Variations in Common Diseases Across 21 Countries From Five Continents

Study Questions:

How does the incidence of common diseases and related mortality compare between high-income countries (HICs), middle-income countries (MICs), and low-income countries (LICs)?

Methods:

Data from the PURE (Prospective Urban Rural Epidemiology) study were used for the present analysis. PURE is a large prospective, population-based cohort of adults (aged 35-70 years) enrolled from 21 countries across five continents. Primary outcomes included the incidence of fatal and nonfatal cardiovascular diseases (CVDs), cancers, injuries, respiratory diseases, and hospital admissions.

Results:

A total of 162,534 adults, enrolled in the first two phases of PURE (January 6, 2005, to December 4, 2016) and followed for a median of 9.5 years were included in the present analysis. During follow-up, 11,307 (7.0%) participants died, 9,329 (5.7%) had a CVD event, 5,151 (3.2%) participants had a cancer, 4,386 (2.7%) participants had injuries requiring hospital admission, 2,911 (1.8%) participants had pneumonia, and 1,830 (1.1%) participants had chronic obstructive pulmonary disease (COPD). CVD events occurred more often in LICs (7.1 cases per 1,000 person-years) and MICs (6.8 cases per 1,000 person-years) compared to HICs (4.3 cases per 1,000 person-years). In contrast, incident cancers, injuries, COPD, and pneumonia were most common in HICs and least common in LICs. Overall mortality rates in LICs (13.3 deaths per 1,000 person-years) were double those in MICs (6.9 deaths per 1,000 person-years) and four times higher than in HICs (3.4 deaths per 1,000 person-years). However, mortality rates for cancer deaths were similar across country income levels. CVD was the most common cause of deaths overall (40%) but accounted for only 23% of deaths in HICs (vs. 41% in MICs and 43% in LICs), despite more CVD risk factors in HICs and the fewest such risk factors in LICs. Rates of first hospital admission and CVD medication use were lowest in LICs and highest in HICs.

Conclusions:

The investigators concluded that among adults aged 35-70 years, CVD is the major cause of mortality globally. However, in HICs and some upper-MICs, deaths from cancer are now more common than those from CVD, indicating a transition in the predominant causes of deaths in middle age. As CVD decreases in many countries, mortality from cancer will probably become the leading cause of death. The high mortality in poorer countries is not related to risk factors, but it might be related to poorer access to health care.

Perspective:

These data suggest that prevention efforts to manage CVD risk factors and secondary management of CVD in LICs and MICs may help to reduce CVD deaths as is observed among HICs. In addition, given these data on cancer deaths, efforts to reduce both CVD and cancer risk is warranted.

Clinical Topics: Prevention

Keywords: Cardiovascular Diseases, Developed Countries, Health Services Accessibility, Hospitalization, Income, Middle Aged, Neoplasms, Pneumonia, Primary Prevention, Poverty, Pulmonary Disease, Chronic Obstructive, Risk Factors


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