Lung function in workers exposed to polyvinyl chloride dust.

Abstract

Several reported studies on the effects of polyvinyl chloride (PVC) dust in animals and man have been conflicting. The present study of the ventilatory function of 509 male workers exposed to PVC dust was made in 1977. Altogether 104 men exposed to PVC dust only, 112 men exposed to non-chlorinated solvents only, and 293 men exposed to a mixture of both completed the MRC questionnaire on respiratory function and performed simple spirometric tests (forced expiratory volume in one second and forced vital capacity). No differences were found between the three groups after allowance was made for age, height, and smoking. When exposure and smoking effects were considered separately, the latter was shown to be the dominant cause of reduced lung function. In this study work with PVC dust has not produced deleterious effects on ventilatory function.Polyvinyl chloride (PVC), a large tonnage raw material of fundamental importance to the plastics industry, is a white powder that was until recently considered to be inert. The basic material is formed from its monomer, the gas vinyl chloride (VCM). Although VCM and PVC have been synthesised for over 30 years, it is only in the past 10 years that the sinister nature of VCM has become apparent. VCM has been found to produce a wide spectrum of clinical conditions, the most important being angiosarcoma of the liver in workers exposed to high concentrations of the gas in PVC production plants. This was discovered in 1974 and because a small quantity of the gas is carried forward with the PVC powder to its containers, and thus to the formulating industries the effects, if any, of the PVC powder came into question. The chance of finding effects similar to those associated with VCM is considered remote, since the concentrations are greatly reduced. The possibility of pulmonary changes being caused by inhalation of the dust however, has led to experimental and clinical research.The cytotoxicity of various polymer dusts, including PVC, to suspensions of rat alveolar and peritoneal macrophages in culture' indicated that PVC caused deaths of cells similar in amount to kaolin, magnesium trisilicate, and polyethylene. These materials produced less than 2 % fibrogenicity compared with over 10 % for asbestos.On such evidence PVC had been considered inert and therefore incapable of producing lung changes.

Pulmonary manifestations of polyvinyl chloride exposure

“…Konu hakkında yapılan araştırmalar, PVC toz maruziyetinin hem obstrüktif hem de restriktif solunum fonksiyon bozukluğuna yol açtığını göstermektedir (14). Ça-lışmalarda 6-12 yıllık uzamış maruziyetin veya 20 yıl-dan daha uzun süreli maruziyetin tütün alışkanlığından bağımsız olarak FEV 1 /FVC oranını azalttığı ve %70'in altına düşürdüğü gösterilmiştir (15,16). Benzer biçimde PVC tozuna 10 yıldan daha fazla süre maruz kalmış ça-lışanların %50'sinden fazla bir kısmında FEV 1 /FVC oranının %75'ten düşük olduğu saptanmıştır (14).…”

“…Ayrıca, PVC tozuna bağlı deskuamatif interstisyel pnömoni saptanmış bir olguda orta-akım hızlarında azalma bildirilmiştir (6). Ancak konu hakkındaki çalışmaların tümü bu sonuçları doğrulamamakta ve bazı çalışmalar PVC tozunun ventilatuvar fonksiyonlar üzerine çok ciddi bir etkiye neden olmadığını, hatta tümüyle etkisiz olduğu-na işaret etmektedir (12,13,16 Çalışmamızda günlük PEF değişkenliğinin tatil ve çalış-ma günlerinde hem idari hem de maruziyet grubunda anlamlı farklılık taşımadığını saptadık. Ancak toz maruziyeti olan grubun çalışma günlerindeki günlük PEF değişkenliğinin tatil günlerine kıyasla anlamlı oranda daha yüksek olduğunu tespit ettik.…”

Pulmonary effects of polyvinyl chloride dust exposure on compounding workers.

“…It would appear, however, that, in many of the earlier studies, control of possible biases or confounding was less than adequate because of the lack of appropriate reference groups, failure to take into account the influences of age or cigarette smoking properly, or the absence of standardized procedures in radiographic reading such as the use of standard radiographs of the International Labour Office (lLO) or multiple readers blind to the exposure status of the subjects. Several studies have also provided conflicting evidence for lung function impairment (4,6,7).…”

“…Since then, several epidemiologic studies have investigated the pulmonary effects of occupational exposure to vinyl chloride monomer (VCM) and polyvinyl chloride (PVC). These studies have shown an increased prevalence of radiological, lung function , or subjective abnormalities (2)(3)(4)(5)(6)(7)(8)(9). It would appear, however, that, in many of the earlier studies, control of possible biases or confounding was less than adequate because of the lack of appropriate reference groups, failure to take into account the influences of age or cigarette smoking properly, or the absence of standardized procedures in radiographic reading such as the use of standard radiographs of the International Labour Office (lLO) or multiple readers blind to the exposure status of the subjects.…”

“…PVC fabrication workers have also been studied (7)(8)(9), but these included other process workers, such as in calendering, laminating, or extruding, with potential exposur e to thermal degradation products, solvents, and possibly additives known to cause acute bronchial reaction .…”