Factors affecting respiratory function of rice millers in Anuradhapura district

Rice is the most important crop cultivated in Sri Lanka and rice milling is the largest agro-based industry in the country. Objectives To compare lung functions of rice millers and controls with predicted normal values for Sinhalese and to determine the effects of rice husk dust on lung functions of rice millers in relation to length (years) of exposure. Methods Rice millers (male: 84, female: 84) and controls (male: 84, female: 84) were selected and matched for determinants of lung functions. Data were collected via a validated questionnaire and spirometry. Observed mean lung functions were compared with lung function norms published for non-smoking Sinhalese. Results Most of the male millers and controls were smokers while none of the females were. All mean lung functions tested FVC, FEV1, PEFR and FEF25-75%, were significantly lower than the predicted values among male millers. While some lung functions were significantly reduced in female millers and male controls, all were comparable with predicted values in female controls. Duration of employment in rice mills was significantly and inversely related to FVC and FEV1 of millers. Conclusions Observed deficiencies in lung functions of rice millers were probably caused by occupational exposure to rice husk dust and tobacco smoke. The cumulative effect of the two were found to be more harmful than each alone. Wearing face masks, worker education and adequate ventilation in mills are recommended. Advantages of cessation of smoking should be further stressed to communities of lower socioeconomic and educational backgrounds.