Longitudinal decline in lung function measurements among Saskatchewan grain workers.

Ambikaipakan Senthilselvan,Punam Pahwa,Helen H McDuffie,James A Dosman

doi:10.1155/2003/914753

Ambikaipakan Senthilselvan, Punam Pahwa

Open Access

https://doi.org/10.1155/2003/914753

Copy DOI

Abstract

To evaluate the relationship between the long term effects of grain dust and decline in lung function among grain elevator workers in Saskatchewan, studied over a 15-year period. The Grain Dust Medical Surveillance Program was started by Labour Canada in 1978 and longitudinally studied the respiratory health of Canadian grain elevator workers over a 15-year period (1978 to 1993). Data on respiratory symptoms and pulmonary function tests (forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC]) were collected once every three years; each three-year interval was called a 'cycle'. Data from Saskatchewan were analyzed for this report. A transitional model using the generalized estimating equations approach was fitted using a SAS macro to predict the annual decline in FEV1 and FVC. Previous lung function, as one of the covariates in the transitional model, played an important role. Significant predictors of FEV1 were previous FEV1, base height, weight, years in the grain industry, current smoking status, cycle II, cycle III and cycle V. Significant predictors of FVC were previous FVC, base height, weight, years in the grain industry, cycle II, cycle III and cycle IV. The estimated annual decline in FEV1 and FVC increased according to length of time in the grain industry among nonsmoking, ex-smoking and smoking grain elevator workers. Lung function values improved after dust control, and yearly declines in FEV1 and FVC after dust control were smaller compared with yearly losses before dust control.

Highlights

In the present paper, we evaluated the relationship between the long term effects of grain dust and the decline in lung function measurements among grain elevator workers in Saskatchewan, studied over a 15-year period
We found that the yearly loss in lung function test variables amplified with increasing years in the industry among nonsmoking, ex-smoking and smoking grain workers, and that the decline in lung function during the first three cycles was much faster compared with the decline in cycles IV and V
The mean forced expiratory volume in 1 s (FEV1) values were higher in the younger age groups of grain workers; after a certain age, these values were smaller compared with the general male population in the six cities study

Summary

OBJECTIVE

To evaluate the relationship between the long term effects of grain dust and decline in lung function among grain elevator workers in Saskatchewan, studied over a 15-year period. Huy et al [7] studied the long term effect of grain dust exposure on the longitudinal decline in lung function among grain elevator workers over a 15-year period. They reported a doseresponse relationship between grain dust exposure and a longitudinal change in FEV1 and FVC, as well as an increase in respiratory symptoms. Rosner et al [4] presented a first order autoregressive model in which linear multiple regression was used to relate change in response variables to explanatory variables They used this method to analyze longitudinal data for the case of a continuous outcome variable (lung function) with lung function testing spaced over time. This approach was extended to evaluate the relationship between the long term effects of grain dust and the decline in lung function among grain elevator workers in Saskatchewan, studied over a 15-year period

METHODS

RESULTS

DISCUSSION