Asthma severity is associated with body mass index and early menarche in women

Asthma severity and exposure to occupational asthmogens

RATIONALE

Severe asthma is a public health problem with limited information regarding preventable causes. Although occupational exposures have been implicated as important risk factors for asthma and asthma exacerbations, associations between occupational exposures and asthma severity have not been reported.

OBJECTIVE

To examine associations between occupational exposures and asthma severity.

METHODS

The Epidemiological Study on the Genetics and Environment of Asthma combines a case-control study with a family study of relatives of patients with asthma. Adult patients (n = 148) were recruited in chest clinics and control subjects without asthma (n = 228) were population-based. Occupational exposures to nonasthmogenic irritants and asthmogens (classified as "any asthmogen" including three broad groups: high-molecular-weight agents, low-molecular-weight agents, and mixed environments) were assessed by an asthma-specific job exposure matrix. Asthma severity was defined from an 8-grade clinical score (frequency of attacks, persistent symptoms, and hospitalization). Patients with severe (score >or= 2) and mild asthma were compared with control subjects using nominal logistic regression.

MAIN RESULTS

Significant associations were observed between severe adult-onset asthma and exposure to any occupational asthmogen (odds ratio [OR], 4.0; 95% confidence interval [CI], 2.0-8.1), high-molecular-weight agents (OR, 3.7; CI, 1.3-11.1), low-molecular-weight agents (OR, 4.4; CI, 1.9-10.1), including industrial cleaning agents (OR, 7.2; CI, 1.3-39.9), and mixed environments (OR, 7.5; CI, 2.4-23.5). No significant associations were found between nonasthmogenic irritants and asthma severity, nor between asthmogens and childhood-onset asthma or mild adult-onset asthma.

CONCLUSIONS

Our results suggested a strong deleterious role of occupational asthmogens in severe asthma. Clinicians should consider occupational exposures in patients with moderate to severe asthma.

Sex differences in factors associated with childhood- and adolescent-onset wheeze

RATIONALE

Factors predicting the development of wheeze may differ between sexes and between childhood and adolescence.

METHODS

A New Zealand birth cohort of 1,037 children was followed to age 26. For this analysis, those reporting recurrent wheezing at two or more assessments were classified as "wheezers." We examined risk factors for development of wheeze before age 10 (childhood) and subsequently (adolescent-onset) for males and for females separately using Cox regression modeling.

RESULTS

Males more often developed childhood wheeze (p = 0.002) and females adolescent-onset wheeze (p < 0.001). Maternal atopy (asthma or hay fever) was a risk factor for childhood wheeze in both sexes (hazard ratio [HR], 1.48, p < 0.05 for males; HR, 2.37, p < 0.001 for females). Paternal atopy also influenced childhood wheeze, significantly for males (HR, 1.72; p = 0.01), and similarly but not significantly for females (HR, 1.70; p = 0.08). For adolescent-onset wheeze, neither maternal (HR, 1.41; p = 0.19) nor paternal history (HR, 0.73; p = 0.42) was a risk factor in males, but maternal history (HR, 2.08; p < 0.01) was a significant risk factor for females. When both age ranges were combined, providing greater power for analysis, paternal history was a stronger risk factor for wheeze in females (HR, 1.62; p = 0.02) than in males (HR, 1.35; p = 0.12).

CONCLUSION

The influence of parental atopy on the development for wheeze differs between males and females and between childhood- and adolescent-onset wheeze.