‘Bad’ cholesterol levels fall sharply in high-income nations but rising in low, middle-income countries: Study
Cholesterol levels are declining sharply in Western nations, but rising in low- and middle-income nations, particularly in Asia, according to a large study of global cholesterol levels. The researchers found that high cholesterol is responsible for about 3.9 million worldwide deaths. Half of these deaths happen in East, South, and Southeast Asia, says the analysis led by Imperial College London, UK. The research team, which includes hundreds of experts from across the world, used data from 102.6 million individuals, and examined cholesterol levels in 200 countries, across 39 years, from 1980 to 2018.
The analysis shows that “for the first time, the highest levels of ‘bad’ cholesterol are outside of the Western world”. The team found that total and bad cholesterol levels have fallen considerably in high-income nations, particularly those in North-western Europe, North America, and Australasia. They have, however, gone up in low- and middle-income nations, particularly in East and Southeast Asia. These countries had some of the lowest levels of bad cholesterol in 1980, but one of the largest rates of increase in non-HDL over the 39-year study period.
Cholesterol is a waxy substance found in the blood. The body needs cholesterol to build healthy cells, but too much can lead to a build-up in the blood vessels. Cholesterol comes in different types. “High-density lipoprotein (HDL) 'good' cholesterol, which should be 1mmol/L or above, is thought to have a protective effect against heart attack and stroke, by mopping up excess 'bad' cholesterol. Non-HDL 'bad' cholesterol, which should be as low as possible, around 2mmol/L, can block blood supply and lead to heart attacks and strokes. This type of cholesterol is usually raised by diets high in saturated and trans fats, which is found in many processed foods, instead of healthier unsaturated fats. It can be lowered effectively through the use of statins,” says the study published in Nature.
Countries with the highest levels of non-HDL cholesterol, which is a marker of cardiovascular risk, changed from those in Western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland, and Malta in 1980 to those in Asia and Pacific, such as Tokelau, Malaysia, the Philippines, and Thailand.
According to the researchers, some of the reduction in non-HDL cholesterol levels in Western nations are due to increased use of statins in Western countries, which are not yet used widely in low- and middle-income countries. The team also said that some countries had fewer data compared to others, which could influence how certain one can be about cholesterol levels and changes over time. The research, which produced cholesterol comparisons for all 200 countries, also found that bad cholesterol for US women ranked 50th highest in the world in 1980, while it ranked 127th highest in the world in 2018. Similarly, for US men, bad cholesterol ranked 42th highest in the world in 1980, but in 2018, it ranked 108th highest in the world.
“Non-HDL cholesterol for UK women ranked 18th highest in the world and 16th highest in Europe in 1980. In 2018, it ranked 130th highest in the world and 34th highest in Europe. Non-HDL cholesterol for UK men ranked 18th highest in the world and 16th highest in Europe in 1980. In 2018, it ranked 106th highest in the world and 35th highest in Europe,” says the study. The research team, however, cautions that one must not be complacent. “High numbers of people still have undiagnosed or uncontrolled levels of non-HDL cholesterol putting them at greater risk of heart and circulatory diseases. We strongly encourage people, especially those over 40, to have their cholesterol checked. It's important for those diagnosed with high non-HDL cholesterol to follow their doctor's advice for lowering it,” says Professor Sir Nilesh Samani, medical director at the British Heart Foundation, in the report.
The researchers also recommend putting in place pricing and regulatory policies globally that shift diets from saturated to non-saturated fats, and to prepare health systems to treat those in need with effective medicines. “This will help save millions of deaths from high non-HDL cholesterol,” says the research team.