I love this blog because it's really the only place that keeps me up to date on current studies that otherwise I wouldn't even know existed now that I'm out of grad school. Clearly I don't read the whole study, but this blog does a great job posting the important snippets.
The current study being discussed is one that shows exposure to lead and maternal prenatal smoking are linked to a diagnosis of ADHD when taken as individual factors, but when taken together have an even greater correlation to a diagnosis of ADHD.
I don't think any of us are surprised.
Here's the thing though- I knew very little about lead exposure before a few years ago when I had a student with significant special needs due to lead poisoning. I went and read everything I could google on the subject and learned a few interesting facts:
1) Lead is sweet. They used it as a sweetener in Ancient Greece until someone made them stop because it was literally making them stupider.
2) No matter how many times lead paint has been painted over, once the top coat of paint cracks, the lead paint underneath will crack and fall off as well.
Picture a baby crawling along the floor, putting everything that crosses his path into his mouth because, well, that's what babies do. Somehow a small paint chip ends up on his hand as it makes its way to his mouth. One small taste- but it tastes good. Sweet. So why not go back for more? It's not that your mom isn't watching you- or that your house hasn't been repainted- or that you're allowed to suck on a lead-painted toy. It's that you are a baby, you explore with your mouth, and when something tastes good you're going to put it in your mouth again.
That year I also learned that a child needs to have a certain level of lead in their blood for it to be considered significant. But other children in my class also had high levels of lead in their blood, but because their official level was a point or two below the cut off the lead was not considered to be a problem.
I'm not a doctor, and I only know my facts from google, and not somewhere professional so I could be way off base. But I think lead exposure occurs more than we think it does, especially in schools where children grow up in subsidized housing. As this study shows, when combined with other factors like prenatal exposure to smoke, it can lead to significant problems that interfere with learning.