# College Athletes and Sudden Cardiac Death: Why Do Male Basketball Players Have Such a High Risk?

There’s an interesting story in today’s Wall Street Journal, by Katherine Hobson about a new method some cardiologists have come up with to better diagnose life-threatening heart conditions among student athletes. Apparently, since the hearts of well-conditioned athletes sometimes put out more electrical voltage than average, their ECG’s can often look like that of someone with a heart problem. This has led to an underestimation of the risks that sudden cardiac death (SCD) poses to student athletes, according to the study, even though it’s their leading medical cause of death during exercise. The findings were published this month in the American Heart Association journal Circulation. You can read the abstract here.

What really caught my eye though was an info-graphic the WSJ ran next to the story. Using data from Circulation, the graphic depicts the overall rates of SCD, from high to low, per year from 2004 to 2008 among NCAA college athletes, broken out by different sports. I’ve reproduced it in a table below:

 Overall Men Women Basketball 1 in 11,394 1 in 6,993 1 in 37,799 Swimming 1 in 21,293 1 in 34,552 1 in 16,457 Lacrosse 1 in 23,357 1 in 19,770 1 in 30,531 Football 1 in 38,497 1 in 38,497 N/A Cross-Country 1 in 41,695 1 in 59,484 1 in 32,801

Why, I wonder, do male basketball players have such an abnormally high rate of SCD compared to other athletes? And why do female swimmers rate so high as well?

#### Mike

Marfan Syndrome might explain some of the difference for Men's basketball players.

http://en.wikipedia.org/wiki/Marfan_syndrome

#### pshrink

Marfans should also increase the rate in female Basketball players.

#### MRB

I dunno, Marfan's Syndrome?

#### Juan

We would need the data from necropsies, if avalaible, to draw up a theory

#### Joe in Jersey

Seems to me that the first thing I would do is break that data out by height, weight and race. Then I would check for patterns geographically (did you know that southerners have a pretty big sweet tooth, to the point that the most popular wines in Georgia are sweet wines, such as moscato) and versus family history. Without having access to this data I would guess that these athletes come from a family which has a history of cardiac issues, and score higher on tests (such as cholesterol levels) that indicate cardiac warning signs. It would also seem to me that basketball players are taller than other athletes (on average), don't doctors say that this would make hearts work harder to circulate the blood. Are female swimmers taller than other female athletes on average? Are they taller than female basketball players on average?

#### cackalacka

Nah, female swimmers are not significantly larger than the general population in a way that women b-ball or even volleyball players are.

Generally speaking, after gymnastics, there aren't any college sports that put anywhere near the amount of aerobic stress on an athlete's body than swimming (and conditioning for swimming, ) particularly middle-distance and distance swimmers.

#### Aaron

My first guess would be due to socioeconomic reasons. Male basketball players may have had a worse diet, less health care and more stress prior to becoming a college athlete.

Diet could also potentially explain female swimmers as they may have more body image issues from competing in a skin tight swim suit.

#### Emily

It's so obvious that this is confounded by race. Blacks and males have higher rates of SCD due to genetic reasons, and they also compose a higher proportion of the basketball playing population. Control for race and these differences would vanish.

#### Jazi

What are the confidence intervals?

Is there enough data to make the anomaly significant?
(remember it being an ex post observation in four sports two genders.
Anything below 1/500 p value is nothing here

#### Jim

I wonder about the statistical significance of the differences. The abstract indicates that there were 45 cardiac related deaths in five years across all sports, or an average of only 9 per year. Most sport probably only had a few deaths during the entire study period. A difference of only one or two deaths may be enough to skew some of these numbers and that might be simply random variations.

#### Joel Upchurch

I agree with Jim. The numbers are simply too small to be statistically significant. I'd like to see a comparison to the general student population for sudden cardiac death. When you are talking about 9 deaths a year compared to 350,000 deaths per year nationwide, it is just a statistical fluke.

This also leads to another question: was drug use alone responsible for the death of Len Bias or were other factors responsible that seem to be more common among basketball players than the general population?

#### Barry

Hypertrophic Cardiomyopathy (HOCM or HCM) is the most common cause of sudden cardiac death in young, healthy athletes in the United States. It is inherited as an autosomal dominant trait in 50% of patients who have it. Some say it is more common in African-Americans, but it might just be underdiagnosed in African-Americans which would lead to more deaths due to the condition (http://www.theheart.org/article/259021.do). This could help explain the observation in basketball players. Swimmers, not so much.

-Barry (medical student)

#### Ken Rabin

Several years ago two University of Maryland basketball players, both of them big men, died of cardiac failure. In both cases, I recollect that it was found that both suffered from Marfan Syndrome (which Abraham Lincoln was alleged also to have).

#### Carolyn Thomas

Marfan syndrome often affects the long bones of the body, leading to traits like a tall, thin build with long arms, legs, fingers, and toes, and flexible joints. Marfan is an equal-opportunity diagnosis, afflicting men, women and children in similar numbers, so if this is the culprit in basketball, why ARE so many more male basketball players affected than their female counterparts?

Women with Marfan syndrome are apparently at significantly higher risk of aortic dissection during pregnancy (maybe a time when they are less likely to be playing competitive basketball?) Interesting stats here.