Just as cholesterol levels start to drop in Europe and North America, many countries in Asia are starting to see a sharp rise. This major shift in global health – detailed in the largest study of cholesterol levels across the world to date – is a tale of changing diets, reshaped lifestyles, and globalization, as well as the rise of medication.

Cholesterol is a waxy substance that circulates in your blood and is mainly made by your liver, although some is drawn from your diet. Despite its nasty reputation, not all cholesterol is bad. Some is needed to build healthy functioning cells and it could even have a protective effect against heart attacks and strokes, a type known as high-density lipoprotein (HDL) cholesterol. However, there is some bad cholesterol, known as non-HDL, which can clog up blood vessels and increase the risk of heart attacks and strokes. 

The study, reported in the journal Nature in June 2020, saw hundreds of researchers look at data on 102 million people in 200 countries, examining their cholesterol levels between 1980 and 2018. It shows how total and non-HDL cholesterol levels have dramatically fallen in high-income nations, especially countries in North-western Europe, North America, and Australasia, but have risen significantly in low- and middle-income nations, especially in East and Southeast Asia.

Between 1980 and 2018, countries with the highest levels of non-HDL cholesterol changed from Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland, and Malta to countries in Asia and the Pacific, such as Tokelau, Malaysia, the Philippines, and Thailand. Some of the strongest decreases in non-HDL cholesterol since 1980 were found in Belgium and Iceland. 

China is an especially noteworthy example in this new study. Back in 1980, the country had some of the lowest levels of non-HDL cholesterol worldwide, but it went through one of the largest rates of increase in non-HDL in the following 39 years. 

The explanation behind these changes in cholesterol levels are complex, but they can largely be reduced down to two factors: diet and drugs. For starters, nations with declining cholesterol have seen a change in diet that replaced saturated fats with unsaturated fats and reduced trans fats. Many of the same countries have also seen an uptick in the use of statins – drugs that help lower cholesterol levels in the blood – since the 1990s. 

Conversely, other parts of the world have seen a shift in diet go the other way. Many of these countries with rising non-HDL cholesterol levels have witnessed a substantial increase in the consumption of meat, dairy, refined carbohydrates, and palm oil, whereas the use of statins has remained low. This is most likely a reflection of globalization, increased production of processed food, rapid urbanization, and changing lifestyles.

With these changes in tides, the researchers warn we can expect to see a rise of heart and circulatory diseases across many parts of our ever-changing world.

"For the first time, the highest levels of non-HDL cholesterol are outside of the Western world. This suggests we now need to set into place throughout the world pricing and regulatory policies that shift diets from saturated to non-saturated fats, and to prepare health systems to treat those in need with effective medicines." Professor Majid Ezzati, lead author of the research from Imperial College London's School of Public Health, said in a statement, "This will help save millions of deaths from high non-HDL cholesterol in these regions.”