Environmental Alarmism: The Children's Crusade
The next generation of Americans has long been a focus of attention for policymakers and policy advocates, but in the past several years, children have been so frequently cited as the beneficiaries of various policy prescriptions that the term virtually has become a shibboleth. Nowhere is parental concern for the welfare of their children more regularly appealed to, it seems, than in the area of environmental protection.
We all need to be concerned about health risks to children, but several recent environmental policy initiatives advanced in the interest of protecting children actually address relatively small or unproven dangers. This might seem to be a form of insurance to many, but some of the policies, such as those affecting food production, could actually do more harm than good if they have the effect of increasing other known risks. We need to look more carefully at the evidence for environmental risks to children and to put these risks in context with other threats to children's health.
A 1993 report by the National Research Council (NRC) focused attention on the potential risks of pesticide residues in food and beverages. Pesticides in the Diets of Infants and Children addressed the question of whether the current approach to regulating pesticides in food adequately protects infants and children. It did not, however, compare the risks of pesticides to the benefits of a varied and plentiful food supply, nor did it consider exposures to natural toxins.
The NRC report found that the toxicity of pesticides may differ between children and adults. Quantitative differences result from "age-related differences in absorption, metabolism, detoxification, and excretion of xenobiotic compounds," as well as physical and biological differences such as body size and the maturity of body systems. Qualitative differences result from "brief periods early in development when exposure to a toxicant can permanently alter the structure or function of an organ system."
The report also found that exposure to pesticides differs between children and adults. Compared to adults, children eat more food in proportion to their mass, have less variety in their diets, and may eat more of certain foods such as processed foods and juices. The report found that "differences in diet, and thus in dietary exposure to pesticide residues, account for most of the differences in pesticide-related health risks that were found to exist between children and adults."
The report recommended that exposure estimates reflect the unique diets of children and infants and that these estimates include nondietary exposure. It suggested that the Environmental Protection Agency (EPA) give health considerations a larger role in setting tolerances, called for better data on food consumption and pesticide residues in food, and recommended toxicity testing focused on infants and children.
The NRC report has had a substantial impact on policy, perhaps greater than its findings support. In September 1993, the Clinton administration proposed tighter pesticide tolerances for foods that children tend to consume, citing the NRC report (which made no recommendation to reduce tolerances, per se). In October 1995, EPA Administrator Carol Browner announced EPA's new national children's health policy to ensure that the agency's risk assessments and public health standards take into account environmental threats to children and infants.
In the summer of 1996, Congress passed the Food Quality Protection Act (FQPA), which explicitly provides for children's health protection by requiring that pesticides be tested for their effects on children. The act allows no pesticide residue in foods unless a "reasonable certainty of no harm" can be demonstrated. Where data on children are not available or are uncertain, EPA may apply an added 10-fold safety factor to a pesticide tolerance to protect children. The FPQA also requires EPA to consider the cumulative risk posed by exposure to all pesticides of similar classes.
In September 1996, EPA released a report titled "Environmental Health Threats to Children," which included recommendations to ensure that all standards set by EPA protect children from the potentially heightened risks they face, expand research on child-specific susceptibility and exposure to environmental pollutants, develop new comprehensive policies to address cumulative and simultaneous exposures faced by children (as opposed to the chemical-by-chemical approach used in the past), and provide the necessary funding to address children's environmental health issues as a top priority among relative health risks.
In September 1997, EPA held a conference on "Preventable Causes of Cancer in Children," which focused on the possible link between environmental contaminants and childhood cancer. On April 21, 1998, Vice President Al Gore announced an initiative to screen all high-production industrial chemicals in the United States, with special attention given to their effects on children's health.
Many of the concerns expressed about children's health are legitimate. Children are physiologically different from adults and face different health risks. What is troubling about the agenda some have put forward, however, is that environmental health risks have not been established as one of the top threats to children's health.
Where's the evidence?
Environmental and children's health advocates point to downward trends in several indicators of children's health to make the case that children are endangered by environmental contaminants. Some attribute the increased incidence of certain types of childhood cancer, birth defects, and asthma to environmental factors.
At EPA's September 1997 conference, Browner said that although the death rate from childhood cancer has declined, the incidence of cancer in children has increased. National Cancer Institute (NCI) data for the periods from 1973-74 to 1994-95 show a rise in the annual incidence of all cancers in the 0 to 14 age group from 12.8 to 13.6 per 100,000 children. EPA cites NCI data from 1973-74 and 1993-94 as evidence of alarming trends for specific childhood cancers: The incidence of Wilm's tumor (a kidney tumor) rose by 46 percent, brain cancers rose by 40 percent, and testicular cancer rose by 37 percent.
These statistics are very misleading, however. Take, for example, the Wilm's tumor statistic: NCI data for 1973-74 to 1993-94 do show a rise in the annual incidence of kidney and renal pelvis cancers from 0.7 to 1.0 case per 100,000 children, an increase of over 40 percent. But in 1994-95, the rate was 0.8 per 100,000, an increase of 14 percent over the period, or one additional case per million children.
Compared with cancer incidence in all age groups, cancer in children is a relatively rare event. In 1995, the 0 to 14 age group accounted for only 8,300 of the 1.3 million reported incident cases of cancer. It is also worth noting that the annual cancer mortality rate for 0- to 14-year-olds fell from 5.4 per 100,000 in the 1973-1974 period to 2.8 per 100,000 in the 1994-95 period, reflecting improvements in the detection and treatment of childhood cancer.
Evidence of increasing incidence of birth defects is also thin. At EPA's 1997 conference, Philip Landrigan of EPA's Office of Children's Health Protection and Mount Sinai School of Medicine observed that certain birth defects are increasing. He cited a near doubling in the rate of hypospadias from 1970 to 1994. A 1997 study reported in Pediatrics did find an apparent doubling of the hypospadias rate during the 1970s and 1980s. But the authors cautioned against concluding that their data confirms an actual increase: "Better identification of mild cases by physicians, therefore, cannot be ruled out as at least a partial cause of the increase in the hypospadias rate."
The growing prevalence of asthma is also offered as evidence of environmental damage to kids. Approximately 15 million Americans, including 5 million children, have asthma. Statistics show that asthma rates have doubled in the past decade, and death rates from asthma have increased in recent years. EPA statistics indicate that 14 Americans die each day from asthma, which is triple the rate of 20 years ago. In promoting EPA's new National Ambient Air Quality Standards for ozone and particulate matter air pollution (issued in July 1997), Administrator Browner made frequent references to asthmatic children.
But the link is dubious. U.S. air quality has improved dramatically over the past several decades: From 1970 to 1996, aggregate emissions of the six major urban air pollutants decreased 32 percent. Ozone concentrations have declined 30 percent, and direct emissions of particulates have decreased by 73 percent.
A better candidate for the rise in asthma incidence might be indoor air pollution, including tobacco smoke, molds, mites, and cockroach dust. A 1997 New England Journal of Medicine study found that exposure to elevated levels of cockroach allergen was associated with increased hospitalizations and unscheduled medical visits as a result of asthma attacks among inner-city children. Energy conservation measures enacted during and after the 1970s to reduce excessive ventilation have had the effect of raising levels of indoor air contaminants. A January 1997 Science article by William Cookson and Miriam Moffatt offers another hypothesis: The increase in childhood asthma could be related to a decrease in respiratory and other infections. They argue that contracting these infections during childhood could protect against developing asthma. The reality is that we don't know why asthma is becoming more prevalent, but the link to air pollution is hardly compelling.
Despite the concern that environmental contaminants are an important source of birth defects and the increased incidence of children's cancer, these risks have not been well quantified. Even if their magnitude were known, these risks would need to be evaluated relative to other risks. The data on children's health suggest that reduction of other risks such as accidents, poor prenatal care, fast-food diets, smoking, drug use, and gunshot wounds may offer greater potential for improving children's health than does addressing the uncertain risks posed by environmental contaminants.
The overall trend in children's health is unmistakably favorable. Life expectancy at birth is up and infant mortality is down, thanks to advances in science, medicine, and public health. Rising per capita income has made it possible for more people to afford good health care and healthful food. Improved agricultural technology, including synthetic pesticides, have made fresh fruit and vegetables plentiful and affordable. A diet rich in fruit and vegetables is associated with reduced risk of degenerative diseases, including cancer, cardiovascular disease, and brain dysfunction. Bruce Ames and Lois Swirsky Gold of the University of California at Berkeley report that the rate of most types of cancer is roughly twice as high in the quarter of the population with the lowest intake of fruits and vegetables as in the quarter with the highest.
When considering restrictions on the use of pesticides as a way to improve public health, one should take into account accompanying effects. A 1993 study by researchers at Texas A&M University found that a 50 percent reduction in pesticide use on crops of nine fruits and vegetables (apples, grapes, lettuce, onions, oranges, peaches, potatoes, sweet corn, and tomatoes) would reduce average yields by 37 percent, and a complete elimination of pesticide use would reduce yields by 70 percent. A 1995 study by C. Robert Taylor of Auburn University estimated that eliminating the application of pesticides to U.S. fruits and vegetables would increase production costs 75 percent, wholesale prices 45 percent, and retail prices 27 percent. He estimates that this would cause domestic consumption to fall by 11 percent. Taylor also explains that reducing pesticide use would lead to an increase in natural toxins and carcinogens in produce.
If our goal is to protect children from harm, we should focus on the most important causes. Data on the causes of childhood deaths shed some light on the question of which risks pose the greatest threats to children. According to the National Center for Health Statistics, accidents are by far the leading cause of death for children aged 1 to 14, accounting for 36 percent of deaths in the 1 to 4 age group and 41 percent of deaths in the 5 to 14 age group. The National Safe Kids Campaign reports that accidents cause approximately 246,000 hospitalizations, 8,700,000 emergency room visits, and 11,000,000 visits to physicians every year.
The good news is that many of the deaths and injuries caused by accidents are relatively easy to prevent. Former U.S. Surgeon General C. Everett Koop testified at a May 1998 Senate Labor and Human Resources Committee hearing on unintentional childhood injuries and death that 90 percent of all childhood injuries are preventable. In fact, substantial progress has been made toward reducing the rate of childhood deaths due to accidents. According to the National Safe Kids Campaign, deaths due to accidents for the 14 and under age group declined 18 percent from 1987 to 1995, from 8,069 to 6,611 per year. Some of the credit should go to efforts to increase the use of seat belts, bicycle safety helmets, smoke detectors, child safety seats, and similar safety measures.
Birth defects and cancer are both in the top four categories of childhood deaths. Cancer is the third leading cause of death in the 1 to 4 age group, accounting for about 8 percent of all deaths and is the second leading cause for the 5 to 14 age group, accounting for about 12 percent of all deaths. The causes of childhood cancer are not well understood, in part because it is a relatively rare phenomenon. Cancers other than leukemia and brain cancers, which together account for about half the cancers in children under age 14, are especially rare. Until the causes of childhood cancer are better understood, there probably is little that can be done to reduce its incidence.
Birth defects are the second leading cause of death for the 1 to 4 age group, accounting for about 11 percent of all deaths, and are the fourth leading cause of death for the 5 to 14 age group, accounting for about 5 percent of all deaths. The good news is that many birth defects are preventable. About 1 in 1,000 infants in the United States are born with either spina bifida (incomplete closure of the spinal column) or anencephaly (incomplete development of the skull bones and an incomplete brain). About 4,000 pregnancies are affected by these birth defects each year. The Centers for Disease Control and Prevention estimates that as many as 3,000 of these cases could be prevented if women consumed an adequate daily dose of folic acid before and during early pregnancy (which can be easily accomplished by taking a multivitamin). For this reason, the U.S. Food and Drug Administration announced regulations in 1996 to require U.S. food manufacturers to add folic acid to enriched breads, flours, pastas, and other grain products beginning in 1998.
Fetal alcohol syndrome is another leading cause of birth defects and mental retardation, causing approximately 2,000 cases of preventable birth defects every year. An additional 4,000 children may not meet the definition of fetal alcohol syndrome, but suffer cognitive and behavioral impairment from fetal alcohol exposure. Programs to convince pregnant women to abstain from alcohol consumption could make a difference.
When one looks at the known dangers to children and the opportunities for action to enhance thesafety of children, environmental contamination does not play a prominent role. Cancers and birth defects are both important threats to children's health, but environmental contaminants have not been established as a major risk factor for these diseases. Americans should certainly support more research to investigate possible links between environmental contaminants and cancer, birth defects, andother childhood diseases, but there is no convincing evidence at this time that tighter regulation of environmental contaminants will make a major contribution to the well-being of our children. Rather than using children's health as a rhetorical weapon in regulatory debates, we should publicize the proven dangers to children and promote the actions that we know can make a difference.
Stephen Huebner is a research associate at the Center for the Study of American Business at Washington University in St. Louis. Kenneth Chilton is a distinguished senior fellow and manager of environmental programs at the center. This article is based on a longer study that is available from the center.