Creating a specialist physician workforce in low-resource settings: reflections and lessons learnt from the East African Training Initiative.

Many African countries have extremely low ratios of physicians to population, and there are very, very few specialists. This leaves most patients without access to specialised care, and importantly also leaves many countries with insufficient expertise to properly evaluate the burden of illness and the needs of the population overall. The challenges to training a specialised physician workforce in resource-limited settings are many, and they go far beyond the (relatively simple) task of transmission of clinical skills. We initiated a capacity-building programme to train pulmonary physicians in Ethiopia, a country of 105 million persons with a high burden of lung disease that had no prior existing training programme in pulmonary medicine. Using volunteer faculty from the USA and Europe, we have provided high-quality training and established a cohort of pulmonary specialists there. We have identified several components of training that go beyond clinical skills development but which we feel are crucial to sustainability. These components include the delineation of viable career pathways that allow professional growth for subspecialist physicians and that support the permanent establishment of a local faculty; the development of important non-clinical skills, including leadership and pedagogical techniques; training in clinical research methodologies; and the development of mechanisms to amplify the impact of a still relatively small number of specialised physicians to address the needs of the population generally. Our programme, the East African Training Initiative, has successfully addressed many of these challenges and we hope that it can be replicated elsewhere.

Factors associated with cessation of smoking among Swiss adults between 1991 and 2011: results from the SAPALDIA cohort.

INTRODUCTION: Smoking is still the most preventable cause of disease and premature death in Switzerland, as elsewhere. We aimed to assess the main determinants of smoking cessation in the population-based cohort of SAPALDIA (Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults). METHODS: The SAPALDIA study was initiated in 1991 with 9651 participants aged 18 to 60 years from eight areas (S1). Follow-up assessments were conducted in 2002 (S2; 8047 participants) and 2010/11 (S3; 6088 participants). At each survey, detailed information on health and potential health-related factors was collected and lung function measured. Using logistic regression, we assessed predictors of smoking cessation between S1 and S2 and between S2 and S3. RESULTS: In both periods, highest educational level (summary odds ratio [OR] 1.49, 95% confidence interval [CI] 1.08-2.06; ref. lowest level), FEV1/FVC <0.5 (OR 6.19, 95% CI 2.44-15.7, ref. FEV1/FVC ≥0.7), higher age in men (OR 1.02, 95% CI 1.01-1.03, per year) and overweight (OR 1.38, 95% CI 1.16-1.64) were significant predictors of smoking cessation. Nicotine dependence (OR 0.97, 95% CI 0.96-0.98, per cigarette smoked a day) and female sex between age 45 and 60 (e.g., OR 0.74, 95% CI 0.61-0.91, at age 50) were negatively associated with smoking cessation. Moreover, smokers at S2 reporting a diagnosis of depression were less likely to quit smoking by S3 (OR 0.53, 95% CI 0.30-0.93). CONCLUSIONS: Prospective tobacco control policies in Switzerland should be addressed to women, younger persons and persons of lower education.

An official American Thoracic Society workshop report: Climate change and human health.

This document presents the proceedings from the American Thoracic Society Climate Change and Respiratory Health Workshop that was held on May 15, 2010, in New Orleans, Louisiana. The purpose of the one-day meeting was to address the threat to global respiratory health posed by climate change. Domestic and international experts as well as representatives of international respiratory societies and key U.S. federal agencies convened to identify necessary research questions concerning climate change and respiratory health and appropriate mechanisms and infrastructure needs for answering these questions. After much discussion, a breakout group compiled 27 recommendations for physicians, researchers, and policy makers. These recommendations are listed under main issues that the workshop participants deemed of key importance to respiratory health. Issues include the following: (1) the health impacts of climate change, with specific focus on the effect of heat waves, air pollution, and natural cycles; (2) mitigation and adaptation measures to be taken, with special emphasis on recommendations for the clinical and research community; (3) recognition of challenges specific to low-resource countries when coping with respiratory health and climate change; and (4) priority research infrastructure needs, with special discussion of international needs for cooperating with present and future environmental monitoring and alert systems.

Early versus late pulmonary rehabilitation in chronic obstructive pulmonary disease patients with acute exacerbations: a randomized trial.

BACKGROUND: Around the world, the timing of referral of chronic obstructive pulmonary disease (COPD) patients for pulmonary rehabilitation differs from immediately after exacerbation (early) to later on when patients are in a stable state (late). There are no trials comparing the different time points of referral for pulmonary rehabilitation. OBJECTIVES: Our aim was to compare the effects of early and late pulmonary rehabilitation on exacerbation rates and health-related quality of life (HRQOL) in COPD patients with exacerbations. METHODS: We randomized COPD patients (Global Initiative for Chronic Obstructive Lung Disease stages II-IV) with a recent exacerbation to early (within 2 weeks) or late pulmonary rehabilitation (starting 6 months after randomization and in a stable state). The primary outcome was the exacerbation rate over 18 months, and secondary outcomes included HRQOL and mortality. We used multivariate analyses and an intention-to-treat analysis approach. RESULTS: We randomized 36 patients to pulmonary rehabilitation. On average, patients with early rehabilitation (n = 19) had 2.61 (SD 2.96) exacerbations requiring systemic corticosteroids and/or antibiotics, compared to 2.77 (SD 3.41) in patients with late rehabilitation (adjusted incidence rate ratio 0.83, 95% confidence interval 0.43-1.63; p = 0.60). Over the 18-month period, patients with late rehabilitation experienced more dyspnea (difference on Chronic Respiratory Questionnaire dyspnea domain 0.74 and on the Medical Research Council dyspnea scale 0.37), but neither these differences nor any difference in HRQOL domains reached statistical significance. CONCLUSIONS: We did not find any statistically significant differences between early and late pulmonary rehabilitation. However, our trial indicates that early rehabilitation may lead to faster recovery of HRQOL after exacerbations compared to rehabilitation later on when patients are in a stable state.

[Tuberculosis in Switzerland]. / Tuberkulose in der Schweiz.

Tuberculosis (TB) is currently a rare disease in Switzerland (2.8 per 100'000 native Swiss), but is still more prevalent in some population groups especially among migrants. After more than a century on the decrease, from 2007 to 2009 the TB cases have increased from 478 to 556 for unknown reasons. The occurrence of multidrug-resistant forms (1.4 % MDR- TB) and the frequently late diagnosis represent challenges for the medical profession and the public health authorities. The Swiss Lung Associations are engaged with contact examinations and therapy of TB cases and support a "TB Manual" with guidelines and a TB Hotline.

[Smoking history worldwide--cigarette smoking, passive smoking and smoke free environment in Switzerland]. / Die Geschichte des Rauchens--wie Nichtrauchen wieder gesellschaftsfähig wird.

After the invention of the cigarette 1881 the health consequences of active smoking were fully known only in 1964. Since 1986 research findings allow increasingly stronger conclusions about the impact of passive smoking on health, especially for lung cancer, cardiovascular and respiratory disease in adults and children and the sudden infant death syndrome. On the basis of current consumption patterns, approximately 450 million adults will be killed by smoking between 2000 and 2050. At least half of these adults will die between age 30 and 69. Cancer and total deaths due to smoking have fallen so far only in men in high-income countries but will rise globally unless current smokers stop smoking before or during middle age. Higher taxes, regulations on smoking, including 100 % smoke free indoor spaces, and information for consumers could avoid smoking-associated deaths. Irland was 2004 the first country worldwide introducing smoke free bars and restaurants with positive effects on compliance, health of employees and business. In the first year after the introduction these policies have resulted in a 10 - 20 % reduction of acute coronary events. In Switzerland smoke free regulations have been accepted by popular vote first in the canton of Ticino in 2006 and since then in 15 more cantons. The smoking rate dropped from 33 to 27 % since 2001.

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.

Effect of physical activity on heart rate variability in normal weight, overweight and obese subjects: results from the SAPALDIA study.

Many studies have demonstrated an association of both a sedentary lifestyle and a high body mass index (BMI) with greater risk for cardiovascular disease. Within the prospective SAPALDIA cohort (Swiss cohort Study on Air Pollution and Lung Diseases in Adults), we investigated whether regular exercise was protective against reduced heart rate variability (HRV), a clinically relevant predictor of cardiovascular morbidity and mortality, and whether adverse effects of obesity and weight gain on HRV were modified by regular exercise. Twenty-four-hour electrocardiograms were recorded in 1,712 randomly selected SAPALDIA participants aged >or=50, for whom BMI was assessed in the years 1991 and 2001-2003. Other examinations included an interview investigating health status (especially respiratory and cardiovascular health and health relevant behaviours including physical activity) and measurements of blood pressure, body height and weight. The association between regular physical activity and HRV and interactions with BMI and BMI change was assessed in multivariable linear regression analyses. Compared to sedentary obese subjects, SDNN (standard deviation of all RR intervals) was 14% (95% CI: 8-20%) higher in sedentary normal weight subjects; 19% (CI: 12-27%) higher in normal weight subjects exercising regularly >or=2 h/week; and 19% (CI: 11-28%) higher in obese subjects exercising regularly >or=2 h/week. Compared with sedentary subjects who gained weight, those who gained weight but did exercise regularly had a 13% higher SDNN (CI: 7-20%). Regular physical exercise has strong beneficial effects on cardiac autonomic nervous function and thus appears to offset the negative effect of obesity on HRV.

SERPINA1 gene variants in individuals from the general population with reduced alpha1-antitrypsin concentrations.

BACKGROUND: Individuals with severe deficiency in serum alpha(1)-antitrypsin (AAT) concentrations are at high risk for developing chronic obstructive pulmonary disease (COPD), whereas those carrying the PI*MZ genotype are at slightly increased risk. Testing appropriate subgroups of the population for AAT deficiency (AATD) is therefore an important aspect of COPD prevention and timely treatment. We decided to perform an exhaustive investigation of SERPINA1 gene variants in individuals from the general population with a moderately reduced serum AAT concentration, because such information is currently unavailable. METHODS: We determined the Z and S alleles of 1399 individuals enrolled in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) with serum AAT concentrations < or = 1.13 g/L and submitted 423 of these samples for complete exon 2-->5 sequencing. RESULTS: We found that 900 of 1399 samples (64%), carried the normal PI*MM genotype, whereas 499 samples (36%) carried at least 1 SERPINA1 deficiency variant. In the subpopulations in which AAT concentrations ranged from > 1.03 to < or = 1.13 and from > 0.93 to < or = 1.03 g/L, individuals with the PI*MM genotype represented the majority (86.5% and 53.8%, respectively). The PI*MS genotype was predominant (54.9%) in the AAT range of 0.83 to 0.93 g/L, whereas PI*MZ represented 76.4% in the AAT range of > 0.73 to < or = 0.83 g/L. CONCLUSIONS: This analysis provided a detailed molecular definition of intermediate AATD, which would be helpful in the diagnostic setting.

Circulating alpha1-antitrypsin in the general population: determinants and association with lung function.

BACKGROUND: Severe alpha1-antitrypsin (AAT) deficiency associated with low AAT blood concentrations is an established genetic COPD risk factor. Less is known about the respiratory health impact of variation in AAT serum concentrations in the general population. We cross-sectionally investigated correlates of circulating AAT concentrations and its association with FEV1. METHODS: In 5187 adults (2669 females) with high-sensitive c-reactive protein (CRP) levels < or = 10 mg/l from the population-based Swiss SAPALDIA cohort, blood was collected at the time of follow-up examination for measuring serum AAT and CRP. RESULTS: Female gender, hormone intake, systolic blood pressure, age in men and in postmenopausal women, as well as active and passive smoking were positively, whereas alcohol intake and BMI inversely correlated with serum AAT levels, independent of CRP adjustment. We observed an inverse association of AAT with FEV1 in the total study population (p < 0.001), that disappeared after adjustment for CRP (p = 0.28). In addition, the AAT and FEV1 association was modified by gender, menopausal status in women, and smoking. CONCLUSION: The results of this population-based study reflect a complex interrelationship between tobacco exposure, gender related factors, circulating AAT, systemic inflammatory status and lung function.

Effects of passive smoking on heart rate variability, heart rate and blood pressure: an observational study.

BACKGROUND: Exposure to environmental tobacco smoke (ETS) has been shown to increase the risk for cardiovascular diseases and death, and autonomic dysfunction (specifically, reduced heart rate variability (HRV)) is a predictor of increased cardiac risk. This study tests the hypothesis that ETS exposure reduces HRV in the general population and discusses possible pathways. METHODS: This cross-sectional study was conducted between 2001 and 2003 and is part of the SAPALDIA (Swiss Cohort Study on Air Pollution and Lung Diseases in Adults) study. The analysis included 1218 randomly selected non-smokers aged 50 and above who participated in 24-h electrocardiogram recordings. Other examinations included an interview, investigating health status (especially respiratory and cardiovascular health and health relevant behaviours and exposure to ETS) and measurements of blood pressure, body height and weight. RESULTS: Subjects exposed to ETS at home or at work for more than 2 h/day had a difference of -15% in total power (95%CI: -26 to -3%), low frequency power (-28 to -1%), low/high frequency ratio (-26 to -3%) and -18% (-29 to -4%) in ultralow frequency power of HRV compared with subjects not exposed to ETS at home or work. We also found a 2.7% (-0.01 to 5.34%) higher heart rate during the recording in exposed subjects. CONCLUSIONS: Exposure to ETS at home and work is associated with lower HRV and with higher heart rate in an ageing population. Our findings suggest that exposure to ETS increases cardiac risk through disturbances in the autonomic nervous system.

Glutathione S-transferase genotypes modify lung function decline in the general population: SAPALDIA cohort study.

BACKGROUND: Understanding the environmental and genetic risk factors of accelerated lung function decline in the general population is a first step in a prevention strategy against the worldwide increasing respiratory pathology of chronic obstructive pulmonary disease (COPD). Deficiency in antioxidative and detoxifying Glutathione S-transferase (GST) gene has been associated with poorer lung function in children, smokers and patients with respiratory diseases. In the present study, we assessed whether low activity variants in GST genes are also associated with accelerated lung function decline in the general adult population. METHODS: We examined with multiple regression analysis the association of polymorphisms in GSTM1, GSTT1 and GSTP1 genes with annual decline in FEV1, FVC, and FEF25-75 during 11 years of follow-up in 4686 subjects of the prospective SAPALDIA cohort representative of the Swiss general population. Effect modification by smoking, gender, bronchial hyperresponisveness and age was studied. RESULTS: The associations of GST genotypes with FEV1, FVC, and FEF25-75 were comparable in direction, but most consistent for FEV1. GSTT1 homozygous gene deletion alone or in combination with GSTM1 homozygous gene deletion was associated with excess decline in FEV1 in men, but not women, irrespective of smoking status. The additional mean annual decline in FEV1 in men with GSTT1 and concurrent GSTM1 gene deletion was -8.3 ml/yr (95% confidence interval: -12.6 to -3.9) relative to men without these gene deletions. The GSTT1 effect on the FEV1 decline comparable to the observed difference in FEV1 decline between never and persistent smoking men. Effect modification by gender was statistically significant. CONCLUSION: Our results suggest that genetic GSTT1 deficiency is a prevalent and strong determinant of accelerated lung function decline in the male general population.

Respiratory effects of environmental tobacco exposure are enhanced by bronchial hyperreactivity.

RATIONALE: Exposure to environmental tobacco smoke (ETS) is associated with increased reports of respiratory symptoms and reduced lung function, but the long-term effects of ETS are unclear, notably in healthy individuals with bronchial hyperresponsiveness (BHR). OBJECTIVE: To assess the longitudinal effects of ETS exposure on the development of respiratory symptoms and spirometry in subjects with BHR. METHODS: The study population included 1,661 never-smokers from the SAPALDIA (Swiss Study on Air Pollution and Lung Diseases in Adults) cohort, assessed in 1991 (baseline) and 11 yr later, who were symptom-free at baseline. Incident reports of respiratory symptoms and results of spirometry were assessed at the follow-up survey. MAIN RESULTS: Exposure to ETS reported in the two surveys was strongly associated with the development of cough (odds ratio, 2.1; 95% confidence interval, 1.2-3.7; p = 0.01). In subjects with BHR exposed to ETS at both surveys, a trend for strong associations were observed for wheeze, cough, dyspnea, and chronic bronchitis; however, the association reached statistical significance only for the symptom of dyspnea (p < 0.01). Lower FEV1/FVC (mean +/- SD, 72.9 +/- 7.7 vs. 76.8 +/- 6.1%; p < 0.01) and FEF(25-75) (forced expiratory flow, midexpiratory phase)/FVC (mean +/- SD, 56.1 +/- 22.5 vs. 68.1 +/- 21.6%; p < 0.01) were observed in subjects with BHR exposed to ETS compared with nonexposed subjects without BHR. Lower values were found in subjects continuing exposure by the follow-up survey. CONCLUSION: Exposure to ETS was strongly associated with the development of respiratory symptoms in previously asymptomatic subjects with BHR within 11 yr. Furthermore, subjects with underlying BHR had reduced lung function at follow-up, thus suggesting a higher risk for the development of chronic respiratory disease in this subset of the population.

Heart rate variability in an ageing population and its association with lifestyle and cardiovascular risk factors: results of the SAPALDIA study.

AIMS: (i) To report associations between cardiovascular risk factors and heart rate variability (HRV) in a general population and (ii) to provide normal values for various HRV measurements in a healthy European general population sample aged >or=50. METHODS AND RESULTS: Twenty-four-hour electrocardiograms were recorded in 1742 randomly selected SAPALDIA (Swiss cohort study on Air Pollution and Lung Diseases in Adults) participants aged >or=50. In multivariate regression analyses, women (n=895) had a 6.1% lower standard deviation of all normal RR (NN) intervals (SDNN), a 11.4% lower total power (TP), and a 27.2% lower low-frequency (LF) power than men (n=847). Per unit increase in BMI, SDNN decreased by 0.7% and TP decreased by 1.2%. Persons with high blood pressure had a 9.2% lower LF than normotensive persons and current smokers a 15.5% lower LF than never smokers. Each hour of heavy physical exercise was associated with a 2.0% increase in SDNN, a 3.6% increase in the high frequency (HF) range power and a 4.2% increase in LF power. Higher levels of uric acid, high-sensitive C-reactive protein and non-HDL-cholesterol were associated with lower TP, HF and LF. Percentiles of TP and LF/HF as a function of age were calculated for an asymptomatic subsample of participants (n=499) free of cardioactive medications. CONCLUSION: Heart rate variability in a general population sample shows expected associations with all known cardiovascular risk factors, although not identically for all HRV domains. Together with our percentile estimates for HRV as a function of age, these findings could assist scientists in interpreting 24 h HRV values and factors influencing them in an ageing population.

Prevalence of renal impairment and its association with cardiovascular risk factors in a general population: results of the Swiss SAPALDIA study.

BACKGROUND: Impaired renal function is evolving as an independent marker of the risk of cardiovascular morbidity and mortality. Little is known about the prevalence of impaired renal function and its relationship to cardiovascular risk factors in the Swiss general population. METHODS: SAPALDIA comprises a random sample of the Swiss population established in 1991, originally to investigate the health effects of long-term exposure to air pollution. Participants were reassessed in 2002/3 and blood measurements were obtained (n = 6317). Renal function was estimated using the Cockcroft-Gault equation and the modified MDRD (four-component) equation incorporating age, race, gender and serum creatinine level. RESULTS: The estimated prevalence of impaired renal function [estimated glomerular filtration rate <60 ml/min/1.73 m(2)] differed substantially between men and women, particularly at higher ages, and amounted to 13% [95% confidence interval (CI) 10-16%] and 36% (95% CI 32-40%) in men and women, respectively, of 65 years or older. Smoking, obesity, blood lipid levels, high systolic blood pressure and hyperuricaemia were all more common in men when compared with women. These cardiovascular risk factors were also associated independently with creatinine in both women and men. Women were less likely to receive cardiovascular drugs, in particular angiotensin-converting enzyme inhibitors and beta-blockers, when compared with men of the same age. CONCLUSION: Moderate renal impairment seems to be prevalent in the general population, with an apparent excess in females which is not explained by conventional cardiovascular risk factors. The unexpected finding questions the validity of the prediction equations, in particular in females.

Reference values for methacholine reactivity (SAPALDIA study).

BACKGROUND: The distribution of airway responsiveness in a general population of non-smokers without respiratory symptoms has not been established, limiting its use in clinical and epidemiological practice. We derived reference equations depending on individual characteristics (i.e., sex, age, baseline lung function) for relevant percentiles of the methacholine two-point dose-response slope. METHODS: In a reference sample of 1567 adults of the SAPALDIA cross-sectional survey (1991), defined by excluding subjects with respiratory conditions, responsiveness during methacholine challenge was quantified by calculating the two-point dose-response slope (O'Connor). Weighted L1-regression was used to estimate reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope. RESULTS: Reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope were estimated using a model of the form a + b* Age + c* FEV1 + d* (FEV1)2 , where FEV1 corresponds to the pre-test (or baseline) level of FEV1. For the central half of the FEV1 distribution, we used a quadratic model to describe the dependence of methacholine slope on baseline FEV1. For the first and last quartiles of FEV1, a linear relation with FEV1 was assumed (i.e., d was set to 0). Sex was not a predictor term in this model. A negative linear association with slope was found for age. We provide an Excel file allowing calculation of the percentile of methacholine slope of a subject after introducing age--pre-test FEV1--and results of methacholine challenge of the subject. CONCLUSION: The present study provides equations for four relevant percentiles of methacholine two-point slope depending on age and baseline FEV1 as basic predictors in an adult reference population of non-obstructive and non-atopic persons. These equations may help clinicians and epidemiologists to better characterize individual or population airway responsiveness.

Longitudinal validity of spirometers--a challenge in longitudinal studies.

QUESTION UNDER STUDY: Pulmonary function testing (PFT) in longitudinal studies involves the repeated use of spirometers over long time periods. We assess the comparability of PFT results taken under biologic field conditions using thirteen certified devices of various technology and age. Comparability of measurements across devices and over time is relevant both in clinical and epidemiological research. METHODS: Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1) and Forced Expiratory Flow 50% (FEF50) were compared before and after the data collection of the Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) and the European Community Respiratory Health Survey (ECRHS) cohort studies. Three test series were conducted with 46, 50 and 56 volunteers using various combinations of spirometers to compare the eight flow-sensing spirometers (Sensormedics 2200) used in the SAPALDIA cross-sectional and follow-up, two new flow-sensing instruments (Sensormedics Vmax) and three volume displacement spirometers (two Biomedin/Baires and one Sensormedics 2400). RESULTS: The initial comparison (1999/2000) of eight Sensormedics 2200 and the follow-up comparison (2003) of the same devices revealed a maximal variation of up to 2.6% for FVC, 2.4% for FEV1 and 2.8% for FEF50 across devices with no indication of systematic differences between spirometers. Results were also reproducible between Biomedin, Sensormedics 2200 and 2400. The new generation of Sensormedics (Vmax) gave systematically lower results. CONCLUSIONS: The study demonstrates the need to conduct spirometer comparison tests with humans. For follow-up studies we strongly recommend the use of the same spirometers.

Follow-up of the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA 2) 1991-2003: methods and characterization of participants.

OBJECTIVES: The Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) was designed to investigate the health effects from long-term exposure to air pollution. METHODS: The health assessment at recruitment (1991) and at the first reassessment (2001-3) consisted of an interview about respiratory health, occupational and other exposures, spirometry, a methacholine bronchial challenge test, end-expiratory carbon monoxide (CO) measurement and measurement for atopy. A bio bank for DNA and blood markers was established. Heart rate variability was measured using a 24-hour ECG (Holter) in a random sample of participants aged 50 years and older. Concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3) and particulates in ambient air have been monitored in all study areas since 1991. Residential histories collected over the 11 year follow-up period coupled with GIS modelling will provide individual long-term air pollutant exposure estimates. RESULTS: Of 9651 participants examined in 1991, 8715 could be traced for the cohort study and 283 died. Basic information about health status was obtained for 8047 individuals (86% of alive persons), 6 528 individuals (70%) agreed to the health examination and 5 973 subjects (62%) completed the entire protocol. Non-participants in the reassessment were on average younger than participants and more likely to have been smokers and to have reported respiratory symptoms in the first assessment. Average weight had increased by 5.5 kg in 11 years and 28% of smokers in 1991 had quit by the time of the reassessment.