Bruce Lanphear, MD, MPH, is a clinician scientist at the Child & Family Research Institute, BC Children's Hospital and professor in the Faculty of Health Sciences at Simon Fraser University. His primary research goal is to quantify and ultimately prevent disease and disability—like asthma, learning problems and ADHD—due to exposures to environmental contaminants such as lead, tobacco and pesticides. He is leading an effort to build an online Atlas of Environmental Health to enhance public understanding of how environmental influences impact human health.
Docs Talk: How can the environment affect children's health?
Dr. Lanphear: In myriad ways. If exposures to toxins occur at key developmental stages, they can result in spontaneous abortion, stunted growth, cancer, preterm birth, asthma or behavioural problems.
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DT: How are impacts different for children than adults?
Dr. Lanphear: First, children's tissues are growing rapidly, and rapidly growing tissues are often more vulnerable to toxins. Second, children eat more food, drink more fluids and inhale more air than adults, pound for pound. Since our food, drinks and air are often contaminated, children get exposed to more toxins. Toddlers often put their hands and toys in their mouths, and as a result usually have higher concentrations of lead, cotinine (a breakdown product of nicotine) and pesticides in their blood and urine than non-smoking adults.
Young children also lack enzymes that help detoxify some chemicals. And they are more susceptible to diseases that take 20 to 30 years or more to develop simply because they will live longer than adults.
DT: Which environmental exposures concern you the most?
Dr. Lanphear: I don't like to pit one type of exposure against another, but toxins in consumer products are particularly worrisome because it's difficult to link exposures to diseases or disorders unless you conduct large and expensive studies.
It's also difficult to prove that an environmental contaminant is harmful because studies need to be replicated many times before government agencies deem them definitive. And while replicating a study is important, it delays our ability to protect children from environmental toxins by decades.
The real problem is that we have misplaced the burden of proof. Industry should be required to prove its products are safe before marketing them.
DT: Protecting children's health seems like a no-brainer. What are the barriers to reducing exposure to these contaminants?
Dr. Lanphear: We usually spend considerably more on medical services and research for adults. On the surface, this seems reasonable because death and disease are more prevalent among adults. But diseases usually have their roots in early childhood. Preventing them will involve long-term investments in reducing exposure to environmental hazards like unsafe consumer products, beginning in early childhood.
Some critics argue that investing in prevention isn't cost-effective. But the impact of environmental toxins on children's health—including learning problems, asthma, obesity and behavioural problems—costs about $50 billion annually in the U.S. alone. For every dollar we invest in protecting children from lead hazards, society would benefit by $17 to $220, a cost-benefit ratio that is better than vaccines for developing countries.
DT: Can you point to any success stories that show the results of promoting healthy environments for children?
Dr. Lanphear: There are several, and they all involved large-scale, population-wide interventions rather than lifestyle modifications. First, we've dramatically reduced instances of childhood lead poisoning over the past four decades. In the 1960s, hundreds of children died each year in large North American cities. In the past decade, only one child died. Blood lead levels in children have plummeted by more than 90 per cent.
Second, by banning smoking in public places, we've reduced rates of childhood asthma, low-birth-weight babies and preterm babies. These reductions were much greater than expected and show how small doses of toxins have substantial impacts on disease and disability.
And finally, the use of car seats, childproof medicine caps, fire alarms and other safety devices has dramatically reduced child deaths in the past three decades.
DT: What can parents and caregivers do to protect children from needless toxic exposures?
Dr. Lanphear: In the short term, families should try to eat fresh, unprocessed and organic foods. Parents shouldn't allow smoking in their households, and if they plan to renovate, they should make sure not to expose their children to lead, asbestos or other hazards. They should also avoid using fresheners, plastics and chemical cleaners in their homes.
The only real solution, however, is to change our regulatory framework and require industries to prove that their products aren't toxic.