Posts Tagged ‘Causation’

Five CHD Questions: Where?

May 11, 2010

Where do Congenital Heart Defect (CHD) Survivors live?

The answer to this question seems to be obvious – everywhere! If the disease does not discriminate about who it strikes (CHD affects 1 an average of every 125 live births in America) then it stands to reason it isn’t very particular about where it strikes, either. But that isn’t always true.

As I have mentioned before, there seems to be an area of Baltimore, Maryland that contains a “cluster” of CHD occurrences, most of them Hypoplastic Left Heart Syndrome (HLHS). And while the national incidence of CHD is 1 in 125 live births; in the state of Wisconsin the average is 1 in 74 live births.

The occurrence of CHDs in mainland China has quadrupled in the past 20 years, from 6.2 CHDs per 10,000 live births to 25.1 Heart Defects per 10,000 live births. They haven’t caught the United States, where the number of CHDs is 80 per 10,000, but China has so many people that approximately 1 million children per year are born with some type of birth defect. China has a growing pollution problem that is probably a major contributor to the number of birth defects that occur in that country.

Back home, an area of primary concern has to be Butte, Montana, home of the Berkeley Pit. The Pit is a former open-pit copper mine that was abandoned in 1982. Since then, water has seeped into the pit and is very toxic. The toxic brew is about a mile deep and can kill birds that stay too long. This area needs monitoring not only for CHDs, but for increased occurrences of all birth defects.

If you read the first link in this post (“an area of Baltimore, Maryland”) you’ll find that the researchers tried to determine exactly what in the area was causing HLHS in the cluster by finding the common thread that linked all of the events together. They found very little commonality. (One or both parents creating painted works of art seemed to be somewhat of a factor, but only in that one area.)

So what does trigger the occurrence of a Congenital Heart Defect? Most experts agree that it is an unknown combination of genetics and environment. But what combination is the proper mix? And what exactly happens to trigger a heart defect?

Answer these questions, and we’re on our way to beating CHDs.