Finding the Causes of Childhood Diseases.
Many experts think so, and some states are taking action.
Eleven children in the small farming community of Fallon, Nev., were diagnosed with leukemia within a two-year period. While that might not seem like a lot in an urban area, in tiny Fallon, population 7,590, it's almost 30 times higher than expected.
Assemblywoman Marcia de Braga says Nevada has to find out why. And even though less than 1 percent of cancer cluster investigations find preventable causes, the Legislature has agreed to spend $500,000 to try to find an answer in the small town that has been home to the Navy's premier tactical air warfare training facility for 55 years.
The Community is concerned that pesticide use, dumping of jet fuel by naval aircraft and high arsenic levels in drinking water may be contributing to the elevated leukemia rates.
"Maybe we don't learn the cause," de Braga says, "but if we identify and clean up potential environmental hazards, we improve the health in Fallon and maybe get rid of some of the things that contributed to these childhood leukemia cases. It's well worth whatever we spend to further our knowledge."
Fallon is not alone. Residents of Brick Township in New Jersey had long felt that autism rates in their community were unusually high, and a federal investigation validated those suspicions. Unfortunately it left them with more questions than answers. Investigators from the Centers for Disease Control and Prevention (CDC) concluded that while the rates in Brick Township were far higher than average, there was not enough information on autism to say whether it could be defined as a 'cluster' compared with the rest of the country.
Further adding to the residents' confusion is the fact that the causes of autism are not well understood. While toxins are suspected of playing a role, there is not enough available research to prove it. This case underscores how little is known about the rise in certain children's diseases and how they might be influenced by exposure to substances in the environment.
We don't know what causes asthma, for example, but the suspects include second-hand tobacco smoke, air pollutants, allergens in the household and inherited predisposition. Asthma rates have nearly doubled over the last 20 years; more than 5 percent of the people in the United States suffer from the disease--children under 5 being the hardest hit.
Scientists do know that there are "profoud differences between children and adults both in susceptibility and exposure to environmental contaminants," says Lynn Goldman, a professor at the Johns Hopkins University School of Hygiene and Public Health.
Even after being born, a baby's brain, as well as its nervous, immune and hormonal systems, are still developing. "This creates huge vulnerabilities if a child is exposed at the wrong moment," says Phil Landrigan, director of the Center for Children's Health and Environment at the Mt. Sinai School of Medicine. "A chemical that wouldn't have any effect on an adult can have devastating effects on kids," Landrigan says, giving fetal alcohol syndrome and low-level lead poisoning as examples. "Levels that hurt children are often rally quite harmless to adults."
Children eat, drink and breathe more in relation to their body weight, so they get a bigger dose of pollutants that might be in the air, food or water. Such things as playing on the ground and putting their hands in their mouths also increase their exposure.
Environmental contaminants are suspected to cause cancer, birth defects, immune system defects, reduced IQ, behavioral abnormalities, decreased fertility, altered Sex hormone balance, altered metabolism and specific organ dysfunctions. And every day children are exposed to chemicals that have not been tested.
Landrigan says some 3,500 "high production volume" (HPV) chemicals (produced here or imported in quantities greater than million pounds per year, including a variety of solvents and pesticides) can escape into the environment. "Fewer than half of them have been tested at all for their toxicity, and less than 25 percent have been tested for their toxic effects on childhood development," he says. Not even basic information is available for half the chemicals in consumer products.
Frank Rathbun of the American Chemistry Council realizes that a health information gap exists, but says the industry is working to change that. "We're starting a major effort to do some baseline testing on a number of these high production volume chemicals," he says. Under the program, which was developed in cooperation with the EPA, chemical manufacturers will voluntarily provide the EPA and the public with information on the health and environmental effects of many HPV chemicals by 2004.
The number of children suffering from asthma, autism and cancer is increasing, and all these diseases are thought to have environmental connections. "The biggest increase is in children's brain cancer, which has gone up 35 percent," Landrigan asserts.
"In young men there has been a 58 percent increase in testicular cancer, and we don't know why," he adds.
Birth defects and developmental disabilities are considered priority childhood conditions by the CDC. Birth defects are the No. 1 killer of children under 1. Seventeen percent of U.S. children under 18 have a developmental disability, such as mental retardation, autism, cerebral palsy or attention deficit hyperactivity disorder. The National Academy of Sciences reports that environmental agents alone may cause 3 percent of developmental disabilities, while an additional 23 percent are thought to be the result of interactions between genes and the environment. That means nearly one in 20 children has a developmental disability that resulted from environmental exposures.
TARGETING THE TOXICS
Lead is probably the most harmful known environmental pollutant to cause disease in children. The widespread heavy metal in paints, gasoline and solder has caused lower IQs and behavioral problems in children for years. Action by the federal government helped to eliminate lead from gasoline and paint, which dramatically reduced the number of childhood lead poisonings. Still, low-income children living in older housing are 30 times more likely to be poisoned by lead than their middle-income counterparts living in newer housing.
The study of lead poisoning led to the discovery that children may be more sensitive than adults. In the 1960s, children were not considered poisoned until the levels of lead in their blood were six times higher than what is considered to be hazardous today. Overt symptoms of lead poisoning do not usually occur until lead concentrations surpass this higher level. Subsequent research, however, showed that lead causes less visible but permanent effects, such as IQ deficits and behavioral problems, at much lower levels. Indeed some of the latest research indicates that negative health effects occur below today's lower accepted level.
Mercury, another heavy metal, has garnered a good deal of attention recently because it is highly toxic, persists in the environment and tends to accumulate in living organisms. Due to the industrial revolution, it is now in nearly every body of water on earth. The U.S. Food and Drug Administration (FDA) issued a warning in January 2001 that pregnant women and young children should avoid eating swordfish, king mackerel and shark because those fish may contain enough mercury to damage a child's developing brain. The National Academy of Sciences estimates that each year 60,000 children are born in the United States with neurological problems caused by pre natal exposure to mercury.
Air pollution also harms children's health. Levels in some U.S. cities have been found to damage lungs and induce asthma attacks. Nearly 30 million children live in areas that do not meet current standards for clean air, according to the EPA, and they are at risk for related adverse health effects such as asthma and respiratory illnesses.
Widespread pesticides use also has raised concern that exposure from food, water and household use may cause long-term damage to children. In a 1993 report by the National Academy of Sciences, Pesticides in the Diets of Infants and Children, researchers found that because of special dietary patterns and susceptibilities, young children respond differently to pesticides than do adults. They reported that children may be at risk under the current regulatory scheme and that regulations should be redesigned to adequately protect children.
Congress responded to the childhood pesticide threat by passing the Food Quality Protection Act in 1996. It ensures that children's health is taken into account when assessing the safety of pesticides? for agricultural and household use. So far, the EPA has restricted the residential uses of some common organophosphate pesticides, including chlorpyrifos used in numerous well-known products such as Hartz flea collars and Raid bug sprays. EPA is also developing new tests to better assess whether pesticides and other chemicals cause develop mental and immunological problems, as well as determine if they can disrupt the hormonal system. "Our biggest goal is to get as much data from the USDA and industry as we can to make the best decisions," notes Ramona Trovato, director of the EPA Office of Children's Health Protection.
Not all agree that chemicals are a significant source of risk for children. "We feel that most, if not all, standards have been set to be protective of all people, including children," says Sandra Tirey, director of the Public Health Team at the American Chemistry Council. "In a relative sense, there is an overemphasis on environmental chemical risks. It's important that parents pay attention to the biggest and likeliest risks for their children," Tirey says. Some worry that this overemphasis may direct resources away from efforts to attack known and preventable risks like accidents, which are the leading cause of death for the 1 to 14 age group.
"I don't think we have a good handle on the effects of other environmental contaminants," says Thomas Sinks from the CDC. Although many chemicals have demonstrated risks in numerous studies--PCBs, Dioxin, phthalates (softeners found in common plastics) and many pesticides-conclusive assessments cannot be made for the low levels to which children are exposed.
"Clearly not every chemical has been tested for every health endpoint," says Frank Rathbun, from the American Chemistry Council. "But we're committed to finding out all we can about chemicals. While we've got a lot of work to do in exposure and risk assessment, it's important not to lose sight of the health and safety benefits of chemistry--there are millions of people alive today because of products developed through chemistry."
On the government level, the Pew Environmental Health Commission at Johns Hopkins University contends that state and federal governments need to better track and monitor diseases that may be influenced by environmental factors. A tracking system could provide a better understanding of the environment's effect on public health, and aid in tracking down the causes of many chronic diseases.
Without knowing the effects or the exposure levels of pollutants, it is impossible to make policy that efficiently protects public health. Projects that may help include CDC's National Chemical Exposure Report, which randomly samples the U.S. population on exposure to multiple chemicals. The first report, released in March, tested for 27 chemicals, and found that lead and nicotine levels have dropped significantly. The drop shows that public health efforts to control lead and smoking in public areas have had good results. Other findings suggest that exposure to mercury and some pthalates may not be providing adequate margins of safety for certain portions of the population.
Another project that will help bridge the knowledge gap, authorized by the Children's Health Act of 2000, is the first large-scale study to follow children from conception to age 18. It will answer questions like "what are the environmental factors that contribute to health or to disease, and what can we do to help promote the health and well-being of all Americans?" says Trovato. The EPA is working with the CDC and the Department of Health and Human Services to develop the study. "I think this is a critical thing to support so we can get the information we need to make the best decisions about children's health," she explains.
WHERE DO THE STATES STAND?
States have a significant role in protecting children from harm in the environment, says Indiana Senator Beverly Gard. "Now we know that children are not just miniature adults. Physiologically they react very differently to many toxins."
States' approaches are varied. California and Maryland are reviewing all of their state environmental regulations to ensure that they protect children. In California, Senator Martha Escutia introduced the Children's Environmental Health Act of 2000, which was the first bill in the country to require the assessment of air quality and toxic contaminant standards to ensure that they protect infants and children, not just adults. Escutia says she was shocked to discover that "standards for air and toxic contaminants in California were based on their impact on a 180-pound adult male."
Maryland House Bill 313, enacted in 2000, created a children's environmental health protection advisory panel to review regulations, statutes and proposed regulations, assess whether they will sufficiently protect children and make recommendations based on this assessment. Delegate James Hubbard, sponsor of the bill, says, "I don't think the federal government is doing enough in this area--states need to address issues until Congress sees it needs to play a role too."
Other states have also acted. Some have passed disease-specific laws, such as Virginia, which requires the development of a comprehensive, statewide asthma strategy. Other states target specific hazards, such as pesticides, lead and mercury. Still others seek to fill the gaps in knowledge by creating better disease tracking programs that can be used to determine the links between environment and disease.
Indiana has been working on such a tracking bill, according to Senator Gard. "We want to establish a state registry to better identify pockets of health problems and see if there's any tie-in to specific environmental conditions that may exist. With newer technology, our ability to collect data and relate it to possible effects is much better than it used to be."
Senator Escutia also introduced a bill in California this session to create a statewide tracking system for chronic illnesses, such as asthma, neurological disorders, birth defects and cancers of unknown origin. Its aim is to provide public health professionals and communities with reliable information about chronic diseases as they relate to the environment. She calls it "a basic tool of prevention."
While some have raised concerns about the economic impacts of more protective regulations, Escutia responds that her bill would "reduce the human and financial cost of chronic illnesses, such as asthma, birth defects and lead poisoning." Delegate Hubbard, who introduced the Maryland bill agrees, saying, "It's a burden to society when you don't take risks into account. Once children get sick, treatment ends up costing more than prevention."
Glen Andersen specializes in environmental health issues for NCSL.
WHAT ROLES DO GENES PLAY?
It is clear that children are more sensitive to environmental contaminants. Yet it is not clear what causes many chronic children's diseases and conditions. One of the most important questions relates to the role genetics plays. Ken Olden, director of the National Institute of Enviornmental Health Sciences, uses this simple analogy to explain the interaction between genetics and the environment: "Genetics loads the gun, but the environment pulls the trigger."
Hereditary factors are thought to account for 10 percent to 20 percent of children's chronic diseases, while the causes of the rest remain unknown. A gene may increase a person's susceptibility to disease, but is usually only one of many potential risk factors, including diet, lifestyle and chemical exposure. Thanks to new technologies, researchers are discovering a growing number of genes that influence the likelihood that exposure to toxics will cause harm.
A DELUGE OF CHEMICALS
* More than 7 billion pounds of toxic chemicals were released into the nation's air, water, and soil in 1998 according to EPA's Toxic Release Inventory, which gathers voluntary submissions by industry. This total excludes agricultural chemical application.
* 80,000 chemicals are in commercial use in the United States and 2,000 new chemicals are introduced every year.
* Of the 3,000 chemicals that the United States imports or produces at more than million pounds per year, only 23 percent have been tested for developmental toxicity.
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|Date:||Jun 1, 2001|
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