Delayed occupational asthma from epoxy exposure

BACKGROUND

A delayed asthma reaction occurring several hours after exposure is difficult to diagnose.

AIMS

To confirm a delayed asthma reaction in five workers following epoxy exposure.

CASE REPORT

Working conditions with exposure to epoxy encountered at the workplace were reproduced in a challenge chamber. Specific inhalation challenge (SIC) with epoxy was compared to a control challenge. All five cases had delayed a asthma response 6-15 h after epoxy exposure.

CONCLUSIONS

Our study confirms that SIC is a useful tool in diagnosing delayed asthma response.

Chronic mucus hypersecretion: prevalence and risk factors in younger individuals

SETTING

Chronic mucus hypersecretion (CMH) is a common condition in patients with chronic respiratory diseases. Little is known about the incidence, prevalence and determinants of CMH in younger individuals.

OBJECTIVE

To determine prevalence, incidence and risk factors for CMH in a young general population.

DESIGN

A cohort of Danish twins (aged 12-41 years) was prospectively examined using questionnaires in 1994 (n = 29 180) and in 2002 (n = 21 130). Prevalence and incidence of CMH were determined, and risk factors for the condition were assessed using logistic regression.

RESULTS

Lifetime prevalence of CMH was 8.6% in females and 6.9% in males in 1994, and the cumulative incidence among females and males was respectively 10.7% and 8.7% during the study period. Smoking and asthma were risk factors for CMH, with a dose-response effect of tobacco consumption, and smoking habits also predicting incidence of CMH.

CONCLUSION

Among the young, CMH is a condition related to asthma and smoking, with a dose-response relationship with tobacco consumption and a relation between smoking habits and incidence. Female susceptibility to development of CMH was observed, as well as signs of greater susceptibility related to young age.

Association between obesity and asthma in a twin cohort

BACKGROUND

Obesity is linked to asthma in a yet poorly understood manner. We examined the relationship between obesity and asthma in a population-based sample of twins.

METHODS

From the cohorts born between 1953 and 1982, who were enrolled in The Danish Twin Registry, a total of 29 183 twin individuals participated in a nationwide questionnaire study, where data on height, weight and asthma were collected. Latent factor models of genetic and environmental effects were fitted using maximum likelihood methods.

RESULTS

The age-adjusted risk of asthma was increased both in obese females, OR = 1.96 (1.45-2.64), P < or = 0.001 and in obese males, OR = 1.59 (1.08-2.33), P = 0.02. According to best-fitting models, the heritability for obesity was 81% in males and 92% in females, whereas the heritability for asthma was 78% and 68% in males and females respectively. The age-adjusted genetic liabilities to obesity and asthma were significantly correlated only in females, r = 0.28 (0.16-0.38).

CONCLUSIONS

Obese subjects have an increased risk for asthma, which in females seems partly because of common genes.

Findings on the atopic triad from a Danish twin registry

OBJECTIVE

To estimate to what extent the same genetic and environmental risk factors influence asthma, hay fever and eczema.

DESIGN

From the nationwide Danish Twin Registry, twin cohorts born between 1953 and 1982 were contacted for a questionnaire survey, and a total of 29 183 twin individuals (86%) responded. Subjects were classified as cases when responding affirmatively to three questions about the lifetime occurrence of asthma, hay fever and eczema. Variance components twin analysis was conducted using maximum likelihood methods.

RESULTS

The phenotypic (within-subject) correlations in liability between the different diseases were 0.57 (95% CI 0.54-0.59) for asthma and hay fever, 0.40 (95% CI 0.36-0.42) for asthma and eczema, and 0.33 (95% CI 0.29-0.36) for hay fever and eczema. Decomposition of these correlations into their genetic and environmental contributions showed that shared genes explained between 70% and 85% of the correlation between the different diseases. The remaining parts were explained by environmental factors shared between the diseases.

CONCLUSION

To a large extent, atopic diseases share a common genetic background, although disease-specific genes also play a considerable role. These results can prove informative when counselling families with atopy, and may furthermore be used to guide the search for pleiotropic genes of importance for these diseases.

Risk factors for asthma in young adults: a co-twin control study

BACKGROUND

The liability to asthma is influenced both by genetic and environmental factors. The objective of this study was to identify risk factors for asthma in young adult twin pairs during an 8-year period.

METHODS

From the birth cohorts 1953-1982 of the Danish Twin Registry, 6,090 twin pairs who were initially unaffected with respect to asthma at a nationwide questionnaire-based study in 1994 participated in a similar follow-up study in 2002. Subjects were regarded incident asthma cases when responding affirmatively to the question 'Do you have, or have you ever had asthma'? in 2002. Pairs in which only one twin developed asthma -- discordant pairs -- were identified and conditional logistic regression was applied to detect effects of risk factors.

RESULTS

A total of 126 monozygotic (MZ) and 273 dizygotic (DZ) discordant twin pairs were identified. In MZ twins hay fever (OR = 3.16, 95% CI: 1.29-7.73, P = 0.007) and exercise (OR for inactivity = 0.35, 95% CI: 0.13-0.91, P = 0.023) were significantly associated with asthma, whereas in DZ twins, hay fever (OR = 2.44, 95% CI: 1.44-4.13, P = 0.001), eczema (OR = 1.96, 95% CI: 1.02-3.78, P = 0.040), female sex (OR between males and females = 0.54, 95% CI: 0.36-0.80, P = 0.002), and increasing levels of body mass index (BMI; OR per unit = 1.11, 95% CI: 1.02-1.20, P = 0.009) were significant predictors of asthma.

CONCLUSIONS

Hay fever, eczema, female sex, exercise and increasing levels of BMI were risk factors for asthma in young adults. The different risk profile observed in MZ twins compared with DZ twins may reflect an underlying genetic vulnerability shared between those risk factors and asthma.

[Significance of genetic and environmental factors for asthma. A population-based study of 11.688 Danish twin pairs]

The aim of this study was to estimate the relative influence of genetic and environmental factors on the aetiology of asthma. The classic twin study design was used to analyse data on self-reported asthma obtained by a questionnaire mailed to 34,076 individuals, aged 12-41 yrs and originating from the Danish Twin Register. The cumulative incidence proportion was 6.2% in the pooled sample. No overall sex or zygosity difference was observed. Substantially higher concordance rate, odds ratio and correlation for asthma were estimated in monozygotic than dizygotic twin pairs. Using biometric modelling, a model including additive genetic and non-shared environmental effects provided the best fit to the data. According to this model, 73% of the variation in liability to asthma was explained by genetic effects. The results emphasize a major genetic component in the aetiology of asthma.

Genetic and environmental influence on asthma: a population-based study of 11,688 Danish twin pairs

The aim of this study was to estimate the relative influence of genetic and environmental factors on the aetiology of asthma. The classic twin study design was used to analyse data on self-reported asthma obtained by a questionnaire mailed to 34,076 individuals, aged 12-41 yrs and originating from the Danish Twin Register. The cumulative incidence of asthma was 6.2% in the pooled sample. The data showed a decreasing cumulative incidence with age for males, but no sex or zygosity difference was observed. Substantially higher concordance rates, odds ratios and correlations for asthma were estimated in the monozygotic than in the dizygotic twins. Using biometric modelling, a model including additive genetic and nonshared environmental effects provided the best overall fit to the data. According to this model, 73% of the variation in liability to asthma was explained by genetic factors. No sex difference or age-dependency in the magnitude of genetic effects was observed. The biometric analysis emphasized a major influence of genetic factors in the aetiology of asthma. However, a substantial part of the variation in liability to asthma is due to the impact of environmental factors specific to the individual. There is no evidence for a substantial impact of genetic dominance or the shared environment.