The general public is well aware of the health hazards of tobacco smoking. The cocktail of chemical compounds in cigarette smoke poses a significant risk for chronic obstructive pulmonary disease and malignancies of the lungs, mouth, throat and other parts of the body. Additionally, pregnant women who smoke put their developing children at risk for birth defects.
However, as with many carcinogens, the chemical compounds in cigarette smoke rarely exert their effects in isolation from other substances. Previous research has demonstrated that asbestos, radon and other products aggravate the health risks posed by cigarettes. One team of scientists from Uppsala University suggested that high blood levels of polychlorinated biphenyls will also elevate the impact of smoking, as published in the journal PLOS ONE.
What are PCBs?
The U.S. Environmental Protection Agency describes PCBs as substances once used as plasticizers in paints, rubber, plastics and dyes, as well as dielectric fluid for various electrical appliances. This utility is attributed to PCBs' properties as non-flammable, chemically stable and electrically insulating.
Use of PCBs in the U.S. was ubiquitous until October 1976, when the federal government banned the processing, manufacturing or distribution of these substances because of their link to negative health effects. Specifically, PCBs were associated with cancer and intellectual disabilities. Additionally, animal studies have shown that PCB may hurt the immune system, endocrine system, nervous system and reproductive system.
Despite the ban, the EPA still allowed preexisting products made with PCBs to be used as long as they were properly monitored. However, the scientists from Uppsala University pointed out that PCB tends to stay in the body for extended periods of time. Additionally, PCB tends to accumulate among organisms up the food chain.
'PCB increases the risk dramatically'
To understand the impact of PCB in smokers, the authors of the new study kept track of the health of about 1,000 individuals who were at least 70 years of age at the outset of the research. The scientists analyzed mortality data that was collected over the course of eight years.
Results showed the mortality risk was for smokers with low levels of PCB in their blood was 40 percent higher than it was for non-smokers. For smokers with high levels of PCB, that risk increase was 640 percent. Among former smokers, high levels of PCB raised the mortality risk by 370 percent, compared to 20 percent for former smokers who had low PCB levels.
"These data show that exposure to PCB increases the risk dramatically in both smokers and former smokers. For non-smokers, no elevated risk was found, at any rate not after eight years. More studies are needed to clarify the risks for this group," Lars Lind, professor of cardiovascular epidemiology at the Department of Medical Sciences, Uppsala University, said in a statement.
To help protect people in the U.S. from further exposure to PCBs, the EPA published several guidelines pertaining to the contamination of water as a result from mining and other industrial operations.
