Two reports published in The Lancet providing new data about common disease incidence in high-, middle-, and low-income countries has revealed that while globally cardiovascular diseases (CVD) remains the most common cause of death, in high-income countries cancer is now the leading cause of death for middle-aged adults. The reports are part of the PURE (Prospective Urban Rural Epidemiology) study and were presented together at the ESC Congress 2019 this week in Paris.
The first study focused on the variation of common diseases, as well as hospital admissions and mortality for 162,534 middle-aged adults (aged 35 to 70) in 21 countries across the world. Globally, CVD is still the leading cause of death for middle-aged adults, accounting for 40 percent of all deaths. They found that adults were 2.5 times more likely to die of CVD in lower-income countries (LIC), compared to high-income countries (HIC), despite LIC countries experiencing lower risk factors for CVD than richer countries. The authors suggest a lower quality of healthcare, or economic factors prohibiting people seeking healthcare could be a factor for this. However, in HIC they found cancer has overtaken to become the leading cause of death, with 10 cancer deaths for every 4 CVD deaths.
"The world is witnessing a new epidemiologic transition among the different categories of non-communicable diseases, with CVD no longer the leading cause of death in HIC," lead author Dr Gilles Dagenais, Emeritus Professor at Laval University, said in a statement. "Our report found cancer to be the second most common cause of death globally in 2017, accounting for 26% of all deaths. But as CVD rates continue to fall, cancer could likely become the leading cause of death worldwide, within just a few decades."
The second report focused on cardiovascular disease. According to their findings, 70 percent of CVD cases and deaths worldwide are due to modifiable risks. Among these risks, there are metabolic, behavioral, socioeconomic, and psychosocial factors, strength, and environment. Metabolic was the largest contributor reaching 41.2 percent of all cases. Hypertension was the leading factor within this group, with slightly less than a quarter of all cases (22.3 percent).
Globally, the main risk factor leading to death in CVD was behavioral risk, but in low- and middle-income countries the importance of household air pollution, poor diet, low education, and low grip strength was much larger than in high-income countries.
"While some risk factors certainly have large global impacts, such as hypertension, tobacco, and low education, the impact of others, such as poor diet, household air pollution, vary largely by the economic level of countries," Sumathy Rangarajan, who coordinated the study said. "There is an opportunity now to realign global health policies and adapt them to different groups of countries based on the risk factors of greatest impact in each setting."
The results are informative and indicate the need for improving resources and focusing on more ad-hoc solutions for different countries. That said, the authors admit the limitation of the studies; focusing on just 21 countries (with no inclusion of countries in North and West Africa or Australia) means it's not possible to generalize for every country.