ENDOTOXIN EXPOSURE AND LUNG FUNCTION AMONG RICE MILLERS IN MALAYSIA

Abstract

Introduction: The health effects of inhaling rice dust contaminated with endotoxin include respiratory problems, asthma, chronic bronchitis and chronic obstructive pulmonary disease. Thus, this comparative cross-sectional study aims to associate the concentration of endotoxin levels in inhalable rice dust and the lung function decline among rice millers. 

Materials and Methods: The endotoxin level in inhalable dust for both area and personal samplings were collected using 25 mm Glass Fiber (A) filter loaded in IOM samplers connected to a pump by tygon tubing. The pump was operated at 2.0 litres/min and clipped around the breathing zone of the rice millers for eight hours. The endotoxin concentrations were analysed using Limulus Amoebocyte Lysate Chromogenic Endpoint assay at 405 nm. Lung function tests were carried out using Spirometer (Pony FX), for both the rice millers and the non-exposed groups. 

Results: Findings for the mean concentration of endotoxin for areas was 0.26 (standard deviation (SD) = 0.12) EU/m³ whereas the mean personal inhalable endotoxin level among the rice millers was 0.29 (SD = 0.15) EU/m³. Post-shift lung function tests for FEV1/FVC measured appeared lower among rice millers (54%) compared to non-exposed workers (62%), but not statistically significant (p = 0.313). However, there were significant correlations between endotoxin concentration and post-shift LFT parameters of measured FVC, FEV1 and PEFR (p < 0.05). 

Conclusion: Despite the low level of endotoxin exposure, proper protective measures should be applied for rice millers for long term protection.