Jennifer Lovejoy, Arivale Chief Science Officer, PhD
LDL-cholesterol is often referred to as the “bad” cholesterol because many epidemiological studies demonstrate a strong association between higher LDL-C levels and increased risk of developing and dying from cardiovascular disease.
However, the majority of these studies were conducted in high-risk groups or the general population. Studies examining how LDL-C levels relate to cardiovascular disease in people with low short-term risk for developing cardiovascular disease are limited.
A study recently published in the American Heart Association’s journal Circulation and covered by Reuters sought to determine the long-term associations of LDL-C and mortality from cardiovascular disease in over 35,000 individuals with low short-term risk for cardiovascular disease.
At baseline, study participants had no history of cardiovascular disease or diabetes and were at low risk for having events related to atherosclerotic cardiovascular disease over the next 10 years. The researchers defined this low short-term risk using a set of equations that incorporated factors like the individual’s sex, age, race, total cholesterol, systolic blood pressure, and smoking habits.
In total, 36,375 participants (72 percent men, with a median age of 42 years) were followed for a median of approximately 27 years. Over the course of this time, 1,086 cardiovascular disease and 598 coronary heart disease deaths occurred.
Researchers found that in comparison to those with low LDL-C levels (under 100 mg/dL), people with levels ranging from 100 mg/dL to 159 mg/dL had on average a 30 percent to 40 percent increased risk of dying from cardiovascular disease. People with LDL-C levels of 160 mg/dL or greater had on average a 70 percent to 90 percent increased risk of death from cardiovascular disease.
Next, researchers accounted for cardiovascular disease risk factors (such as sex, smoking, hypertension, etc.) that may influence their results. They found that LDL-C levels of 160 mg/dL or greater remained independently associated with cardiovascular disease mortality. Individuals with such levels had on average a 50 percent to 70 percent increased risk of death from cardiovascular disease.
Overall, researchers’ data suggests that in a population with a low short-term atherosclerotic cardiovascular disease risk, those with LDL-C levels of 160 mg/dL or greater are at increased relative risk for long-term cardiovascular disease mortality.
Interestingly, the most recent American Heart Association/American College of Cardiology cholesterol guidelines from 2013 don’t generally recommend statin therapy in low 10-year risk individuals unless the individual has an LDL-C level of 190 mg/dL or greater.
The researchers of this study conclude that their results warrant further consideration of appropriate LDL-C thresholds for lipid-lowering interventions in individuals with low short-term cardiovascular disease risk.
Despite its findings, this study alone is not likely to cause the American Heart Association to change its current guidelines on statins due to some limitations within the study.
First, this was an epidemiological study and doesn’t provide evidence that lowering LDL-C will improve outcomes in people with low short-term cardiovascular disease risk. Second, the study participants were from higher socioeconomic groups and primarily white, making the study population not representative of the overall US population. Third, the use of lipid-lowering medications was not documented in this study, which could have biased results.
While knowing your short-term risk for cardiovascular disease and your LDL-C levels is important for understanding your heart health, so are other pieces of information, such as your genetics. For example, at Arivale we examine your genetic susceptibility to higher LDL-C levels in tandem with your current LDL-C levels. By knowing your genetics and blood values, you can be more informed in decisions regarding your health. (However, remember that regardless of genetic influence on your LDL-C, there are many lifestyle choices that can help lower your “bad” cholesterol. Dietary changes, exercise, and weight loss (if needed) can all make big impacts.)
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[Arivale Hot Topics address health stories currently in the news. The Arivale Clinical Team’s commentary on these news articles is not a review of the scientific evidence, nor an endorsement of a specific study, and is not meant as official medical opinion.]