If these chromosomal abnormalities show up – does this mean that people are more likely to develop cancer 10 years down the line, 15 years down the line?
No. This is a general finding at the population level. We can’t make any risk predictions for any one child. And in fact some of the chromosomal aberrations may disappear. So we don’t really know what the life course is going to be. It’s simply that the finding is an early warning of potential risk in terms of cancer. But we really have to emphasize that it is not cancer. We cannot make risk predictions based on it.
If you had unlimited resources, how long would you want to follow your cohort?
If we could, we’d want to follow this group just as long as they would be willing to have us follow them. There are no studies like this with such in-depth assessment of early-life exposures and also other risk factors that then follow the children through their early years and on through adolescence. We know that adolescence is another vulnerable period where there are many hormonally related changes and reorganization of the brain. All kinds of things are happening that are important to track.
How do race and poverty fit into the picture of environmental exposures?
Race and poverty are important in that there are racial and economic disparities in exposure. Although air pollution affects everyone and it’s not confined to any one area, the levels tend to be higher in the lower income and inner city neighborhoods. Our population is drawn from one such community here in NYC. There are disparities both in exposure and in rates of the different outcomes that we’re concerned about.
Do you feel like there are parts of your research that are relevant to area outside of NYC?
Oh, I think so. The exposures we’re measuring are prevalent, they’re widespread, and they’re common in urban environments. We see consistent effects in our cohorts in Poland and in China. Those studies have not been going for so long and are not as in-depth as the one in New York, but we do have parallels in terms of the methods and the outcomes. The effects seem to be consistent, certainly for birth outcomes and neurodevelopment.
What are the questions you would like to answer in the future?
We’re very interested in prevention. Our focus more than anything is on research that can lead to prevention. That’s our reason for being. To prevent disease you need to have understanding of the associations between certain preventable risk factors and your outcomes of concern. Certainly all the outcomes I’ve mentioned [low birthweight, developmental delays, asthma, cancer] are of enormous concern. These are all health problems in children that have been increasing in recent years, and they have enormous individual and social costs, so obviously we want our research to help find ways to reduce those burdens.
The environment is one source that by its nature is amenable to intervention. What we would like to do in the future is keep the research going to document the long-term consequences of early life exposure, and to carefully document and then translate that work so it’s accessible and usable by policymakers. We also want to begin to understand better how the social environment, how the psychosocial factors, may interact with the physical environment in terms of either exacerbating the health effects or preventing and improving those outcomes.
Are there prevention measures or policy measures that you want to see in place now, that you wish would happen, that you think we have enough evidence to implement?
We know what can work. We’ve been able to see in our own cohort that efforts to clean up the air in New York City have led to decreasing levels of the PAH air pollutant. We know that over a period of time when we were monitoring the personal air that women were breathing in during pregnancy – the years between 1998 and 2006 – there were measures taken to reduce diesel fuel and other pollutant sources. And we’ve seen a decrease in our monitored levels.
We’ve seen that also in China, where a coal-burning power plant was shut down. We saw direct benefits in the subsequent group of children that were born in that city. We also have seen that regulations of pesticides work. The pesticide that we have been concerned about, chlorpyrifos, was banned for residential use for spraying and use for pest control in homes and in apartments [in 2000]. We were able to see that in cord blood after the phase-out ban, the levels [of chlorpyrifos] were dramatically lower.
So the good news is that these interventions can work. There are ways of reducing these exposures and directly measuring those benefits. Of course, we do need to do much better, and there are readily available means to reduce air pollution levels.
What can moms and dads do to try to protect their children from harmful exposures?
Certainly moms and dads have control in their own house of the smoking issue: not smoking themselves, and asking others not to smoke in the home. They also control other exposures to potentially toxic chemicals: cleaning and pest control. There are alternatives for those. And so we can make our home environment as safe as possible.
This doesn’t take care of the problem of outdoor air. There are strategies that are effective in reducing air pollution emissions to the air, and those have included the cleanup of the diesel bus fleet in New York. The bus fleet now has standards for diesel fuel and restrictions on idling. These standards, plus idling restrictions for school buses and trucks – these are things we know can work.