Thirst as the threshold symptom to prevent worsening heat-related illness.

INTRODUCTION: The heat-related illness (HRI) is a continuum illness ranging from minor health effects to life-threatening medical emergencies when the pathological effects of heat load are not prevented. The aim of this study was to demonstrate the threshold HRI symptom for deciding to take simple preventative actions both by the individual workers and employers. METHOD: A total of 328 municipal workers were enrolled in April to March 2016 were asked to recall if they experienced eleven HRI symptoms during the previous work day. Rasch Measurement Model was used to examine the unidimensional parameters and bias for gender before identifying the threshold of HRI symptoms. We determined the threshold symptom based on the person-item map distribution on a logit ruler value. RESULTS: A total of 320 respondents were analysed. The psychometric features HRI symptoms suggested evidence of unidimensionality and free of bias for gender (DIF size =0.57; DIF t value =1.03). Based on the person-item map distribution, the thirst item was determined as the threshold item (Cut-off point = -2.17 logit) for the preventative action purposes to group the person as mild and moderate/severe HRI groups. CONCLUSION: Thirst item is viewed as threshold symptoms between mild and moderate or severe HRI symptoms. It is a reliable symptom to initiate behavioural response to quench the thirst by adequate fluids. Failure to recognise the thirst symptom may lead to devastating unwanted health complications.

Effects of hydration practices on the severity of heat-related illness among municipal workers during a heat wave phenomenon.

INTRODUCTION: The continue rise in temperatures due to climate change increases the risk of heat-related illness (HRI) among outdoor workers. This study aims to evaluate the effects of hydration practices on the severity of HRI during a heat wave episode among municipal workers in Negeri Sembilan. METHOD: A cross-sectional study was performed in March and April 2016. The outdoor temperatures were measured using the wet-bulb globe temperature (WBGT) tool. The participants completed a self-administered questionnaire containing sociodemographic factors prior to work shift; while working profile, hydration practices, and HRI symptoms at the end of work shift. The hydration status of the respondents was assessed by direct observation of their urine colour. Multiple logistic regression was performed to ascertain the effects of age, working profile, hydration practice, history of previous HRI, and hydration status on the likelihood that outdoor workers having moderate to severe HRI. RESULTS: A total of 320 respondents completed the questionnaire. The mean (standard deviation) outdoor workplace temperature was 30.5°C (SD 0.53°C). The percentage of respondents who experienced moderate to severe HRI was 44.1%. The likelihood that outdoor workers experienced moderate to severe HRI symptoms was associated with irregular fluid intake [odds ratio (OR): 16.11, 95% confidence interval (95%CI): 4.11; 63.20]; consumption of non-plain water (OR: 5.92, 95%CI: 2.79; 12.56); dehydration (OR: 3.32, 95%CI: 1.92; 5.74); and increasing outdoor workplace temperature (OR: 1.85, 95%CI: 1.09; 3.11). CONCLUSION: Irregular drinking pattern and non-plain fluid intake was found to have a large effect on HRI severity among outdoor workers exposed high temperatures during a heat wave phenomenon.