Chapter 15.1 Links Between Human Health and the Environment emerging diseases (avian flu, SARS, Ebola) appear as we continue to manipulate the natural environment and change ecological relationships however, old and familiar diseases take the greatest toll on human life malaria, diarrhea, respiratory viruses

risk = hazard x vulnerability in the context of environmental health, hazard is anything that can cause injury, disease, or death to humans damage to personal or public property deterioration or destruction of environmental components risk: the probability of suffering injury, disease, death, or some other loss as a result of exposure to a hazard Ex. presence of avian flu in poultry is a hazard that presents the risk of humans contracting the disease; people working with poultry are much more vulnerable

health WHO defines as “state of complete mental, physical, and social well-being” environmental health focuses on disease; as a result, health is usually defined as absence of disease two measures are used in the study of disease in societies: morbidity—incidence of disease in a population mortality—incidence of death in a population epidemiology—study of the presence, distribution, and prevention of disease in populations

public health in U.S., lead agency for protecting the health and safety of the public is the Centers for Disease Control and Prevention (CDC) agency under Department of Health and Human Services other countries normally have a similar ministry of health

life expectancy universal indicator of health 1955 average was 48 years today, average is 67 years expected to be 73 years in 2025 progress is result of social, medical, and economic advances (epidemiologic transition) 20% of annual deaths in the world are children under the age of 5 in the developing world infectious diseases responsible for 54% of deaths in developing countries, but only 7% in developed countries

environmental hazards two ways to consider hazards: 1. lack of access to necessary resources Ex. lack of access to clean water and nourishing food is harmful to a person 2. exposure to hazards in the environment cultural hazards matter of choice, or at least can be influenced by choice examples include eating too much, using harmful drugs, smoking, sunbathing, choosing hazardous occupations

environmental hazards biological hazards history: black plague, smallpox, antibiotics, immunizations ~25% of global deaths are due to infectious and parasitic diseases physical hazards hurricanes, tornadoes, floods, forest fires, earthquakes, landslides, volcanic eruptions some can be anticipated, others are a consequence of where people choose to live

environmental hazards biological hazards history: black plague, smallpox, antibiotics, immunizations ~25% of global deaths are due to infectious and parasitic diseases physical hazards hurricanes, tornadoes, floods, forest fires, earthquakes, landslides, volcanic eruptions some can be anticipated, others are a consequence of where people choose to live

environmental hazards chemical hazards industrialization has brought a host of technologies that use chemicals such as cleaning agents, pesticides, fuels, paints, and medicines manufacture, use, and disposal of these chemicals often brings humans into contact with them exposure is either by ingestion of contaminated foods or drinks, breathing contaminated air, absorption through the skin, direct use, or by accident toxicity (condition of being harmful, deadly, or poisonous) depends not only on exposure, but also on the dose people have different thresholds of toxicity for given substances Ex. children are often at greater risk; embryos are even more sensitive

carcinogens cancer-causing agents because cancer often develops over a period of years, it is often difficult to connect the cause with the effect in the U.S., 23% of all deaths in 2003 were traced to cancer cancer is a cell line that has lost its normal control over growth at least 3 dozen genes have been studied that can bring about malignant cancer two-hit hypothesis

Chapter 15.2 Pathways of Risk 2002 WHO annual report: Reducing Risks, Promoting Healthy Life shows that a small number of risk factors is responsible for a vast proportion of premature deaths and disease top 10 factors are responsible for more than one- third of all deaths and much of the global disease burden

risks of being poor

cultural risk of tobacco use

risk and infectious disease

toxic risk

disaster risk