Analysis of Half a Billion Lipid Tests from Five Continents Reveals Wide Variation of Lipid-Associated Risk of Heart Disease by Country and Sex

Organized by nine laboratories on five continents, the study by some members of the Global Diagnostics Network, a Quest Diagnostics-led strategic working group, is the largest to evaluate worldwide variability in cholesterol and triglyceride test results

People tested in seven of 17 countries had total cholesterol results signifying heightened cardiovascular disease risk relative to the World Health Organization target

SECAUCUS, N.J., July 10, 2023 /PRNewswire/ -- A new analysis of more than 460 million lipid test results of patients living in 17 countries on five continents provides new evidence that where a person lives and their sex influences their lipid-associated risk of cardiovascular disease, possibly due in part to differences in genetics, lipid testing, lifestyle habits, and pharmacologic treatment. Performed by researchers from Johns Hopkins University, Quest Diagnostics (NYSE: DGX) and eight other laboratories participating in the Quest-led Global Diagnostics Network (GDN), the analysis is believed to be the largest ever to evaluate worldwide variability in lipid levels.

The analysis finds that people tested in seven of 17 countries had suboptimal total cholesterol levels relative to the World Health Organization (WHO) target, suggesting heightened disease risk, and that dangerous cholesterol levels reached their zenith during middle age in both sexes in most countries, although males peaked a decade earlier than females.   

Published in European Heart Journal, the analysis includes medically recognized laboratory markers of cardiovascular disease risk, including levels of total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglyceride. The WHO and clinical practice guidelines in different countries recognize lipid testing's clinical value. Yet, little research on lipid levels has been attempted on a global scale. The new study aims to identify geographical differences to highlight and share best practices and focus global public policy resources on high-risk populations.  

"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 lead author Seth S. Martin, MD, MHS, Professor of Medicine, Ciccarone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine. "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."

Based on analysis of results of laboratory tests performed between 2018 and 2020, the study's key findings include:

• Highest total cholesterol levels in two European countries: Seven countries evaluated had mean total cholesterol levels exceeding the WHO-defined risk threshold of 5.00 mmol/L (193 mg/dL): Japan, Australia, North Macedonia, Switzerland, Germany, Slovakia, and Austria. Of these, the highest mean total cholesterol levels were in Austria (5.40 mmol/L, 208.8 mg/dL) and Germany (5.35 mmol/L, 206.9 mg/dL).
• Countries with lowest cholesterol levels spanned the Americas, Middle East and Asia: The countries with 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 Americas region showed strikingly similar patterns, with age group-based patterns of total cholesterol in females and males remarkably similar among three countries in the Western Hemisphere (Brazil, Canada, and the United States).
• Differences by sex held steady in most countries, with total cholesterol and LDL cholesterol levels peaking in males between ages 40-49 years, roughly a decade earlier than females' peak at ages 50-59 years. Yet, a higher proportion of females than males had rates of LDL cholesterol levels at or above 4.91 mmol/L, a level the WHO considers highly elevated, in all but four countries (Brazil, Saudi Arabia, Spain and United Arab Emirates). In every country except India, total cholesterol levels among females were highest in the 50-59-year age group.
• North Macedonia had the highest proportions of LDL cholesterol results greater than 4.91 mmol/L (>190 mg/dL) for both females (9.9%) and males (8.7%).

The authors speculate that the country-based variations in test results may reflect different "cultural dietary and physical activity patterns," economic conditions and access to lipid testing and treatment. The authors also cite the possible role of genetic differences between countries and give the example of familial hypercholesterolemia (FH). FH is an inherited genetic disorder that causes dangerously elevated levels of LDL cholesterol and is estimated to affect 30 million people worldwide, with significant variability in prevalence across countries.

The study involved lipid testing performed by 9 laboratories that are members of the Global Diagnostics Network, a strategic working group of 12 laboratories organized in 2018 by USA-based Quest Diagnostics, a leading U.S. provider of laboratory services, to improve global laboratory innovation, insights and quality. The members that participated in the study include Healius (Australia), DASA (Brazil), Life Labs (Canada), Strand Life Sciences (India), LSI Medience (Japan), GC Labs (Republic of Korea), Al Borg Diagnostics (Saudi Arabia), SYNLAB (Austria, Germany, North Macedonia, Slovakia, Spain, Switzerland, Turkey, United Arab Emirates, and the United Kingdom) and Quest Diagnostics (United States). Data was deidentified and aggregated by participating laboratory prior to analysis.

"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 U.S.A., and cultural and genetic factors likely contribute to development of this largely preventable disease," said co-author Harvey W. Kaufman, MD, senior medical director, Quest Diagnostics. "We hope our study ignites greater focus of public health resources on the global problem of cardiometabolic disorders."

Strengths of the study include its uniquely large size while limitations include lack of patients' medical data to contextualize test data. While the laboratories involved in the analysis are leaders in their respective countries, their laboratory data may not fully represent any particular country or geography.

Click here to access the full study online via European Heart Journal.

About Heart Disease
The WHO states ischemic heart disease, also known as coronary heart disease, is the leading cause of death worldwide, responsible for 16% of the world's total deaths. Since 2000, the largest increase in deaths has been for this disease, rising by more than 2 million to 8.9 million deaths in 2019. Advanced age, hypertension, diet, physical activity, tobacco use, overweight and obesity, diabetes, genetics and other factors influence risk.

About the GDN
The Global Diagnostics Network (GDN) is a strategic working group of diagnostic laboratories, each committed to unleashing and sharing local innovation to increase global access to diagnostic science and services — ultimately generating diagnostic insights and enhancing global healthcare. Organized by Quest Diagnostics, the GDN includes some of the world's leading diagnostics companies across the globe. Collectively, this worldwide community of 12 healthcare companies has a presence in countries with two-thirds of the world's population, and over 90% of the global pharmaceutical market. www.GlobalDiagnosticsNetwork.com 

About Quest Diagnostics
Quest Diagnostics empowers people to take action to improve health outcomes. Derived from the world's largest database of clinical lab results, our diagnostic insights reveal new avenues to identify and treat disease, inspire healthy behaviors and improve healthcare management. Quest annually serves one in three adult Americans and half the physicians and hospitals in the United States, and our nearly 50,000 employees understand that, in the right hands and with the right context, our diagnostic insights can inspire actions that transform lives. www.QuestDiagnostics.com

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