October 20th, 2014
Are Women Who Live Near Roadways at Greater Risk for Sudden Cardiac Death?
Jaime E Hart, Sc.D and Harlan M. Krumholz, MD, SM
CardioExchange’s Harlan M. Krumholz interviews Jaime E. Hart about her research group’s study of the relation between residential proximity to roadways and sudden cardiac death in women. The study is published in Circulation.
Krumholz: Please describe your main findings for our readers.
Hart: Among 107,130 women in the Nurses’ Health Study, women living within 50 meters of a major roadway had a 38% greater risk for sudden cardiac death (SCD) and a 24% greater risk for fatal coronary heart disease, compared with women living at least 500 meters away. The findings persisted after adjustment for multiple traditional cardiovascular risk factors.
Krumholz: During a period of 26 years, the SCD rate was 0.5%, or 0.02% per year. Does the fact that living near a roadway was associated with almost a 40% increased risk have any practical importance?
Hart: This is an excellent point. For any given individual, the risk for SCD, even with residential exposure to a major roadway, is very low. However, this level of increased risk is important on a population level.
Krumholz: Given that property near roadways may be less expensive, could the risk be related to socioeconomic factors?
Hart: Residual confounding by socioeconomic status is always a concern in studies of roadway proximity. However, women in this cohort tend to be of middle to upper SES, as they all had to be nurses at enrollment. We also adjusted our analyses for a number of individual-level and census-tract–level measures of SES, so there isn’t likely to be substantial residual confounding.
Krumholz: What do you think people should do as a result of this research?
Hart: First, wait for confirmation in other studies. Although the findings are consistent with the literature suggesting that roadway proximity is associated with increased risk for several adverse cardiovascular outcomes, our specific results need to be confirmed in other populations. An important next step is to identify what specific exposures, such as noise or air pollution, may underlie these findings.
JOIN THE DISCUSSION
Share your thoughts on the findings from Dr. Hart’s study.
The authors are to be congratulated. This is quite an interesting study that points out yet again that environmental pollution may be a modifiable risk factor for coronary disease. This overall topic, of course, is also addressed, by inference, in the work we did with chelation therapy. We demonstrated that infusions of a metal chelator reduced cardiovascular events, particularly in patients with diabetes.
My questions are obvious – can this be tested in a secondary prevention population in order to have more events? Also, was there a particular signal of harm in patients with diabetes? Urine metal levels would have been quite interesting. Also, what about proximity to airports? Piston-driven aircraft engines still use leaded gasoline, although this is being phased out. Lead has robust links to cardiovascular disease.
I think the era when we can ignore what we take in from the environment is passing. There is increasing evidence that metal and other pollutants may cause measurable cardiovascular damage. We need to actively search for pharmacology to undo or prevent the damage.
Dr. Lamas- noise levels near airports(Heathrow, in this instance)have been correlated, but perhaps , noise is a surrogate marker for particulate/lead exposure.(BMJ 2013; 347 doi: http://dx.doi.org/10.1136/bmj.f5432 (Published 08 October 2013)
Very important findings of socioeconomic consequences.In the German medical literature there are articles linking proximity to highways to a high incidence of lung cancer.