A number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs.A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on abscence or prescence of gender differences in asthma were included and reviewed, and cross‐references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender‐specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals.In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender‐specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated.

Rationale: Increased risk for cardiovascular morbidity and mortality has been related to both lung function impairment and metabolic syndrome. Data on the relationship between lung function and metabolic syndrome are sparse. Objectives: To investigate risk for lung function impairment according to metabolic syndrome traits. Methods: This cross-sectional population-based study included 121,965 men and women examined at the Paris Investigations Préventives et Cliniques Center between 1999 and 2006. The lower limit of normal was used to define lung function impairment (FEV₁ or FVC < lower limit of normal). Metabolic syndrome was assessed according to the American Heart Association/National Heart, Lung, and Blood Institute statement. Measurements and Main Results: We used a logistic regression model and principal component analysis to investigate the differential associations between lung function impairment and specific components of metabolic syndrome. Lung function impairment was associated with metabolic syndrome (prevalence = 15.0%) independently of age, sex, smoking status, alcohol consumption, educational level, body mass index, leisure-time physical activity, and cardiovascular disease history (odds ratio [OR] [95% confidence interval], 1.28 [1.20–1.37] and OR, 1.41 [1.31–1.51] for FEV₁ and FVC, respectively). Three factors were identified from factor analysis: “lipids” (low high-density lipoprotein cholesterol, high triglycerides), “glucose–blood pressure” (high fasting glycemia, high blood pressure), and “abdominal obesity” (large waist circumference). All factors were inversely related to lung function, but abdominal obesity was the strongest predictor of lung function impairment (OR, 1.94 [1.80–2.09] and OR, 2.11 [1.95–2.29], for FEV₁ and FVC, respectively). Similar results were obtained for women and men. Conclusions: We found a positive independent relationship between lung function impairment and metabolic syndrome in both sexes, predominantly due to abdominal obesity. Further studies are required to clarify the underlying mechanisms.

Objective: To assess whether the severity of asthma is associated with sensitisation to airborne moulds rather than to other seasonal or perennial allergens. Design: Multicentre epidemiological survey in 30 centres. Setting: European Community respiratory health survey. Participants: 1132 adults aged 20-44 years with current asthma and with skin prick test results. Main outcome measure: Severity of asthma according to score based on forced expiratory volume in one second, number of asthma attacks, hospital admissions for breathing problems, and use of corticosteroids in past 12 months. Results: The frequency of sensitisation to moulds ( Alternaria alternata or Cladosporium herbarum , or both) increased significantly with increasing asthma severity (odds ratio 2.34 (95% confidence interval 1.56 to 3.52) for either for severe v mild asthma). This association existed in all of the study areas (gathered into regions), although there were differences in the frequency of sensitisation. There was no association between asthma severity and sensitisation to pollens or cats. Sensitisation to Dermatophagoides pteronyssinus was also positively associated with severity. In multivariable logistic regressions including sensitisation to moulds, pollens, D pteronyssinus , and cats simultaneously, the odds ratios for sensitisation to moulds were 1.48 (0.97 to 2.26) for moderate v mild asthma and 2.16 (1.37 to 3.35) for severe v mild asthma (P<0.001 for trend). Conclusions: Sensitisation to moulds is a powerful risk factor for severe asthma in adults. This should be taken into account in primary prevention, management, and patients' education.

The European Community Respiratory Heath Survey (ECRHS) was the first study to assess the geographical variation in asthma and allergy in adults using the same instruments and definitions. The database of the ECRHS includes information from ∼140,000 individuals from 22 countries. The aim of this review is to summarize the results of the ECRHS to date.The ECRHS has shown that there are large geographical differences in the prevalence of asthma, atopy and bronchial responsiveness, with high prevalence rates in English speaking countries and low prevalence rates in the Mediterranean region and Eastern Europe. Analyses of risk factors have highlighted the importance of occupational exposure for asthma in adulthood. The association between sensitization to individual allergens and bronchial responsiveness was strongest for indoor allergens (mite and cat). Analysis of treatment practices has confirmed that the treatment of asthma varies widely between countries and that asthma is often undertreated.In conclusion, the European Community Respiratory Health Survey has shown that the prevalence of asthma varies widely. The fact that the geographical pattern is consistent with the distribution of atopy and bronchial responsiveness supports the conclusion that the geographical variations in the prevalence of asthma are true and most likely due to environmental factors.