Personality, Health and Mortality of Workers in a PVC Production Plant in Sweden A longitudinal study

Abstract: A longitudinal study was initiated in a PVC production plant in 1967. It was repeated in 1987. A cohort of 101 workers was followed. The aim of the 1967 study was, after a heavy rise in absenteeism and sick leave, to analyze perceptions of work environment and health. The aim of the second study was to investigate possible health effects of the workers after the change of threshold limit value, TLV, in 1975 and, further, to study the personality, disease and mortality pattern over time. In 1967, the TLV for exposure to vinyl chloride (VC) solvents, used in polyvinyl chloride (PVC) production in Sweden, was 500 PPM (parts per million). It was changed to 1 PPM from January 1, 1975, after discovery of a rare type of cancer in the liver, angiosarcoma, among PVC workers in the world. In 1979, high mortality in heart disease, cancer, accidents and suicide was reported in a study of disease and mortality among PVC workers in Sweden. The research method of the present study involved use of two self rating questionnaires, the MNT scale, a personality scale, based on Sjöbring´s personality psychology model and the MFS questionnaire, a medical health inventory. Further, a structured interview concerning perception of the work environment was employed. As appendices to the thesis, three reports are presented. The first report concerns health and work perception of the workers in 1967, as compared to a corresponding group of workers not exposed to solvents. The second report studies the disease and mortality pattern of the workers as well as the relation between these factors and personality. The third report concerns the development of health and personality as a function of time for a group of 68 persons investigated both in 1967 and 1987, as well as for a sub-group of 16 persons working at the PVC plant at both occasions. The results demonstrate that the PVC workers had many more physical and mental symptoms than the group of workers not exposed. In addition, the PVC workers perceived their work environment as highly straining and characterised by heavy work load. Significant correlation between the Sjöbring personality factor Validity and mortality in coronary heart disease, CHD, and suicide was found as well as between personality and symptoms from the endocrinological system. After a major reduction of PVC exposure, significant improvements in health were seen for the group of 68 persons. The improvements were less marked for the group of 16 persons still in the same work-place. The development and change of the personality pattern were studied as functions of time. In the first study, low Validity, the level of energy, was identified. In the second study, this level had increased, now reaching a level which, as referring to the age of the workers, could have been expected in the first investigation. The results indicate that high levels of solvents affect personality as well as health in a highly significant manner. However, the study also shows that, after elimination of exposure to solvents, a recovery to normal values is possible.