Environmental health can be described as those aspects of human health, disease or injury,
that are determined by physical, chemical, biological, social and psycho-social factors in the
environment. Environmental threats to human health are instigated by living and experiencing
environmental conditions that differ per location, infrastructure and even season. They can be
divided into traditional and modern hazards. Traditional hazards occur due to lack of
development and poverty, such as lack of safe drinking water, inadequate sanitation, food
contamination, inadequate waste disposal and occupational injury hazards. Modern
environmental hazards are mainly the result of rapid development lacking safeguards for the
environment and human health. In addition, they also include the unsustainable consumption of
natural resources, such as water pollution, urban air pollution, solid and hazardous waste
accumulation, (re-)emerging infectious diseases, deforestation, land degradation and global
climate changes (Corvalan, Kjellstrom, & Smith, 1999). As countries are developing with time
on a social and economic level, the change in patterns of exposure and in health risks from
traditional to modern, can be described as a risk transition, occurring before the well-described
epidemiological and demographical transition. In developing countries with low-income and
middle-income population, the processes of globalization and industrialization often result in
simultaneous exposure to both traditional and modern environmental risks, a double jeopardy
known as risk overlap (Nriague, Meliker, & Johnson, 2005; Corvalan, Kjellstrom, & Smith, 1999).
It has been estimated that 25-30% of the global disease burden in developing countries is
attributable to environmental factors. Among the leading environmentally related risk factors
are; underweight or having nutritional deficiencies, persistence of inadequate water supply and
sanitation, indoor air pollution, lead pollution, outdoor air pollution and climate change. There
are large disparities in the environmentally related disease burden for various population
groups. Demographic trends, lifestyle transitions and changes in the distribution of
environmental risk factors (migration to overcrowded urban areas) resulted in a rapid increase in
non-communicable diseases in developing countries. As a result of the risk overlap, developing
countries are confronted with a more complex and more diverse pattern of diseases with a
higher risk of premature death and higher proportion of living in poor health (Lim, Lopez,
Murray, & Ezzati, 2012). The health transition theory does not entirely apply to developing countries at present since, in
some instances; there is a tendency to underestimate the continuing burden of infectious
diseases and the significance of different disease determinants in these populations. It is
important to identify key differences associated with gender, ethnicity and socioeconomic status
that are relevant to the health transition theory in epidemiological profiles of subpopulations
(Gaylin & Kates, 1997) (McCracken & Phillips, 2009).