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Biomedical subjects

A Tobías

Publications and source records attributed to A Tobías.

12 recordsLinked to original sources
PubMed2000

Patients with chronic obstructive pulmonary disease are at increased risk of death associated with urban particle air pollution: a case-crossover analysis.

The authors assessed the acute association between particulate air pollution and mortality among subjects suffering from chronic obstructive pulmonary disease by using a case-crossover analysis. This design avoided the common concerns about the methods used to assess the acute effects of air pollution. The 1,845 men and the 460 women included were residents of Barcelona, Spain, who were over age 35 years, had died during the period 1990-1995, and had visited emergency rooms because of a chronic obstructive pulmonary disease exacerbation during the period 1985-1989. Particle levels (measured as black smoke at the city monitoring stations) were associated with mortality for all causes (odds ratio (OR) for an increase of 20 microg/m3, the interquartile change, adjusted for temperature, humidity, and influenza = 1.112, 95 percent confidence interval (CI): 1.017, 1.215). The association was stronger for respiratory causes (OR = 1.182, 95 percent CI: 1.025, 1.365), but was not significant for cardiovascular causes (OR = 1.077, 95 percent CI: 0.917, 1.264). Older women, patients admitted to intensive care units, and patients with a higher rate of emergency room visits were at greater risk of dying associated with black smoke. The results reinforced the deleterious role of urban pollution and provided information on factors possibly conferring susceptibility to the acute role of air pollution.

Adult↗
PubMed2000

Causality and temporality in the study of short-term effects of air pollution on health.

BACKGROUND: The relationship between air pollution and health is usually analysed by time series analysis. However, temporality (i.e. looking to see whether the cause precedes the effect) is rarely examined in detail. METHODS: Models were fitted to daily levels of black smoke, nitrogen dioxide, sulphur dioxide, ozone and mortality from Barcelona 1986-1995 to account for seasonality, environmental temperature, days of the week and influenza epidemics. Cross-correlations of the residuals were plotted for different lags. RESULTS: Clear evidence of a temporal relationship between mortality and air pollution found for all four pollutants in that changes in the pollutant preceded changes in mortality, implying causality. However the pattern of dependence was different for each pollutant. CONCLUSION: The cross-correlation plot is a useful tool in the analysis of air pollution time series.

Air Pollution↗
PubMed1999

Sinonasal cancer, occupation, and tobacco smoking in European women and men.

BACKGROUND: In this analysis of European case-control studies on sinonasal cancer, we examined the risk for occupation and smoking, by gender and histological type. METHODS: The pooled data included 104 female and 451 male cases, and 241 female and 1,464 male controls. Lifetime smoking and occupational history were recoded following uniform criteria, and job-exposure matrices were applied for wood and leather dust. RESULTS: Wood dust exposure was associated with an excess risk in men (OR = 2.36, 95% CI 1.75-3.2) but not in women (OR = 1.17, 95% CI 0.31-4.47). Exposure to leather dust was associated with an excess risk in both genders. Both wood and leather dust were associated with adenocarcinomas rather than squamous cell carcinomas. Excess risks for smoking were higher for squamous cell carcinomas and higher in men than in women. CONCLUSIONS: In these European populations, occupation was associated with about 11% of all sinonasal cancers in women and 39% in men. This difference can, in part, be attributed to variation in exposure patterns between genders.

Adenocarcinoma↗
PubMed1999

Modelling asthma epidemics on the relationship between air pollution and asthma emergency visits in Barcelona, Spain.

We have investigated different methods of controlling for asthma epidemics in the time series regression of the relationship between air pollution and asthma emergency visits in Barcelona, Spain. The relationship between air pollution and asthma emergency room visits was modelled using autoregressive Poisson models. We examined the effect of using no control by epidemics, and modelling asthma epidemics with a single dummy variable, six dummy variables, and a dummy variable for each epidemic day. Air pollution coefficients increased when controlling asthma epidemics with six dummy variables instead of a single variable. They further increased when autocorrelation was allowed for. Standard errors were relatively unaffected when either the epidemics or the autocorrelation were included in the model. Black smoke, nitrogen dioxide and ozone were statistically significant associated to asthma emergency visits after using six dummy variables to control for asthma epidemics. We have shown that different models, including different confounding variables, give markedly different estimates of the effect of a pollutant on health. Care is needed in the interpretation of such models, and careful reporting so it is clear how the confounding variables have been modelled.

Air Pollutants↗
PubMed1999

Risk of asthma in the general Spanish population attributable to specific immunoresponse. Spanish Group of the European Community Respiratory Health Survey.

BACKGROUND: Individuals with asthma are more atopic than the general population, but few reports have quantified this association, i.e. the proportion of asthma in the community due to specific immunoresponse. We aimed to determine the population attributable risk of asthma in the community due to atopy, and the quantity and quality of specific immunoresponses to common aeroallergens involved. METHODS: We used data from a cross-sectional study in a random sample of the general Spanish population, 20-44 years old, from five areas. In all, 1816 participants were given a symptoms questionnaire, a methacholine challenge and were assessed for atopy. Bronchial responsiveness (BR) was defined as a > or =20% fall in forced expiratory volume in one second (FEV1) after methacholine. Asthma was defined as symptomatic bronchial responsiveness. Atopy was assessed by measuring serum specific IgE or skin tests for sensitivity to Alternaria, birch, cat, Cladosporium, Dermatophagoides pteronyssinus, olive, Parietaria, ragweed or timothy grass. RESULTS: Sensitivity to any of the individual allergens tested significantly increased the risk of being asthmatic, at least twofold compared to non-atopic individuals. The population attributable risk of atopy in explaining asthma is 41.97% (95% CI: 29.2-60.3) when adjusting for area of residence, age, sex, and smoking. In symptomatic individuals, atopy was an independent factor in producing an early measurable PD20 (methacholine dose producing 20% fall in FEV1), especially in those atopic to two or more aeroallergens, and irrespective of the particular aeroallergen. CONCLUSIONS: Specific immunoresponse is strongly associated with asthma, but positivity to single allergens (quality) and the number of positive immunoresponses (quantity) do not change the per se risk of asthma in atopic individuals.

Adult↗
PubMed1998

Sex differences in mortality of people who visited emergency rooms for asthma and chronic obstructive pulmonary disease.

We assess the sex differences in mortality in a population-based cohort of those Barcelona residents older than 14 yr of age who received emergency room services (ERS) for either chronic obstructive pulmonary disease (COPD) or asthma, during the period from 1985 to 1989. Vital status was followed to the end of 1995. A total of 15,517 individuals, 9,918 males and 5,599 females were included in the study. Asthma was diagnosed in 16% of males and 53% of females. Overall, 50% of males and 30% of females died during the follow-up period. The mortality rates in both males and females who visited emergency rooms for COPD or asthma were significantly higher than the expected rates in the general population. These relative increases in the mortality rates were significantly higher in females than in males for both causes of death, COPD (age-adjusted female/male ratio = 2.39), and asthma (ratio = 3.95). However, survival was better in females than males among individuals in the study. The higher fatality in males than females was observed for all causes of death, all respiratory causes, and COPD (risk ratio among patients with COPD = 0.42, 0.29-0.59, and among patients with asthma = 0.11, 0.02-0.60), but not for asthma. Mortality for asthma was higher in females with a diagnosis of COPD (2.79, 1.52-5.13), but it was not different among individuals in whom asthma was diagnosed (1.02, 0.56-1.87). Greater severity of COPD in males than in females could explain a higher risk of dying for all respiratory causes and COPD in males. The increased risk of asthma death in females may be due to problems of coding the term "asthma" in death certificates. The higher rates in females than in males when comparing with the general population, may be an expression of a greater similarity in risk factors, such as smoking, in our population than in males and females of the general population.

Adolescent↗
PubMed1997

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.

Adult↗
PubMed1996

Atopy and nonspecific bronchial responsiveness. A population-based assessment. Spanish Group of the European Community Respiratory Health Survey.

The relative importance of specific immunoresponse in explaining nonspecific bronchial responsiveness (BR) has scarcely been examined. We provide quantitative estimates of the proportion of BR attributable to specific atopy to different common aeroallergens. We used data from a cross-sectional study on a random sample of the general population 20 to 44 yr of age from five Spanish areas. There were 1,816 participants who performed a methacholine challenge and had atopy assessed. BR was defined as a 20% or more fall in FEV1. Atopy was assessed by measuring serum-specific IgE or skin tests to cat, Dermatophagoides pteronyssinus, Cladosporium, Alternaria, timothy grass, olive, birch, Parietaria, or ragweed. The strongest associations between BR and specific IgE response were against timothy grass (prevalence rate ratio = 1.78; 95% confidence interval 1.2 to 2.6), Dermatophagoides pteronyssinus = 1.64 (1.2 to 2.2), and olive = 2.36 (1.5 to 3.7), all after adjustment by age, sex, area of residence, smoking, and a positive response to any of the other eight allergens measured. The population attributable risk of BR for a positive response to any of the nine allergens measured was 20.96% (10.2 to 43.2%) when adjusting for area of residence, age, sex, and smoking. Nonspecific bronchial responsiveness in the general population was found to be related to atopy against single specific allergens, but the population risk attributable to atopy may be lower than previously suggested.

Adult↗