Sayo Awosika-Olumo
April 19, 2001
MPHP 439
Chapter for On Line Textbook
Children’s Health and Public
Policy
Introduction:
Children today face an array of exposures to potentially toxic environmental hazards. Hazardous substances such as lead, PCBs, solvents, asbestos, radon, pesticides, and air pollution have found their way into the homes, schools, and playgrounds of children. These exposures can have a significant impact on children's health and well-being: all children are at risk of developing learning disabilities, chronic and acute respiratory diseases, cancers, and illnesses caused by damage to the nervous system from hazardous substances.
Children today live in an
environment that is vastly different from that of previous generations.
Explosions in technology, information, population and material goods mark the
end of the 20th century. One of the key contributions to the current
technological age has been the discovery and the use of thousands of new
chemicals. During the last 50 years hundreds of thousands of chemicals have
been developed and the production of synthetic chemicals has increased from 1.3
billion lbs in 1940 to 320 billion lbs in 1980.1 Chemicals are
ubiquitous in our environment worldwide, and traces of man-made chemical
compounds (toxicants) are found in all humans and animals.2
Currently, use of more than 70,000 chemicals is allowed in the United States
and little is known about the health effects of majority of these chemicals on
children.3 Exposures to environmental toxins, such as lead, are now
known to cause permanent damage to a child’s nervous system. 5 Other
toxicants are being implicated in causing adverse health effects in children.
6,7 While exposures to some environmental hazards have decreased because
of new regulations and standards, children continue to be exposed to toxicants
in the air, water and food. 8
Why Children
are Considered Special Population:
A knowledge of the normal
growth and development of children is essential for preventing and detecting
disease by recognizing overt deviations from normal patterns. Although the
processes of growth and development are not completely separable, it is
convenient to refer to “growth” as the increase in the size of the body as a
whole, or the increase in separate parts, and to reserve “development” for
changes in function which includes those influenced by the emotional and social
environment. 4 Children form a unique subgroup within the population
who require special consideration in risk assessment. Children are not little
adults. Their tissues and organs grow rapidly, developing and differentiating.
These development processes create windows of great vulnerability to
environmental toxicants. 9 One goal of pediatrics is to help each
child achieve his or her individual potential for growth and development, thus
becoming a mature adult. 4 The development of a human being from
conception through adolescence affords particular windows of vulnerability to
environmental hazards. Exposure at those moments of vulnerability can lead to
permanent and irreversible damage. An important means of accomplishing this
goal involves periodically monitoring each child for the normal growth and
progression of growth and development and screening for abnormalities.4
Infancy is considered to be from 0 – 12 months, early childhood is from 15
months – 4 years, late childhood is from 5 years – 12 years and adolescence
from 14 years – 20 years. 4 Exposure patterns of children to
environmental chemicals are very different from those of adults. Traditional
risk assessment has generally failed to consider the special exposures and the
unique susceptibilities of infants and children. 9
Children, beginning at the
fetal stage and continuing through adolescence, are physiologically very
different from adults. They are in dynamic state of growth, with cells
multiplying and organ systems developing at a rapid rate. At birth their
nervous, respiratory, reproductive and immune systems are not fully developed.
In the first four months of life an infant more than doubles its weight. Young
children breathe more rapidly and take in more air in proportion to their body
weight than do adults. They also have higher metabolic rates and a higher
proportionate intake of food and liquid than do adults. 10
The rate at which children
absorb nutrients from the gastrointestinal tract is likewise different than the
rate for adults, a fact that can impact their exposure to toxicants. For
example, children have a greater need for calcium for bone development than do
adults and will absorb more of this element when it is present in the
gastrointestinal tract. When lead has been ingested into the gut, however, the
body will absorb it in place of calcium. Consequently, an adult will absorb 10%
of ingested lead, while a toddler will absorb 50% of ingested lead. 11
Because metabolic systems
are still developing in the fetus and child their ability to detoxify and
excrete toxins differs from that of adults. This difference is sometimes to the
child’s advantage, but more frequently they are not able to excrete toxins as
well as adults, and thus more vulnerable to them.12 Not only does a
child’s physiology differ from an adult’s, so does its environment. In its first
environment, its mother’s womb, the fetus may be permanently damaged by
exposure to a wide variety of chemicals that can cross into the blood stream
through the placenta. These chemicals include lead, 13
polychlorinated biphenyls, 14 methylmercury15 ethanol and
nicotine from environmental tobacco smoke. 11
Behavior characteristic of
early childhood also affect a child exposure to toxicants. In the first year of
life the young child spends hours close to the ground where he or she may be
exposed to toxicants in dust, soil and carpets as well as to pesticide vapors
in low-lying layers of air.
Normal development in early
childhood includes a great deal of hand-to-mouth behavior, providing another
avenue for exposure to such toxicants as lead in paint dust or chips and to
pesticide residues.
Children spend more time
outdoors than do most adults, often engaged in vigorous play. Because children
breathe more air per pound body weight than adults and because their
respiratory systems are still developing, they are prone to greater exposure to
and potential adverse effects from air particulates, ozone and other chemicals
that pollute outdoor air. 16, 17
Finally, a child’s diet
differs in important ways from that of an adult. Children eat more fruits and
vegetables and drink more liquids in proportion to their body weight, their
potential exposure to ingested toxicants such as lead, pesticides, and nitrates
is greater. For example, the average infant’s daily consumption of six ounces
of formula or breast milk per kilogram of body weight is equivalent to an adult
male drinking 50 eight-ounce glasses of milk a day. 11 Likewise,
proportionate to its body weight, the average one-year-old eats two to seven
times more grapes, bananas, pears, carrots and broccoli than an adult. 18
The fact that children are
exposed to toxicants at an earlier age than adults, they have more time to
develop environmentally-triggered diseases such as cancer and possibly
Parkinson’s disease. 19
All children are affected by
environmental hazards. Pollution and environmental degradation know no county,
state, regional, or national border. Contaminants are transported through many
media including air, water, soil and food throughout the world. However,
children living in poverty and children in racial or ethnic communities are at
disproportionate risk for exposures to environmental hazards. Poverty can
compound the adverse effects of exposure to toxicants because it is so often
associated with inadequate housing, poor nutrition, and limited access to
health care. A primary source of exposure to lead, for example, is from flaking
lead-based paint, a condition that is more common in poorly-maintained older
housing often found in low-income neighborhoods.
Higher rates of poverty are
one of the factors that place children of ethnic and minority communities at
disproportionate risk for environmental exposures.
Communities of color are
disproportionately exposed to hazardous wastes, dioxin, and air pollution.
Existing data demonstrate that children of color are the subgroup of the
population most exposed to certain pollutants, including lead, air pollution,
and pesticides.
The health status of
children belonging to low-income and racial ethnic communities reflects their increased
risk of exposure to environmental hazards. Eight percent of low-income children
are lead poisoned compared to 1.9% of middle- and 1.0% of high-income children.
African-American and Mexican-American children have higher rates of lead
poisoning than white non-Hispanic children (11.2% and 4.0% respectively
compared to 2.15). 21 Rates for asthma-related deaths and
hospitalizations are routinely higher for African-American children than for
Caucasian children. Coupling the risk factors of poverty with environmental
exposures places children in racial and ethnic communities at multi-factorial
risk for illness.
Children face myriad
environmental hazards: including radiation, solvents, asbestos, mercury,
arsenic, sulfur dioxide and ozone. They fall into categories such as
neurotoxins, endocrine disruptors, carcinogens, and respiratory irritants and
inflammatants. Selected environmental hazards known to seriously impact
children’s health are discussed below.
Lead poison has been
referred to as the most important environmental health hazards for children.
Exposure to lead has been associated with an array of neuro-developmental
effects, including attention deficits, decreased IQ scores, hyperactivity and
juvenile delinquency. 21,22 Research has also shown an association
between slightly elevated blood lead levels in children at the age of 24 months
and lower general cognitive function at age 5 years of age. 23
The elimination of gasoline
in the 1970s, one of the great public health success stories of that decade,
resulted in significant decreases in blood lead levels. 24 Although
lead has been removed from most paint products now in the market, lead-based
paint in older homes is still the most common source of high-dose lead exposure
for preschool-aged children. Nationwide, approximately 3 million tons of lead
remain in an estimated 57 million occupied private housing units built before
1980, a figure that represents 74% of the nation’s housing stock. 25
Childhood lead exposures can occur through ingestion of paint chips or dust
from deteriorating surfaces, from chewing on painted cribs or through
inhalation of lead paint dust produced by sanding during renovation. 24
Lead is also found in drinking water as a result of leaching from lead-soldered
plumbing and in soil containing lead residues form automobile exhaust. 6
Air pollution affects
children more than adults because of their narrow airways, more rapid rate of
respiration, and the fact that they inhale more pollutants per pound of body
weight. 27 Common indoor air pollutants include carbon monoxide,
radon environmental tobacco smoke, asbestos, formaldehyde and mercury. Common
outdoor air pollutants include ozone and particulate matter.
Health effects associated
with both indoor and outdoor air pollution include increased perinatal
mortality, increased acute respiratory illnesses (e.g. bronchitis and
pneumonia), aggravation of asthma, increased frequency of physician visits for
chronic cough and ear infections, and decreases in lung function. 17
During the last 25 years, several hundred papers have been published on
respiratory health effects of environmental tobacco smoke (ETS). Various
independent assessments have concluded that ETS causes lung cancer in adult
non-smokers and increases the risk of various non-cancer effects, principally
in children. The effects on children include pneumonia, bronchitis and
bronchiolitis in young children: chronic middle ear effusion: increased
frequency and severity of attacks among asthmatics; possible induction of
asthma in previously asymptomatic individuals; small reductions in lung
function; and symptoms of upper respiratory tract infection. 20 A
recent study of neonatal mortality found an association between elevated
concentrations of fine particulates and neonatal deaths, including sudden
infant death syndrome (SIDS). 28 There is little doubt that high
levels of air pollution are responsible for increased morbidity, and in some
cases mortality in children. 17
Increased indoor air
pollution can be attributed to what are generally considered to be improvements
in our quality of life. These include energy saving measures such as better
insulation and decreased ventilation rates in houses, increased furnishings, increased
mean indoor temperature and increased indoor humidity. 29 In
addition, the number of airtight buildings has increased since the 1970s, as
has the use of synthetic building materials and unvented combustion appliances.
30 These factors coupled with an increase in the amount of time we spend
indoors have increased the concentration of indoor environmental pollutants and
our exposure to them.
In the outdoor environment,
there has been as effort to reduce exposure to ozone and particulates. Ozone,
the most pervasive air pollutant in the United States, is produced when
hydrocarbons and nitrogen oxides emitted from motor vehicles and other sources
react in the presence of sunlight. 31 Exposure to ozone has been
associated with increased asthma rates in children32 as well as a
reduction in lung function, and also causes exercise-related wheezing, coughing
and chest tightness. 31 Most recently the US Environmental
Protection Agency has issued regulations to decrease the levels of ozone and
air particulates in outdoor air.
Children are often exposed
to toxicants through the agricultural and home use of pesticides or the
ingestion of pesticide residues on food or in water. Pesticides used today
generally fit into five main categories: insecticides, herbicides, fungicides,
nematocides and rodenticides. 33 Increased awareness of acute
pesticide poisoning has led to an apparent decrease in acute episodes of
toxicity, and public health concern has thus shifted to evaluating the effects
of low level chronic pesticide exposures. 33 Again, children may be
more vulnerable than adults to experiencing latent or delayed effects over the
long course of their lifetime. Researchers have become concerned about the
potential associations between chronic pesticide exposures and chemical
carcinogenesis, environmental estrogen disruption and developmental
neurotoxicity.
There has been an increase in some childhood
diseases over the years. As noted, childhood asthma has increased by more than
40% since 1980, affecting more than 4.2 million children under the age of 18 in
the U.S. The incidence of two types of childhood cancers has risen
significantly over the past 15 years: acute lymphocytic leukemia is up 10% and
brain tumors are up more than 30%.32 There are various environmental
causes of cancer in children. Etiologically, these are divided into physical
agents, chemical agents, and microbiologic agents. 4 The physical
agents include ionizing radiation causing leukemia, thyroid and breast cancer,
and ultraviolet radiation causing melanoma, basal and squamous cell cancer in
xeroderma pigmentosum. Chemical agents include cigarette/tobacco causing lung,
oropharynx and laryngeal cancer, diethylstibestrol – vaginal carcinoma,
asbestos – mesothelioma, androgens, aflatoxin, vinyl chloride – hepatic cancer,
alkylating agents, benzene – leukemia, immunosuppressant drugs, phenytoin –
lymphoma, and cyclophosphamide causing bladder cancer. 4
Microbiological agents include Hepatitis B, C viruses causing hepatic cancer,
HIV – Kaposi Sarcoma, lymphoma, Schistosoma hematobium – bladder cancer,
Epstein-Barr virus – African Burkitts lymphoma, Papillomavirus – cervical
cancer, Human T lymphotropic virus 1 – T-cell lymphoma, and SV40 virus causing
ependymoma, choroid plexus tumor. 4
The key to protection is
prevention. Recently there has been a dramatic shift in the recognition of
children’s environmental health issues in the Congress and federal agencies.
Identification of environmental hazards as it affects children dated back in
1774 where there was increase in scrotal cancer among young chimney sweeps.
Lead was discovered (in Australia, 1904) and then mercury, causing neurological
damage to the unborn child (in Sweden, 1953, in Japan, 1958, 1965, in Iraq,
1971 and New Mexico in 1972). In 1970, the Clean Air Act was adopted by
President Nixon. 31 In the 1970s, the EPA tackles lead in gasoline.
In 1989, pesticides were labeled “intolerable risk” in children’s food. Alar
was removed for use on apples. 31 In November 1996, the U.S.
Environmental Protection Agency (EPA) released a report Environmental Health
Threats to Children and announced that for the first time children would be
considered in all EPA risk assessment and standard-setting procedures. Adoption
of a new child-centered agenda for research and risk assessment is necessary if
disease in children of toxic environmental origin is to be identified,
understood, controlled, and prevented. 9 Congress passed the Food
Quality Protection Act in 1996, which specifically focuses on setting standards
to protect children from pesticide residues and other hazards in foods. In
April 1997, President Clinton signed an Executive Order on Children’s
Environmental Health and Safety (#13045) requiring federal agencies to include
children and their unique susceptibilities in standard-setting procedures and
establishing an interagency task force to ensure coordination of regulations
and research. 9 These actions provide an important framework for
protecting children. Whether they prove effective will depend on how diligently
they are implemented. Over the years, there has been training of Pediatricians
to include children’s environmental health. A lot of conferences, symposia and
seminars have taken place to increase public awareness. Research has had its place and a lot of research,
prevention and the policies focuses on key research priority areas in the field
of children's environmental health and these include asthma and respiratory
diseases; childhood cancer; endocrine disorders and neurodevelopmental effects.
In a bid to provide better protection for children’s health, U.S. Senators
(Barbara Boxer and Frank Lautenberg) introduced the Children’s Environmental
Protection Act (CEPA) on 24 May 1999. CEPA is an amendment to the Toxic
Substances Control Act of 1976 and seeks to protect children from exposures to
hazardous substances such as air pollutants and pesticides sprayed in schools.
The Act provides parents about how to protect their children against such
health threats. 39 There is on-going research being done and
legislation being worked on to further advocate for children’s health and make
the world a better place to live in.
-
Choose
to use fewer chemicals, in your home, on your lawn.
-
Don't
use pesticides if you don't have to - look for alternatives.
-
Have
your child's blood lead level tested, especially if your child spends time in a
house built before 1960.
-
Don't
smoke or let others smoke near your kids.
-
Kids
and pregnant women should obey area fish advisories.
-
Vary
children's diets as much as possible while giving them plenty of fruits and
vegetables. Consider buying organic foods if available.
-
Pay
attention to air pollution reports and limit children's outdoor activities on
ozone alert days and other times when air pollution is bad.
-
Learn
about your local drinking water. Read your water system's Consumer Confidence
Report, available from your water supplier.
-
Ask
your pediatric health care provider to take an environmental health history of
your child.
-
Work
with your school, community recreation system and others to decrease their use
of chemicals. Many schools are cutting back on pesticide use and are giving
parents advance notice before applying pesticides.
-
Tell
your elected officials that you want government policies to specifically take
children into account that protect children's health.
With children being so
susceptible to many hazards of life especially environmental, one has to be
sensitive to the continuous environmental changes. One should educate oneself
and understand more about children’s health and talk to other people about the
problems children face. Health education should not be limited to professionals
but also to the at-risk group. Ways of communication should be devised to those
who cannot read. Letters can be written to senators, representatives, congress
and other government officials to work together to put a policy in place to
improve children’s health. An effective policy is reliant upon knowledge and
understanding of the effects of environmental hazards on children’s health.
Research also has to be geared towards identifying patterns of environmental
diseases, assessing children’s exposures to environmental toxicants so as to
determine developmental periods of vulnerability. Quantification of dose
response relationships will also lead to preventive measures.
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