A case-reference study of neuropsychiatric disorders among workers exposed to solvents in the Danish wood and furniture industry

Abstract

A case-reference study was conducted to estimate the association between neuropsychiatric diseases leading to early retirement pensioning and exposure to organic solvents in the Danish wood industry. Cases were defined as all members of the Carpenter/Cabinet Makers' Trade Union who were diagnosed with a neuropsychiatric disease and received disability or early old-age pensions during the period January 1, 1971 to December 31, 1975. The case group comprised 171 disability pensioners and 35 early old-age pensioners. A reference group of equal size was selected among union members with other diseases who were pensioned over the same time-period. Controls were matched to cases according to age and type of pension. Among a total of 412 eligible study subjects, 342 (i.e., 287 disability pensioners and 55 early old-age pensioners) could be located in 1978. Of these, 9.8% of the disability pensioners and 12.7% of the early old-age pensioners did not respond to the questionnaire. Information regarding occupational exposure and vocational training was obtained both directly from study subjects and from the files of the trade union. Medical diagnoses were obtained through registry linkage and by manual search of hospital records. Former employees with high levels of exposure to organic solvents were more likely to receive disability pensions for neuropsychiatric reasons compared to more modestly-exposed individuals. Cabinet-makers and especially cabinet-makers with high exposure to lacquers and glues had a higher risk of receiving a disability pension for a neuropsychiatric disease than carpenters. Possible sources of bias are discussed in the article.