Study on occupational allergy risks (SOLAR II) in Germany: design and methods

Work-related stress and atopic dermatitis: Results from the study on occupational allergy risks

Chronic stress at work is ubiquitous in modern societies. However, its influence on atopic dermatitis (AD) has hardly been investigated. This study aimed to elucidate the association between work-related stress and AD via a longitudinal study. The analysis comprised data from three phases (2002-2003, 2007-2009, 2017-2018) of the prospective Study on Occupational Allergy Risks (SOLAR), including 1,240 young adults aged 16 to 18 years at baseline (61% female) who were originally recruited for the International Study of Asthma and Allergies in Childhood Phase II in 1995-1996. AD was assessed at all three phases based on self-reports of a physician's diagnosis and symptoms. Work-related stress was measured at all three periods using the work discontent and work overload scales from the Trier Inventory for the Assessment of Chronic Stress with adaptions to school and university. Generalized estimating equations were used to analyze the association between stress and AD, treating work discontent and work overload first as continuous and then as categorical exposure variables. We observed 50 AD cases (4%) at SOLAR I, 48 (4%) at SOLAR II, and 42 (3%) at SOLAR III. A one-point increase in the work discontent score was associated with an odds ratio (OR) for AD of 1.05 (95% confidence interval [CI], 1.00-1.10). The respective increase in the work overload score led to an OR of 1.03 (95% CI, 0.99-1.06). In the categorical analysis, there was no clear indication of elevated odds of AD in the highest vs. lowest exposure group (4th vs. 1st quartile: OR, 1.53; 95% CI, 0.92-2.53 for work discontent; OR, 1.38, 95% CI, 0.83-2.27 for work overload). Altogether, we observed limited to no evidence for an association between work-related stress and AD. Our study's ability to detect stronger evidence may have been compromised by shortcomings such as nondifferential misclassification of the outcome or insufficient statistical precision due to small numbers of AD cases. Another explanation could be that AD predominantly becomes evident in childhood, not in adulthood.

Parental occupational exposures prior to conception and offspring wheeze and eczema during first year of life

PURPOSE

Parental exposures prior to conception might influence asthma and allergy risk in offspring. As occupational exposures are established risk factors for asthma and allergies, we investigated if parental occupational exposures prior to conception cause wheeze and eczema in offspring during the first year of life.

METHODS

We analysed data of 436 families from an offspring cohort based on a follow-up study of German participants of the International Study of Asthma and Allergies in Childhood (ISAAC). Offspring cohort data was collected between 2009 and 2019. Occupational exposures were based on participants' work histories and measured by a Job-Exposure-Matrix. We used Bayesian logistic regression models for analysis. Inference and confounder selection were based on directed acyclic graphs.

RESULTS

In mothers, for both allergic and irritative occupational exposures prior to conception suggestive effects on offspring eczema during the first year of life were found (allergens: odds ratio (OR) 1.22, 95% compatibility interval (CI) 0.92-1.57; irritants: OR 1.36, 95% CI 0.99-1.77), while no relation with wheeze was suggested.

CONCLUSIONS

Our results suggest that reduction of asthma-related occupational exposures might not only reduce the burden of disease for occupationally induced or aggravated asthma and allergies in employees but also in their children.

Trajectories of asthma and allergy symptoms from childhood to adulthood

BACKGROUND

Phenotypes of asthma and allergic diseases are mainly studied separately for children and adults. To explore the role of adolescence and young adulthood, we investigated symptom trajectories at the transition from childhood into adulthood.

METHODS

Latent class analysis (LCA) was conducted in a population initially recruited for the German arm of Phase II of the International Study of Asthma and Allergies in Childhood and followed-up three times until their early 30s (N=2267). Indicators included in LCA were 12-month prevalences of symptoms of wheeze, rhinoconjunctivitis, and eczema. Latent classes were further characterised regarding important traits such as skin prick tests. Logistic regression models were used to investigate associations with environmental determinants such as smoking and occupational exposures.

RESULTS

Six latent classes were identified: an asymptomatic one as well as three with single and two with co-occurring symptoms. All trajectories essentially established between baseline assessment at around 10 years and the first follow-up at around 17 years. Probabilities for symptoms increased from childhood to adolescence, especially for wheeze-related latent classes, while they remained constant in adulthood. Wheeze-related latent classes were also positively associated with exposures during adolescence (e.g. active smoking).

CONCLUSION

Distinct trajectories of asthma and allergy symptoms establish from childhood through adolescence and stabilize during early adulthood. This pattern was most notable in wheeze-related latent classes which also showed the strongest positive associations with environmental exposures in adolescence/young adulthood. Therefore, not only childhood but also adolescence is relevant for disease development and offers considerable potential for prevention and health promotion.

Antibiotic Resistance in Wastewater Treatment Plants and Transmission Risks for Employees and Residents: The Concept of the AWARE Study

Antibiotic resistance has become a serious global health threat. Wastewater treatment plants may become unintentional collection points for bacteria resistant to antimicrobials. Little is known about the transmission of antibiotic resistance from wastewater treatment plants to humans, most importantly to wastewater treatment plant workers and residents living in the vicinity. We aim to deliver precise information about the methods used in the AWARE (Antibiotic Resistance in Wastewater: Transmission Risks for Employees and Residents around Wastewater Treatment Plants) study. Within the AWARE study, we gathered data on the prevalence of two antibiotic resistance phenotypes, ESBL-producing E. coli and carbapenemase-producing Enterobacteriaceae, as well as on their corresponding antibiotic resistance genes isolated from air, water, and sewage samples taken from inside and outside of different wastewater treatment plants in Germany, the Netherlands, and Romania. Additionally, we analysed stool samples of wastewater treatment plant workers, nearby residents, and members of a comparison group living ≥1000 m away from the closest WWTP. To our knowledge, this is the first study investigating the potential spread of ESBL-producing E. coli, carbapenemase-producing Enterobacteriaceae, and antibiotic resistance genes from WWTPs to workers, the environment, and nearby residents. Quantifying the contribution of different wastewater treatment processes to the removal efficiency of ESBL-producing E. coli, carbapenemase-producing Enterobacteriaceae, and antibiotic resistance genes will provide us with evidence-based support for possible mitigation strategies.

Third Follow-Up of the Study on Occupational Allergy Risks (SOLAR III) in Germany: Design, Methods, and Initial Data Analysis

Introduction: Asthma and allergies are complex diseases affected by genetic and environmental factors, such as occupational and psychosocial factors, as well as interactions between them. Although childhood is a critical phase in the development of asthma and allergies, few cohort studies on occupational outcomes followed up participants from childhood onwards. We present design, methods, and initial data analysis for the third follow-up of SOLAR (Study on Occupational Allergy Risks), a prospective and population-based German asthma and allergy cohort. Methods: The SOLAR cohort was initially recruited in 1995-1996 for Phase II of the German branch of the International Study of Asthma and Allergies in Childhood (ISAAC II) and followed up three times since, in 2002-2003, 2007-2009, and 2017-2018. During the third follow-up (SOLAR III), participants were between 29 and 34 years old. Since SOLAR focuses on occupational exposures, follow-ups were conducted at important points in time of the development of participants' career. To evaluate the potential of selection bias, responders and non-responders were compared based on variables from earlier study phases. In responders, frequency and pattern of missing values were examined and compared within the subsets of paper and online versions of the used questionnaires. Results: In total, 1,359 participants completed the questionnaire of the third follow-up (47.3% of eligible participants). Initially, the cohort started with 6,399 participants from the ISAAC II questionnaire study. A selection process led to a study population that is more female, higher educated, smokes less and has a higher proportion of certain asthma and allergy symptoms (also in their parents) than the initial cohort. Pattern and frequency of missing values were different for paper and online questionnaires. Discussion: The third follow-up of the SOLAR cohort offers the opportunity to analyze the course of asthma and allergies and their associations to environmental, occupational and psychosocial risk factors over more than 20 years from childhood to adulthood. Selection processes within the cohort might lead to bias that needs to be considered in future analyses.

Long-term effects of asthma medication on asthma symptoms: an application of the targeted maximum likelihood estimation

Background

Long-term effectiveness of asthma control medication has been shown in clinical trials but results from observational studies with children and adolescents are lacking. Marginal structural models estimated using targeted maximum likelihood methods are a novel statistiscal approach for such studies as it allows to account for time-varying confounders and time-varying treatment. Therefore, we aimed to calculate the long-term risk of reporting asthma symptoms in relation to control medication use in a real-life setting from childhood to adulthood applying targeted maximum likelihood estimation.

Methods

In the prospective cohort study SOLAR (Study on Occupational Allergy Risks) we followed a German subsample of 121 asthmatic children (9–11 years old) of the ISAAC II cohort (International Study of Asthma and Allergies in Childhood) until the age of 19 to 24. We obtained self-reported questionnaire data on asthma control medication use at baseline (1995–1996) and first follow-up (2002–2003) as well as self-reported asthma symptoms at baseline, first and second follow-up (2007–2009). Three hypothetical treatment scenarios were defined: early sustained intervention, early unsustained intervention and no treatment at all. We performed longitudinal targeted maximum likelihood estimation combined with Super Learner algorithm to estimate the relative risk (RR) to report asthma symptoms at SOLAR I and SOLAR II in relation to the different hypothetical scenarios.

Results

A hypothetical intervention of early sustained treatment was associated with a statistically significant risk increment of asthma symptoms at second follow-up when compared to no treatment at all (RR: 1.51, 95% CI: 1.19–1.83) or early unsustained intervention (RR:1.38, 95% CI: 1.11–1.65).

Conclusions

While we could confirm the tagerted maximum likelihood estimation to be a usable and robust statistical tool, we did not observe a beneficial effect of asthma control medication on asthma symptoms. Because of potential due to the small sample size, lack of data on disease severity and reverse causation our results should, however, be interpreted with caution.

From workplace to home environment: spreading of mouse allergens by laboratory animal workers

PURPOSE

Laboratory animal workers (LAW) working with laboratory mice are exposed to mouse allergens (MA). If MA are spread to home environments, this might increase the risk for allergies in LAW and their families. This study aimed to assess 1. whether spreading of MA from workplace to home environment takes place; 2. which factors increase spreading of MA.

METHODS

In a cross-sectional study, dust samples were taken on the mattress and seating in homes of LAW (n = 105) and an unexposed comparison group (n = 13). From 89 LAW, additional dust samples were taken from their workplaces. Samples were analysed using Mus m1 ELISA kits [detection limit (DL) 0.2 ng mus m1/ml]. Sociodemographic data, personal history of allergies and cleaning habits, as well as work-related characteristics (LAW only) were assessed by questionnaire. Latent factors were assessed via factor analysis. Tobit models were fitted to analyse the latent factors' contribution to MA spreading.

RESULTS

MA concentration on the seating was significantly higher in home environments of LAW (median = 1.28 ng mus m1/m²) than in the comparison group (median < DL, p = 0.019). The highest workplace MA concentration was found on the floor of the scullery (median = 140,000.00 ng mus m1/m²), followed by hair-covering caps (median = 76.02 ng mus m1/m²). Cage and mouse facility cleaning tasks and infrequent changing of bed linen at home were statistically significantly associated with higher MA concentrations at home.

CONCLUSIONS

Spreading of MA from LAW's workplace to their home environment takes place, especially among LAWs involved in cleaning tasks.

Association Between Occupational Exposure to Disinfectants and Asthma in Young Adults Working in Cleaning or Health Services: Results From a Cross-Sectional Analysis in Germany

OBJECTIVE

To analyze the association of occupational disinfectants use with asthma and wheezing in young professionals.

METHODS

Three hundred sixty-five participants from the German Study on Occupational Allergy Risks II aged 20 to 24 years and working in cleaning or health services answered a questionnaire on respiratory health, occupational exposure to disinfectants, and potential confounders. By logistic regression, we calculated the association between duration of occupational disinfectants exposure and doctor-diagnosed asthma, current asthma, and current wheezing.

RESULTS

Individuals exposed to disinfectants for more than 12 months had almost three times the odds of doctor-diagnosed asthma compared with those not exposed (odds ratio [OR]: 2.99, 95% confidence interval [CI]: 1.36-6.55).

CONCLUSIONS

Our findings provide some further evidence for an association between occupational exposure to disinfectants and asthma, indicating that this association can be seen already after the first year of exposure.

Nickel allergy is associated with wheezing and asthma in a cohort of young German adults: results from the SOLAR study

Background

Nickel allergy is the most prevalent contact allergy. It belongs to a different hypersensitivity type to asthma and rhinoconjunctivitis. The aim of this analysis was to assess whether self-reported nickel allergy is associated with incident wheezing, asthma and rhinoconjunctivitis in young German adults, taking into account potential effect modification by sex.

Methods

In total, 2051 (70.6%) participants aged 19–24 years took part in the second phase of SOLAR (Study on Occupational Allergy Risks), a follow-up study of ISAAC II (the second phase of the International Study of Asthma and Allergies in Childhood) in Germany. Self-reported nickel allergy, as well as having pierced ears, and the three outcomes incident wheezing, asthma and rhinoconjunctivitis, were analysed stratified for sex. Logistic regression adjusted for potential confounders was performed.

Results

An association between self-reported nickel allergy and incident wheezing was observed for men and women, while only in males did pierced ears show a significant association with the outcome (adjusted OR 2.26, 95% CI 1.10–4.62). Also only in males, self-reported nickel allergy was associated with elevated odds for incident asthma (adjusted OR 4.34, 95% CI 1.22–15.41). Neither in men nor in women was a significant association observed for incident rhinoconjunctivitis.

Conclusion

Our results suggest that self-reported nickel allergy is associated with incident wheezing. Whether this association is due to environmental or genetic predisposition, or due to an overlap of the mechanisms of type I and type IV hypersensitivity, needs to be elucidated.

Self-reported nickel allergy is associated with incident wheezing in young German males and females, and with incident asthma in males, whereas no significant association was observed for self-reported nickel allergy and incident rhinoconjunctivitishttp://bit.ly/2YHmwBA

Work-related stress and incident asthma and rhinitis: results from the SOLAR study

OBJECTIVES

This study analyzes the association of work-related stress with incident asthma and rhinitis in young adults with a special focus on gender-specific differences.

METHODS

Incident asthma, wheezing and rhinitis were measured in a cohort of 2051 young German adults (aged 16-18 years at baseline) recruited by the prospective population-based SOLAR study (Study of Occupational Allergy Risks). Work-related stress was measured by the Trier Inventory for the Assessment of Chronic Stress (TICS). Two TICS scales, work overload and work discontent, were analysed. Logistic regression was conducted to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

In females, the odds for incident asthma were found to be 17% higher for each increase of the work discontent score by one point (OR 1.17, 95% CI 1.04-1.31). In males, no association was statistically significant. Incident rhinitis showed no association with any exposure variable.

CONCLUSION

This study shows a link between work-related stress and incident asthma which seems to be confined to women. This study adds evidence about the association of work-related stress and asthma in young adults and can contribute to prevention for that particular age group.

Greenness and job-related chronic stress in young adults: a prospective cohort study in Germany

OBJECTIVES

We aimed to prospectively study the association between normalised difference vegetation index (NDVI) as a measure of greenness around homes and occupational stress.

SETTING

A population-based cohort in Munich and Dresden cities was followed from age 16-18 years to age 20-23 years (n=1632).

PARTICIPANTS

At baseline, all participants attended high-school while at follow-up some had started working and others studying at university. At baseline and in each follow-up, we assigned NDVI based on participants' residential geocoded addresses and categorised it by quartiles.

OUTCOME MEASURES

School-related, university-related or job-related self-reported chronic stress was assessed at the two follow-ups by the Trier Scale for Assessment of Chronic Stress using work discontent and work overload as outcomes. We modelled the association employing ordinal generalised estimating equations model accounting for changes in sociodemographics, non-job-related stress, job history and environmental covariates. Stratified analysis by each city was performed.

RESULTS

NVDI at baseline was higher for participants from Dresden (median=0.36; IQR 0.31-0.41) than Munich (0.31; 0.26-0.34). At follow-up, it decreased only for participants in Dresden (0.34; 0.30-0.40). Higher greenness (quartile 4 vs quartile 1) was associated with less work discontent (OR 0.89; 95% CI 0.80 to 0.99) and less work overload (OR 0.87; 95% CI 0.78 to 0.96). In stratified analyses, results were more consistent for Munich than for Dresden.

CONCLUSIONS

Our results suggest that residential green spaces, using the vegetation index as a proxy for exposure, are inversely associated with two types of job-related chronic stress in German young adults transitioning from school to university or working life.

Pregnancy and perinatal conditions and atopic disease prevalence in childhood and adulthood

BACKGROUND

Previous studies showed controversial results for the influence of pregnancy-related and perinatal factors on subsequent respiratory and atopic diseases in children. The aim of this study was to assess the association between perinatal variables and the prevalence of asthma, bronchial hyperreactivity (BHR), flexural eczema (FE), allergic rhinitis, and sensitization in childhood and early adulthood.

METHODS

The studied population was first examined in Munich and Dresden in 1995/1996 at age 9-11 years. Participants were followed until age 19-24 years using questionnaires and clinical examinations. Associations between perinatal data and subsequent atopic diseases were examined using logistic regression analyses adjusting for potential confounders.

RESULTS

Cesarean section was statistically significantly associated with BHR in early adulthood (odds ratio 4.8 [95% confidence interval 1.5-15.2]), while assisted birth was associated with presence of asthma symptoms in childhood (2.2 [1.2-3.9]), FE symptoms (2.2 [1.2-4.3]) and doctor's diagnosis of atopic dermatitis (1.9 [1.0-3.4]) in childhood, and sensitization in early adulthood (2.2 [1.1-4.3]). Lower birth length (1.9 [1.1-3.2]), lower birthweight (0.5 [0.3-0.9]), and higher birthweight (0.6 [0.4-1.0]) were predictive of sensitization in early adulthood compared to average birth length and birthweight, respectively. None of the other perinatal factors showed statistically significant associations with the outcomes.

CONCLUSIONS

Our results indicate that children who are born by cesarean section and especially by assisted birth, might be at greater risk for developing asthma, FE, and sensitization and should hence be monitored. Prenatal maternal stress might partly explain these associations, which should be further investigated.

Chronic Stress in Young German Adults: Who Is Affected? A Prospective Cohort Study

We aimed to prospectively assess changes in chronic stress among young adults transitioning from high school to university or working life. A population-based cohort in Munich and Dresden (Germany) was followed from age 16–18 (2002–2003) to age 20–23 (2007–2009) (n = 1688). Using the Trier Inventory for the Assessment of Chronic Stress, two dimensions of stress at university or work were assessed: work overload and work discontent. In the multiple ordinal generalized estimating equations, socio-demographics, stress outside the workplace, and job history were additionally considered. At follow-up, 52% of the population were university students. Work overload increased statistically significantly from first to second follow-up, while work discontent remained constant at the population level. Students, compared to employees, reported a larger increase in work overload (adjusted odds ratio (OR): 1.33; 95% confidence interval (95% CI): 1.07, 1.67), while work discontent did not differ between the groups. In conclusion, work overload increases when young adults transition from school to university/job life, with university students experiencing the largest increase.

Association of household cleaning agents and disinfectants with asthma in young German adults

OBJECTIVES

We scrutinised the association of private use of household sprays and disinfectants with asthma incidence in young adults in the transition from school to working life.

METHODS

Between 2007 and 2009,2051 young adults aged 19-24 years living in two major German cities took part in the Study on Occupational Allergy Risks II. Self-reported exposure to household sprays and disinfectants was characterised according to a composite score for frequency of use as no use (score=0), low use (score between 1 and the median), medium use (score between the median and the 90th percentile) and high use (score above the 90th percentile). Two outcome variables (current asthma and current wheezing) with four mutually exclusive categories (never, incident, persistent and remittent) were used for the risk analyses. Multinomial logistic regression models examined the association between the frequency of using household sprays and disinfectants with asthma and wheezing adjusting for potential confounders.

RESULTS

Compared with no use, high use of disinfectants was associated with a more than twofold increased odds of incident asthma (OR 2.79, 95% CI 1.14 to 6.83). In addition, low/medium use of disinfectants was associated with remittent asthma (OR 2.39, 95% CI 1.29 to 4.47). The evidence for an association between high usage of household sprays and asthma incidence was weak (OR 2.79, 95% CI 0.84 to 9.20).

CONCLUSION

Our results support the hypothesis of an association between the use of cleaning products and elevated risks for asthma and wheezing in young adults at the start of working life.

Establishing a birth cohort to investigate the course and aetiology of asthma and allergies across three generations - rationale, design, and methods of the ACROSSOLAR study

Background

Atopic diseases are a major burden of disease on a global scale. Regarding their aetiology, the early years of life are assumed to play a crucial role. In addition, there is growing evidence that elucidating the impact of cross-generational effects and epigenetic mechanisms such as DNA methylation can substantially widen the scientific knowledge of the occurrence and progression of these diseases. We are thus aiming at following the course of asthma, allergies, and potential risk factors for their occurrence across three generations by establishing a birth cohort in the offspring of an existing population-based cohort.

Methods/Design

2051 young adults who have been recruited in 1995 for Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC) and who have subsequently been followed-up by the Study on Occupational Allergy Risks (SOLAR) are asked bi-annually since 2009 if they conceived a child in the meantime. If parenthood is reported, parents are invited to enrol along with their children in the ACROSSOLAR cohort. Participation involves completing a questionnaire assessing general and health-related information about the course of the pregnancy and the first year of life of their children. Subsequently, the children are followed up until primary school age when asthma and allergies can be diagnosed reliably. In addition, DNA for epigenetic analysis will be collected and analysed. Longitudinal data analysis techniques will then be used to assess potential associations between early-life exposures and onset of childhood asthma and allergies taking into account epigenetics.

Discussion

Birth cohorts are especially suited to elucidate the impact of genetic predisposition, epigenetics, exposures during the first years of life, and gene-environment interactions on the occurrence and progression of asthma and allergies. By building upon an existing cohort, ACROSSOLAR offers a unique and cost-effective opportunity to investigate the aetiology of atopic disease in a prospective and cross-generational way.

Do young adults with atopic dermatitis avoid harmful workplace exposure at their first job? A prospective cohort study

PURPOSE

Patients with atopic dermatitis (AD) are at high risk of chronic hand eczema. In this prospective cohort study, we assessed the influence of pre-hire-onset AD on the first job choice. We also analysed the potential association between AD and usage of preventive measures in high-risk occupations.

METHODS

Subjects (aged 19-24 years) who were followed from childhood until the second Study on Occupational Allergy Risks and indicated a job were included (n = 1566). We defined AD as doctor-diagnosed AD and symptoms of an itchy rash during the past 12 months before the study. Pre-hire-onset AD was having AD prior to the first job. Preventive measure usage was self-reported gloves use or use of ointment or moisturizer. We performed multiple imputations to deal with missing values and analysed associations using logistic regression models adjusted for several potential confounders.

RESULTS

Risk categories of the first job did not differ between participants with pre-hire-onset AD and those without (odds ratio 1.05, 95 % confidence interval 0.59-1.87). AD status was not statistically significantly associated with usage of preventive measures (1.22, 0.56-2.64). Conversely, having received job counselling (2.76, 1.15-6.63) and a family history of AD (2.09, 1.01-4.31) were associated with a higher use of such measures.

CONCLUSION

We could not confirm a healthy hire effect in this cohort of young adults. Although subjects with AD in high-risk occupations do not seem to use more preventive measures than their non-affected peers, job counselling seems to be an effective approach to encourage secondary prevention.

Hormonal factors and incident asthma and allergic rhinitis during puberty in girls

BACKGROUND

Accumulating evidence is indicating that hormonal factors play a role in new-onset allergic rhinitis and asthma after puberty.

OBJECTIVE

To determine whether age at menarche and use of hormonal contraceptives predict new-onset allergic rhinitis and asthma after puberty in young German women.

METHODS

A prospective community-based cohort study followed 1,191 girls 9 to 11 years old to early adulthood (19-24 years old). Self-administrated questionnaires concerning age at menarche, use of hormonal contraceptives, and status and age at onset of physician-diagnosed allergic rhinitis and asthma were collected at 16 to 18 and 19 to 24 years of age. Logistic regression models were used to analyze the incidence of asthma and allergic rhinitis after puberty and pooled estimates were obtained from the final model.

RESULTS

Eleven percent of girls developed allergic rhinitis after menarche and 3% reported new-onset asthma. Late menarche (>13 years of age) was statistically significantly inversely related to allergic rhinitis (adjusted odds ratio [OR] 0.32, 95% confidence interval [CI] 0.14-0.74) but did not reach the level of statistical significance for asthma (OR 0.32, 95% CI 0.07-1.42). Use of hormonal contraceptives was inversely associated with new-onset allergic rhinitis (OR 0.14, 95% CI 0.08-0.23) and asthma (OR 0.27, 95% CI 0.12-0.58) after puberty.

CONCLUSION

This study shows that girls with late onset of menarche are less likely to develop allergic rhinitis after puberty compared with those who have menarche at an average age. These findings also suggest that, in addition to endogenous hormones, hormonal contraceptives play a role and might protect young women from allergies and asthma.

Influence of asthma definition on the asthma-obesity relationship

Background

Epidemiological studies suggest an association between obesity and asthma in adults and children. Asthma diagnosis criteria are different among studies. The aim of this study was to test the influence of asthma definition on the asthma-obesity relationship.

Methods

In a cross-sectional analysis of 1922 men and women, subjects completed a translated questionnaire from the European Community Respiratory Health Survey and underwent spirometry and a bronchial challenge test. Weight, height and waist circumference were measured. Multiple logistic regression analysis was carried out to assess the association of variables related to obesity and asthma. Asthma was defined either by the presence of symptoms with bronchial hyperresponsiveness (BHR) or by a self-report of a physician-made diagnosis. The following variables were separately tested for associations with asthma: socioeconomic characteristics, schooling, physical activity, smoking status, anthropometry and spirometry.

Results

No association was detected between asthma confirmed by BHR and obesity indicators, odds ratio (OR) = 1.08 (95% confidence interval: 0.69 - 1.68) for obesity assessed by body mass index ≥ 30 kg/m²; OR = 1.02 (0.74 - 1.40) for obesity assessed by abnormal waist-to-height ratio; and, OR = 0.96 (0.69 - 1.33) for abnormal waist circumference. On the contrary, a previous diagnosis of asthma was associated with obesity, OR = 1.48 (1.01 - 2.16) for body mass index ≥ 30 kg/m²; OR = 1.48 (1.13 - 1.93) for abnormal waist-to-height ratio; and, OR = 1.32 (1.00 – 1.75) for abnormal waist circumference. Female gender, schooling ≥ 12 years and smoking were associated with BHR-confirmed asthma. Physically inactive subjects were associated with a previous diagnosis of asthma.

Conclusions

Our findings indicate that the relationship between asthma and obesity in epidemiological studies depends on the definition adopted. Certain components of asthma, for instance, symptoms may be more prone to the obesity influence than other ones, like bronchial hyperresponsiveness.

Testing Skype as an interview method in epidemiologic research: response and feasibility

INTRODUCTION

Despite its popularity, Skype has not been tested as a tool for epidemiologic research. We examined its feasibility in Germany.

METHODS

A population-based sample of young adults was randomly invited to a Skype (n = 150) or a phone interview (n = 150). Response and duration of interviews were analysed to evaluate the feasibility of Skype interviews.

RESULTS

Response was low and, with 10 % (95 % CI 5-15 %), even worse among Skype candidates, compared to 22 % (15-28 %) in the phone group. A third of the Skype group asked for being interviewed by phone. Median duration was 34.0 minutes for Skype interviews and 37.0 minutes for phone interviews.

CONCLUSIONS

Skype is not yet a feasible tool for data collection in Germany.