Exposures to polyvinyl chloride, methyl ketone and other chemicals. The pulmonary and non-pulmonary effect

As part of the continuing assessment of the health impact of exposures in the emerging industries of Nigeria, a study was conducted to determine the relative impact of exposures encountered in four operations of a shoe factory. The health impact assessment consisted of spirometric lung function evaluations and environmental measurement for polyvinyl chloride (1.6 +/- 5 ppm). The study showed that there were differences among exposure subgroups with respect to pulmonary, neurological and dermal toxicities and that these differences were dictated by the types of exposure encountered. Pulmonary toxicity was most severe in the vinyl chloride-exposed subgroup. Neurological impact was most severe in the leather and methylethyl ketone-exposed subgroup and dermal toxicity most severe in the subgroup exposed to plasticizers and stabilizers. There existed substantial deficits in lung function (forced expiratory volume, forced vital capacity FEV1, FVC) among the subgroups relative to normal, non-industrially exposed Nigerians of similar age and height. The deficits in lung function, particularly in FVC, paralleled the variations in the prevalence of restrictive lung disease, which for the whole study group was 56.5 cases per 1000 person-years. The vinyl chloride-exposed subgroup had the highest prevalence of restrictive lung disease, 92.6 cases per 100 person-years. Step-wise multiple regression suggested that 27% of the deficit in FEV1 was explainable by the number of exposures. The use of person-years as a denominator gives a better estimate of risk than the total number of subjects as it incorporates both the number exposed and the total exposure experience.(ABSTRACT TRUNCATED AT 250 WORDS)