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

Abstract

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. The most powerful approach for studying long-term effects from ambient air pollution on health is the long-term prospective follow-up of well-defined population-based cohorts with well-characterized air pollution exposure information (European Science Foundation 1998). There are currently only five cohort studies in adults, with published results, that address the long-term impact of air pollution (Abbey et al. 1999;Dockery et al. 1993;Finkelstein et al. 2004;Hoek et al. 2002; Pope et al. 2002;. All studies but one are based in the US and three of them (Dockery et al. 1993;Hoek et al. 2002; Pope et al. 2002), have only published findings related to mortality. The relation of longterm exposure to air pollution with respiratory and cardiovascular health and morbidity has yet to be measured in a large prospective cohort study in Europe. The large European Community Respiratory Health Survey (ECRHS) de- Probst-Hensch NM, et al. Follow-up of SAPALDIA 2, 1991-2003 signed to measure natural history and risk factors for respiratory diseases (particularly asthma and allergy) across Europe has recently included air pollution exposure assessment in its protocol (Burney et al. 1994;Hazenkamp-von Arx et al. 2004). However, the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) is the only prospective cohort study of respiratory and cardiovascular health in adults in Europe with detailed individual residential exposure hi...

The Association of a Variant in the Cell Cycle Control GeneCCND1and Obesity on the Development of Asthma in the Swiss SAPALDIA Study

“…The methods of the SAPALDIA study have been described in detail elsewhere (16,17). In short, the study population consists of a random population sample of white adults aged 18-60 years from eight areas of Switzerland.…”

“…Genotyping DNA extraction from EDTA-buffered whole blood has been previously described (17). Originally, in each of three candidate genes pivotal for cell cycle control (CCND1, TP53, and CDKN1A, the gene encoding cyclindependent kinase inhibitor 1A, also called p21), one promising candidate SNP was selected according to its frequency and its reported functionality in cell division and apoptosis (rs9344 in CCND1, rs1042522 in TP53, and rs1801270 in CDKN1A).…”

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

“…Details of its design and objectives have been reported elsewhere. 17,18 In 1991, a random sample of the Swiss population was recruited from eight areas featuring distinct geographical and environmental conditions. SAPALDIA participants were examined in 1991 and 2001-03 for risk factors of cardiovascular disease, respiratory symptoms, pulmonary function evolution and development of lung diseases.…”

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

“…The FEV1/FVC ratio was calculated for every subject and a low ratio (defined as <0.7) was considered an indicator of obstruction to air flow in accordance with the GOLD report definition of Chronic Obstructive Pulmonary Disease (COPD) [9]. The SAPALDIA methodology has been described in detail [10,11]. All participants gave written informed consent and ethical approval was granted by the Swiss Academy of Medical Sciences and the respective cantonal ethics committees.…”