With over 30% of the global burden of disease in children attributable to environmental factors, the United Nations health agency delivered the first ever report highlighting youngsters' special susceptibility to harmful chemical exposures at different periods of their growth, and the potential effects later in life.
The stage in a child's development when exposure occurs may be just as important as the magnitude of the exposure, according to the UN World Health Organization's (WHO) Principles for Evaluating Health Risks in Children Associated with Exposure to Chemicals, the most comprehensive work yet undertaken on the scientific principles to be considered in assessing such health risks. Emerging evidence suggests that an increased risk of certain diseases in adults such as cancer and heart disease can result in part from exposures to certain environmental chemicals during childhood. "Children are not just small adults," WHO's team leader for the Interregional Research Unit Terri Damstra said. "Children are especially vulnerable and respond differently from adults when exposed to environmental factors, and this response may differ according to the different periods of development they are going through. "For example, their lungs are not fully developed at birth, or even at the age of eight, and lung maturation may be altered by air pollutants that induce acute respiratory effects in childhood and may be the origin of chronic respiratory disease later in life." Air and water contaminants, pesticides in food, lead in soil, as well many other environmental threats which alter the delicate organism of a growing child may cause or worsen disease and induce developmental problems. Children have different susceptibilities during different life stages, due to their dynamic growth and developmental processes. Some examples of health effects resulting from prenatal developmental exposures and at birth include miscarriage, still birth, low birth weight and birth defects; in young children, infant mortality, asthma, neuron-behavioral and immune impairment; and in adolescents, precocious or delayed puberty. The vulnerability of children is increased in degraded environments. Neglected and malnourished children suffer the most. For example, lead is known to be more toxic to children whose diets are deficient in calories, iron and calcium. One in five children in the poorest parts of the world will die before the age of five mainly because of environment-related disease.