When I (or anyone else) speaks of the number of Congenital Heart Defect (CHD) cases in the United States, where do we get our numbers? And how do we know they are accurate?
An accurate estimate relies on two factors: Reliable numbers and good math. I usually start with the estimate provided by the American Heart Association. That number has changed recently: They now report that out of every 1000 births, 9 will have some form of Congenital Heart Disease. (1 defective heart per 111.111 births; 1000 divided by 9 equals 111.111) We can confirm that number by looking at data from other Heart Health organizations; in this case, most of the other prominent organizations – including the March of Dimes – contend that the correct number is 8 in 1000. (1 defective heart per 125 lives births; 1000 divided by 8 equals 125.0) So for the moment, we’ll stick with 8 in 1000, which is the number I have been using.
Which brings us to our first question: Why does the American Heart Association feel that the number is higher? Are there more heart defects occurring? Or are doctors getting better at detecting them? That’s a question I don’t have an answer for – and something to investigate later.
So if we accept that 8 children in 1000 are born with a CHD, how many is that per year? Now we need good math – The United States Bureau of the Census reports that on average, there is 1 birth every 7 seconds in the United States. Since we know there are 86,400 seconds in a day, there must be 12,343 people born every day. 12342.857 people to be exact, but since you can’t have 0.857 of a person, you round up all fractions.
8 out of every 1000 births can be converted to a decimal number: 0.008. Total number of births divided by the occurrence of heart defects (12,343 multiplied by 0.008) means there are an average of 99 people born every day with a heart defect. (98.744, to be exact)
Remember, we’re still assuming that 8 out of every 1000 births has a heart defect. Let’s assume for the moment that the American Heart Association is correct and say that 9 out of every 1000 live births has a CHD.
That doesn’t change the birth rate (1 every 7 seconds) or the number of seconds in a day (86,400), so we can still use those original numbers. The number of people born every day won’t change, it is still 12,343, and 9 in 1000 converts to 0.009, obviously. 12,343 multiplied by 0.009 equals 112 people per day. (111.087)
99 people vs. 112 people. The difference 1 person per 1000 can make is astounding.