Journal of Occupational

Background: Changes in global temperature and its health effects have recently been under much investigated. Consequently, these changes have affected mortality and morbidity rates which are important public health indices. The present study examines the effect of mean temperature on the frequency of hospitalization due to cardiovascular and respiratory diseases in Ali Ibn Abi Talib Hospital of Rafsanjan, Iran.

Materials and Methods: In this ecological study, data on hospitalization were gathered from electronic systems of hospitals and the data from the weather organizations were extracted from the weather station. All patients not living in Rafsanjan were excluded. Data were entered into SPSS and SAS software and the association between mean temperature and hospitalization frequency were analyzed using Poisson regression models.

Results: A negative significant association was found between mean temperature and mean number of hospitalizations due to cardiovascular and respiratory diseases. By each 1 °C decrease in mean temperature, the mean number of hospitalizations due to cardiovascular and respiratory diseases increased by 1% (95% CI 0.63-1.26%) and 4.33% (95% CI 4-4.64%), respectively. For cardiovascular diseases, there was no significant difference in mean number of admissions based on different age groups. However, in the 0-4-year age group, the mean number of hospitalizations due to respiratory diseases was significantly higher than the other age groups. For both cardiovascular and respiratory diseases, there was no significant difference between females and males in terms of the mean number of hospitalizations.

Conclusions: Reduction in mean temperature, in the present study, increased the mean number of hospitalizations due to cardiovascular and respiratory diseases and it was stronger for respiratory diseases. According to these findings, people who are at risk of cardiovascular and respiratory diseases should be forbidden from exposure to extremely cold temperatures.

Background: The role of temperature changes, as an environmental risk factor, in the human health status has been investigated in recent studies. Accordingly, the present two-year study was conducted to evaluate the incidence of myocardial infarction (MI) in warm and cold seasons in Ali-ibn Abi Talib Hospital, Rafsanjan, Iran.

Materials and Methods: In this descriptive and cross-sectional study, 264 patients hospitalized with MI during a two-year period (2013-2014) were included. Data on the participants were obtained from their electronic medical files and on the weather from the official Rafsanjan Weather Bureau station. The collected data was then analyzed using statistical tests including chi-squared test, Fisher's exact test, and logistic regression model in SPSS software.

Results: Data showed that 41.80% of MI occurred in hot weather, 14% in cold, and the remaining 37.12% in mild weather. According to the type of MI, 49.47% of non-ST elevation myocardial infarction (NSTEMI) and 44.44% of ST-segment elevation myocardial infarction (STEMI) occurred in very hot weather while 13.54% of NSTEMI and 18% of STEMI occurred in very cold weather. This difference was not significant.

Conclusions: Based on our data, MI had occurred mostly in hot weather and more than half of the cases were NSTEMI.

Background: Heat stress is one of the harmful factors present in many workplaces. It can lead to performance loss and low functionality of the labor force. Therefore, the aim of this study was to evaluate exposure to heat stress and its consequent performance loss among workers functioning in indoor high-temperature workplaces.

Materials and Methods: This descriptive, analytical study was conducted on indoor high-temperature occupations in spring 2014. This study was conducted on 15 bakeries, 11 restaurants and kitchens, and 2 industries with heating processes in Gonabad city, Iran. In total, 1450 individuals worked on the investigated sites and were exposed to thermal stress. The inclusion criterion for this study was working in an environment that included a heating process and the exclusion criterion was unwillingness to participate in the study. Heat stress was measured based on wet-bulb globe temperature(WBGT) and the ISO 7243standard. The graph of performance loss versus thermal stress proposed by Kjellstrom et al. was used to determine the performance loss caused by thermal stress.All individuals and managers were informed of the aims of the project and were assured of the confidentiality of the data. Statistical analyses were performed using SPSS software.

Results: The mean exposure to heat stress in Barbari, Sangak, and Lavash (three types of bread) bakeries were 29.73, 27.89, and 29.43 °C, with a mean performance loss of 65%, 23%, and 64%, respectively. In some cases, the performance loss in Lavash bakeries was as high as 98%. The mean exposure to heat stress in refractory brick and porcelain manufacturing industries were 32.04 ºC and 32.35 °C, leading to a concomitant performance loss of 89% and 92%, respectively. The mean WBGT in the kitchens was 31.88, which could lead to a performance loss of 80%.

Conclusions: In addition to a host of diseases and complications caused by heat stress, extreme heat in the workplace can significantly reduce the performance of the labor force, and consequently,their production. Through appropriate planning and control of heat stress in the workplace, not only are many diseases prevented, but also the performance and efficiency of workers are greatly improved.