'Global Epicenter' of Problematic Cholesterol Has Shifted

By Linda Carroll

June 04, 2020

(Reuters Health) - High cholesterol is on the rise in low- and middle-income countries while declining in wealthier ones, an international team of researchers finds in a new analysis.

Based on more than 1,000 population-based studies that measured blood lipids in over 100 million adults from around the world, the results show that between 1980 and 2018, prevalence of high non-HDL cholesterol has fallen in wealthier nations, while it has risen in low- and middle-income nations.

"There has been a massive shift in where the highest levels of hazardous cholesterol are: from western countries, especially northwestern Europe, North America and Australia/New Zealand to countries in southeast Asia and some other middle-income regions," said study coauthor Majid Ezzati, a professor and Chair in Environmental Health at Imperial College London, in the UK.

What's driving the shift?

"Changes in diet - especially the balance between saturated fats/trans fats and non-saturated fats - and how widely treatment is used," Ezzati said in an email.

To look at trends in "non-optimal" cholesterol, Ezzati and his team analyzed data from 1,127 population-based studies that measured blood lipids in 102.6 million adults from 200 countries between the years 1980 and 2018.

Although the researchers found little change in total cholesterol or non-HDL cholesterol worldwide, they did find a shift: over the nearly four decades studied, high cholesterol levels had decreased in wealthier countries, especially those in northwestern Europe and central and eastern Europe, and they had increased in poor and middle-income countries, especially in east and southeast Asia.

China, for example, was among the countries with the lowest prevalence of high non-HDL cholesterol in 1980, but by 2018 it was among those with the highest prevalence, the authors report in Nature.

And the impact of those high cholesterol levels could be seen in death rates. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million worldwide deaths from ischemic heart disease and ischemic stroke, the researchers calculate. From 1990 to 2017, the annual number of deaths caused by ischemic heart disease and ischemic stroke attributable to non-HDL cholesterol increased by 910,000 globally. Particularly striking, though, was a net decrease in mortality from those causes in western countries during the same time period, from a high of 950,000 to 480,000 annually.

What's the best way to fix the problem? "Regulatory and fiscal policies that shift from saturated fats and trans fats to unsaturated fats, and scaling up treatment," Ezzati said.

The new study confirms what many have suspected, said Dr. Albert Wu, an internist and a professor of health policy and management at the Johns Hopkins Bloomberg School of Public Health, in Baltimore.

"It used to be that high-income westernized countries had a franchise on high cholesterol," Dr. Wu said. "We have exported our bad habits in a particularly unfortunate consequence of cultural imperialism."

"In these low- and middle-income countries people are also suffering from more obesity, diabetes and hypertension and that's largely attributable to diets that are high in animal-based foods, saturated fats and refined carbohydrates."

Increasing rates of high cholesterol in people from Asian and African countries has come as their economies have improved, said Dr. Aryan Aiyer, an assistant professor of medicine at the University of Pittsburgh School of Medicine and a preventive cardiologist at the UPMC Heart and Vascular Institute.

Dietary changes, which included more foods from animal sources and processed foods, have come with those economic improvements, Dr. Aiyer said in an email. "In addition, a more sedentary lifestyle and decreased physical activity both contribute to an increase in weight which very likely leads to higher cholesterol," he added.

Even with lower cholesterol levels in western countries, cardiovascular disease remains a major problem, Dr. Aiyer said.

"While overall cholesterol levels may have decreased in higher income countries, the prevalence of obesity has not, Dr. Aiyer said. "In fact, obesity has increased steadily in the U.S. So, there is a disconnect between obesity and observed cholesterol levels. I suspect it's because a lot more people in the U.S. are prescribed statins by their doctors to treat the high cholesterol due to poor dietary habits."

SOURCE: https://bit.ly/306IXCX Nature, online June 3, 2020.