Comparison of pulmonary function test abnormalities between stone crushing dust exposed and nonexposed agricultural...

The aim of this study is to examine the effects of stone crushing in West Bengal, India, by comparing pulmonary functions of stone crushing workers with those of nonexposed agricultural workers.

Two hundred seventy two stone crushing workers and 123 nonexposed workers were analyzed in terms of occupational and personal histories, radiological findings, and pulmonary function test (PFT) results including slow vital capacity (FVC), forced vital capacity (FVC) and peak expiratory flow rate (PEFR). Different lung volumes i.e. FEV(1), FEV(1%), and flow rates i.e. FEF(200-1200ml), FEF(25-75%) and FEF(75-85%), were analyzed with regard to sex, smoking habit, work status, age and work duration.

Contrary to our expectations, the incidences of suspected (2.94%) and definite (1.84%) pneumoconioses were very low and the results of some PFT such as those for FVC and FEV(1%), in the exposed group were better than those in the nonexposed group, although a gradual decline the performance in PFT was observed with age and work duration. There was a higher prevalence of restrictive impairment among the exposed group and a higher prevalence of obstructive impairment in the nonexposed group.

Some of the results were unexpected. Possible reasons for these include (i) undetectable concentrations of free silica in the stone dust in the work environment of the exposed workers and (ii) factors, such as climate, in the work environment of the nonexposed agricultural workers that could cause pulmonary impairment. Further protective measures should be undertaken to prevent pulmonary impairment in both groups of workers.