A recent study in China concluded that the incidences of neurasthenia and of ultrasonographic abnormalities in the livers of vinyl chloride-exposed workers increased with increasing cumulative exposure dose.1 This is an important finding, especially as the exposure to vinyl chloride studied was below the current Chinese permissible occupational limit. The same study also reported that the CYP2E1 c1c2/c2c2 genotype was significantly associated with liver damage (OR 3.3).

How should occupational health and safety professionals use these data? A further decrease in the occupational health standard for vinyl chloride in China should be the immediate reply. How about the data on polymorphic CYP2E1?

We are on the threshold of a new revolution in understanding the interaction of genes with the environment. The relative roles of heritable and environmental causes in occupational hazards are an important scientific issue, with many practical consequences. Traditional geneticists have emphasised genes, while epidemiologists have argued for the environment. The literature on disease causation is full of overstatements, but recent data from twin and family studies offer …