Increasing prevalence of bronchial hyperresponsiveness in three selected areas in East Germany. Bitterfeld Study Group

Current Asthma Prevalence Using Methacholine Challenge Test in Korean Children from 2010 to 2014

BACKGROUND

Most epidemiological studies depend on the subjects' response to asthma symptom questionnaires. Questionnaire-based study for childhood asthma prevalence may overestimate the true prevalence. The aim of this study was to investigate the prevalence of "Current asthma" using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and methacholine challenge test in Korean children.

METHODS

Our survey on allergic disease included 4,791 children (age 7-12 years) from 2010 to 2014 in Korean elementary schools. Bronchial hyperresponsiveness (BHR) was defined as provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1) (PC20) ≤ 16 mg/mL. "Current asthma symptoms" was defined as positive response to "Wheezing, current," "Treatment, current," or "Exercise, current." "Current asthma" was defined when the subjects with "Current asthma symptoms" showed BHR on the methacholine challenge test or had less than 70% of predicted FEV1 value.

RESULTS

The prevalence of "Wheezing, ever," "Wheezing, current," "Diagnosis, ever," "Treatment, current," "Exercise, current," and "Current asthma symptoms" was 19.6%, 6.9%, 10.0%, 3.3%, 3.5%, and 9.6%, respectively, in our cross-sectional study of Korean elementary school students. The prevalence of BHR in elementary school students was 14.5%. The prevalence of BHR in children with "Wheezing, ever," "Wheezing, current," "Diagnosis, ever," "Treatment, current," and "Exercise, current" was 22.3%, 30.5%, 22.4%, 28.8%, and 29.9%, respectively. BHR was 26.1% in those with "Current asthma symptoms." The prevalence of "Current asthma" was 2.7%.

CONCLUSIONS

Our large-scale study provides 2.7% prevalence of current asthma in Korean elementary school children. Since approximately one third of the children who have "Current asthma symptoms" present BHR, both subjective and objective methods are required to accurately predict asthma in subjects with asthma symptoms.

The pertussis hypothesis: Bordetella pertussis colonization in the etiology of asthma and diseases of allergic sensitization

Decades of peer reviewed evidence demonstrate that: 1)Bordetellapertussisand pertussis toxin are potent adjuvants, inducing asthma and allergic sensitization in animal models of human disease, 2)Bordetella pertussisoften colonizes the human nasopharynx, and is well documented in highly pertussis-vaccinated populations and 3) in children, a history of whooping cough increases the risk of asthma and allergic sensitization disease. We build on these observations with six case studies and offer a pertussis-based explanation for the rapid rise in allergic disease in former East Germany following the fall of the Berlin Wall; the current asthma, peanut allergy, and anaphylaxis epidemics in the United States; the correlation between the risk of asthma and gross national income per capita by country; the lower risk of asthma and allergy in children raised on farms; and the reduced risk of atopy with increased family size and later sibling birth order. To organize the evidence for the pertussis hypothesis, we apply the Bradford Hill criteria to the association between Bordetella pertussisand asthma and allergicsensitization disease. We propose that, contrary to conventional wisdom that nasopharyngealBordetella pertussiscolonizing infections are harmless, subclinicalBordetella pertussiscolonization is an important cause of asthma and diseases of allergic sensitization.

Prevalence of asthma and bronchial hyperreactivity in Danish schoolchildren: no change over 10 years

AIM

To describe the point prevalence of current physician-diagnosed asthma and bronchial hyperreactivity (BHR) in 2001 among unselected Danish schoolchildren aged 6-17 years, compared with the prevalence from a similar study from 1990 to 1991.

METHODS

Cross-sectional study using parental questionnaire on asthma and respiratory symptoms combined with a 6-min free running test with peak expiratory flow rate (PEFR) measurement (n = 1051, response rate 89.3%). Results were compared with those of a similar study in the same area from 1990 to 1991. Main outcome measures were current physician-diagnosed asthma or BHR in children without physician-diagnosed asthma measured by either a decrease in lung function after standardized running test and/or variability in PEFR on home monitoring.

RESULTS

The prevalence of current physician-diagnosed asthma was 4.0% [95% confidence interval (CI) 2.7-5.3%] in 1990-1991 and 3.6% (95% CI 2.4-4.8%) in 2001. The prevalence of BHR was 3.2% (95% CI 2.0-4.4%) in 1990-1991 and 2.0% (95% CI 1.1-2.9%) in 2001. The combined prevalence was 7.2% (95% CI 5.4-8.9%) in 1990-1991 and 5.6% (95% CI 4.2-7.1%) in 2001.

CONCLUSION

The point prevalence of current physician-diagnosed asthma and BHR among unselected Danish schoolchildren aged 6-17 years was unchanged over 10 years between 1990-1991 and 2001.

Airway hyperresponsiveness and acute chest syndrome in children with sickle cell anemia

To determine the occurrence and magnitude of airway hyperresponsiveness (AHR) in children with sickle cell anemia (SCA) who had or had not had acute chest syndrome (ACS) episodes. A subsidiary aim was to determine whether cold air and exercise challenge testing gave similar results in children with SCA. AHR would be greater in SCA children who had had an ACS episode compared to those who had not. Prospective observational study. Forty-two SCA children (median age of 11.5 [range 6.1-16.8] years); 12 children had been previously hospitalized for an ACS episode. AHR was assessed by the change in forced expiratory volume in 1 sec (FEV1) to a cold air challenge and in a subset of the children to an exercise challenge. A positive result to either challenge was deemed to have occurred if the FEV1 fell by at least 10% from the pre-challenge baseline. The magnitude of change in FEV1 following the cold air challenge was similar in children who had or had not had an ACS episode. Six children had a positive response to the cold air challenge (AHR); none had had an ACS hospitalization. Similar proportions of children responded to the cold air and exercise challenge and the magnitude of response to the two tests was similar. Some children, however, responded only to a cold air challenge and others only to an exercise challenge. SCA children who had had an ACS hospitalization episode compared to those who had not were not more likely to respond to a cold air challenge. Importantly, if AHR is to be correctly diagnosed, some SCA children will require to undergo both cold air and exercise challenge testing.

TH1-directed modulation of in vitro cytokine production in human peripheral blood mononuclear cells by styrene-7.8-oxide

Styrene and its chiral main metabolite styrene-7.8-oxide are well characterized regarding their cytotoxic, genotoxic and neurotoxic properties. To our knowledge, no data exist on the influence of styrene and styrene-7.8-oxide on immune reactions. Epidemiological studies suggest that exposure to environmental pollutants, specifically volatile organic compounds (VOCs), including styrene is one factor contributing to increasing prevalence rates of allergic diseases. In this study, we investigated the modulation of the immune system by styrene-7.8-oxide in vitro. Human peripheral blood mononuclear cells were incubated with styrene-7.8-oxide, either as (S)-enantiomer, (R)-enantiomer, or racemic styrene-7.8-oxide. Subsequently, the secretion of T(H1)-cytokines IFNgamma and IL-12 as well as T(H2)-cytokines IL-4 and IL-5 were measured by ELISA. We introduced a novel mathematical approach to quantify and compare cytokine responses. The results revealed a stimulation of cytokine secretion with emphasis on T(H1)-cytokines IFNgamma and IL-12. The stimulating effects were elicited at concentrations of styrene-7.8-oxide comparable to what would be encountered at industrial workplaces where styrene is processed. Therefore, we conclude that styrene-7.8-oxide exhibits immunomodulating capacities, which can be of clinical relevance for individuals with high styrene exposure.