as derived from official hospital discharge data. Methods Annual hospitalisation rates were modelled according to nationwide use of statins, antihypertensive, antidiabetic and antiplatelet drugs, and prevalences of smoking, obesity and overweight. Additive generalised models and mixed Poisson regression models were used for the purpose, taking year as the random-effect variable and adjusting for age, sex, prevalence of vascular risk factors and the number of hospital beds in intensive and coronary care units. Results Across 28 years and 671.5 million person-years of observation, there were 2 986 834 hospitalisations due to coronary disease; of these, 1 441 980 (48.28%) were classified as incident. Hospitalisation rates increased from 1982 to 1996, with an inflection point in 1997 and a subsequent 52% decrease until 2009. Prevalences of smoking, obesity, overweight and use of vascular risk drug therapy were significantly associated with hospitalisation rates (p<0.001): incidence rates ratios (95% CI) for the fourth versus the first quartile were 1.46 (1.42 to 1.50), 1.80 (1.78 to 1.83), 1.58 (1.55 to 1.60) and 0.57 (0.51 to 0.63), respectively. These variables accounted for 92% of interannual variability. Conclusions After decades of continuous rises, hospitalisation due to incident ischaemic heart disease has been cut by half, an achievement associated with the decline in smoking and the increase in vascular risk drug therapy. These results indicate that these two primary prevention strategies have been effective at a population level, thanks to an appropriate balance between financial and health goals, something that should be left intact despite the current economic crisis. Future strategies ought to lay special stress on excessive body weight prevention.