Ursula Ackermann-Liebrich

Prevalence of Atopy and Pollinosis in the Adult Population of Switzerland (SAPALDIA Study)

The Swiss SAPALDIA study is a large multicenter cross-sectional study initiated in 1991 to evaluate the relationship between environment and respiratory symptoms and diseases in adults, and included subjects from eight areas in Switzerland with distinctive environmental characteristics. We present here prevalence data for atopy, pollinosis and atopic asthma obtained from a random sample of 8,357 adults (18-60 years) assessed by standardized computer-based interview as well as by allergy skin prick tests (SPTs) (performed with Phazet) to grass, birch and Parietaria pollen, house dust mite, cat and dog epithelia and the moulds Alternaria and Cladosporium and by an in vitro allergy screen test (Phadiatop CAP FEIA system). On the basis of a positive Phadiatop (total 28.9%; males 32.9%, females 25.0%; p < 0.001) and/or a positive SPT (total 23%; males 25.0%, females 20.8%; p < 0.001), 32.3% of the study population were considered atopic (males 35.7%, females 28.8%; p < 0.001). Concerning the prevalence of skin sensitization (SPT wheal > or = 3 mm), the highest rate was observed for grass (12.7%), followed by house dust mite (8.9%), silver birch (7.9%), cat (3.8%) and dog (2.8%), whereas moulds and Parietaria elicited less than 1% positive SPTs. The prevalence of atopic rhinitis (rhinitis symptoms associated with atopy) was 13.5% (males 14.3%, females 12.6%; p < 0.05) and the prevalence of current hay fever varied between 9.1% (questionnaire answer and a positive SPT to at least one pollen), 11.2% (questionnaire answer and presence of atopy) to 14.2% (questionnaire answer only) with no significant difference by sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of current and childhood exposure to cat and atopic sensitization

BACKGROUND Clinical and population studies have shown that exposure and sensitization to allergens derived from furred pets, particularly cats, represent an important risk factor of allergic respiratory disease and also a significant risk factor for asthma. OBJECTIVE In the framework of the multicenter European Community Respiratory Health Survey an analysis of the association of current and childhood exposure to cat with atopic sensitization to cat was conducted. METHODS This study included cross-sectional data from 35 centers representing 16 countries. Altogether, 18,097 subjects were included, of whom 13,509 (75%) provided a blood sample for the measurement of specific IgE. Exposure data and data for potential confounders were extracted from an interviewer-led questionnaire. RESULTS The prevalence of sensitization to cat (serum specific IgE >0.35 kU/L) was 9%. Among those who did not report allergic symptoms in the presence of pets or house dust, those who owned cats were significantly more likely to be sensitized to cats than were those who did not (odds ratio [95% confidence interval] 1.57 [1.20-2.06]. Childhood exposure to pets including cats was associated with lower sensitization to cats in adulthood, particularly among those with a positive family history of atopy (odds ratio [95% confidence interval] 0.68 [0.51-0.93]. Positive correlations were found between the community prevalence of cat and the prevalences of sensitization to cat, respiratory symptoms, physician-diagnosed asthma, and current asthma medication. CONCLUSIONS Current cat ownership represents a significant risk for sensitization to cat if cats are allowed indoors. Our results support the hypothesis that childhood exposure to pets, including cats, might modulate immunologic mechanisms and reduce sensitization to cat in adulthood. The significant correlation found between the community prevalence of cat ownership and community prevalence of specific sensitization to cat represents the first documentation of such a relationship.

Do Baby-Friendly Hospitals Influence Breastfeeding Duration on a National Level?

Objectives. In Switzerland, the Baby-Friendly Hospital Initiative (BFHI) proposed by the United Nations Childrens Fund (UNICEF) was introduced in 1993 to promote breastfeeding nationwide. This study reports results of a national study of the prevalence and duration of breastfeeding in 2003 throughout Switzerland and analyzes the influence of compliance with UNICEF guidelines of the hospital where delivery took place on breastfeeding duration. Methods. Between April and September 2003, a random sample of mothers who had given birth in the past 9 months in Switzerland received a questionnaire on breastfeeding and complementary feeding. Seventy-four percent of the contacted mothers (n = 3032) participated; they completed a 24-hour dietary recall questionnaire and reported the age at first introduction of various foods and drinks. After excluding questionnaires with missing information relevant for the analyses, we analyzed data for 2861 infants 0 to 11 months of age, born in 145 different health facilities. Because it was known whether each child was born in a designated baby-friendly hospital (45 hospitals) or in a health facility in the process of being evaluated for BFHI inclusion (31 facilities), we were able to assess a possible influence of the BFHI on breastfeeding success. For this purpose, we merged individual data with hospital data on compliance with the UNICEF guidelines, from a data source collected on an annual basis for quality monitoring of designated baby-friendly hospitals and health facilities in the evaluation process. Information on actual compliance with the guidelines allowed us to investigate the relationship between breastfeeding outcomes and compliance with UNICEF guidelines. We were also able to compare the breastfeeding results with those for non–baby-friendly health facilities. The comparison was based on median durations of exclusive, full, and any breastfeeding calculated for each group. To allow for other known influencing factors, we calculated adjusted hazard ratios by using Cox regression; we also conducted logistic regression analyses with the 24-hour dietary recall data, to calculate adjusted odds ratios for validation of results from the retrospectively collected data. Results. In 2003, the median duration of any breastfeeding was 31 weeks at the national level, compared with 22 weeks in 1994, and the median duration of full breastfeeding was 17 weeks, compared with 15 weeks in 1994. The proportion of exclusively breastfed infants 0 to 5 months of age was 42% for infants born in baby-friendly hospitals, compared with 34% for infants born elsewhere. Breastfeeding duration for infants born in baby-friendly hospitals, compared with infants born in other hospitals, was longer if the hospital showed good compliance with the UNICEF guidelines (35 weeks vs 29 weeks for any breastfeeding, 20 weeks vs 17 weeks for full breastfeeding, and 12 weeks vs 6 weeks for exclusive breastfeeding). To control for differences in the study population between the different types of health facilities, hazard and odds ratios were calculated as described above, taking into account socioeconomic and medical factors. Although the analysis of the retrospective data showed clearly that the duration of exclusive and full breastfeeding was significantly longer if delivery occurred in a baby-friendly hospital with high compliance with the UNICEF guidelines, whereas this effect was less prominent in other baby-friendly health facilities, this difference was less obvious in the 24-hour recall data. Only for the duration of any breastfeeding could a positive effect be seen if delivery occurred in a baby-friendly hospital with high compliance with the UNICEF guidelines. Known factors involved in the evaluation of baby-friendly hospitals showed the expected influence, on the individual level, on duration of exclusive, full, and any breastfeeding. If a child had been exclusively breastfed in the hospital, the median duration of exclusive, full, and any breastfeeding was considerably longer than the mean for the entire population or for those who had received water-based liquids or supplements in the hospital. A positive effect on breastfeeding duration could be shown for full rooming in, first suckling within 1 hour, breastfeeding on demand, and also the much-debated practice of pacifier use. After controlling for medical problems before, during, and after delivery, type of delivery, well-being of the mother, maternal smoking, maternal BMI, nationality, education, work, and income, all of the factors were still significantly associated with the duration of full, exclusive, or any breastfeeding. Conclusions. Our results support the hypothesis that the general increase in breastfeeding in Switzerland since 1994 can be interpreted in part as a consequence of an increasing number of baby-friendly health facilities, whose clients breastfeed longer. Nevertheless, several alternative explanations for the longer breastfeeding duration for deliveries that occurred in baby-friendly hospitals can be discussed. In Switzerland, baby-friendly hospitals actively use their certification by UNICEF as a promotional asset. It is thus possible that differences in breastfeeding duration are attributable to the fact that mothers who intend to breastfeed longer would choose to give birth in a baby-friendly hospital and these mothers would be more willing to comply with the recommendations of the UNICEF guidelines. Even if this were the case, however, this selection bias would not explain the differences in breastfeeding duration between designated baby-friendly health facilities with higher compliance with the UNICEF guidelines and those with lower compliance. Especially this last point strongly supports a beneficial effect of the BFHI, because mothers do not know how well hospitals comply with the UNICEF program. The fact that breastfeeding rates have generally improved even in non–baby-friendly health facilities may be indirectly influenced by the BFHI; its publicity and training programs for health professionals have raised public awareness of the benefits of breastfeeding, and the number of professional lactation counselors has increased continuously. Breastfeeding prevalence and duration in Switzerland have improved in the past 10 years. Children born in a baby-friendly health facility are more likely to be breastfed for a longer time, particularly if the hospital shows high compliance with UNICEF guidelines. Therefore, the BFHI should be continued but should be extended to include monitoring for compliance, to promote the full effect of the BFHI.

Exposure to motor vehicle traffic and allergic sensitization

We examined the association between the presence of an allergic sensitization and seasonal allergic diseases or symptoms and the exposure to road traffic in Basel, Switzerland. Traffic counts at the domiciles of subjects ranged from 24 to 32,504 cars per 24 hours, with a median of 1,624. To investigate the relation of road traffic and allergies, we matched the data of the traffic inventory of Basel with those of the 820 participants of the SAPALDIA study (Swiss Study on Air Pollution and Lung Diseases in Adults), ages 18-60 years, who had completed a detailed respiratory health questionnaire and had undergone allergy testing (skin prick tests and serologic examinations). We observed a positive association with a sensitization to pollen that was most pronounced among persons with a duration of residence of at least 10 years. The odds ratios (adjusted for educational level, smoking behavior, number of siblings, age, sex, and family history of atopy) for cars, contrasting four exposure categories with the lowest quartile as referent category, were 1.99 [95% confidence interval (CI) = 0.91-4.38], 2.47 (95% CI = 1.06-5.73), and 2.83 (95% CI = 1.26-6.31). These results suggest that living on busy roads is associated with a higher risk for a sensitization to pollen and could possibly be interpreted as an indication for interactions between pollen and air pollutants. We did not, however, find a similar relation between motor vehicle traffic and hay fever or seasonal allergic symptoms, and we saw no trend that increasing traffic exposure was associated with a rise in sensitization rates to indoor allergens.

Smoking cessation, lung function, and weight gain : a follow-up study

BACKGROUND Only one population-based study in one country has reported effects of smoking cessation and weight change on lung function, and none has reported the net effect. We estimated the net benefit of smoking cessation, and the independent effects of smoking and weight change on change in ventilatory lung function in the international European Community Respiratory Health Survey. METHODS 6654 participants in 27 centres had lung function measured in 1991-93, when aged 20-44 years, and in 1998-2002. Smoking information was obtained from detailed questionnaires. Changes in lung function were analysed by change in smoking and weight, adjusted for age and height, in men and women separately and together with interaction terms. FINDINGS Compared with those who had never smoked, decline in FEV1 was lower in male sustained quitters (mean difference 5.4 mL per year, 95% CI 1.7 to 9.1) and those who quit between surveys (2.5 mL, -1.9 to 7.0), and greater in smokers (-4.8 mL, -7.9 to -1.6). In women, estimates were 1.3 mL per year (-1.5 to 4.1), 2.8 mL (-0.8 to 6.3) and -5.1 mL (-7.5 to -2.8), respectively. These sex differences were not significant. FEV1 changed by -11.5 mL (-13.3 to -9.6) per kg weight gained in men, and by -3.7 mL per kg (-5.0 to -2.5) in women, which diminished the benefit of quitting by 38% in men, and by 17% in women. INTERPRETATION Smoking cessation is beneficial for lung function, but maximum benefit needs control of weight gain, especially in men.

Increase in diagnosed asthma but not in symptoms in the European Community Respiratory Health Survey

Background: Information on the epidemiology of asthma in relation to age is limited and hampered by reporting error. To determine the change in the prevalence of asthma with age in young adults we analysed longitudinal data from the European Community Respiratory Health Survey. Methods: A self-administered questionnaire was completed by 11 168 randomly selected subjects in 14 countries in 1991–3 when they were aged 20–44 years and 5–11 years later from 1998 to 2003. Generalised estimating equations were used to estimate net change in wheeze, nocturnal tightness in chest, shortness of breath, coughing, asthma attacks in the last 12 months, current medication, “diagnosed” asthma, and nasal allergies. Results: Expressed as change in status per 10 years of follow up, subjects reporting asthma attacks in the previous 12 months increased by 0.8% of the population (95% CI 0.2 to 1.4) and asthma medication by 2.1% (95% CI 1.6 to 2.6), while no statistically significant net change was found in reported symptoms. Reported nasal allergies increased, especially in the youngest age group. Conclusions: As this cohort of young adults has aged, there has been an increase in the proportion treated for asthma but not in the proportion of those reporting symptoms suggestive of asthma. Either increased use of effective treatments has led to decreased morbidity among asthmatic subjects or those with mild disease have become more likely to label themselves as asthmatic.

Is age at menopause increasing across Europe? : results on age at menopause and determinants from two population-based studies

Objective: To investigate the variability and determinants of menopause age in two European cohort studies, the European Respiratory Health Survey and the Swiss Air Pollution and Lung Disease in Adults Cohort. Methods: Age at menopause was estimated in 5,288 women, aged 30 to 60 years, randomly selected in nine European countries between 1998 and 2002. Determinants of natural and surgically induced menopause were investigated by Cox regression and heterogeneity by meta-analysis. Follicle-stimulating hormone and luteinizing hormone levels were assessed in a subsample. Results: A quarter of the women were postmenopausal by age 50.8 years. Median age of natural menopause was 54 years. Hormone levels were within expected ranges for premenopausal and postmenopausal women. Surgically induced menopause was highly prevalent (22%-47%), associated with earlier timing of menopause. Determinants of earlier menopause were current smoking (hazard ratio [HR], 1.59; 95% CI, 1.27-1.98), body mass index greater than 30 kg/m2 (HR, 1.32; 95%, CI, 1.02-1.70), and low physical activity (HR, 1.37; 95%, CI, 1.12-1.67). The determinant for later menopause was multiparity (HR, 0.74; 95% CI, 0.62-0.89). Predictors were similar for naturally and surgically induced menopause. Oral contraceptive use yielded heterogeneous effects on timing of menopause. Later birth was associated with later menopause (HR, 0.934; 95% CI, 0.91-0.96). This evidence of a secular trend is heterogeneous across countries. Conclusions: Age at menopause varies across Europe, shifting toward higher ages. This secular trend seems paradoxical because several adult determinants, that is, overweight, smoking, sedentarity, and nulliparity, associated with early menopause are on the rise in Europe. The heterogeneity of the secular trend suggests additional country-specific factors not included in the study, such as improved childhood nutrition and health, that have an influence on reproductive aging.

Improvements in PM10 Exposure and Reduced Rates of Respiratory Symptoms in a Cohort of Swiss Adults (SAPALDIA)

RATIONALE Reductions in mortality following improvements in air quality were documented by several studies, and our group found, in an earlier analysis, that decreasing particulate levels attenuate lung function decline in adults. OBJECTIVES We investigated whether decreases in particulates with an aerodynamic diameter of less than 10 microm (PM10) were associated with lower rates of reporting respiratory symptoms (i.e., decreased morbidity) on follow-up. METHODS The present analysis includes 7,019 subjects who underwent detailed baseline examinations in 1991 and a follow-up interview in 2002. Each subject was assigned model-based estimates of average PM10 during the 12 months preceding each health assessment and the difference was used as the exposure variable of interest (DeltaPM10). Analyses were stratified by symptom status at baseline and associations between DeltaPM10 and change in symptom status during follow-up were adjusted for important baseline characteristics, smoking status at follow-up, and season. We then estimated adjusted odds ratios for symptoms at follow-up and numbers of symptomatic cases prevented due to the observed reductions in PM10. MEASUREMENTS AND MAIN RESULTS Residential exposure to PM10 was lower in 2002 than in 1991 (mean decline 6.2 microg/m3; SD = 3.9 microg/m3). Estimated benefits (per 10,000 persons) attributable to the observed changes in PM10-levels were: 259 (95% confidence interval [CI]: 102-416) fewer subjects with regular cough, 179 (95% CI, 30-328) fewer subjects with chronic cough or phlegm and 137 (95% CI, 9-266) fewer subjects with wheezing and breathlessness. CONCLUSIONS Reductions in particle levels in Switzerland over the 11-year follow-up period had a beneficial effect on respiratory symptoms among adults.

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.

Clinical diagnosis of current asthma: predictive value of respiratory symptoms in the SAPALDIA study

Bronchial asthma is a very common disease which often remains underdiagnosed. The aim of this study was to determine the predictive value of the most common respiratory symptoms and to explore the best symptom combinations to predict diagnosis of asthma. A questionnaire comprising common respiratory symptoms was submitted to 9,651 subjects aged 18-60 yrs, randomly selected from the Swiss population, of whom 225 subjects (2.3%) had current asthma as confirmed by their general practitioner. Based on these data the authors calculated the predictive values of single symptoms and symptom combinations to diagnose asthma. Wheezing was the most sensitive single symptom (sensitivity 75%). Simple symptoms such as wheezing with dyspnoea, chronic phlegm or chronic cough had specificity greater than 95%. Wheezing with dyspnoea (WD) or nocturnal dyspnoea (ND) had the best positive predictive value (PPV) as isolated symptoms (24% and 21%, respectively). When combining symptoms, wheezing associated with daily dyspnoea at rest or nocturnal dyspnoea showed the best PPV (42% and 39%, respectively), almost double single symptoms such as WD or ND. Wheezing associated with at least two of the three nocturnal symptoms (nocturnal dyspnoea, nocturnal cough or nocturnal chest tightness) had a sensitivity of 80% to diagnose asthma. In conclusion, respiratory symptoms obtained by medical history are reliable predictors of asthma. The findings suggest that particular combinations of symptoms are clinically useful in the differential diagnosis of asthma.