In a paper published this week in the premier open-access global health journal PLoS Medicine, Majid Ezzati and colleagues from Harvard School of Public Health conclude that a large proportion of the world's population who live in low-income and middle-income countries should be the focus for intervention against risk factors for cardiovascular disease because major cardiovascular risk factors will increasingly be concentrated in these populations. Together with an aging population, this will result in high levels of cardiovascular disease.
Traditionally, cardiovascular diseases have been considered a "Western" disease or a "disease of affluence" and not a pressing public health concern for low-income populations. Ezzati and colleagues examined when interventions should be started by looking at the relationship between nutritional cardiovascular risk factors - overweight and obesity, and elevated blood pressure and cholesterol - and three economic indicators, using data for more than 100 countries.
They found that body mass index (BMI) and cholesterol increased rapidly in relation to national income, then flattened, and eventually declined. Cholesterol showed a similar pattern, but with some delay. The authors also found that as the proportion of people living in cities increased so did BMI and cholesterol, which may be due to changes in patterns of diet and physical activity with city life. Blood pressure levels were independent of the economic development.
The authors conclude that changes in patterns of living and with economic development and adoption of clinical interventions for blood pressure and cholesterol in high-income countries mean that the burden of cardiovascular risk factors is being shifted to the developing world; as a result, low-income and middle-income countries will simultaneously face the burden of infectious disease and cardiovascular risk factors.
Unless better interventions are pursued, we will face a world in which all major diseases are the diseases of the poor, the authors warn.