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Dr. Paul Thompson offers perspective on the recent "Pollution and the Heart" article published in NEJM and provides insight into the potential for metal pollution from beer on influencing risk of cardiovascular disease.
Pollution, greenhouse gases, and global warming are finally on everybody’s agenda, including the New England Journal of Medicine’s (NEJM) whose November 11, 2021, edition included an article entitled “Pollution and the Heart”.1 Pollution is defined as the release of unwanted materials into the environment by human activity.
The article summarizes evidence linking air, metal, and chemical pollution to cardiovascular disease (CVD), primarily coronary artery disease (CAD). Both indoor and outdoor air pollution are a larger problem in less affluent countries because environmental regulation, such as the United States’ Clean Air Act of 1970, has reduced pollution in wealthier countries, and because indoor pollution is often a household problem and poorer homes cook and heat with polluting heat sources.
The article also cites evidence linking metals including lead, mercury, arsenic, and cadmium to CVD. Lead is a known hypertension risk factor, but also appears to increase CAD even at low levels. Mercury enters environment from gold mining and burning coal. Mercury from burning coal precipitates into water, is consumed by fish, and enters the fish-to-man food chain. Arsenic is usually obtained from drinking water from international “hot spots” including the southwest US and northern New England. Arsenic in New England enters the water from the granite bedrock. Cadmium pollution comes from tobacco smoke and work exposure, as well as green leafy and tuberous vegetables grown in contaminated soil.
The authors note the cadmium discussion that a randomized controlled clinical trial (RCCT), found that chelation therapy using EDTA reduced the composite endpoint of total mortality, myocardial infarction, coronary revascularization, stroke, and hospitalization by 18% (95% CI, 1-31%, P <.04) with a larger effect in patients with diabetes. I guess I should not have been so critical of my patients who asked about chelation therapy. Another RCCT of chelation therapy is underway to verify these results. The authors suggested that the benefit from chelation therapy might be due to removing toxic metals such as cadmium. The review also notes that chemical pollutants including halogenated hydrocarbons, perfluoroalkyl compounds, and chemicals associated with plastics have all been related to CVD.
But they forgot the beer. I was a medical student in the early 1970’s and not far removed from my fraternity house, undergraduate days when a lecturer mentioned that in 1965-6, there had been an outbreak of heart failure in Quebec, Canada linked to beer.2 I woke up immediately. A brewery in Quebec had added cobalt to their beer in order to stabilize the beer’s foam “head”.2 The added cobalt was determined to be the cause of the cardiomyopathy.
The cobalt cardiomyopathy was associated with elevated hemoglobin levels and pericardial effusions. A total of 48 habitual beer drinkers were affected in Quebec with a mortality rate of 46%. Similar epidemics related to beer consumption were subsequently reported from Omaha, NE; Minneapolis, MN; and Belgium. The dose of cobalt was not large and was below the dose of cobalt used at the time to treat anemia. This led to the hypothesis that it was the combination of cobalt and alcohol that lead to the cardiomyopathy. Concern about cobalt heart disease re-appeared with evidence that some patients developed heart failure from chromium leakage from failed hip replacements.2 This concern has abated, but not totally disappeared.3 It may require the combination of a failed hip replacement and excessive alcohol consumption.
In fairness to the pollution review, the chromium in the beer was not unwanted and was added intentionally, so should probably not have been included in a pollution review. In fairness to me, I only focused on the metal section of the NEJM article to make sure my beer was safe.