Cement dust and chronic obstructive pulmonary disease: a nested case-control study among plant workers

Abstract

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. It results in a substantial and increasing economic and social burden for individuals, families, health care organizations, and society. Cement plant workers are at increased risk for COPD. According to data obtained from the head doctor of Ararat polyclinic, the prevalence rate of COPD was 128 per 1,000 in this occupational group during 1999-2000. To assess the relationship between cement dust exposure and COPD and to conduct dose-response analysis, a nested case-control study among “Ararat cement” plant workers will be conducted. Cases are defined as cement plant employees with a clinical diagnosis of COPD who worked in the plant during 1995-2000. Controls are cement plant employees who worked in the plant during 1995-2000 and have not been diagnosed with COPD by the general practitioner. The required sample size is 78 for each group. The selection of cases and controls will be done by simple random sampling and systematic sampling techniques using the polyclinic’s rosters of workers. Ascertainment of cases and controls will occur during face-to face interviews using a standardized questionnaire with specific questions about COPD-related symptoms (American Thoracic Society Adult Questionnaire-78). During interviews, information about potential confounders will also be gathered. Information about work history of cases and controls will be obtained from work employee records and interviews. The exposed workers will be divided according to the duration of work in an exposed job, to determine if increased duration led to increased risk of COPD (dose-response analysis). Logistic regression will be used for analysis to estimate a summary odds ratio after adjustment for confounders and to evaluate interactions between variables. The total budget is about $17,538.