Occupational exposure to particles in relation to chronic obstructive pulmonary disease and cardiovascular disease

Objective: The working life is expanding with increased retirement ages as the population is aging, in Sweden but in also other parts of the world. However, workers with poor health might not cope with working in higher ages. Two of the world's most common causes of death, chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVDs) are partly due to exposures from work. Exposure to particles increase the risk of incident COPD and CVD. However, more research is needed on the effect of occupational exposure of particles of different origin, and to which extent they contribute to COPD and different types of CVD, including dose-response relationships. The overall aim of this thesis was to investigate occupational particle exposure in relation to COPD and CVD, investigate effects of different particle types, dose-response relationships, and potential differences in effects in men and women.Methods: This thesis comprises four studies, two epidemiological studies, one on COPD and one on CVD resulting in two papers, and two field studies on CVD. Study I is a populationbased longitudinal study in which we investigated the smoking-adjusted risk of COPD associated with occupational exposure to 13 particles/groups (inorganic, organic, combustion particles, and welding fumes). We formed a cohort of subjects born in 1965 or earlier who responded to the Stockholm Public Health Survey in 2002, 2006, or 2010 with follow-up surveys in 2007, 2010, and 2014, in total 43,641 subjects. Participants were identified as COPD cases if they had been diagnosed with COPD by a physician during 1990-2014 or were prescribed anticholinergic medication specific for COPD. A job exposure matrix (JEM) was used to estimate occupational particle exposure. Study II and III investigated the association between particle exposure and markers of CVD. They are based on measurements of respirable silica, respirable dust, and dust of PM 0.1-10, and on biological sampling of included participants within construction industry. Study II, based on 65 participants, investigated if occupational particle exposure is affecting common biomarkers for CVD, both cross-sectionally at work and longitudinally before and after vacation. In study III, based on 46 participants, our aim was to study short-term effects on pulse rate and blood pressure associated with rapid varying particle levels at work, but also intermittent noise. Study IV analyzed the association between occupational exposure to 41 different particles and chemicals and first MI adjusted for joint exposures of lack of decision authority, physical workload, noise, and other particles/chemicals. It is based on the Swedish National Cohort on Work and Health (SNOW) and includes all persons who were born between 1930 and 1990 and working in Sweden (6,437,660 subjects), in this study working at any time between 1985-2013. Occupational history was retrieved from the 1980, 1985, and 1990 National censuses and the Occupational register within the Statistic Sweden's Longitudinal Integrated Database for Health Insurance and Labour Market Studies (LISA). Cases of first MI were identified from the National Patient Register and the National Cause of Death Register. Other registries and cohorts were matched to add additional information of education, smoking, and body mass index (BMI). Four different JEMs were used to estimate the different occupational exposures.Results: After adjusting for smoking, men occupationally exposed to any type of inorganic, organic, high levels to any combustion particles, and high levels of welding fumes had increased risk of incident COPD.