What symptoms predict the bronchial response to histamine? Evaluation in a community survey of the bronchial symptoms questionnaire (1984) of the International Union Against Tuberculosis and Lung Disease

Identification of subtypes in subjects with mild-to-moderate airflow limitation and its clinical and socioeconomic implications

PURPOSE

The purpose of this study was to identify subtypes in patients with mild-to-moderate airflow limitation and to appreciate their clinical and socioeconomic implications.

METHODS

Subjects who were aged ≥20 years and had forced expiratory volume in 1 second (FEV₁) ≥60% predicted and FEV₁/forced vital capacity <0.7 were selected from the fourth Korea National Health and Nutrition Examination Survey (KNHANES) in 2007-2012. The data were merged to the National Health Insurance reimbursement database during the same period. k-Means clustering was performed to explore subtypes. For clustering analysis, six key input variables - age, body mass index (BMI), FEV₁% predicted, the presence or absence of self-reported wheezing, smoking status, and pack-years of smoking - were selected.

RESULTS

Among a total of 2,140 subjects, five groups were identified through k-means clustering, namely putative "near-normal (n=232)," "asthmatic (n=392)," "chronic obstructive pulmonary disease (COPD) (n=37)," "asthmatic-overlap (n=893)," and "COPD-overlap (n=586)" subtypes. Near-normal group showed the oldest mean age (72±7 years) and highest FEV₁ (102%±8% predicted), and asthmatic group was the youngest (46±9 years). COPD and COPD-overlap groups were male predominant and all current or ex-smokers. While asthmatic group had the lowest prescription rate despite the highest proportion of self-reported wheezing, COPD, asthmatic-overlap, and COPD-overlap groups showed high prescription rate of respiratory medicine. Although COPD group formed only 1.7% of total subjects, they showed the highest mean medical cost and health care utilization, comprising 5.3% of the total medical cost. When calculating a ratio of total medical expense to household income, the mean ratio was highest in the COPD group.

CONCLUSION

Clinical and epidemiological heterogeneities of subjects with mild-to-moderate airflow limitation and a different level of health care utilization by each subtype are shown. Identification of a subtype with high health care demand could be a priority for effective utilization of limited resources.

Changes in symptoms of asthma and rhinitis by sensitization status over ten years in a cohort of young Chilean adults

Background

We investigated the net changes in prevalence of symptoms of asthma and rhinitis over 10 years in a cohort of young by baseline sensitization status.

Methods

One thousand one hundred ninety three Chilean adults subjects aged 22–28 living in a semi-rural area of central Chile answered a lifestyle and the European Community Respiratory Health Survey (ECRHS) questionnaires. Bronchial hyper-responsiveness (BHR) and skin prick test (SPT) to eight allergens were measured at baseline in 2001. Ten years later, 772 participants completed the questionnaires again. Estimates of adjusted net changes in prevalence of symptoms by sensitization status at baseline and association between sensitization status at baseline and respiratory symptoms ten years later were assessed.

Results

A quarter of the participants were sensitized to at least one allergen in 2001. Prevalence of wheeze had a net change per year of −0.37 % (95 % Confidence Interval −0.71 to 0.02 %; p = 0.067). Self-reported nasal allergies in the last 12 months increased by 0.83 % per year (95 % CI 0.49 to 1.17 %; p < 0.001). Those sensitized to either cat fur (OR 1.76; CI 1.01 to 3.05), cockroach, (OR 2.09; 1.13 to 3.86) blend of grass and pollens (1.78; 95 % CI 1.08 to 2.92), or weeds (OR 1.77; 95 % CI 1.01 to 3.12) in 2001 were more likely to have wheeze in the last 12 months 10 years later.

Conclusion

Symptoms of asthma remained stable or slightly changed over 10 years in adults, whilst rhinitis and nasal allergies greatly increased. Being sensitized to at least one allergen is a risk factor for persistent symptoms of asthma and rhinitis, but not for determining net changes of symptoms over time. The underlying causes for the contrasting trends between asthma and nasal allergy are unknown.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0273-6) contains supplementary material, which is available to authorized users.

Associations between obstructive lung disease and symptoms of obstructive sleep apnoea in a general population

OBJECTIVES

To examine the prevalence of self-reported symptoms of obstructive sleep apnoea (OSA) in relation to asthma, respiratory symptoms and pulmonary function. A secondary objective was to determine how sex impacted these relationships.

METHODS

A random sample of all adults aged 47-48 and 71-73 years living in Bergen, Norway, were invited. Participants (3506, 69%) underwent spirometry testing and completed a questionnaire on sleep, respiratory symptoms and past medical history. OSA was defined by positive answers to questions on snoring, breathing cessations and daytime sleepiness. Current asthma was defined by ever having received a physician's diagnosis of asthma and current use of anti-asthma medication. Logistic regression analyses, including interaction analyses between sex and the different explanatory variables, were used to examine associations between OSA and current asthma, pre- and post-bronchodilator pulmonary function tests, smoking habits and respiratory symptoms. All models were adjusted for age, sex, waist-hip ratio and smoking.

RESULTS

OSA was more prevalent in the middle-aged compared to the elderly (6.2% vs 3.6%), and in subjects reporting respiratory symptoms. 4.8% had OSA and 6.1% had current asthma. Current asthma and the lowest quartile of post-bronchodilator FVC were significantly associated with OSA with ORs of 2.5 (1.5, 4.2) and 1.7 (1.1, 2.7), respectively. In interaction analyses, women with post-bronchodilator FEV₁ /FVC < 0.7 had an increased risk of OSA [OR of 4.1 (1.7, 9.7)] compared to women with a FEV₁ /FVC ≥ 0.7.

CONCLUSIONS

Current asthma was associated with increased risk of OSA. Women with chronic airflow limitation, but not men, had increased risk of OSA.

Validation of the Korean version of the European Community Respiratory Health Survey screening questionnaire for use in epidemiologic studies for adult asthma

BACKGROUND

Standardized questionnaire is one of key instruments for general population surveys.

OBJECTIVE

The present study aimed to develop and validate the Korean version of the European Community Respiratory Health Survey (ECRHS) screening questionnaire for adult asthma surveys.

METHODS

The ECRHS screening questionnaire was translated into Korean language according to the international criteria. Study participants were prospectively recruited from six referral hospitals and one health check-up center. Comprehensibility of the translation was tested in a pilot study of 10 patients. The reliability was evaluated by internal consistency and test-retest repeatability. Validity was assess with regard to physician-diagnosed asthma.

RESULTS

A total of 100 adult asthma patients and 134 volunteers were recruited. Reliability was examined for 10 items in 100 asthmatics; Cronbach α coefficients were 0.84, and test-retest repeatability was good (Cohen κ coefficient, 0.71-1.00). Validity was assessed for 8 items in 234 participants; in particular, 'recent wheeze' showed a high sensitivity (0.89) for physician-diagnosed asthma. 'Recent asthma attack' and 'current asthma medication' showed high specificity (0.96-0.98).

CONCLUSION

The present study demonstrated that the Korean version of the ECRHS screening questionnaire was comprehensible, reliable and valid. We suggest the questionnaire to be utilized in further epidemiological studies for asthma in Korean adult populations.

Can spirometric norms be set using pre- or post- bronchodilator test results in older people?

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is defined by post-bronchodilator spirometry. Data on "normal values" come predominantly from pre-bronchodilator spirometry. The effects of this on diagnosis are unknown.

METHODS

Lower limits of normal (LLN) were estimated from "normal" participants in the Burden of Obstructive Lung Disease (BOLD) programme. Values separately derived using pre- and post-bronchodilator spirometry were compared. Sensitivity and specificity of criteria derived from pre-bronchodilator spirometry and pre-bronchodilator spirometry adjusted by a constant were assessed in the remaining population. The "gold standard" was the LLN for the post-bronchodilator spirometry in the "normal population". For FEV1/FVC, sensitivity and specificity of criteria were also assessed when a fixed value of < 70% was used rather than LLN.

RESULTS

Of 6,600 participants with full data, 1,354 were defined as "normal". Mean differences between pre- and post- bronchodilator measurements were small and the Bland-Altman plots showed no association between difference and mean value. Compared with using the gold standard, however, tests using pre-bronchodilator spirometry had a sensitivity and specificity of detecting a low FEV1 of 78.4% and 100%, a low FVC of 99.8% and 99.1% and a low FEV1/FVC ratio of 65% and 100%. Adjusting this by a constant improved the sensitivity without substantially altering the specificity for FEV1 (99%, 99.8%), FVC (97.4%, 99.9%) and FEV1/FVC (98.7%, 99.5%).

CONCLUSIONS

Using pre-bronchodilator spirometry to derive norms for lung function reduces sensitivity compared to a post-bronchodilator gold standard. Adjustment of these values by a constant can improve validity of the test.

Communities near toluene diisocyanate sources: an investigation of exposure and health

Toluene diisocyanate (TDI) is a well-known cause of occupational asthma, but we know little about the potential for exposure and health effects among residents who live near facilities that release TDI. In the mid-1990's, the North Carolina Department of Health and Human Services and the Agency for Toxic Substances and Disease Registry investigated exposures to TDI and health outcomes in one community, which left some unanswered questions. This cross-sectional study evaluated the potential associations between living near a TDI source and the prevalence of three variables: asthma or asthma-like respiratory symptoms, antibodies specific to TDI, and verifiable levels of TDI in residential air. Results among North Carolina residents living near such facilities (five target communities) were compared with the results from residents living further away (five comparison communities). Overall, the prevalence of reporting either asthma or asthma-like respiratory symptoms was higher (odds ratio = 1.60; 95% confidence interval = 0.97-2.54) among residents in target communities than those in comparison communities. However, this difference was not statistically significant. Symptom prevalence varied greatly among the community populations. The prevalence of respiratory symptoms was higher near facilities with historically higher TDI emissions. Among the 351 participants who provided blood samples, only one had immunoglobulin G specific antibodies to TDI. This participant lived in a target area and may have had non-occupational exposure. TDI was detected at an extremely low level (1 ppt) in one of the 45 air samples from target communities. One ppt is one-tenth the EPA reference concentration. Overall, air sample and antibody test results are not consistent with recent or ongoing exposure to TDI.

Dietary patterns and adult asthma: population-based case-control study

BACKGROUND

Epidemiological studies of diet and asthma have focused on relations with intakes of individual nutrients and foods and evidence has been conflicting. Few studies have examined associations with dietary patterns.

METHODS

We carried out a population-based case-control study of asthma in adults aged between 16 and 50 in South London, UK. Information about usual diet was obtained by food frequency questionnaire and we used principal components analysis to define five dietary patterns in controls. We used logistic and linear regression, controlling for confounders, to relate these patterns to asthma, asthma severity, rhinitis and chronic bronchitis in 599 cases and 854 controls.

RESULTS

Overall, there was weak evidence that a 'vegetarian' dietary pattern was positively associated with asthma [adjusted odds ratio comparing top vs bottom quintile of pattern score 1.43 (95% CI: 0.93-2.20), P trend 0.075], and a 'traditional' pattern (meat and vegetables) was negatively associated [OR 0.68 (0.45-1.03), P trend 0.071]. These associations were stronger amongst nonsupplement users (P trend 0.030 and 0.001, respectively), and the association with the 'vegetarian' pattern was stronger amongst whites (P trend 0.008). No associations were observed with asthma severity. A 'prudent' dietary pattern (wholemeal bread, fish and vegetables) was positively associated with chronic bronchitis [OR 2.61 (1.13-6.05), P trend 0.025], especially amongst nonsupplement users (P trend 0.002).

CONCLUSIONS

Overall there were no clear relations between dietary patterns and adult asthma; associations in nonsupplement users and whites require confirmation. The finding for chronic bronchitis was unexpected and also requires replication.

Approach to blood donors with microcytosis

The aim of this paper is to find microcytosis in donors, to establish prevalence of iron deficiency anaemia (IDA) and beta-thalassemia trait (BTT) in them and to evaluate which index is most effective in differentiating these two conditions. IDA and BTT are the most common causes of microcytic anaemia. Traditional approach is trial of iron treatment. Where thalassemias are common, this can lead to iron overload and failure to provide diagnosis/counselling in BTT. Initially 925 donor samples were evaluated on cell counter. Of these, 50 were found microcytic. These were subjected to Ferritin and HbA2 determination. Subsequently, additional 51, age- and sex-matched normocytic donor samples were selected as controls. These were subjected to the same tests. Nine indices namely RBC, RDW, Mentzer's, Shine and Lal, England and Fraser, Srivastava, Green and King, RDW index and Ricerca were used to differentiate IDA and BTT. Prevalence of microcytosis was 5.4%. Of these microcytic samples, 52% were IDA, 36% were BTT, 8% had both and 4% were undiagnosed. IDA had significantly lower Hb, mean corpuscular volume (MCV) and Ferritin levels than the control group. BTT had lower MCV, higher Ferritin and comparable Hb levels with control group. The Youden's index of Mentzer's was highest and RBC was the only index which had both sensitivity and specificity more than 80% for both IDA and BTT. It is desirable to routinely perform hemograms for all blood donors and further analyse the microcytic samples for Ferritin and HbA2 to diagnose IDA and BTT and to provide appropriate counselling/treatment.

Asthmatic symptoms after exposure to ethylenebisdithiocarbamates and other pesticides in the Europit field studies

We conducted a multicenter prospective study to assess the effects of occupational exposure to ethylenebisdithiocarbamate fungicides and/or other pesticides on self-reported asthma and asthmatic symptoms. This multicenter study was conducted among 248 workers exposed to pesticides and 231 non-exposed workers from five field studies. The five field studies were carried out in The Netherlands, Italy, Finland, and two studies in Bulgaria. Subjects constituting this cohort completed a self-administered questionnaire at baseline (before the start of exposure). Ethylenethiourea in urine was determined to assess exposure to ethylenebisdithiocarbamates. In multivariate analyses adjusted for all potential confounders (age, education, residence, smoking, gender, and field study), we found inverse associations, all not statistically significant, between occupational exposure to pesticides and asthma diagnosis (OR 0.41; 95% CI 0.15-1.11), complains of chest tightness (OR 0.60; 95% CI 0.36-1.02), wheeze (OR 0.56; 95% CI 0.32-0.98), asthma attack (OR 0.52; 95% CI 0.12-2.25), and asthma medication (OR 0.79; 95% CI 0.25-2.53). Furthermore, we reported null associations for multivariate analysis using ethylenethiourea as determinant for exposure. Although exposure to pesticides remains a potential health risk, our results do not suggest an association between exposure to ethylenebisdithiocarbamates and/or other pesticides used in our study on asthma and asthmatic symptoms.

Validation of the Brazilian-Portuguese version of the European Community Respiratory Health Survey in asthma patients

BACKGROUND

The European Community Respiratory Health Survey (ECRHS) questionnaire was planned to answer questions about the distribution of asthma. Our objective was to determine the cultural equivalence of the ECRHS into the Brazilian-Portuguese language.

METHODS

We translated the ECRHS according to international criteria.

RESULTS

Small cultural adaptations were necessary. Among the 80 participating patients, the Cronbach indices were higher (0.98-1.00) and the Kappa indices varied from 0.77 to 1.00.

CONCLUSION

The study suggests that the Brazilian version of the ECRHS is conceptually equivalent to the original and similarly reliable and may be used in international studies involving Portuguese-speaking respiratory patients.

Impulse oscillometry: an alternative modality to the conventional pulmonary function test to categorise obstructive pulmonary disorders

Impulse oscillometry (IOS) was introduced as an alternative modality to the conventional pulmonary function test (cPFT) to test lung mechanics. The objective of this study is to assess the use of IOS as an alternative, or in conjunction with cPFT, to categorise an obstructive respiratory disorder as chronic obstructive pulmonary disease (COPD) or asthma. Patients referred to the PFT laboratory, with different diagnoses of obstructive airways disorders, completed a standardised respiratory questionnaire prior to testing. All recruited subjects completed both modalities of PFT. A total of 146 patients were included. The overall mean age was 51+/-18.4 SD. The majority were non-smokers (68.7%). A standardised diagnosis of asthma was found for 51 subjects, while COPD was diagnosed in 36 subjects and 59 subjects were categorised as normal. The sensitivity of IOS in relation to asthma was 31.3% and 19.6% for cPFT. Among cases of COPD, the cPFT had better sensitivity (47.4%) than IOS (38.95%). The specificity was comparable for IOS and cPFT in relation to asthma and COPD. IOS had better sensitivity (45.8%) in detecting normal subjects than cPFT (28.8%), while specificity was comparable (80.5% and 86.2%, respectively). IOS may replace cPFT where the latter cannot be carried out due to feasibility or lack of cooperation. It can, however, discriminate between diseased and non-diseased subjects.

Assessing future need for acute care in adult asthmatics: the Profile of Asthma Risk Study: a prospective health maintenance organization-based study

STUDY OBJECTIVES

To develop simple clinical tools predictive of acute asthma care and to identify modifiable risk factors.

DESIGN

Prospective cohort study.

SETTING

A large health maintenance organization (430,000 members).

PATIENTS/PARTICIPANTS

Adult members (18 to 55 years old) with asthma.

INTERVENTIONS

Data from a questionnaire, skin-prick testing for inhalant allergens, and spirometry were collected at the baseline visit. Acute care utilization data were obtained from administrative databases for a subsequent 30-month period.

METHODS

This two-phase study first identified and performed a split-sample validation on three clinical tools to determine their predictive ability by employing data from a questionnaire, questionnaire plus spirometry, and questionnaire plus spirometry and skin-prick testing. Second, it identified modifiable independent risk factors.

MEASUREMENTS AND RESULTS

The 554 study participants generated 173 episodes of acute care over 1,258 person-years of follow-up (0.14 episodes per person per year). Of these, 101 participants had at least one episode, and one third of this group had two or more episodes. Clinical scoring into risk groups was done by reverse stepwise regression analyses. Using relative risks (RRs) as a guide, high-risk, moderate-risk, and low-risk groups were identified. The high-risk groups, 13 to 21% of the validation sample, had a 7- to 11-fold increased risk for hospital care compared to the low-risk groups. The moderate-risk groups, 46 to 50% of the validation sample, had a twofold- to fourfold-increased risk. FEV(1) was the most significant predictor (RR, 4.33). Of the four potentially modifiable risk factors identified, current cigarette smoke exposure (RR, 1.6) and ownership and skin-prick test positivity to cat or dog (RR, 1.5) were the most significant.

CONCLUSIONS

These models stratify asthma patients at risk for acute care. Patients with lower FEV(1) values are at significantly higher risk, underscoring the importance of spirometry in asthma care.

Nonspecific provocation of target organs in allergic diseases: EAACI-GA(2)LEN consensus report

It is widely accepted that nonspecific tissue reactivity is a distinct pathophysiological hallmark of allergic diseases, influenced by genetic and environmental factors different from those involved in causing sensitization and allergen response of target organs. This consensus document aims at reviewing procedures currently used for nonspecific provocation of the bronchi, nose and eye and for measuring their responsiveness to nonspecific stimuli.

Asthma in American Indian adults: the Strong Heart Study

BACKGROUND

Despite growing recognition that asthma is an important cause of morbidity among American Indians, there has been no systematic study of this disease in older adults who are likely to be at high risk of complications related to asthma. Characterization of the impact of asthma among American Indian adults is necessary in order to design appropriate clinical and preventive measures.

METHODS

A sample of participants in the third examination of the Strong Heart Study, a multicenter, population-based, prospective study of cardiovascular disease in American Indians, completed a standardized respiratory questionnaire, performed spirometry, and underwent allergen skin testing. Participants were > or = 50 years old.

RESULTS

Of 3,197 participants in the third examination, 6.3% had physician-diagnosed asthma and 4.3% had probable asthma. Women had a higher prevalence of physician-diagnosed asthma than men (8.2% vs 3.2%). Of the 435 participants reported in the asthma substudy, morbidity related to asthma was high: among those with physician-diagnosed asthma: 97% reported trouble breathing and 52% had severe persistent disease. The mean FEV(1) in those with physician-diagnosed asthma was 61.3% of predicted, and 67.2% reported a history of emergency department visits and/or hospitalizations in the last year, yet only 3% were receiving regular inhaled corticosteroids.

CONCLUSIONS

The prevalence of asthma among older American Indians residing in three separate geographic areas of the United States was similar to rates in other ethnic groups. Asthma was associated with low lung function, significant morbidity and health-care utilization, yet medications for pulmonary disease were underutilized by this population.

Bronchodilator response to adrenergic beta2-agonists: relationship to symptoms in an adult community

BACKGROUND

Wheeze and chest tightness has traditionally been associated with enhanced bronchial responsiveness. However, no community studies are available on the associations between bronchodilator response and respiratory symptoms among adults.

AIM

To examine how respiratory symptoms predict bronchodilator response.

METHODS

An age and gender stratified random sample of all adults aged 47-48 and 71-73 years in Bergen, Norway, were invited. The 3506 participants (69%) filled in questionnaires including nine symptoms and performed bronchodilator reversibility tests. Subjects without current anti-asthmatic medication performing acceptable reversibility tests were included in the analyses (n=3088).

RESULTS

A reversibility with FEV(1) increase 12% and 200 ml was obtained in 2% of middle-aged and 4% of elderly subjects (p=0.001). In multiple linear regression analysis bronchodilatation was positively associated with wheezing without cold (FEV(1) increase of 1.5%, 95% CI: (0.9, 2.2)% in all participants and 31 ml, 95% CI: (1, 61)ml in men only) and dyspnoea climbing two flights of stairs (0.9%, 95% CI: (0.5,1.4)% and 12 ml, 95% CI: (1,23)ml). Chronic cough predicted the response negatively (-0.7%, 95% CI: (-1.3,-0.1)% and -17 ml, 95% CI: (-32,-2)ml). In multiple logistic regression analysis morning cough predicted an FEV(1) increase 12% and 200 ml (OR: 1.8, 95% CI: (1.1,2.8)).

CONCLUSIONS

A small fraction of adults in a general population has bronchodilatation after salbutamol inhalation. "Wheezing without cold", "dyspnoea climbing two flights of stairs", and "morning cough" predict an increased bronchodilator response among subjects without current anti-asthmatic medications.

Effects of a smoke-free law on hair nicotine and respiratory symptoms of restaurant and bar workers

OBJECTIVE

Bar and restaurant workers' exposure to secondhand smoke (SHS) was compared before and 3 and 6 months after implementation of a smoke-free ordinance.

METHODS

Hair nicotine, self-reported exposure to SHS, and respiratory symptoms were assessed on 105 smoking and nonsmoking workers from randomly selected establishments in Lexington, Kentucky. Thirty-eight percent were current smokers with more than half smoking 10 or fewer cigarettes per day. Workers provided a hair sample at baseline and at the 3-month interview.

RESULTS

There was a significant decline in hair nicotine 3 months postlaw when controlling for cigarettes smoked per day. Bar workers showed a significantly larger decline in hair nicotine compared with restaurant workers. The only significant decline in SHS exposure was in the workplace and other public places. Regardless of smoking status, respiratory symptoms declined significantly postlaw.

CONCLUSIONS

Hospitality workers demonstrated significant declines in hair nicotine and respiratory symptoms after the law. Comprehensive smoke-free laws can provide the greatest protection to bar workers who are the most vulnerable to SHS exposure at work.

Lupus patients with pulmonary involvement have a pro-inflammatory cytokines profile

OBJECTIVES

The literature on cytokine response in systemic lupus erythematosus (SLE) is confusing. It is possible that different disease phenotypes have different cytokine profiles. Our aim was to examine the levels of selected pro-inflammatory and anti-inflammatory cytokines in SLE patients with and without pulmonary involvement.

METHODS AND SUBJECTS

Patients with SLE were interviewed and were subjected to the pulmonary function test and high-resolution computed tomography studies. Serum levels of interleukin (IL)-6, IL-8, IL-10, Il-12, interferon (IFN) gamma, and tumor necrosis factor (TNF) alpha were estimated by enzyme-linked immunosorbent assay.

RESULTS

Forty-nine of the 61 SLE patients had pulmonary involvement. Median levels of IL-8, IFNgamma, and TNFalpha were significantly higher in the pulmonary group as compared to the non-pulmonary group (p = 0.027, 0.027 and 0.002, respectively). Ratios of pro-inflammatory cytokines to anti-inflammatory cytokines were higher in the pulmonary group as compared to the non-pulmonary group as well as in the pulmonary restrictive subgroup compared to the obstructive subgroup.

CONCLUSION

Lupus patients with pulmonary involvement have a stronger pro-inflammatory cytokine bias than those without pulmonary involvement.

Occupational respiratory health of New Zealand horse trainers

OBJECTIVES

To confirm that working with horses is an occupational respiratory hazard and observed associations are not attributable to confounding.

METHODS

A postal survey of the respiratory health of 659 horse trainers and a comparison group of 506 vegetable growers was conducted. Data were analysed using logistic regression.

RESULTS

Relative to vegetable growers, horse trainers reported higher rates of chronic bronchitis [odds ratio (OR) = 6.8, 95% confidence interval (CI): 2.2-21.4] and organic dust toxic syndrome/farmers' lung (ODTS/FL) (OR = 3.5, 95% CI: 1.8-6.8). Grinding oats, spreading hay, and using powdered feed supplements were associated with increased respiratory symptoms among trainers. Associations between symptoms and working with horses increased for full-time workers.

CONCLUSIONS

This study found evidence that working with horses is a risk factor for ODTS/FL and bronchitis. The associations did not appear to be explained by bias, including confounding. However, the possibility of confounding cannot be entirely ruled out, and confirmatory studies are needed. Future studies should consider inorganic dust exposures.

[Geographic variation in the prevalence of asthma symptoms in Spanish children and adolescents. International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3, Spain]

OBJECTIVE

To analyze geographic variations in the prevalence of symptoms related to asthma in Spanish children and adolescents.

POPULATION AND METHODS

In 2001 and 2002, the Spanish arm of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3 collected information on 28 445 children in the age bracket of 6-7 years in 10 metropolitan areas (A Coruña, Asturias, Barcelona, Bilbao, Cartagena, Castellón, Madrid, Pamplona, San Sebastián, and Valencia) and on 31 257 adolescents in the bracket 13-14 years in 11 areas (the previously named areas plus Valladolid). An asthma symptom questionnaire was filled in by parents or the adolescents themselves. Differences in symptoms between geographic areas were analyzed by fitting a logistic regression model. The relationship between symptoms and age was analyzed by linear correlation.

RESULTS

The prevalence of recent wheezing (last 12 months) ranged from 7.1% to 12.9% among 6-7-year-olds and from 7.1% to 15.3% among the 13-14-year-olds. The greatest risk of recent wheezing was observed for children in A Coruña (odds ratio [OR] =1.96 in comparison with the area of lowest prevalence; 95% confidence interval [CI], 1.65-2.33) and Bilbao (OR=1.83; 95% CI, 1.54-2.18) and for adolescents in A Coruña (OR=2.38; 95% CI, 2.04-2.79) and Asturias (OR=2.37; 95% CI, 2.03-2.77). A strong correlation (r=0.72) was observed between the prevalence of recent wheezing and age in each of the geographic areas.

CONCLUSIONS

Considerable geographic variation in the prevalence of asthma symptoms can be seen in Spain even among young children. Symptoms are more frequent in children and adolescents who live on the Spain s northern Atlantic coast.

Case-by-case assessment of adult-onset asthma attributable to occupational exposures among members of a health maintenance organization

OBJECTIVE

In a general population of employed persons with health insurance, what proportion of adult-onset asthma is caused by occupational exposures?

METHOD

We conducted a 2-year prospective study to identify adult-onset asthma among health maintenance organization (HMO) members. Telephone interviews regarding occupational exposures, symptoms, medication use, and triggers were used to assess likelihood of work-related asthma for each case. Weighted estimating equations were used to adjust the proportion of asthma attributable to workplace exposures for factors associated with interview participation.

RESULTS

Overall, 29% (95% confidence interval, 25-34%) of adult-onset asthma was attributable to workplace exposures; 26% (21-30%) and 22% (18-27%) of cases had asthma attributable to occupational irritant and sensitizer exposures, respectively.

CONCLUSIONS

Occupational exposures, including irritants, are important causes of adult-onset asthma.

Validation of an asthma questionnaire for use in healthcare workers

BACKGROUND

Previous studies have described increased occurrence of asthma among healthcare workers, but to our knowledge there are no validated survey questionnaires with which to study this occupational group.

AIMS

To develop, validate, and refine a new survey instrument on asthma for use in epidemiological studies of healthcare workers.

METHODS

An initial draft questionnaire, designed by a multidisciplinary team, used previously validated questions where possible; the occupational exposure section was developed by updating health services specific chemical lists through hospital walk-through surveys and review of material safety data sheets. A cross-sectional validation study was conducted in 118 non-smoking subjects, who also underwent bronchial challenge testing, an interview with an industrial hygienist, and measurement of specific IgE antibodies to common aeroallergens.

RESULTS

The final version consisted of 43 main questions in four sections. Time to completion of the questionnaire ranged from 13 to 25 minutes. Test-retest reliability of asthma and allergy items ranged from 75% to 94%, and internal consistency for these items was excellent (Cronbach's alpha > or = 0.86). Against methacholine challenge, an eight item combination of asthma related symptoms had a sensitivity of 71% and specificity of 70%; against a physician diagnosis of asthma, this same combination showed a sensitivity of 79% and specificity of 98%. Agreement between self-reported exposures and industrial hygienist review was similar to previous studies and only moderate, indicating the need to incorporate more reliable methods of exposure assessment. Against the aerollergen panel, the best combinations of sensitivity and specificity were obtained for a history of allergies to dust, dust mite, and animals.

CONCLUSIONS

Initial evaluation of this new questionnaire indicates good validity and reliability, and further field testing and cross-validation in a larger healthcare worker population is in progress. The need for development of more reliable occupational exposure assessment methods that go beyond self-report is underscored.

Agreement between responses to a standardized asthma questionnaire and a questionnaire following a demonstration of asthma symptoms in adults

Asthma epidemiology relies heavily on standardized questionnaires, but little is known about the understanding of asthma symptoms among adults in the community. In 2004, the authors assessed the level of agreement between responses to a standardized questionnaire and responses to a questionnaire completed by participants after viewing a demonstration of asthma symptoms. The study involved 601 young adults from Chile. The field-workers were trained to explain and demonstrate the asthma symptoms to the participants. The symptoms were wheeze, waking at night with breathlessness, breathlessness following exercise, and waking with cough. The kappa statistic did not exceed 0.4, and the recorded prevalence of asthma symptoms following the demonstration was 30-60% lower than that for the standardized questionnaire. Using bronchial responsiveness as the proxy gold standard, the positive likelihood ratios for wheeze and waking short of breath were higher following symptom demonstration. The low agreement between the standardized questionnaire and the postdemonstration questionnaire and the likelihood ratios' closeness to 1 for the standardized questionnaire decreases the authors' confidence in the appropriateness of this tool for estimating the prevalence of asthma in the community. For etiologic studies of asthma, it may contribute to the lack of consistency between different studies analyzing the same etiologic exposures.

A population-based study of asthma, quality of life, and occupation among elderly Hispanic and non-Hispanic whites: a cross-sectional investigation

BACKGROUND

The U.S. population is aging and is expected to double by the year 2030. The current study evaluated the prevalence of asthma and its correlates in the elderly Hispanic and non-Hispanic white population.

METHODS

Data from a sample of 3021 Hispanics and non-Hispanic White subjects, 65 years and older, interviewed as part of an ongoing cross-sectional study of the elderly in west Texas, were analyzed. The outcome variable was categorized into: no asthma (reference category), current asthma, and probable asthma. Polytomous logistic regression analysis was used to assess the relationship between the outcome variable and various socio-demographic measures, self-rated health, asthma symptoms, quality of life measures (SF-12), and various occupations.

RESULTS

The estimated prevalence of current asthma and probable asthma were 6.3% (95%CI: 5.3-7.2) and 9.0% (95%CI: 7.8-10.1) respectively. The majority of subjects with current asthma (Mean SF-12 score 35.8, 95%CI: 34.2-37.4) or probable asthma (35.3, 34.0-36.6) had significantly worse physical health-related quality of life as compared to subjects without asthma (42.6, 42.1-43.1). In multiple logistic regression analyses, women had a 1.64 times greater odds of current asthma (95%CI: 1.12-2.38) as compared to men. Hay fever was a strong predictor of both current and probable asthma. The odds of current asthma were 1.78 times (95%CI: 1.24-2.55) greater among past smokers; whereas the odds of probable asthma were 2.73 times (95%CI: 1.77-4.21) greater among current smokers as compared to non-smokers. Similarly fair/poor self rated health and complaints of severe pain were independently associated with current and probable asthma. The odds of current and probable asthma were almost two fold greater for obesity. When stratified by gender, the odds were significantly greater among females (p-value for interaction term = 0.038). The odds of current asthma were significantly greater for farm-related occupations (adjusted OR = 2.09, 95%CI: 1.00-4.39); whereas the odds were significantly lower among those who reported teaching as their longest held occupation (adjusted OR = 0.36, 95%CI = 0.18-0.74).

CONCLUSION

This study found that asthma is a common medical condition in the elderly and it significantly impacts quality of life and general health status. Results support adopting an integrated approach in identifying and controlling asthma in this population.

Use of acetaminophen and the risk of self-reported allergic symptoms and skin sensitization in Butajira, Ethiopia

BACKGROUND

Studies in developed countries suggest that acetaminophen use is associated with increased risk of asthma, but it is unclear whether this association is causal.

OBJECTIVE

To determine the relation among acetaminophen use, asthma, and allergy, and to explore potential biases in acetaminophen use, in a developing country population.

METHODS

We surveyed 7649 adults and children from Butajira, Ethiopia, collecting data on self-reported symptoms of allergic disease, skin sensitization to Dermatophagoides pteronyssinus and cockroach, acetaminophen use, and potential confounders. We then collected detailed data on indications for acetaminophen use and reasons for aspirin avoidance in a nested follow-up study.

RESULTS

Allergic symptoms increased significantly with frequency of acetaminophen use, with odds ratios in those using >3 tablets in the past month relative to none 1.89 (95% CI, 1.51-2.36) for wheeze, 2.14 (1.72-2.67) for nocturnal shortness of breath, 2.52 (1.99-3.20) for rhinitis, and 1.90 (1.39-2.61) for eczema. Cockroach sensitization was also more common in the highest acetaminophen category (odds ratio, 1.40; 95% CI, 1.10-1.79), but D pteronyssinus sensitization was not. Less than 1% of participants with asthma or wheeze in our nested study reported avoidance of aspirin because of asthma symptoms. None volunteered using acetaminophen to treat allergic symptoms.

CONCLUSION

There is a dose-related association between acetaminophen use and self-reported allergic symptoms in this population that is not a result of aspirin avoidance, reverse causation, or other bias. Acetaminophen may therefore be involved in the etiology of asthma and allergic disease.

Socioeconomic risk factors for asthma in Chilean young adults

OBJECTIVES

We studied the association between socioeconomic status (SES) and asthma symptoms, severity of asthma, atopy, and bronchial hyperresponsiveness (BHR) to methacholine.

METHODS

We studied 1232 men and women born between 1974 and 1978 in a semirural area of Chile. We assessed asthma symptoms with a standardized questionnaire, atopy with a skin-prick test to 8 allergens, and BHR to methacholine with the tidal breathing method. SES was derived from several indicators: education, occupation, completion of a welfare form, belongings, housing, number of siblings, and overcrowding.

RESULTS

Those with fewer belongings had more asthma symptoms. Those who had higher education and those who owned cars had fewer asthma symptoms and BHR. Overcrowding was negatively related to atopy, atopy with asthma symptoms, and BHR. Higher education and noncompletion of a welfare form were risk factors for atopy.

CONCLUSION

The strength and direction of the association between asthma and SES depended on what definition of asthma was analyzed. Asthma symptoms were more common among poor people. There was some support for the hygiene hypothesis, as overcrowding was associated with less wheezing with atopy, less atopy, and less BHR.

Lung health in workers exposed to reed dust

We conducted a cross-sectional survey in a cellulose plant among 109 reed workers, exposed to reed dust and 78 unexposed office workers, to investigate respiratory health effects of reed dust exposure. Investigations included dust measurements, serum total IgE, skin prick test, pulmonary function testing and questionnaire on respiratory symptoms. Total dust level in the reed processing unit was higher than the office (9.7 and 0.02 mg/m3, respectively). Reed workers had a higher rate of current smoking (67% and 46%, respectively). After the adjustment for smoking status and age, reed dust exposure was significantly associated with wheezing, chronic cough, dyspnea, itching eyes and itching nose. Chest tightness and ODTS symptoms were only reported by reed workers (27.5% and 23.9%, respectively). After the adjustment for pack-years of smoking, percentage of predicted FEV1, FVC, FEV1/FVC and FEF25-75 in reed workers were significantly lower than office workers. Among reed workers, wheezing was associated with older age (>40 years) and ever smoking, and cross-shift decline in FVC and FEV1 with shorter duration of work. Reed dust exposure in the workplace could provoke respiratory symptoms, possibly due to an irritating effect. Health selection bias is likely, and could have underestimated the health effects of reed dust exposure.

Utilization of the pulmonary function test laboratory in the evaluation of respiratory disorders in the Al-Amiri Hospital: a secondary medical center

OBJECTIVE

The aim of this study was to describe the current use of pulmonary function tests (PFT) and the degree of matching between the diagnoses at referral and after the test.

SUBJECTS AND METHODS

A pre-test questionnaire was administered to 464 (5-88 years) patients referred to the PFT laboratory followed by a complete PFT test. The results of the patients' tests were analyzed in terms of the diagnosis before the test, its relation to symptoms, and the rate of concordance between the diagnoses before and after the test.

RESULTS

The most referrals were from the medical Outpatient Department; 61%) and the most frequent diagnosis before the test was asthma (31.8%). Of the 464 patients, 34% were currently smoking cigarettes, and the most common symptoms were chronic dyspnea (30.2%) and chronic cough (19.6%). The chronicity of symptoms showed some association with the diagnosis before PFT in the case of chronic obstructive pulmonary disease (COPD) showing the symptom of dyspnea (p = 0.05), and COPD and restrictive lung disease with cough (p < 0.05). The overall rate of concordance in matching diagnoses before and after the test was 60.4% by consultant physicians and 51.9% by non-consultants, with an overall rate of 55% by all physicians.

CONCLUSION

Our findings show that there should be better utilization of the PFT laboratory by physicians in all sub-specialities and there is a need to facilitate its use to make a better functional diagnosis.

Building-related respiratory symptoms can be predicted with semi-quantitative indices of exposure to dampness and mold

Using a semi-quantitative mold exposure index, the National Institute for Occupational Safety and Health (NIOSH) investigated 13 college buildings to examine whether building-related respiratory symptoms among employees are associated with environmental exposure to mold and dampness in buildings. We collected data on upper and lower respiratory symptoms and their building-relatedness, and time spent in specific rooms with a self-administered questionnaires. Trained NIOSH industrial hygienists classified rooms for water stains, visible mold, mold odor, and moisture using semi-quantitative scales and then estimated individual exposure indices weighted by the time spent in specific rooms. The semi-quantitative exposure indices significantly predicted building-related respiratory symptoms, including wheeze [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-4.5], chest tightness (OR = 2.2; 95% CI = 1.1-4.6), shortness of breath (OR = 2.7; 95% CI = 1.2-6.1), nasal (OR = 2.5; 95% CI = 1.3-4.7) and sinus (OR = 2.2; 95% CI = 1.2-4.1) symptoms, with exposure-response relationships. We found that conditions suggestive of indoor mold exposure at work were associated with building-related respiratory symptoms. Our findings suggest that observational semi-quantitative indices of exposure to dampness and mold can support action to prevent building-related respiratory diseases.

PRACTICAL IMPLICATIONS

Current air sampling methods have major limitations in assessing exposure to mold and other biological agents that may prevent the demonstration of associations of bioaerosol exposure with health. Our study demonstrates that semi-quantitative dampness/mold exposure indices, based solely on visual and olfactory observation and weighted by time spent in specific rooms, can predict existence of excessive building-related respiratory symptoms and diseases. Relative extent of water stains, visible mold, mold odor, or moisture can be used to prioritize remediation to reduce potential risk of building-related respiratory diseases. From a public health perspective, these observational findings justify action to correct water leaks and repair water damage in order to prevent building-related respiratory diseases. This approach can also be a basis for developing practical building-diagnostic tools for water-incursion.

Dietary salt intake as a potential modifier of airway responsiveness in bronchial asthma

While pharmacologic treatment of chronic asthma is usually highly effective, medications often have significant side-effects or exhibit tachyphylaxis. Alternative and/or complementary treatments that reduce dependence on pharmacologic medications are of interest in reducing the severity of asthma. This review analyzes the literature that has evaluated dietary salt intake as a potential modifier of the severity of asthma and airway responsiveness. High dietary intakes of salt, greater than 9 g/d, are common in Western civilizations, as is asthma. The question is whether reducing dietary salt intake potentially would improve pulmonary function and airway responsiveness in individuals with asthma. This review details the existing studies in this regard and includes the studies that have evaluated dietary salt on the severity of exercise-induced asthma (exercise-induced bronchoconstriction [E1B]). From a critical analysis of the existing literature, the data that support a role for dietary salt reduction for reducing severity of asthma and airway responsiveness in individuals with asthma is considered encouraging but not clinically convincing. The existing studies have suffered from a variety of experimental and population limitations. In contrast, the data from studies that have altered dietary salt and evaluated severity of EIB in nonatopic individuals is much more convincing. In each study so far, lowering dietary salt has reduced the severity of EIB to subclinical levels. Correspondingly, the supplementing of diets to higher than normal salt intake increased EIB significantly. This review concludes that the data are sufficient to warrant a clinical trial that is properly controlled and randomized to further investigate the influence of dietary salt intake on pulmonary function, airway responsiveness, symptoms, quality of life, and medication requirements in asthma and EIB.

Rationale for the Dutch hypothesis. Allergy and airway hyperresponsiveness as genetic factors and their interaction with environment in the development of asthma and COPD

The Dutch hypothesis, formulated in the 1960s, holds that the various forms of airway obstruction are different expressions of a single disease entity. It suggests that genetic factors (eg, airway hyperresponsiveness [AHR] and atopy), endogenous factors (eg, sex and age), and exogenous factors (eg, allergens, infections, and smoking) all play a role in the pathogenesis of chronic nonspecific lung disease. This review finds evidence that AHR and smoking are common risk factors for asthma and COPD. To prove the Dutch hypothesis definitively, however, genetic studies, preferably longitudinal, must be performed. Such studies must include subjects who have airway obstruction that does not necessarily meet the current strict definitions of asthma or COPD (ie, the extremes of these conditions) that are used in clinical studies.

IgE level and Phadiatop in an elderly population from the PAQUID cohort: relationship to respiratory symptoms and smoking

BACKGROUND

In the last decades in industrialized countries, the increase of life expectancy has resulted in an increase in the population of the elderly. However, little is known about the prevalence of allergies in the elderly population. The aim of the study was to investigate the specific relationship of serum IgE and Phadiatop, with asthma, rhinitis, and smoking in a sample of an elderly population.

METHODS

Subjects from the Paquid cohort living in Gironde Department (age 65 years and over) in France were followed up since 1988 (PAQUID cohort).

RESULTS

Among the randomized sample of 352 subjects, there were 158 men (45%) and 194 women (55%). The lowest levels of IgE were in subjects with chronic sputum; and in normal subjects (47.1 +/- 56.4 vs 56.2 +/- 73.9, NS). Multiple linear regression was performed with log(10) IgE values as a dependent variable and age, Phadiatop test, smoking, and respiratory symptoms independently in men and in women. In men, a significant relationship was observed between IgE values and Phadiatop test (P < 0.001), asthma history (P = 0.002), and smoking (P = 0.019).

CONCLUSIONS

Respiratory allergy is present in persons >65 years of age. There is an association between smoking and IgE level independent of allergic reactivity to common allergens in the elderly.

Prevalence of asthma and related symptoms in Sivas, Central Anatolia

BACKGROUND

In our clinical experience, asthma is an important health problem in our region, but we did not know its prevalence.

OBJECTIVE

The main objective of our study was to assess the prevalence of asthma in Sivas, a city in Central Anatolia.

METHODS

A cross-sectional study was performed using a screening questionnaire adopted from European Community Respiratory Health Survey (ECRHS). A total of 5448 adults of both genders between 20 and 107 yr of age living in Sivas, a city in the central region of Anatolia in Turkey, participated in the survey. Of the cohort, 2691 were men (49.4%) and 2757 (50.6%) were women.

RESULTS

The mean age was 38.2 yr (SD = 12.7 yr), almost half of the study population was at or younger than 40 yr of age. The prevalence of wheezing in the last 12 months, diagnosis of asthma, asthma attack in the last 12 months, and use of asthma medicine were 20.9%, 4.5%, 4.9%, and 3.4%, respectively. Awakening with chest tightness, with shortness of breath, or with cough were reported as 14.2%, 14.8%, and 22.7%, respectively. The prevalence of respiratory symptoms related to asthma was statistically higher in women than that of men (p = 0.000, OR 1.346, 95% CI: 1.228-1.475). Those who had asthma/allergic symptoms in their family members were significantly younger than others (p: 0.001).

CONCLUSIONS

The results of this study demonstrate that symptoms suggestive of asthma are quite common and constitute a major health problem in Sivas, Turkey. This study also showed that, despite a high rate of reported symptoms exists, the rate of diagnosis and treatment of asthma is low among the adult population in Sivas.

Most reliable indices in differentiation between thalassemia trait and iron deficiency anemia

BACKGROUND

Iron deficiency anemia (IDA) and thalassemia trait (TT) are the most common forms of microcytic anemia. Some discrimination indices calculated from red blood cell indices are defined and used for rapid discrimination between TT and IDA. However, there has been no study carried out in which the validity of all of the defined indices are compared in the same patient groups. Youden's index is the most reliable method by which to measure the validity of a particular technique, because it takes into account both sensitivity and specificity.

METHODS

We calculated eight discrimination indices (Mentzer Index, England and Fraser Index, Srivastava Index, Green and King Index, Shine and Lal Index, red blood cell (RBC) count, red blood cell distribution width and red blood cell blood distribution width index (RDWI)) in 26 patients with IDA and in 37 patients with beta TT (betaTT). We determined the number of correctly identified patients by using each discrimination index. We also calculated sensitivity, specificity, positive and negative predictive value and Youden's index of each discrimination index.

RESULTS

None of the discrimination indices showed a sensitivity and specificity of 100%. Youden's indices of RBC count and RDWI were the highest with the value of 82 and 80%, respectively. Ninety percent and 92% of the patients were correctly identified with RBC and RDWI, respectively.

CONCLUSIONS

Red blood cell count and RDWI are the most reliable discrimination indices in differentiation between betaTT and IDA.

Childhood asthma in an urban community: prevalence, care system, and treatment

OBJECTIVES

We describe the system of asthma care in Hartford, CT, an urban, minority community.

METHODS

The health field concept was used to organize factors influencing asthma prevalence and severity. Data were obtained from national, state, and municipal reports, and from surveys of children in Hartford seeking medical care in an asthma program called Easy Breathing.

RESULTS

Between June 1, 1998, and May 1, 2000, 21% of children receiving Medicaid in Hartford did not file a medical claim. Between 1998 and 2000, the number of providers in Hartford decreased by 37% while the number of outpatient visits increased by 8%. Using claims data, we found the following: 19.0% of Hartford children had asthma (data from the International Classification of Disease, ninth revision, and the National Drug Code); and 12% of children with asthma filled a prescription for inhaled corticosteroid therapy, 83% for a bronchodilator, and 36% for an oral corticosteroid. Children with asthma were more likely to be hospitalized (10% vs 5%, respectively) and to visit an emergency department (45% vs 29%, respectively), and, on average, they had more hospital days (0.603 vs 0.415 days per child, respectively) and more outpatient visits per year (4.7 vs 2.5 visits, respectively) compared to children without asthma. Asthma prevalence in the 6,643 children surveyed in the Easy Breathing program was 41%. Persistent asthma was diagnosed in 50% of the children with asthma. Asthma prevalence varied by ethnic origin, age, and gender, and was highest in Hispanic/Puerto Rican children, in children 5 to 10 years of age, in boys up to 10 years of age, and in girls after 15 years of age.

CONCLUSION

Improved personal behaviors and medical care will have a limited sustained impact on childhood asthma until basic environmental issues are modified. The health field concept provides a mechanism with which to address the issues surrounding asthma in urban communities.

Prevalence and risk factors for asthma and chronic bronchitis in the capitals Helsinki, Stockholm, and Tallinn

The aim of this part of the FinEsS-studies was to assess whether differences existed in prevalence of asthma, chronic bronchitis, and respiratory symptoms between three Baltic capitals, and to examine risk factor profiles for respiratory conditions. In 1996, a postal survey was performed in these cities with a response rate of 72% in Stockholm, 76% in Helsinki, and 68% in Tallinn. The prevalence of physician-diagnosed asthma was 76% in Stockholm, 6.2% in Helsinki, and 2.3% in Tallinn, while respiratory symptoms were most common in Tallinn. The prevalence of physician-diagnosed chronic bronchitis was 10.6% in Tallinn, 3.4% in Helsinki, and 3.0% in Stockholm. Risk factor analyses revealed a significantly increased risk for those living in Tallinn compared to that of Stockholm for wheezing conditions, OR 1.56-1.69, longstanding cough, OR 1.92 (1.74-2.13), attacks of shortness of breath during the previous 12 months, OR 1.35 (1.20-1.52), and chronic productive cough, OR 1.49 (1.28-1.74). Subjects having symptoms common in asthma were more likely to have physician-diagnosed asthma in Stockholm and Helsinki than in Tallinn, while subjects having bronchitis symptoms had more often physician-diagnosed chronic bronchitis in Tallinn. Prevalence of respiratory symptoms was higher in Tallinn than in Stockholm and Helsinki, while physician-diagnosed asthma was more common in Stockholm and Helsinki. The prevalence of physician-diagnosed chronic bronchitis was three times as high in Tallinn as in Helsinki or Stockholm. Our results also suggest large differences in diagnostic practices between the three countries, while the differences between the capitals in true prevalence of disease may be small.

Issues in identifying asthma and estimating prevalence in an urban school population

This article first presents salient issues related to identifying children in urban schools who might benefit from asthma services. It discusses a brief questionnaire for identifying cases and problems in estimating asthma prevalence. Subsequently, results of case detection in 14 urban schools are presented and discussed in light of these issues. The questionnaire was employed with parents of 4,653 African-American children in Detroit. Results suggest that determining number, type, and frequency of symptoms may be necessary to ascertain prevalence of asthma. Using only number and type produced a rate of asthma of 25%. Adding frequency provided a more conservative estimate of 19%. About 9% of children exhibiting symptoms of asthma had no physician diagnosis. Only 25% with symptoms reflecting mild persistent, 35% with moderate persistent, and 26% with severe persistent disease had prescriptions for anti-inflammatory medicine. Further, 23% of children with asthma-like symptoms had no prescription for asthma medicine of any type.

CONCLUSIONS

(1) low-cost procedures can be used in schools to identify children with suspected undiagnosed and undertreated asthma; (2) prevalence estimates for asthma in the group of urban school children studied are among the highest in the United States; and (3) asthma is undertreated in this sample.

Association of body mass index with respiratory symptoms and atopy: results from the European Community Respiratory Health Survey

BACKGROUND

There are several reports showing that obese adults report more respiratory symptoms suggestive of asthma than those who are not obese.

OBJECTIVE

To determine the association of body mass index with respiratory symptoms and atopy in young adults

METHOD

Information collected from 15,454 participants in the European Community Respiratory Health Survey, a multicentre cross-sectional survey of young adults, was analysed to determine the association of body mass index with respiratory symptoms and atopy.

RESULTS

Men and women with a body mass index of greater than 30 were at an increased risk of wheeze with shortness of breath compared with those with a body mass of 20-24.99 (OR in men 1.85, 95% confidence interval 1.41-2.42; OR in women 2.03, 95% confidence interval 1.59-2.58). Similar associations were observed for other symptoms suggestive of asthma. Body mass index was not associated with 'hayfever or nasal allergies', specific IgE to house dust mite, grass or cat or with total IgE in men or women.

CONCLUSION

Reported associations of body mass index with symptoms suggestive of asthma are unlikely to be explained by a higher risk of atopy in the obese. Alternative explanations must be sought.

Classification methods for the identification of 'case' in epidemiological diagnosis of asthma

The identification of the asthmatic 'case' in epidemiological research is a controversial issue. This study was aimed at classifying asthmatic subjects using a statistical decision rule that minimised the misclassification rate with respect to the clinicians' diagnosis. The rule was defined by a combination of predictors that are easily observed in epidemiological studies (asthma-like questions, physiological tests) without necessarily including the clinical opinion of expert physicians. From pooled data on 1103 subjects at the three Italian centres of the European Community Respiratory Health Survey (ECRHS) a post-consensus clinicians' diagnosis of asthma was obtained, and seven predictors were selected from among 18 potential candidates (specificity ranged from 64 to 99%, but sensitivity ranged from 22 to 62%). This data set was processed with tree-structured classifier techniques (the Classification And Regression Trees, CART), classical discriminant analysis (Fisher's Linear Discriminant Function, LDF), and the neural network method (Multi-Layer Perceptron, MLP model). The results suggest that modifications of the 'classification tree' provide a more useful decision rule, sensitive (93%) and specific (85%), than either LDF or MLP. The decision tree is readily interpretable from a clinical perspective and uses five out of the seven predictors (in descending hierarchical order: ever had asthma, current asthma, shortness of breath, atopy and wheezing and breathless). The findings seem to indicate a considerable success with respect to previous epidemiological studies and await repetition in other ECHRS populations.

Mortality of elderly subjects with self-reported asthma in a French cohort, 1991-1996

The objective of this study is to describe the mortality of subjects with self-reported asthma aged 65 and over and to determine risk factors. PAQUID (Personnes Agées QUID) is a prospective cohort of 3777 elderly people, living at home in the South-west of France. The study of subjects with self-reported asthma started at 3 year follow-up by using three epidemiological questions: 'Did you have an attack of wheezing that made you feel short of breath in the last 12 past months?', 'Have you ever had asthma?', 'Did you have at least one asthma attack in the previous 12 months?'. Data on mortality were available at 8-year follow-up. Among the 2348 subjects who responded to these questions, 206 reported symptoms of asthma. Two groups were defined as 'pure asthma' and 'associated asthma' taking into account chronic bronchitis and smoking. Besides a gender difference, there was no statistical difference between those two groups so they were combined in a single group for further analysis. During the 5-year study period, 29.1% of subjects with self-reported asthma vs. 23.8% nonasthmatics died. A Cox model with delayed entry was used to calculate mortality rates. Interaction terms between each of the factors related to mortality and asthmatic status were analyzed to determine risk factors of mortality. Subjects with self-reported asthma had a higher risk of death than nonasthmatics (relative risk (RR): 1.49; 95% confidence interval (CI) 1.1-1.9; p = 0.009). This risk was significant (RR: 1.4; 95% CI: 1.05-1.8; p = 0.02) even after adjustment on morbidity variables. However no specific mortality risk factors were found for subjects with self-reported asthma.

[Identification of new diagnostic categories within bronchial asthma and COPD. A review of traditional classifications]

The overlapping of function test results and clinical symptoms of airway diseases makes it difficult to differentiate sub-categories of diagnoses. Our aim was to identify "occult" categories within the traditional diagnostic labels for bronchial asthma and chronic bronchitis. We studied 211 patients with those diagnoses by lung function testing (spirometry), variability of obstruction (bronchodilator test, peak expiratory flow, and bronchial challenge testing), atopy (prick test, total serum IgE), biological parameters (eosinophil count), frequency of smoking and symptoms. Multivariant analysis was used to group the data (Quick Cluster) and reclassify the subjects based on the selected parametric clusters with factorial analysis of the principal components. This analysis allowed us to identify four types of patients by diagnosis (atopic asthma, asthmatic bronchitis, simple chronic bronchitis and hyperresponsive chronic bronchitis) which we consider to represent the diagnostic categories with clinical relevance and which would overlap and be partially overshadowed by the diagnoses of bronchial asthma and chronic bronchitis.

Epidemiology of allergic occupational diseases induced by Tetranychus urticae in greenhouse and open-field farmers living in a temperate climate area

BACKGROUND

The role of Tetranychus urticae (TU) as an occupational allergen has thus far been investigated only in selected farmer samples.

METHODS

The prevalence of TU-induced sensitization and occupational diseases in a randomized sample of farmers living in a temperate climate area was investigated. Occupational/nonoccupational symptoms, skin prick test (SPT) results with common allergens and TU, specific occupational test results, and greenhouse or open-field sources of TU exposure were assessed. The study design was cross-sectional.

RESULTS

The prevalence of positive SPT to TU was 6%. TU-induced allergic/nonallergic complaints accounted for 65% of farmers with challenge-confirmed occupational disease. In all farmers, sensitization to common allergens was a risk factor for both current occupational and nonoccupational complaints, while TU sensitization was a prominent risk factor for occupational complaints. Furthermore, in SPT-positive farmers, only the presence of seasonal occupational complaints was significantly associated with TU sensitization. Common allergen sensitization was a risk factor for development of TU sensitization, which was more frequent in greenhouse than in open-field workers.

CONCLUSIONS

TU was a common nontraumatic, allergic occupational hazard for farmers. Since occupational seasonal symptoms could be directly related to the presence of TU sensitization, allergy to this mite should be routinely investigated in farmers.

Dietary antioxidants and asthma in adults: population-based case-control study

A protective role for dietary antioxidants in asthma has been proposed. However, epidemiological evidence to implicate antioxidant vitamins is weak, and data on the role of flavonoid-rich foods and antioxidant trace elements are lacking. We carried out a population-based case-control study in South London, UK, to investigate whether asthma is less common and less severe in adults who consume more dietary antioxidants. Participants were aged 16-50 yr and registered with 40 general practices. Asthma was defined by positive responses to a standard screening questionnaire in 1996, and complete information about usual diet was obtained by food frequency questionnaire from 607 cases and 864 controls in 1997. After controlling for potential confounding factors and total energy intake, apple consumption was negatively associated with asthma (odds ratio [OR] per increase in frequency group 0.89 [95% confidence interval [CI]: 0.82 to 0.97]; p = 0.006). Intake of selenium was also negatively associated with asthma (OR per quintile increase 0.84 [0.75 to 0.94]; p = 0.002). Red wine intake was negatively associated with asthma severity. The associations between apple and red wine consumption and asthma may indicate a protective effect of flavonoids. The findings for dietary selenium could have implications for health policy in Britain where intake has been declining.