Research was conducted by multiple laboratories in the Global Diagnostics Network and included more than 460 million lipid test results from 17 countries to determine risk of cardiovascular disease (CVD).
A groundbreaking analysis of more than 460 million lipid test results from patients in 17 countries across 5 continents sheds light on the wide variation in lipid-associated risk of cardiovascular disease (CVD) based on geographical location and sex.
The analysis was conducted by several laboratories participating in the Global Diagnostics Network (GDN), led by Quest Diagnostics, and represents the largest study to date evaluating global variability in cholesterol and triglyceride levels, according to a Quest Diagnostics press release.1
The study was published in European Heart Journal, and it examined key markers of CVD risk such as total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, and triglyceride levels.2 Patients whose tests were included in the study were aged 20 to 89 years and received lipid testing from 2018 through 2020.
"With nearly half a billion lipid results, this analysis included a huge scale of recent data that was examined across the globe to inform public health," said Seth S. Martin, MD, MHS, professor of medicine at Johns Hopkins University School of Medicine and lead author of the study. "As these results inform the conversation that patients and clinicians have when selecting therapy, the distributions observed in our study might be useful to laboratories in refining interpretative ranges and alert values."
The authors explained that mg/dL units were converted to standard international mmol/L units by multiplying by 0.02586 for cholesterol and 0.01129 for triglycerides.
The results showed that individuals from 7 of the 17 countries had total cholesterol levels dangerously exceeding the World Health Organization (WHO) target, which is defined as below 5.00 mmol/L (193 mg/dL). These countries were Japan, Australia, North Macedonia, Switzerland, Germany, Slovakia, and Austria.
Of these countries, the highest mean total cholesterol levels were seen in Austria (5.40 mmol/L [208.8 mg/dL]) and Germany (5.35 mmol/L [206.9 mg/dL]). The countries displaying the lowest mean total cholesterol levels were the Republic of Korea (4.58 mmol/L [177.1 mg/dL]), Turkey (4.74 mmol/L [183.3 mg/dL]), and the United States (4.75 mmol/L [183.6 mg/dL]).
The analysis also revealed that dangerous cholesterol levels reached their peak during middle age in both sexes across most countries. Men experienced this peak about a decade earlier than women, with peaks at 40 to 49 years and 50 to 59 years, respectively. India was the only country where total cholesterol levels did not peak during that age for women.
Additionally, a higher proportion of women had elevated LDL-C levels compared with men, except in Brazil, Saudi Arabia, Spain, and the United Arab Emirates. The study also showed that total cholesterol patterns based on age group and compared between sexes were strikingly similar among Brazil, Canada, and the United States.
The main limitations of the study are the lack of patient medical data—including any use of lipid-lowering therapies—to contextualize the results of the lipid tests and that most data (79%) were collected from the United States while data from the African WHO region and certain other countries were lacking. However, the authors cited the large sample size as a major strength of the study. Additionally, the GDN plans to expand to more countries, especially low– and middle-income countries, and increase representation of African countries.
The authors also suggested that variations in test results between countries may reflect differences in cultural dietary and physical activity patterns, economic conditions, and access to lipid testing and treatment. They also mentioned the potential influence of genetic differences, citing familial hypercholesterolemia (FH) as an example. FH is an inherited genetic disorder characterized by dangerously elevated levels of LDL-C and has varying prevalence rates across countries, affecting approximately 30 million people.
"The GDN study is important for demonstrating what has long been suspected: that cardiovascular disease is an urgent public health problem in multiple countries, not just the USA, and cultural and genetic factors likely contribute to development of this largely preventable disease," said Harvey W. Kaufman, MD, senior medical director at Quest Diagnostics and co-author of the study. "We hope our study ignites greater focus of public health resources on the global problem of cardiometabolic disorders."