The Arctic regions of the United States (Alaska) and Canada (Northern Canada) have the highest levels of persistent organic pollutants (POPs) on earth. The toxic health-threatening substances are transported over long distances by rivers, oceans and air currents from warmer parts of the world to the colder polar regions. They also accumulate in the fatty tissue of seals and whales which traditionally play a key role in Arctic indigenous peoples' diet and can be passed directly to infants through maternal breast milk, causing disruption of the hormone and immune systems and affecting postnatal growth. Disease patterns among American Indians and Alaska Natives are strongly associated with the adverse consequences of poverty, limited access to health services, and cultural dislocation. Inadequate education, high rates of unemployment, discrimination, and cultural differences all contribute to unhealthy lifestyles and disparities in access to health care for many indigenous peoples.