Estel Plana

Exposure to substances in the workplace and new-onset asthma: an international prospective population-based study (ECRHS-II)

BACKGROUND The role of exposure to substances in the workplace in new-onset asthma is not well characterised in population-based studies. We therefore aimed to estimate the relative and attributable risks of new-onset asthma in relation to occupations, work-related exposures, and inhalation accidents. METHODS We studied prospectively 6837 participants from 13 countries who previously took part in the European Community Respiratory Health Survey (1990-95) and did not report respiratory symptoms or a history of asthma at the time of the first study. Asthma was assessed by methacholine challenge test and by questionnaire data on asthma symptoms. Exposures were defined by high-risk occupations, an asthma-specific job exposure matrix with additional expert judgment, and through self-report of acute inhalation events. Relative risks for new onset asthma were calculated with log-binomial models adjusted for age, sex, smoking, and study centre. FINDINGS A significant excess asthma risk was seen after exposure to substances known to cause occupational asthma (Relative risk=1.6, 95% CI 1.1-2.3, p=0.017). Risks were highest for asthma defined by bronchial hyper-reactivity in addition to symptoms (2.4, 1.3-4.6, p=0.008). Of common occupations, a significant excess risk of asthma was seen for nursing (2.2, 1.3-4.0, p=0.007). Asthma risk was also increased in participants who reported an acute symptomatic inhalation event such as fire, mixing cleaning products, or chemical spills (RR=3.3, 95% CI 1.0-11.1, p=0.051). The population-attributable risk for adult asthma due to occupational exposures ranged from 10% to 25%, equivalent to an incidence of new-onset occupational asthma of 250-300 cases per million people per year. INTERPRETATION Occupational exposures account for a substantial proportion of adult asthma incidence. The increased risk of asthma after inhalation accidents suggests that workers who have such accidents should be monitored closely.

Early life origins of chronic obstructive pulmonary disease

Background: Early life development may influence subsequent respiratory morbidity. The impact of factors determined in childhood on adult lung function, decline in lung function and chronic obstructive pulmonary disease (COPD) was investigated. Methods: European Community Respiratory Health Survey participants aged 20–45 years randomly selected from general populations in 29 centres underwent spirometry in 1991–3 (n = 13 359) and 9 years later (n = 7738). Associations of early life factors with adult forced expiratory volume in 1 s (FEV1), FEV1 decline and COPD (FEV1/FVC ratio <70% and FEV1 <80% predicted) were analysed with generalised estimating equation models and random effects linear models. Results: Maternal asthma, paternal asthma, childhood asthma, maternal smoking and childhood respiratory infections were significantly associated with lower FEV1 and defined as “childhood disadvantage factors”; 40% had one or more childhood disadvantage factors which were associated with lower FEV1 (men: adjusted difference 95 ml (95% CI 67 to 124); women: adjusted difference 60 ml (95% CI 40 to 80)). FEV1 decreased with increasing number of childhood disadvantage factors (⩾3 factors, men: 274 ml (95% CI 154 to 395), women: 208 ml (95% CI 124 to 292)). Childhood disadvantage was associated with a larger FEV1 decline (1 factor: 2.0 ml (95% CI 0.4 to 3.6) per year; 2 factors: 3.8 ml (95% CI 1.0 to 6.6); ⩾3 factors: 2.2 ml (95% CI −4.8 to 9.2)). COPD increased with increasing childhood disadvantage (1 factor, men: OR 1.7 (95% CI 1.1 to 2.6), women: OR 1.6 (95% CI 1.01 to 2.6); ⩾3 factors, men: OR 6.3 (95% CI 2.4 to 17), women: OR 7.2 (95% CI 2.8 to 19)). These findings were consistent between centres and when subjects with asthma were excluded. Conclusions: People with early life disadvantage have permanently lower lung function, no catch-up with age but a slightly larger decline in lung function and a substantially increased COPD risk. The impact of childhood disadvantage was as large as that of heavy smoking. Increased focus on the early life environment may contribute to the prevention of COPD.

Smoking and smoking cessation during early pregnancy and its effect on adverse pregnancy outcomes and fetal growth

Maternal smoking during pregnancy is a significant threat to the fetus. We examined the association between active maternal smoking and smoking cessation during early pregnancy with newborn somatometrics and adverse pregnancy outcomes including preterm delivery, low birth weight, and fetal growth restriction. One thousand four hundred mother–child pairs with extensive questionnaire data were followed up until delivery, within the context of a population-based mother–child cohort study (Rhea study), in Crete, Greece, 2007–2008. Comparing smokers to nonsmokers, the adjusted odds ratio (OR) was 2.8 [95% confidence interval (CI), 1.7, 4.6] for low birth weight and 2.6 (95%CI: 1.6, 4.2) for fetal growth restriction. This corresponded to a 119-g reduction in birth weight, a 0.53-cm reduction in length, and a 0.35-cm reduction in head circumference. Smoking cessation early during pregnancy modified significantly these pregnancy outcomes indicating the necessity for primary smoking prevention.

Occupational risk factors for asthma among nurses and related healthcare professionals in an international study

Objective: The authors examined the relations between self-reported work tasks, use of cleaning products and latex glove use with new-onset asthma among nurses and other healthcare workers in the European Community Respiratory Health Survey (ECRHS II). Methods: In a random population sample of adults from 22 European sites, 332 participants reported working in nursing and other related healthcare jobs during the nine-year ECRHS II follow-up period and responded to a supplemental questionnaire about their principal work settings, occupational tasks, products used at work and respiratory symptoms. Poisson regression models with robust error variances were used to compare the risk of new-onset asthma among healthcare workers with each exposure to that of respondents who reported professional or administrative occupations during the entire follow-up period (n = 2481). Results: Twenty (6%) healthcare workers and 131 (5%) members of the referent population reported new-onset asthma. Compared to the referent group, the authors observed increased risks among hospital technicians (RR 4.63; 95% CI 1.87 to 11.5) and among those using ammonia and/or bleach at work (RR 2.16; 95% CI 1.03 to 4.53). Conclusions: In the ECRHS II cohort, hospital technicians and other healthcare workers experience increased risks of new-onset current asthma, possibly due to specific products used at work.

Socioeconomic status, asthma and chronic bronchitis in a large community-based study

The present study investigated the relationship between socioeconomic status, using measures of occupational class and education level, and the prevalence and incidence of asthma (with and without atopy) and chronic bronchitis using data from the European Community Respiratory Health Survey (ECRHS). Asthma and chronic bronchitis were studied prospectively within the ECRHS (n = 9,023). Incidence analyses comprised subjects with no history of asthma or bronchitis at baseline. Asthma symptoms were also assessed as a continuous score. Bronchitis risk was associated with low educational level (prevalence odds ratio (POR) 1.9; 95% confidence interval (CI) 1.4–2.8) and occupational class (1.8; 1.2–2.7). Incident bronchitis also increased with low educational level (risk ratio (RR) 2.8; 95%CI 1.5–5.4). Prevalent and incident asthma with no atopy were associated with low educational level. Subjects in the low occupational class (incident risk ratio (IRR) 1.4; 95%CI 1.2–1.7) and education group (IRR 1.3; 95% CI 1.1–1.6) had higher mean asthma scores than those in higher socioeconomic groups. Lower educational level was associated with increased risk of prevalent and incident chronic bronchitis and asthma with no atopy. Lower socioeconomic groups tended to have a higher prevalence and incidence of asthma, particularly higher mean asthma scores. Adjustment for variables associated with asthma and bronchitis explained little of the observed health differences by socioeconomic status.

Early Age at Menarche, Lung Function, and Adult Asthma

RATIONALE hormonal and metabolic status appears to influence lung health in women, and there are findings suggesting that early menarche may be related to asthma, cardiovascular disease, diabetes, and breast cancer. OBJECTIVES this study investigates whether age at menarche is related to adult lung function and asthma. METHODS among participants in the European Community Respiratory Health Survey II, 3,354 women aged 27-57 years from random population samples in 21 centers responded to a questionnaire concerning womens health (1998-2002). Of these women, 2,873 had lung function measurements, 2,136 had measurements of bronchial hyperreactivity, and 2,743 had IgE measurements. Logistic, linear, and negative binomial regression analyses included adjustment for age, height, body mass index, education, smoking, family size, and center. MEASUREMENTS AND MAIN RESULTS FEV(1) and FVC were lower and asthma was more common in women with early menarche. Women reporting menarche at age 10 years or less, as compared with women with menarche at age 13 years (reference category), had lower FEV(1) (adjusted difference, -113 ml; 95% confidence interval [CI], -196 to -33 ml) and FVC (-126 ml; 95% CI, -223 to -28 ml); also lower FEV(1) expressed as a percentage of the predicted value (-3.28%; 95% CI, -6.25 to -0.30%) and FVC expressed as a percentage of the predicted value (-3.63%; 95% CI, -6.64 to -0.62%). Women with early menarche more often had asthma symptoms (odds ratio, 1.80; 95% CI, 1.09-2.97), asthma with bronchial hyperreactivity (odds ratio, 2.79; 95% CI, 1.06-7.34), and higher asthma symptom score (mean ratio, 1.58; 95% CI, 1.12-2.21). CONCLUSIONS women with early menarche had lower lung function and more asthma in adulthood. This supports a role for metabolic and hormonal factors in womens respiratory health.

Iodine levels and thyroid hormones in healthy pregnant women and birth weight of their offspring

INTRODUCTION The fetus is most vulnerable to severe iodine deficiency and hypothyroidism during pregnancy. The effects of mild iodine deficiency and subclinical hypothyroidism are poorly known. The present study assesses the association between thyroid hormones (TH)s and urinary iodine concentration (UIC) in healthy pregnant women and the birth weight of their children. METHODS About 657 pregnant women were recruited in Sabadell and followed until delivery. The association between THs during the first trimester, UIC during the first and third trimesters, and birth weight was studied in 557, 251, and 528 mother-newborn pairs respectively, using linear and logistic regression models adjusted for potential confounders. Only 239 women had all the data available (thyroid function and UIC at the first and third trimesters). Six percent of newborns were classified as small for gestational age (SGA). RESULTS The median UIC was 95 and 104 microg/l during the first and third trimesters respectively. Women with the third trimester UICs between 100 and 149 microg/l had lower risk of having an SGA newborn than women with UICs below 50 microg/l (adjusted OR (95%CI): 0.15 (0.03-0.76). There was no significant reduction in SGA among mothers with higher UICs. Lower free thyroxine and higher TSH levels during the first trimester were not associated with birth weight or SGA. Nevertheless, the analyses were repeated including only those women with all the data available, and high TSH levels became statistically significantly associated with lower birth weight and higher risk of SGA. CONCLUSIONS The present study suggests that iodine status during pregnancy may be related to prenatal growth in healthy women.

Occupational exposures and COPD: an ecological analysis of international data

The occupational contribution to chronic obstructive pulmonary disease (COPD) has yet to be put in a global perspective. In the present study, an ecological approach to this question was used, analysing group-level data from 90 sex-specific strata from 45 sites of the Burden of Obstructive Lung Disease study, the Latin American Project for the Investigation of Obstructive Lung Disease and the European Community Respiratory Health Survey follow-up. These data were used to study the association between occupational exposures and COPD Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II or above. Regression analysis of the sex-specific group-level prevalence rates of COPD at each site against the prevalence of occupational exposure and ever-smoking was performed, taking into account mean smoking pack-yrs and mean age by site, sex, study cohort and sample size. For the entire data set, the prevalence of exposures predicted COPD prevalence (0.8% increase in COPD prevalence per 10% increase in exposure prevalence). By comparison, for every 10% increase in the proportion of the ever-smoking population, the prevalence of COPD GOLD stage II or above increased by 1.3%. Given the observed median population COPD prevalence of 3.4%, the model predicted that a 20% relative reduction in the disease burden (i.e. to a COPD prevalence of 2.7%) could be achieved by a 5.4% reduction in overall smoking rates or an 8.8% reduction in the prevalence of occupational exposures. When the data set was analysed by sex-specific site data, among males, the occupational effect was a 0.8% COPD prevalence increase per 10% change in exposure prevalence; among females, a 1.0% increase in COPD per 10% change in exposure prevalence was observed. Within the limitations of an ecological analysis, these findings support a worldwide association between dusty trades and chronic obstructive pulmonary disease for both females and males, placing this within the context of the dominant role of cigarette smoking in chronic obstructive pulmonary disease causation.

Leptin levels in cord blood and anthropometric measures at birth: a systematic review and meta-analysis

The role of intrauterine environment in the development of obesity is increasingly recognised. Adipokines and specifically leptin have been examined as potential biomarkers predicting early development of obesity. We conducted a systematic review and meta-analysis of the epidemiological evidence for the association between leptin levels in cord blood and anthropometric measurements at birth in healthy mother-newborn pairs. A PubMed search was performed between 1994 and 2009 and manual search of reference lists of retrieved articles. Forty-four studies met the inclusion criteria set. All studies reported a positive correlation between leptin levels and birthweight. The combined correlation coefficient (r) was 0.46 [95%CI 0.43, 0.50]. Leptin levels explained 21% of variation in birthweight. Results were similar in males (r=0.55; 0.40, 0.68) and females (r=0.60; 0.50, 0.69), and between Caucasians (r=0.45; 0.39, 0.51) and eastern Asian populations (r=0.47; 0.37, 0.55). Statistically significant positive correlations were also found for birth length (r=0.29; 0.23, 0.34) and ponderal index (r=0.36; 0.31, 0.41). There was no indication of publication bias (Eggers test P-value=0.23). This meta-analysis shows a clear but moderate correlation between leptin levels in cord blood and birthweight that is observed in different population groups.

Respiratory symptoms in adults are related to impaired quality of life, regardless of asthma and COPD: results from the European community respiratory health survey

BackgroundRespiratory symptoms are common in the general population, and their presence is related to Health-related quality of life (HRQoL). The objective was to describe the association of respiratory symptoms with HRQoL in subjects with and without asthma or COPD and to investigate the role of atopy, bronchial hyperresponsiveness (BHR), and lung function in HRQoL.MethodsThe European Community Respiratory Health Survey (ECRHS) I and II provided data on HRQoL, lung function, respiratory symptoms, asthma, atopy, and BHR from 6009 subjects. Generic HRQoL was assessed through the physical component summary (PCS) score and the mental component summary (MCS) score of the SF-36.Factor analyses and linear regressions adjusted for age, gender, smoking, occupation, BMI, comorbidity, and study centre were conducted.ResultsHaving breathlessness at rest in ECRHS II was associated with mean score (95% CI) impairment in PCS of -8.05 (-11.18, -4.93). Impairment in MCS score in subjects waking up with chest tightness was -4.02 (-5.51, -2.52). The magnitude of HRQoL impairment associated with respiratory symptoms was similar for subjects with and without asthma/COPD. Adjustments for atopy, BHR, and lung function did not explain the association of respiratory symptoms and HRQoL in subjects without asthma and/or COPD.ConclusionSubjects with respiratory symptoms had poorer HRQoL; including subjects without a diagnosis of asthma or COPD. These findings suggest that respiratory symptoms in the absence of a medical diagnosis of asthma or COPD are by no means trivial, and that clarifying the nature and natural history of respiratory symptoms is a relevant challenge.Several community studies have estimated the prevalence of common respiratory symptoms like cough, dyspnoea, and wheeze in adults [1–3]. Although the prevalence varies to a large degree between studies and geographical areas, respiratory symptoms are quite common. The prevalences of respiratory symptoms in the European Community Respiratory Health Study (ECRHS) varied from one percent to 35% [1]. In fact, two studies have reported that more than half of the adult population suffers from one or more respiratory symptoms [4, 5].Respiratory symptoms are important markers of the risk of having or developing disease. Respiratory symptoms have been shown to be predictors for lung function decline [6–8], asthma [9, 10], and even all-cause mortality in a general population study [11]. In patients with a known diagnosis of asthma or chronic obstructive pulmonary disease (COPD), respiratory symptoms are important determinants of reduced health related quality of life (HRQoL) [12–15]. The prevalence of respiratory symptoms exceeds the combined prevalences of asthma and COPD, and both asthma and COPD are frequently undiagnosed diseases [16–18]. Thus, the high prevalence of respipratory symptoms may mirror undiagnosed and untreated disease.The common occurrence of respiratory symptoms calls for attention to how these symptoms affect health also in subjects with no diagnosis of obstructive airways disease. Impaired HRQoL in the presence of respiratory symptoms have been found in two population-based studies [6, 19], but no study of respiratory sypmtoms and HRQoL have separate analyses for subjects with and without asthma and COPD, and no study provide information about extensive objective measurements of respiratory health.The ECRHS is a randomly sampled, multi-cultural, population based cohort study. The ECRHS included measurements of atopy, bronchial hyperresponsiveness (BHR), and lung function, and offers a unique opportunity to investigate how respiratory symptoms affect HRQoL among subjects both with and without obstructive lung disease.In the present paper we aimed to: 1) Describe the relationship between respiratory symptoms and HRQoL in an international adult general population and: 2) To assess whether this relationship varied with presence of asthma and/or COPD, or presence of objective functional markers like atopy and BHR.