Recommendation 10-1. Data collection should be improved to provide accurate information about stroke mortality, morbidity, incidence, prevalence, and mechanisms in developing countries using culturally sensitive tools and diagnostic techniques. Pathological studies of stroke should be conducted to determine the relative prevalence of various stroke subtypes among several diverse representative populations in developing countries. This research would be greatly enhanced if conducted in collaboration with research centers in high-income countries utilizing other existing data and research mechanisms.

The term “risk factor” was coined by investigators in the Framingham Heart Study, one of the largest, longest-running, and best-known epidemiological studies of its kind. Considerable data on risk factors for stroke have come from the 850 participants who have experienced a stroke since the U.S. study began in 1950.[78] While several of the predominant modifiable risk factors for stroke identified in the Framingham study—most notably hypertension, diabetes, and smoking—appear generalizable to many populations, data documenting the relative impact of these factors in developing countries are sparse. This represents fertile ground for future epidemiological studies, as does the possibility that new stroke risk factors of particular significance in developing countries might be identified (for example, infectious agents, nutritional factors, or developmental syndromes that rarely occur in developed countries).[30] At present, the risk factors described in this section represent the most promising targets for preventing and treating stroke in the developing world. Additional factors associated with stroke outcome are subsequently discussed.

The foremost risk factor for stroke throughout the industrialized world, hypertension may play an even greater role in causing stroke in low-income communities. Epidemiological studies among populations of East Asia, including the PRC [79] and Africa [80,81], indicate that controlling elevated blood pressure in these populations could prevent proportionately more strokes than equivalent measures in Western populations.[44] The reasons for the apparently stronger influence of hypertension on strokes among East Asian and black African populations remain to be identified, but may include both genetic and environmental effects, as well as longer exposure to untreated conditions of hypertension. Both populations were found to suffer a far higher proportion of hemorrhagic strokes as compared with Western populations.