Abstract

Pulmonary function was studied among pulp and paper workers from a production facility in New Hampshire. Subjects were first tested in the 1960s and then surveyed at regular intervals up to 1985. The current study examined results for the 339 subjects who participated in at least one of the two most recent follow up surveys in 1979 and 1985. For the 171 subjects who were tested in both surveys, the pulmonary function values were higher and the effect of pulp mill work was diminished compared with the findings for the 168 subjects who were tested in just one of the two surveys. To avoid the loss of less healthy subjects and the subsequent bias in effect estimate, the 1985 data were analysed cross sectionally with the inclusion of data from 1979 for those subjects who had not been followed up in the last survey. The subjects with work experience in the pulp mill had mean levels of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) lower than those of unexposed subjects who had never worked in the pulp or paper production areas. Based on parameter estimates from regression analysis, each year of employment in the pulp operation was associated with a -5.8 ml change in FEV1 (p = 0.08) and a -7.2 ml change in FVC (p = 0.04). Ninety one per cent of the subjects with pulp mill experience had terminated employment in that area of the company, so the association with decreased lung function appears to be a non-reversible effect that persisted after the cessation of exposure

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