The SAPALDIA study (Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults) is a multi-center study in eight geographic areas representing the range of environmental, meteorological and socio-demographic conditions of Switzerland.
It was initiated in 1991 (SAPALDIA 1) with a follow-up assessment in 2002 (SAPALDIA 2). This study has allowed to assess 1) prevalence and development of major respiratory and allergic symptoms and diseases and the age-related decline in lung function, 2) the distribution of heart rate variability in the general population over age 50, 3) the association of these health indicators with individual long term exposure to air pollution, other toxic inhalants, life style and molecular factors.
The WHO and the European Research authorities have acknowledged the importance of SAPALDIA as one of the very few population-based adult cohort studies in Europe. It is well positioned to address crucial questions of air pollution epidemiology and important environmental health policy-related questions in the coming years.
When SAPALDIA was initiated in 1991, 9'651 subjects, aged 18 to 60 years, were recruited for a detailed computer-based interview and more than 90% of them underwent lung function and atopy testing. More than 7'000 of the subjects had bronchial reactivity tested by a methacholine challenge. SAPALDIA shares parts of its study protocol with the European Community Respiratory Health Survey (ECRHS) with which it is linked through the study center of Basel.
Since 1991 SAPALDIA has been carefully following address histories of its participants. In the 2002 follow-up, 8'047 (83%) provided health information, 6'528 persons underwent physical re-examination, and 6'345 provided blood samples to establish an extensive blood, plasma, serum and DNA bank. In addition, 1'813 subjects aged 50 or older participated in 24h-ECG Holter monitoring to provide detailed data on parameters of heart rate variability. With the inclusion of cardiovascular endpoints, SAPALDIA is one of the first studies examining effects from long-term exposure to air pollution on cardiovascular health parameters as well as mutual influence between the respiratory and the cardiovascular system.
The SAPALDIA bio-bank has allowed scientific publications on the association between some genetic profiles (gene polymorphism) and the propensity to develop asthma, allergic diseases, or accelerated lung function decline with age. Ongoing studies are focusing on gene-environment interactions a crucial question to understand why some persons suffer more from the effect of air pollution than others.
SAPALDIA is supported by the Swiss National Foundation on Scientific Research (SNF) as well as by several private and public institutions. This funding currently aims at:
1) further study determinants of chronic and cardio-vascular health based on the current database
2) maintain the bio bank, continuously update environmental data, addresses, individual exposure histories, and mortality, and
3) set the stage for a third health examination in 2010 with its scientific potential inherent to the ageing of the cohort.