J Sunyer

Short-term effects of particulate air pollution on cardiovascular diseases in eight European cities

Study objective: As part of the APHEA project this study examined the association between airborne particles and hospital admissions for cardiac causes (ICD9 390–429) in eight European cities (Barcelona, Birmingham, London, Milan, the Netherlands, Paris, Rome, and Stockholm). All admissions were studied, as well as admissions stratified by age. The association for ischaemic heart disease (ICD9 410–413) and stroke (ICD9 430–438) was also studied, also stratified by age. Design: Autoregressive Poisson models were used that controlled for long term trend, season, influenza epidemics, and meteorology to assess the short-term effects of particles in each city. The study also examined confounding by other pollutants. City specific results were pooled in a second stage regression to obtain more stable estimates and examine the sources of heterogeneity. Main results: The pooled percentage increases associated with a 10 μg/m3 increase in PM10 and black smoke were respectively 0.5% (95% CI: 0.2 to 0.8) and 1.1% (95% CI: 0.4 to 1.8) for cardiac admissions of all ages, 0.7% (95% CI: 0.4 to 1.0) and 1.3% (95% CI: 0.4 to 2.2) for cardiac admissions over 65 years, and, 0.8% (95% CI: 0.3 to 1.2) and 1.1% (95% CI: 0.7 to 1.5) for ischaemic heart disease over 65 years. The effect of PM10 was little changed by control for ozone or SO2, but was substantially reduced (CO) or eliminated (NO2) by control for other traffic related pollutants. The effect of black smoke remained practically unchanged controlling for CO and only somewhat reduced controlling for NO2. Conclusions: These effects of particulate air pollution on cardiac admissions suggest the primary effect is likely to be mainly attributable to diesel exhaust. Results for ischaemic heart disease below 65 years and for stroke over 65 years were inconclusive.

Effects of Cold Weather on Mortality: Results From 15 European Cities Within the PHEWE Project

Weather-related health effects have attracted renewed interest because of the observed and predicted climate change. The authors studied the short-term effects of cold weather on mortality in 15 European cities. The effects of minimum apparent temperature on cause- and age-specific daily mortality were assessed for the cold season (October-March) by using data from 1990-2000. For city-specific analysis, the authors used Poisson regression and distributed lag models, controlling for potential confounders. Meta-regression models summarized the results and explored heterogeneity. A 1 degrees C decrease in temperature was associated with a 1.35% (95% confidence interval (CI): 1.16, 1.53) increase in the daily number of total natural deaths and a 1.72% (95% CI: 1.44, 2.01), 3.30% (95% CI: 2.61, 3.99), and 1.25% (95% CI: 0.77, 1.73) increase in cardiovascular, respiratory, and cerebrovascular deaths, respectively. The increase was greater for the older age groups. The cold effect was found to be greater in warmer (southern) cities and persisted up to 23 days, with no evidence of mortality displacement. Cold-related mortality is an important public health problem across Europe. It should not be underestimated by public health authorities because of the recent focus on heat-wave episodes.

An international survey of chronic obstructive pulmonary disease in young adults according to GOLD stages

Background: The recently published GOLD guidelines provide a new system for staging chronic obstructive pulmonary disease (COPD) from mild (stage I) to very severe (stage IV) and introduce a stage 0 (chronic cough and phlegm without airflow obstruction) that includes subjects “at risk” of developing the disease. Methods: In order to assess the prevalence of GOLD stages of COPD in high income countries and to evaluate their association with the known risk factors for airflow obstruction, data from the European Community Respiratory Health Survey on more than 18 000 young adults (20–44 years) were analysed. Results: The overall prevalence was 11.8% (95% CI 11.3 to 12.3) for stage 0, 2.5% (95% CI 2.2 to 2.7) for stage I, and 1.1% (95% CI 1.0 to 1.3) for stages II–III. Moderate to heavy smoking (⩾15 pack years) was significantly associated with both stage 0 (relative risk ratio (RRR)u200a=u200a4.15; 95% CI 3.55 to 4.84) and stages I+ (RRRu200a=u200a4.09; 95% CI 3.17 to 5.26), while subjects with stages I+ COPD had a higher likelihood of giving up smoking (RRRu200a=u200a1.39; 95% CI 1.04 to 1.86) than those with GOLD stage 0 (RRRu200a=u200a1.05; 95% CI 0.86 to 1.27). Environmental tobacco smoke had the same degree of positive association in both groups. Respiratory infections in childhood and low socioeconomic class were significantly and homogeneously associated with both groups, whereas occupational exposure was significantly associated only with stage 0. All the GOLD stages showed a significantly higher percentage of healthcare resource users than healthy subjects (p<0.001), with no difference between stage 0 and COPD. Conclusions: A considerable percentage of young adults already suffered from COPD. GOLD stage 0 was characterised by the presence of the same risk factors as COPD and by the same high demand for medical assistance.

Asthma, chronic bronchitis, and exposure to irritant agents in occupational domestic cleaning: a nested case-control study

Background: Women employed in domestic cleaning are at increased risk for symptoms of obstructive lung disease, but the agents responsible are unknown. Aims: To investigate common tasks and products in occupational domestic cleaning in relation to respiratory morbidity. Methods: Case-control study in domestic cleaning women nested within a large population based survey of women aged 30–65 years; 160 domestic cleaning women with asthma symptoms, chronic bronchitis symptoms, or both and 386 without a history of respiratory symptoms were identified. Detailed exposures were evaluated for 40 cases who reported still having symptoms at the recruitment interview, and 155 controls who reported not having symptoms. All tasks performed and products used when cleaning houses were determined in a face-to-face interview. Lung function, methacholine challenge, and serum IgE testing were performed. Personal exposure measurements of airborne chlorine and ammonia were performed in a subsample. Associations between asthma, chronic bronchitis, and cleaning exposures were evaluated using multiple logistic regression analysis. Results: Airborne chlorine (median level 0–0.4 ppm) and ammonia (0.6–6.4 ppm) were detectable during occupational domestic cleaning activities. Cases used bleach more frequently than controls; adjusted odds ratio (OR) for intermediate exposure was 3.3 (95% CI 0.9 to 11) and for high exposure 4.9 (1.5 to 15). Other independent associations included accidental inhalation of vapours and gases from cleaning agents and washing dishes. These associations were more pronounced for cases with asthma symptoms than for those with symptoms of chronic bronchitis, but were not related to sensitisation to common allergens. Conclusions: Asthma symptoms in domestic cleaning women are associated with exposure to bleach and possibly other irritant agents. The public health impact of the use of irritant cleaning products could be widespread since the use of these products is common both in the workplace and at home.

Operational definitions of asthma in studies on its aetiology

The most popular way to define asthma based on questionnaires is to use definitions taken from cross-sectional international studies on asthma. These definitions may not, however, be optimal for future studies focusing on risk factors of asthma. The current authors, therefore, compared the performance of different operational definitions of asthma. The European Community Respiratory Health Study I was a cross-sectional study of 21,924 subjects aged between 25–44u2005yrs in 18 countries. Operational definitions of asthma compared included different combinations of symptoms of asthma and bronchial hyperresponsiveness. A continuous asthma score, ranging from 0–8, was defined as the sum of positive answers to eight main symptom questions. There was no threshold in the associations of asthma symptoms with severity or risk factors of asthma, which would have suggested a dichotomous definition of asthma. Using dichotomous definitions requiring the presence of several asthma symptoms strengthened associations with studied risk factors, and also increased the estimated specificity and positive predictive value. Using a continuous asthma score also improved the power of the analyses. In conclusion, dichotomous definitions of asthma yielding higher odds ratios are achieved by requiring positive responses to several questions on symptoms. However, symptoms of asthma are possibly best analysed as a continuous asthma score.

Asthma symptoms in women employed in domestic cleaning: a community based study

Background: Epidemiological studies have shown an association between cleaning work and asthma, but the risk factors are uncertain. The aim of this study was to assess the risk of asthma in women employed in domestic cleaning. Methods: A cross sectional study was conducted in 4521 women aged 30 to 65 years. Information on respiratory symptoms and cleaning work history was obtained using a postal questionnaire with telephone follow up. Asthma was defined as reported symptoms in the last year or current use of drugs to treat asthma. Odds ratios (OR) with 95% confidence intervals (CI) for asthma in different cleaning groups were estimated using adjusted unconditional logistic regression models. Results: 593 women (13%) were currently employed in domestic cleaning work. Asthma was more prevalent in this group than in women who had never worked in cleaning (OR 1.46 (95% CI, 1.10 to 1.92)). Former domestic cleaning work was reported by 1170 women (26%), and was strongly associated with asthma (OR 2.09 (1.70 to 2.57)). Current and former non-domestic cleaning work was not significantly associated with asthma. Consistent results were obtained for other respiratory symptoms. Twenty five per cent of the asthma cases in the study population were attributable to domestic cleaning work. Conclusions: Employment in domestic cleaning may induce or aggravate asthma. This study suggests that domestic cleaning work has an important public health impact, probably involving not only professional cleaners but also people undertaking cleaning tasks at home.

Short-term effects of ambient particles on mortality in the elderly: results from 28 cities in the APHEA2 project

Within the framework of the APHEA2 (Air Pollution on Health: a European Approach) project, the effects of ambient particles on mortality among persons ≥65u2005yrs were investigated. Daily measurements for particles with a 50% cut-off aerodynamic diameter of 10u2005µm (PM10) and black smoke (BS), as well as the daily number of deaths among persons ≥65u2005yrs of age, from 29 European cities, have been collected. Data on other pollutants and meteorological variables, to adjust for confounding effects and data on city characteristics, to investigate potential effect modification, were also recorded. For individual city analysis, generalised additive models extending Poisson regression, using a locally weighted regression (LOESS) smoother to control for seasonal effects, were applied. To combine individual city results and explore effect modification, second stage regression models were applied. The per cent increase (95% confidence intervals), associated with a 10u2005µg·m−3 increase in PM10, in the elderly daily number of deaths was 0.8% (0.7–0.9%) and the corresponding number for BS was 0.6% (0.5–0.8%). The effect size was modified by the long-term average levels of nitrogen dioxide (higher levels were associated with larger effects), temperature (larger effects were observed in warmer countries), and by the proportion of the elderly in each city (a larger proportion was associated with higher effects). These results indicate that ambient particles have effects on mortality among the elderly, with relative risks comparable or slightly higher than those observed for total mortality and similar effect modification patterns. The effects among the older persons are of particular importance, since the attributable number of events will be much larger, compared to the number of deaths among the younger population.

Short-term respiratory effects of cleaning exposures in female domestic cleaners

Symptoms of obstructive lung disease in domestic cleaners have been related to the use of bleach and other irritant cleaning products. The short-term effects of cleaning exposures on respiratory symptoms and peak expiratory flow (PEF) were investigated in domestic cleaners with respiratory disorders. In a panel study, 43 female domestic cleaners with a recent history of asthma and/or chronic bronchitis completed a 2-week diary, collecting information on respiratory symptoms, PEF and cleaning exposures. Mixed regression models were used to assess daily changes in symptoms and PEF associated with specific cleaning exposures. The probability of having work-related asthma was individually assessed by a computerised diagnostic system and an occupational asthma expert. Lower respiratory tract symptoms were more common on working days and were predominantly associated with exposure to diluted bleach, degreasing sprays/atomisers and air fresheners. Associations with upper respiratory tract symptoms and PEF were less apparent. Eleven (30%) subjects scored positively for work-related asthma. It is concluded that exposure to certain irritant cleaning products aggravates lower respiratory tract symptoms in female domestic cleaners with asthma or chronic bronchitis.

Risk factors for asthma in young adults. Spanish Group of the European Community Respiratory Health Survey.

We assessed the association of asthma prevalence in young adults with susceptibility factors and environmental exposures, taking into account the age at asthma onset. A random sample of the general population, aged 20-44 yrs, in five areas of Spain (Albacete, Barcelona, Galdakao, Huelva, and Oviedo) was selected in the frame of the European Community Respiratory Health Survey (ECRHS). Overall, 2,646 subjects (response rate = 60.9%) responded to a respiratory questionnaire and 1,797 (41.4%) finalized a bronchial challenge. Atopy to perennial (odds ratio (OR) = 10.2, 95% confidence interval 4.2-25) and seasonal allergens (11.5, 4.6-28), parental asthma (4.5, 2.5-8.4), and birth order (OR for no older siblings in comparison to having more than two = 3.2, 1.2-9.1) were associated with current asthma whatever the age of asthma onset. Past asthma was associated to a lesser extent with atopy (OR around 3.5 to both perennial and seasonal allergens). Lower respiratory tract infections before the age of 5 yrs (LRTI), having had a pet in childhood, and being born in a younger cohort were associated with asthma starting before the age of 15 yrs, but not after. Male gender was more frequent in childhood asthma and female gender in adulthood. In addition to the known risk factors of asthma (atopy to perennial allergens, parental asthma) we provide evidence for an association of asthma (whatever the age of onset) with sensitization to seasonal allergens, and having less than three older siblings; and for an association of childhood asthma with lower respiratory tract infections.

Chronic bronchitis and urban air pollution in an international study

Objectives: The chronic effects of urban air pollution are not well known. The authors’ aim was to investigate the association between the prevalence and new onset of chronic bronchitis and urban air pollution. Methods: Subjects from the general population randomly selected for the European Community Respiratory Health Survey (ECRHS I) during 1991–93 in 21 centres in 10 countries were followed up from the years 2000 to 2002 (nu200a=u200a3232 males and 3592 females; average response rateu200a=u200a65.3%). PM2.5 and elements, with the same equipment at centre level, and home outdoor NO2 in 1634 individuals were measured. Hierarchical models were used. Results: The prevalence and new onset of chronic phlegm during follow up were 6.9% and 4.5%, respectively, 5.3% in males and 3.5% in females. Smoking, rhinitis, poor education, and low social class were associated with (prevalence and new onset of) chronic phlegm in both genders, and occupational exposures in males and traffic intensity (adjusted odds ratio for constant traffic, ORu200a=u200a1.86; 95% CI 1.24 to 2.77) as well as home outdoor NO2 (OR > 50 μg/m3v < 20μg3 u200a=u200a 2.71; 95% CI 1.03 to 7.16) among females. PM2.5 and S content at centre level did not show any association with prevalence or new onset of chronic phlegm. Similar results were obtained with chronic productive cough. Conclusion: Individual markers of traffic at household level such as reported intensity and outdoor NO2 were risk factors for chronic bronchitis among females.