Risk Assessment of Occupational Heat-Related Illness among Cultivated Farmers in Nam Phong District, Khon Kaen Province

Abstract

The cross-sectional descriptive study was designed to assess the risk of occupational heat-related illness in cultivated farmers, Khon Kaen Province. A total of 371 farmers from clustered sampling were from Nam Phong district, Khon Kaen Province. Data were collected from April to September, 2019 at 08.00 – 18.00 h. by the interviewed questionnaire and measurements of working conditions by Wet Bulb Globe Thermometer (WBGT), humidity meter, and air velocity monitor. Risk was evaluated by the matrix of the combination of the likelihood and the severity levels of heat-related illness. A Pearson’s Chi-square test was used to analyze the correlation. Results showed that most participants were the rice farmers,
had planting area ≤ 16,000 square meters. Most of the participants were resting under the shade with average time was 29.94 minutes/time, average daily working duration was more than 6-8 hours/day, average continuous working time without resting was 120 min/day, and working frequency was more than 4-7 days/week. The working condition had an average WBGT at 35.82 °C, average WBGT in the resting area was 33.27 °C, average wind speed while working was 1.38 m/s, average wind speed while resting was 1.11 m/s, average relative humidity while working was 54.40% and average relative humidity while resting was 58.52%. Most farmers (84.10%) had a heavy workload (more than 350 kcal/h.) with an average of the workload at 488.39 kcal/h. and also had an average WBGT higher than legal limits. The most adverse symptom was muscle cramps/pain of legs arms or abdomen. The likelihood of heat-related illness was highest at level 4 (97.57%), followed by level 3 (1.62 %) and level 2 (0.81%), and the severity of symptoms was at moderate (29.92%), followed by severe (18.06%), and mild (17.25%), Farmers had low risk levels 1 (34.50%), followed by level 3 (high) (29.11%), and level 2 (medium) (18.87%)  and level 4 (very high) (17.52%). The proportion of

likely high risk (level 3,4) was 46.63%. Air velocity while working had significantly negative linear correlated with the risk (r = - 0.145), also was relative humidity both while working and resting had negatively linear correlated with risk (r = -0.211, and r = -0.194) In conclusion, farmers who had a high risk of heat-related-illness must be decreased the workload to reduce the risk level of heat-related illness. Further investigations should be focused on the factors associated with heat-related illness to prevent of diseases.