20.2 Global health

Social epidemiology is the study of the causes and distribution of diseases. Social epidemiology can reveal how social problems are connected to the health of different populations. These epidemiological studies show that the health problems of high-income nations differ greatly from those of low-income nations. Some diseases, like cancer, are universal. But others, like obesity, heart disease, respiratory disease, and diabetes are much more common in high-income countries, and are a direct result of a sedentary lifestyle combined with poor diet. High-income nations also have a higher incidence of depression (Bromet et al. 2011). In contrast, low-income nations suffer significantly from malaria and tuberculosis.

How does health differ around the world? Some theorists differentiate among three types of countries: core nations, semi-peripheral nations, and peripheral nations. Core nations are those that we think of as highly developed or industrialized, semi-peripheral nations are those that are often called developing or newly industrialized, and peripheral nations are those that are relatively undeveloped. While the most pervasive issue in the U.S. health care system is affordable access to health care, other core countries have different issues, and semi-peripheral and peripheral nations are faced with a host of additional concerns. Reviewing the status of global health offers insight into the various ways that politics and wealth shape access to health care, and it shows which populations are most affected by health disparities.

Health in high-income nations

Obesity, which is on the rise in high-income nations, has been linked to many diseases, including cardiovascular problems, musculoskeletal problems, diabetes, and respiratory issues. According to the Organization for Economic Cooperation and Development (2011), obesity rates are rising in all countries, with the greatest gains being made in the highest-income countries. The United States has the highest obesity rate. Wallace Huffman and his fellow researchers (2006) contend that several factors are contributing to the rise in obesity in developed countries:

1. Improvements in technology and reduced family size have led to a reduction of work to be done in household production.
2. Unhealthy market goods, including processed foods, sweetened drinks, and sweet and salty snacks are replacing home-produced goods.
3. Leisure activities are growing more sedentary, for example, computer games, web surfing, and television viewing.
4. More workers are shifting from active work (agriculture and manufacturing) to service industries.
5. Increased access to passive transportation has led to more driving and less walking.

Obesity and weight issues have significant societal costs, including lower life expectancies and higher shared healthcare costs.

High-income countries also have higher rates of depression than less affluent nations. A recent study (Bromet et al. 2011) shows that the average lifetime prevalence of major depressive episodes in the 10 highest-income countries in the study was 14.6 percent; this compared to 11.1 percent in the eight low- and middle-income countries. The researchers speculate that the higher rate of depression may be linked to the greater income inequality that exists in the highest-income nations.