The truth about … hog farms and asthma

A favorite line of those who attack hog farms is that our farms trigger – are you ready for this? – asthma. It’s a claim that shows up quite a bit, most recently in a recent Rolling Stone article:

Even people who live much farther away from hog farms can suffer from the fallout. A North Carolina Department of Health and Human Services study found that students in middle schools up to three miles away had higher rates of asthma.

Is this true? Not at all.

First of all, it wasn’t the state agency that did the study. It was a professor who was also an acknowledged activist against our farms.

Let’s look at the study. The professor took an existing 1999-2000 survey of self-reported wheezing among students in middle schools – and then compared it with locations of hog farms. (We’ll set aside the validity of this method as even measuring for asthma for now.)

What the data showed was that students closer to farms reported lower rates of wheezing:

All students age 12-14 at all schools in NC 26.2%
Students age 12-14 within 2 miles of hog farm 26.7%
Students age 12-14 at 2 to 3 miles of hog farm 30.7%

And indeed, those who were at schools within two miles of a hog farm had about the same rate of wheezing as the rest of the state.

Of course, you could manipulate that data. You could collapse that 2- to 3-mile range and create a “within 3 miles” of the farm versus “outside 3 miles.” But what would that tell you? You have to first understand how large an area two or three miles even is… the Beltline in Raleigh, for example, is essentially a three-mile radius of Cameron Village shopping center. So, what would “within 3 miles” tell you? Not much.

There are two reliable sources of information about asthma in North Carolina, and both show that living near a hog farm does not lead a higher prevalence of asthma. The NC State Center for Health Statistics reports asthma levels for 10 distinct regions of the state. More than 60 percent of the state’s hog are raised in Region 8, which includes both Duplin and Sampson counties.

Does Region 8 have the highest asthma rates in the state? No. And it’s not even close.


Region 9 & 10 10.7
Region 1 & 2 9.1
Region 7 8.6
Region 3 8.3
Region 5 8.3
Region 8 7.3
Region 6 7.2
Region 4 7.0

The NC Area Health Education Centers uses a similar approach. It reports the prevalence of asthma across nine statewide regions. North Carolina’s largest hog producing counties are located in the Southern Regional and Southeast regions.

Here’s what the data shows:


Area L & Eastern 10.1
Mountain AHEC 9.5
Wake 8.7
Greensboro 7.9
Northwest 7.6
Charlotte 7.5
Southeast 7.5
Southern Regional 6.4

When you hear outrageous claims about North Carolina hog farms, we urge folks to apply some common sense.