According to a study published in BMJ (British Medical Journal), individuals who use opium for long periods of time, even in relatively low doses, are more than twice as likely to die from several major causes including cancer, circulatory diseases and respiratory conditions. Results from the study, conducted in northern Iran, raise questions regarding the risks of long term prescription opioids for chronic pain treatment. Opium consumption is extremely common in Iran and approximately 20 million individuals worldwide use opium or its derivatives. This study is the first to measure the risks of mortality in opium users vs.non-users. Prior investigations indicate that opium may play a role in coronary heart disease, throat cancer, bladder cancer and other conditions. However, researchers are unsure about the effects opium has on overall mortality, particularly for low-doses used over a long period. In order to examine the association between opium use and subsequent risk of death, the researches studied opium use among 50,045 adults, aged 40 to 75, living in Golestan Province in northern Iran, for an average of 5 years. 8,487 (17%) study participants reported using opium. Those who used opium did so for an average duration of 12.7 years. During the study period 2,145 deaths were reported. The researchers adjusted for several factors, including cigarette smoking and poverty, and found that individuals who use opium were 86% more likely to die from several major causes including: Asthma Circulatory diseases Tuberculosis Chronic obstructive pulmonary disease (CORD) Cancer The researchers excluded participants who self-prescribed opium after the onset of chronic illness, and found that the connections were still strong. In addition, they observed a dose-response relationship. Increased risk of death was associated with both opium ingestion and opium smoking. Assuming this represents a direct (causal) association, the researchers estimate that approximately 15% of all deaths in this population are due to opium use. In order to better understand opium use and mortality and long term opioid analgesics for treatment of pain, further studies are required, say the researchers. In an associated report, Assistant Professor Irfan Dhalla from St Michael\'s Hospital in Toronto says: \"In high income countries doctors rarely, if ever, encounter someone who uses opium. However millions of patients with chronic pain are prescribed opioids such as morphine and codeine that may carry risks that are incompletely understood.\"