Sickness absence has been increasingly used as a health index in workplace populations. Nowadays, it is believed that low back - pain is the main cause of absence and disability among people working in bad ergonomic conditions. Also, researchers found that low back-pain is the main cause of disability among mine workers who manually handle heavy loads. This research was conducted into two phases to determine the absence indexes due to all diseases and low back-pain among 1186 coal miners in the Tezerea coal mine, located in the Shahrood district, in north eastearn Iran.
In the first phase of the study, all medical histories of miners were controlled. The data of those workers who had sickness and low back-pain absence for more than 3 consercutive days during Februray 1999-2000 have been recorded. Risk factors of low back-pain were determined by the Plible method at second phase.
The frequency rate of all sickness and low back-pain absence were 32.8% and 6% , respectively. The incidence rate of all sicknesses and low back - pain were 24% and 5%, respectively. The average absence duration for all sicknesses and low back - pain, respectively were 16.1 and 9.9 days. We found a significant relation between low back-pain absence and manual handling beyond forearm length (p-0.005 and OR=10.75). Also, P values and the Odds Ratio (OR) for repetitive manual handling, contractor workers and working in a cold workplace were p-0.0005 OR 2.21, p=0.025 OR= 2.21, and p=0.018 OR^ 2.54, respectively.
Research on sickness absence is a very complex subject and it is dependent on many factors, such as workforce configuration, employment polices, and absence of a definite perception. We found that 6269 working days were lost due to occupation sickness among 1186 miners, absence rates due to low back-pain among drillers and extractors are high in comparison with other miners. Personal individual characteristics, morphological, biomechanical, psychological stress and workplace conditions are factors causing low back-pain and injureis.