Determinants of change in airway reactivity over 11 years in the SAPALDIA population study.

We investigated determinants of change in bronchial reactivity in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA), a population-based cohort with wide age range (29-72 yrs at follow-up). The role of sex, age, atopic status, smoking and body mass index (BMI) on percentage change in bronchial reactivity slope from the baseline value was analysed in 3,005 participants with methacholine tests in 1991 and 2002, and complete covariate data. Slope was defined as percentage decline in forced expiratory volume in 1 s from its maximal value per micromole of methacholine. Bronchial hyperreactivity prevalence fell from 14.3 to 12.5% during follow-up. Baseline age was nonlinearly associated with change in reactivity slope: participants aged <50 yrs experienced a decline and those above an increase during follow-up. Atopy was not associated with change, but accentuated the age pattern (p-value for interaction = 0.038). Smoking significantly increased slope by 21.2%, as did weight gain (2.7% increase per BMI unit). Compared with persistent smokers, those who ceased smoking before baseline or during follow-up experienced a significant decrease in slope (-27.7 and -23.9%, respectively). Differing, but not statistically different, age relationships and effect sizes for smoking and BMI between sexes were found. Mean bronchial reactivity increases after 50 yrs of age, possibly due to airway remodelling or ventilation-perfusion disturbances related to cumulative lifetime exposures.

Longitudinal change of prebronchodilator spirometric obstruction and health outcomes: results from the SAPALDIA cohort.

BACKGROUND: Understanding the prognostic meaning of early stages of chronic obstructive pulmonary disease (COPD) in the general population is relevant for discussions about underdiagnosis. To date, COPD prevalence and incidence have often been estimated using prebrochodilation spirometry instead of postbronchodilation spirometry. In the SAPALDIA (Swiss Study on Air Pollution and Lung Disease in Adults) cohort, time course, clinical relevance and determinants of severity stages of obstruction were investigated using prebronchodilator spirometry. METHODS: Incident obstruction was defined as an FEV(1)/FVC (forced expiratory volume in 1 s/forced vital capacity) ratio >or=0.70 at baseline and <0.70 at follow-up, and non-persistence was defined inversely. Determinants were assessed in 5490 adults with spirometry and respiratory symptom data in 1991 and 2002 using Poisson regression controlling for self-declared asthma and wheezing. Change in obstruction severity (defined analogously to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) classification) over 11 years was related to shortness of breath and health service utilisation for respiratory problems by logistic models. RESULTS: The incidence rate of obstruction was 14.2 cases/1000 person years. 20.9% of obstructive cases (n = 113/540) were non-persistent. Age, smoking, chronic bronchitis and non-current asthma were determinants of incidence. After adjustment for asthma, only progressive stage I or persistent stage II obstruction was associated with shortness of breath (OR 1.71, 95% CI 0.83 to 3.54; OR 3.11, 95% CI 1.50 to 6.42, respectively) and health service utilisation for respiratory problems (OR 2.49, 95% CI 1.02 to 6.10; OR 4.17 95% CI 1.91 to 9.13, respectively) at follow-up. CONCLUSIONS: The observed non-persistence of obstruction suggests that prebronchodilation spirometry, as used in epidemiological studies, might misclassify COPD. Future epidemiological studies should consider both prebronchodilation and postbronchodilation measurements and take specific clinical factors related to asthma and COPD into consideration for estimation of disease burden and prediction of health outcomes.

Prevalence of airflow obstruction in smokers and never-smokers in Switzerland.

The aim of the present study was to measure age-specific prevalence of airflow obstruction in Switzerland in smokers and never-smokers using pulmonary function tests and respiratory symptoms from 6,126 subjects participating in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults. The lower limit of normal of the forced expiratory volume in 1 s/forced vital capacity ratio was used to define airflow obstruction. Severity of airflow obstruction was graded according to the recommendations of the Global Initiative for Chronic Obstructive Lung Disease. Prevalence of airflow obstruction ranged from 2.5% in subjects aged 30-39 yrs to 8.0% in those aged ≥ 70 yrs. In multivariate analysis, age (OR 2.8, ≥ 70 yrs versus 30-39 yrs), smoking (OR 1.8) and asthma (OR 6.7) were associated with airflow obstruction. Never-smokers constituted 29.3% of subjects with airflow obstruction. Never-smokers with airflow obstruction were younger, more likely to be male and reported asthma more frequently than obstructive smokers. Obstructive smokers and never-smokers had similar level of symptoms and quality of life impairment. The prevalence of airflow obstruction in Switzerland is similar to other developed countries. Never-smokers account for a third of the prevalence, which is higher proportion than elsewhere. Airflow obstruction in never-smokers deserves attention because of its frequency and its similar health impact to that in smokers.

Sex-specific effect of body weight gain on systemic inflammation in subjects with COPD: results from the SAPALDIA cohort study 2.

Systemic inflammation may mediate the association between chronic obstructive pulmonary disease (COPD) and extrapulmonary comorbidities. We measured high-sensitivity C-reactive protein (hs-CRP) in COPD and quantified the effect modification by body weight change and sex. Using data from the Swiss study on Air Pollution and Lung Diseases in Adults (SAPALDIA; n = 5,479) with measurements of forced expiratory volume in 1 s (FEV(1)), body weight and hs-CRP, we examined the association of hs-CRP and categories of body weight change (lost weight and weight gained 0-5%, 5-9%, 9-14% and >14%) with fast FEV(1) decline. hs-CRP was elevated both in association with fast FEV(1) decline and body weight gain. Subjects with fast FEV(1) decline and weight gain (>14%) had higher hs-CRP (2.0 mg L(-1) for females versus 1.6 mg L(-1) for males). After adjustment for age, smoking, physical activity, hormonal therapy and diabetes, elevated hs-CRP (>3 mg) was found to be more likely in subjects with fast FEV(1) decline (OR(males) 1.38, OR(females) 1.42) and in those with weight gain >14% (OR(males) 2.04, OR(females) 4.51). The association of weight gain and fast FEV(1) decline predicts a higher level of systemic inflammation. Since the effect of weight gain on systemic inflammation is larger in females than in males, weight gain may be a risk factor for extrapulmonary comorbidities in females with COPD.

Sensitisation to Ambrosia in Switzerland: a public health threat on the wait.

BACKGROUND: Ambrosia artemisiifolia (short name = Ambrosia common ragweed) pollen is a potent allergen and has recently been found in Switzerland, spreading from the southwest of the country. The aim of this study is to describe Ambrosia sensitisation rates in the population-based SAPALDIA cohort (Swiss Study on Air Pollution And Lung Diseases In Adults) and to test whether an increase in these rates could be observed. METHODS: Among the 6345 participants from 8 areas who provided blood samples in 1991 and 2002, 5823 had valid results for specific IgE against common inhalant allergens tested with Phadiatop. In 2002 Ambrosia sensitisation was measured and positive tests were analysed for Artemisia vulgaris (mugwort). Blood samples taken in 1991 in Ticino and Geneva were also tested for Ambrosia. RESULTS: Sensitisation rate (Phadiatop) did not increase significantly between the two surveys and sensitisation was found in 30% of the participants. A proportion of 7.9% showed specific IgE to Ambrosia pollen. The sensitisation rate in Lugano and Geneva had not changed substantially since 1991. Among those sensitised to Ambrosia 82% also showed specific IgE against Artemisia, suggesting a high rate of cross-reactivity. Only 1.3% were sensitized to Ambrosia alone. The incidence of asthma or hay fever in participants with specific IgE to Ambrosia pollen was not higher than in the general study population. CONCLUSION: Currently Ambrosia pollen does not appear to be an important cause of inhalant allergies in Switzerland. Sensitisation rates are low and have not increased since 1991. Due to cross-reactivity Ambrosia sensitisation may be a consequence of primary sensitisation to Artemisia. Elimination of Ambrosia plants is nevertheless mandatory to avoid a future increase.

Analysis of the relationship between pollinosis and date of birth in Switzerland.

BACKGROUND: The first months of life may represent a vulnerable period in the development of atopic diseases. The objective of this study was to examine the relationship between the month of birth and the development of birch and grass pollen allergy in the Swiss population. METHODS: Data from the Swiss Study on Air Pollution and Lung Diseases in Adults(SAPALDIA) as well as the Swiss Study on Childhood Allergy and Respiratory Symptoms with Respect to Air Pollution and Climate (SCARPOL) were used. A logistic regression was calculated with grass and birch pollen sensitisation (positive skin prick test) or allergy (positive skin prick test and allergic symptoms) as outcome variables and the season of birth as predictor variable. The contribution of the season of birth on pollinosis was further adjusted for well-known risk factors and potential confounding variables. RESULTS: The logistic regression revealed a significant effect of the season of birth on birch pollen sensitisation and an effect of borderline significance on birch pollen allergy, i.e. subjects born in the pollen season (March to April) showed an increased risk of being sensitised/allergic to birch pollen. The results also indicated a tendency towards an increased risk for subjects born in the grass pollen season (May to June) to develop grass pollen allergy. CONCLUSION: Our results support the hypothesis that the first few months of life constitute a sensitive period, during which inhalative exposure to certain allergens may predispose to the subsequent development of atopic respiratory disease.

Vitamin D supplementation in Swiss infants.

BACKGROUND: Various recent publications reported clinical manifestations of vitamin D deficiency in infants. Furthermore new research revealed additional properties of vitamin D for bone health and in the prevention of chronic diseases. However, prevalence data on actual supplementation rates are scarce. This study reports the prevalence of vitamin D supplementation in infants in Switzerland and presents risk factors for non-supplementation. METHODS: In 2003, mothers of 2861 randomly selected infants aged 0-9 months received a questionnaire on infant feeding, including a question on vitamin D supplementation. The prevalence of vitamin D supplementation was calculated and its dependency on various factors analysed by multiple logistic regression. RESULTS: 64% of the infants had received vitamin D. The regression analysis yielded various significant risk factors for non-supplementation: young maternal age, German language region, Swiss nationality, siblings and breastfeeding. Protective factors were intake of folic acid during pregnancy and professional information on infant feeding. The protective effect of professional information varied significantly by region. CONCLUSIONS: Given that the supplementation of vitamin D is recommended for all infants, the supplementation prevalence in Swiss infants is unsatisfactorily low. Various risk factors were identified and a positive impact of professional counselling on the supplementation rate could be demonstrated. In view of the new evidence emerging on additional preventive properties of vitamin D and the resurgence of rickets, the importance of vitamin D for infant health and ways to improve its promotion must be discussed anew.

Cytokine gene polymorphisms and atopic disease in two European cohorts. (ECRHS-Basel and SAPALDIA).

BACKGROUND: Atopy and allergic phenotypes are biologically characterized by an imbalanced T helper cell response skewed towards a type 2 (TH2) immune response associated with elevated serum immunoglobulin E (IgE) levels. Polymorphisms in cytokine genes might modulate regulation of the TH1/TH2 balance. We thus aimed at reproducing our previous findings from a European study population on the association of various cytokine polymorphisms with self-reported hay fever as well as increased total and specific IgE levels in two comparable study populations. METHODS: Two prospective Caucasian cohorts were used. In the Basel center of the European Community Respiratory Health Survey (ECRHS, n = 418) ten distinct cytokine polymorphisms of putative functional relevance were genotyped. In the Swiss cohort Study on Air Pollution And Lung Disease In Adults (SAPALDIA, n = 6003) two cytokine polymorphisms were genotyped. The associations of these polymorphisms with atopy were estimated by covariance and logistic regression analysis. RESULTS: We confirmed IL4, IL10, IL6 and IL18 as candidate genes for atopic health outcomes. In the large, well-characterized SAPALDIA cohort the IL6(-174G>C) and IL18(-137G>C) polymorphisms were associated with circulating total IgE concentrations in subjects with hay fever. The IL18(-137G>C) polymorphism was also associated with the prevalence of hay fever. CONCLUSION: Comprehensive characterization of genetic variation in extended cytokine candidate gene regions is now needed. Large study networks must follow to investigate the association of risk patterns defined by genetic predisposing and environmental risk factors with specific atopic phenotypes.

[Socioeconomic class as a risk factor for cardiovascular diseases]. / Soziale Schicht als kardiovaskulärer Risikofaktor.

It's been known for a long time, that certain diseases are more frequent in lower socioeconomic classes. But knowledge about the nature of this association, its main risk factors and how to improve health outcomes in lower social groups is still limited. Social class has been defined by different indicators by e.g. occupation and job position or the highest school qualification achieved. For international comparisons different classifications such as "The Registrar General's Social Class Classification " or the "International Standard Classification of Education" have been used. Several European Studies show a higher prevalence of cardiovascular diseases and cardiovascular risk factors including smoking, obesity, physical inactivity, hypertension and hypercholesterolemia in lower socioeconomic classes. But this studies also show that all socioeconomic groups have access to medical services. The Data from the Swiss Health Survey show the distribution of cardiovascular risk factors and diseases by three levels of education: Behaviouralfactors such as smoking, obesity and physical inactivity are more commonly present in the lower socioeconomic groups. People with a lower educational level visit their GP more often, whereas people with a higher level of educational consult specialists more frequently. Medical services are often used to check of blood pressure, blood sugar and cholesterol. An indication of state of health may be shown by medication and treatment for cardiovascular disease which is more prevalent in lower socioeconomic groups. The present discussion of explanations of the poorer state of health in lower socioeconomic groups goes beyond the classical risk factors for cardiovascular disease. Studies have shown that after the correction for risk factors a correlation remains between social class and state of health. It is believed, that psychosocial factors such as self-esteem, control in the workplace or coping-strategies play an additional important role in staying healthy. Therefore prevention of cardiovascular disease should not be restricted to minimisation of risk factors or to the measurement of certain blood-values and treatments. Efforts must also go into creating the conditions for a healthier life and promote possibilities for healthier behaviour in all socioeconomic classes.

Acute effects of ambient ozone on respiratory function of Swiss schoolchildren after a 10-minute heavy exercise.

This study was conducted in Switzerland between May and October 1989 to assess possible decrements in lung function occurring as a result of 10 minute exposure to ambient air containing different ozone concentrations. Once a month, 128 children in two different areas of Southern Switzerland (Chiasso and Aurigeno) had a pulmonary function test before and after a standardized 10 minute exercise (pulse rate, 170/min) on a cycle ergometer, outdoors. Ozone concentrations were similar in both areas, ranging from 40 to 157 micrograms/m3 (1/2h means) during the exercise tests. The two communities differed with respect to long-term average pollution levels. The mean NO2 concentration over the six months study period was 70 micrograms/m3 in Chiasso and 18 micrograms/m3 in rural Aurigeno. Of the eligible children 85% participated and attended 4-6 tests. Parents completed a standardized questionnaire on family background, home characteristics and the child's early and present illness history. A total of 500 acceptable pairs of spirograms and corresponding ozone concentrations (average 3.8 per child) were available for analysis. Regressions of each individual's pre-post differences of FVC, FEV1 and peak flow on ozone concentrations measured during the outdoor exercise indicated that elevated ozone levels significantly reduced peak flow values. Adjustments for temperature and relative humidity increased the magnitude of the peak flow slopes. The average adjusted regression coefficient for delta-peak flow on ozone was -2.28 mL/s/micrograms/m3 (95% CI, -0.57 -3.99). It is noteworthy that the observed relationships occurred at ozone concentrations below 160 micrograms/m3 and after an exercise duration of only 10 minutes.

Body mass index in glaucoma.

PURPOSE: To compare body mass index (BMI) of patients with open-angle glaucoma or normal-tension glaucoma with BMI in control subjects. METHODS: BMI was calculated for 288 control subjects, 42 patients with open-angle glaucoma with treated intraocular pressure (IOP) higher than 21 mmHg, 87 patients with open-angle glaucoma with progression of glaucomatous damage despite IOP less than 21 mmHg, and 57 patients with normal-tension glaucoma. RESULTS: There was no statistical difference in BMI between patients with glaucoma and control subjects. If anything, there was a tendency for patients with glaucoma to have a lower BMI than control subjects. CONCLUSION: These data show that obesity seems not to be a risk factor for glaucoma.

Screening mammographies in Switzerland: what makes female and male physicians prescribe them?

QUESTION UNDER STUDY: Physicians play a key role in motivating women to undergo mammography screening. In 1998 we assessed Swiss physicians' attitudes to mammography screening and their prescription behaviour in this regard. METHODS: All female physicians and every second male physician aged 50-69 who were either not board-certified or board-certified in general practice, internal medicine, or obstetrics/gynaecology were sent a questionnaire. The response rate was 50% and thus 738 questionnaires were included in this study. Of the study population 39% were female and 61% male physicians. The distribution of professional backgrounds was: 27% board-certified general practitioners; 23% board-certified internists; 11% board-certified gynaecologists; 39% not board-certified. RESULTS: 55% of all study participants were in favour of a mammography screening programme for women aged over 50 in Switzerland, but breast self-examination and clinical breast examination were judged to have a more positive impact on breast cancer survival. Among clinically practising physicians, 22% reported generally prescribing biannual screening mammographies for women aged 50-69. Irrespective of other determinants, physicians from the Italian- and French-speaking parts of Switzerland prescribed screening mammographies more often than their colleagues from the German-speaking part (odds ratio [OR] 2.5; 95% confidence interval [CI] 1.5-4.2). Clinical practice in obstetrics/gynaecology (OR 2.4; CI 1.3-4.2) and a self-reported high level of knowledge concerning mammography screening (OR 1.9; CI 1.1-3.2) were also positively associated with the prescription of screening mammography. CONCLUSIONS: Since mammography screening programmes exist in only three French-speaking cantons of Switzerland (VS; VD; GE), the gap in prescription of screening mammographies between French/Italian- and German-speaking regions must be narrowed to prevent a higher prevalence of side effects from opportunistic screening among German-speaking women. There is a need to educate physicians and the political community regarding the risks and benefits of mammography screening.

Occupational exposure to inhalative irritants and methacholine responsiveness.

OBJECTIVES: Occupational exposures to inhalative irritants have been associated with an increased reporting of respiratory symptoms in previous studies. Methacholine responsiveness represents a continuous measure of airway responsiveness. As such, it may be less subject to recall bias and more sensitive to detecting effects of occupational exposure on airways. Such effects may be stronger among atopic persons. The objective of the study was to examine the relationship between self-reports of occupational exposure to dusts, gases, vapors, aerosols, and fumes and methacholine responsiveness. METHODS: A sample was studied of never smokers (N=3044) chosen randomly from 8 areas in Switzerland. Atopy was defined as any positive skin test to 8 inhalative allergens. Nonspecific bronchial reactivity was tested using methacholine chloride and quantified by calculating the slope of the dose-response. RESULTS: The methacholine slopes were 19% [95% confidence interval (95% CI) 6-32] higher for never smokers with exposure to dusts, fumes, vapors, gases, or aerosols than for the unexposed group. When only atopic never smokers were examined. the increase was larger (37%, 95% CI 7-75), and for persons with >2 positive skin prick tests the effect was still higher (42%, 95% CI -1.5-104). Exposure to vapors and aerosols was strongly associated with increased methacholine slopes among the atopic subjects. CONCLUSIONS: Occupational exposure, particularly to dusts and fumes, was associated with increased bronchial reactivity in never smokers in this study. The magnitude of the effect was larger among atopic subjects.

Personal exposure to nitrogen dioxide in Switzerland. SAPALDIA team. Swiss Study on Air Pollution and Lung Diseases in Adults.

Home indoor and outdoor levels, and personal exposures to NO2 were determined for more than 500 subjects in a subpopulation of SAPALDIA by using passive samplers. The overall personal NO2 average was found to be 27 micrograms m-3, the overall indoor average 21 micrograms m-3 and the overall outdoor average 31 micrograms m-3. Personal NO2 levels ranged between the outdoor and indoor levels, with the exception of study areas with low NO2 concentrations. In the winter, the indoor/outdoor ratios were lower than in the summer. Outdoor NO2 levels were higher in winter. In some study areas, indoor NO2 levels were lower in the winter than in the summer due to reduced ventilation but this was not consistent. Personal NO2 concentrations were very similar during all seasons. Gas-cooking and smoking were important factors for elevated indoor and personal NO2 levels (contribution: 5 micrograms m-3, 2 micrograms m-3, respectively). Personal exposure to NO2 correlated best with the indoor NO2 concentrations.

Breast cancer screening: should it be introduced and how?

This brief discussion of the papers by Gästrin and Paccaud is looking at differences in the results of different study types. Introducing screening means changing unsystematic to systematic screening: only the latter has been shown to be effective. The comparison between randomized trials, and follow-up of acceptors only, suggests that the non-acceptors have much higher risks. Programmes should therefore concentrate on trying to reach non-acceptors. The combination of mammographic screening and self-examination in a randomized trial could add to the existing evidence.

[The development of children who were breast-fed for a long time]. / Die Entwicklung lange gestillter Kinder.

In the Basle Kindergarten study children who were breast-fed for more than 18 weeks were compared in their development with children who had never received breast milk. The children were grouped according to their origin in Italian and Swiss children. The difference in height between breast-fed and non breastfed children was found to be significative in Italian children. Breast-fed children had higher cholesterol levels than children who had never been suckled.

[Reproductive mortality in Switzerland between 1952 and 1982]. / Reproduktive Mortalität in der Schweiz zwischen 1952 und 1982.

Reproductive mortality includes mortality attributable to pregnancy and childbirth and its sequelae, termination of pregnancy and contraception. The latter is mainly due to an increase of cardiovascular diseases in oral contraceptive users. An estimate of reproductive mortality in Switzerland is based on available figures on cardiovascular mortality, smoking and use of oral contraceptives. The reproductive mortality has been steadily declining since 1952 in the age group of 15-34, a stagnation of this risk can be observed for women over 35 since 1962. Theoretically this stagnation might be due to the use of oral contraceptives and an increase in smoking.

[Sex differences in health and health behavior]. / Geschlechtsunterschiede in Gesundheit und Gesundheitsverhalten.

The higher life expectancy of women is contrasting with the higher female morbidity known from health interview surveys and statistics on use of health services. In the Swiss Health Survey SOMIPOPS, women report higher rates of complaints, diagnoses, chronical impairments and psychic illness, more frequent restrictions of their daily activities for health reasons and a worse overall health status. In men, only higher rates of indicators related to respiratory diseases and accidents were found. On the other hand, women have a stronger health orientation in daily life habits, seem to differ from men in health perception, are more willing to treat symptoms and use health services more often for preventive reasons. Comparison of survey and examination data reveal a different health perception and a higher female willingness to treat symptoms. The question is arised whether the different health behaviour have long-term effects, especially on life-expectancy.

[Air pollution and respiratory tract diseases in children]. / Luftverschmutzung und Atemwegserkrankungen bei Kindern.

Children are particularly susceptible for respiratory diseases, this is why studies on health effects of air pollution are often investigating children. Children have some other advantages: they do not smoke and they are not exposed to potentially noxious environment at work, also they spend their time fairly constantly in their usual environment. Studies from England and the United States show higher incidence of acute and a higher prevalence of chronic respiratory disease in children living in areas with higher concentration of air pollutants than in groups living in areas with lower concentration of pollutants. Some studies show these effects in concentration similar to those observed in swiss townships. Nevertheless specific studies in Switzerland are indicated in order to investigate the effect of the particular composition of pollutants in Switzerland and to assess effects of future possible improvements of the air quality.

[Influences on neuromotor development of 5 to 10-year-old children in Basel]. / Einflüsse auf die neuromotorische Entwicklung 5- bis 10jähriger Basler Kinder.

In a longitudinal study concerning somatic, psychic, and social development of children in Basle, the neuromotor development at the age of 5 and 10 years was examined. Motor retardation shows significant correlations with psychic and social development. The way 5 year old children of working mothers have been taken care of showed a significant influence on motor development. A retardation in motor development of kindergarten children indicates an increased probability for further retardations in school age, too.