Electrocardiogram changes among Iranian coal-mine workers

Aim. This study investigated electrocardiogram changes among coal-Mine workers in Kerman, Iran.
Background. Chronic lung diseases such as pneumoconiosis, which cause air flow limitation are common among coal miners. Pneumoconiosis may results in heart disease and changes in the electrocardiogram. Due to the impact of pulmonary function on cardiovascular status, this index may show the risk of cardiovascular diseases in coal miners.
Method. This retrospective cohort study was conducted among 90 coal-mine workers in kerman as case group and 74 workers in the same mines who were not in contact with coal as controls between 2009-2013. The groups were matched in terms of age and work history. The inclusion criteria included age range of 30-45 years and work experience of at least 15 years. Individuals with a history of smoking, diabetes, obesity with a body mass index over 24, cardiac medications that caused ECG disorders and a history of systolic blood pressure above 120 mmHg were excluded from the study.
Findings. The mean age of the workers was between 32 and 46 with an average of 34.61 years. There was no statistically significant difference between groups in terms of age, weight and work history. Comparing electrocardiogram changes between the groups showed a statistically significant difference in the mean intervals of PR, QRS and QT in the leads D I, D II, and D III, with p≤0.0001, p≤0.01, and p≤0.001, respectively. ST segment interval was not significantly different between the groups.
Conclusion. Long term exposure to the coal may create electrocardiogram changes.