I have often wondered what impact the diesel fumes from yellow school buses might have on students. I know that I don’t like driving behind those buses because the fumes don’t smell good, so it seemed to me that there might be some health consequences. Others have wondered, too, and there is evidence that exhaust levels in buses can have health effects. However, it is hard to study this sort of thing, because finding people that are exposed to high levels of diesel in a controlled environment over long enough periods to measure the effects is challenging. Now, a study from the National Cancer Institute in Maryland looking at people working with another type of big yellow vehicle- the diesel trucks used in mines- has shown that heavy exposure to their fumes can increase the risk of death from lung cancer.
In the study, underground mines with no high levels of other known cancer causing agents were used. The study looked at the rate of lung cancer in workers and measured the levels of exposure to diesel fumes. As would be expected, the higher the level of exposure, the higher the increase in risk of getting cancer. In mines with the highest levels of exhaust the risk of lung cancer was three times the risk in mines with little exhaust, and even in these mines, the risk of lung cancer was increased over levels seen in the population.
Clearly, this suggests that miners should be aware of the levels of exhaust, and that increasing air quality in mines would be to their benefit. However, the results also suggest that people working in other places with high levels of diesel fumes may also be at risk, and this includes millions of workers at warehouses and bus depots. Likewise, people living in cities are exposed to diesel fumes.
Luckily, there is a solution to this problem: reduce emissions from diesel vehicles. In fact, modern diesel engines produce much lower levels emissions than older models, with some diesel cars producing nearly no emissions.
I can’t help thinking back to the kids in the buses. It is hard to tell what the effect might be, but sitting in a bus every day that has diesel fumes coming out the tailpipe might not be very good for all those schoolchildren, and if a child grows up taking buses every day, the exposure will add up. Hopefully, the effects are minimal. Then again, it may be worth investing in buses and other diesels that are cleaner!
Reference: The Diesel Exhaust in Miners Study: A Nested Case–Control Study of Lung Cancer and Diesel Exhaust
J Natl Cancer Inst 2012;104:1–14

Obviously, the earlier individuals have access to information about their health, the longer they have to make appropriate choices. When it comes to mental-health, a properly responsive school environment may be the first place problems can be identified and, if possible mitigated or corrected. The discovery that there are possible early and characteristic differences in scoring on standardized testing, may give crucial warning signs that would allow proper intervention on behalf of affected students, especially those already at higher risk because of a family history of schizophrenia.

The study conducted by Duke University followed 1000 New Zealanders over the course of 30 years, and administered routine standardized testing at age 3, 5, 7, 9, 11, and 13 years of age. By the time study participants had reached 32 years of age, around 1 percent of participants were being treated for schizophrenia, and another 1.5 were diagnosed but untreated. The testing results from those suffering from schizophrenia had characteristic differences by the age of 7; so at least within the first year of schooling, there are already differences that could raise concern.

Doing poorly on certain standardized tests is certainly not in itself an indication of schizophrenia, but it’s the ways in which the children who later suffered from schizophrenia fell behind their peers that is revealing. According to study author Richard Keefe, these children lag behind their peers initially, and then continue to deteriorate. They tended to have more problems with verbal skills and memory; both obvious impediments to successful learning.

Naturally, the question to ask now is can anything be done to improve our early identification of these at-risk children, and intervene? It is already common to treat early identified autistic children with lots of interactive therapy to help them develop and improved social skills. Can we identify potential schizophrenics and stop whatever process that allows the 3-year old “symptomless” child into the 7-year old “high-risk” individual?

The study can be found at:

http://ajp.psychiatryonline.org/cgi/reprint/appi.ajp.2009.09040574v1

Schizophrenia in childhood from G2C Online:

http://www.g2conline.org/819