Did Sept. 11 Cause Heart Attacks?

A new "study" claims a rise in heart attacks treated at a Brooklyn hospital can be traced to the Sept. 11 attacks.

But it's hard to decide which had less thought go into it — this inadequate research or the American Heart Association's decision to promote it.

The study's researchers compared the number of patients admitted to the hospital for possible heart attack or serious heart rhythm disturbance from July 13 to Sept. 10, 2001 (pre-9/11) with the number of patients admitted from Sept. 11 to Nov. 10, 2001 (post-9/11). A similar comparison was done for the same time period during the preceding year of 2000.

A 35 percent increase in heart attacks and a 40 percent increase in arrhythmia were reported from pre-9/11 to post-9/11. For the year 2000, the reported increases in heart attack and arrhythmia were only 6 percent and 7.5 percent, respectively, for the same time periods.

Combined with the indisputable facts that the Sep. 11 attacks caused increased stress among many and stress increases the risk of heart attacks and arrhythmia, the claim that the Sep. 11 attacks increased the number of heart attacks has some intuitive appeal.

It's too bad that the purported analysis falls way short of confirming intuition.

First, the data presented are from only one hospital. But there are about 65 hospitals in New York City — and many other emergency medical facilities — that weren't included in the study. The researchers didn't explain why they thought the data from the Brooklyn hospital were sufficient to make their case.

The study included a total of 113 heart attack cases for 2001 and 103 for 2000. But this is only a small fraction of the total number of heart attacks that occurred in New York City during those years.

There were 4,775 fatal heart attacks in New York City during 2001, according to the City's compilation of vital statistics, meaning there could have been up to tens of thousands more non-fatal heart attacks. The heart attack cases included in this study constitute a very small and likely non-representative proportion of the number of heart attacks in New York City.

Ironically, New York City vital statistics indicate that more fatal heart attacks occurred citywide in 2000 (4,815) than in 2001 (4,775). It's not clear that the heart attack experience at the lone Brooklyn hospital reflects the citywide experience.

It would also be important to compare the 2001 heart attack experience with more than just year 2000 data. After all, how do we know that 2000, rather than 2001 isn't the real anomaly?

Despite the small number of heart attacks involved in this study, no effort was made to see whether any of the heart attacks might have been related to stress caused by the Sep. 11 attacks. The researchers apparently expect us to assume that because there were more heart attacks in the post-9/11 period, the increase can only be due to the Sep. 11 attacks.

Certainly, some of the media fell for that line. Reuters' headline, for example, was "Study: Sept. 11 Attacks Cause Rise in Heart Attack."

About two weeks before the study was released, I contacted University of Texas Medical School researcher Dr. Jianwei Fang for a copy of the full study. Rather than providing a copy, he referred me to the media relations department of the American Heart Association, at whose conference the results were released this week.

The Heart Association responded by sending me a copy of Dr. Fang's abstract, essentially a quick-and-dirty overview of the study results. When I reiterated my request for a copy of the complete study, the Heart Associated responded, "there is no full study at this point."

Persisting in my futile request — I still can't get over the fact that researchers announce study results that can't be validated, verified or even minimally reviewed before being trumpeted to the media — I asked the Heart Association how I was supposed to evaluate the claims without the study.

The Heart Association responded that I was "free to ask other researchers to comment on the abstract to gauge its validity." But how can anyone gauge the validity of a study based on just a sketchy abstract?

The American Heart Association assured me that because the abstract was accepted for presentation "means it offers some degree of credibility."

I beg to differ.

Steven Milloy is the publisher of JunkScience.com, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-defense Against Health Scares and Scams (Cato Institute, 2001).

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