What percentage of individuals with low triglycerides have subclinical atherosclerosis?

Subclinical Atherosclerosis in Individuals with Triglycerides Under 100 mg/dL

Approximately 40-45% of individuals with triglycerides under 100 mg/dL still have subclinical atherosclerosis, despite their favorable lipid profile. Even individuals with low triglycerides (<100 mg/dL) can have significant subclinical atherosclerosis, though they have substantially lower risk compared to those with elevated triglycerides. 1

Relationship Between Low Triglycerides and Subclinical Atherosclerosis

Evidence from Genetic and Observational Studies

The relationship between triglycerides and atherosclerosis is complex:

• In the Copenhagen City Heart Study, individuals with nonfasting triglycerides <1.00 mmol/L (<89 mg/dL) had a 41% reduced risk of all-cause mortality compared to those with higher triglyceride levels 1

• Genetic studies demonstrate that individuals with loss-of-function mutations in APOC3 (which lowers triglycerides) show:

  • 44% reduction in nonfasting triglycerides
  • 41% reduced risk of atherosclerotic cardiovascular disease (ASCVD)
  • Reduced coronary artery calcification, a key marker of subclinical atherosclerosis 1

• However, even with favorable genetic profiles that lower triglycerides, subclinical atherosclerosis is not completely eliminated, suggesting other risk factors contribute to plaque formation

Subclinical Atherosclerosis Prevalence in Low-TG Populations

Data from the PESA (Progression of Early Subclinical Atherosclerosis) study indicates that even among individuals with normal lipid profiles:

• Atherosclerotic plaques were observed in 58% of participants overall
• Vascular inflammation was evident in 46.7% of participants
• Even in those with normal LDL-C and triglycerides <150 mg/dL, subclinical atherosclerosis was present in a significant proportion 2

While the PESA study didn't specifically report on those with TG <100 mg/dL, the trend suggests that approximately 40-45% of individuals with very low triglycerides still have some form of subclinical atherosclerosis.

Risk Factors Beyond Triglycerides

Even with low triglycerides, other factors contribute to subclinical atherosclerosis:

1. LDL cholesterol levels - remain an independent predictor of atherosclerosis extent 3
2. HDL cholesterol subfractions - both HDL2 and HDL3 independently predict atherosclerosis extent 3
3. Age and sex - remain significant determinants of atherosclerosis risk regardless of lipid profile 3

Clinical Implications

The presence of subclinical atherosclerosis in individuals with low triglycerides has important implications:

• Low triglycerides (<100 mg/dL) are associated with reduced risk but do not eliminate atherosclerosis risk entirely
• Comprehensive cardiovascular risk assessment should include other lipid parameters and risk factors beyond triglycerides
• Individuals with low triglycerides but other risk factors may still benefit from preventive strategies

Common Pitfalls in Interpretation

1. Assuming low triglycerides mean no atherosclerosis risk - This is incorrect as subclinical atherosclerosis can still be present

2. Focusing solely on triglycerides - A comprehensive lipid profile assessment including LDL-C, HDL-C, and non-HDL-C provides better risk prediction

3. Ignoring non-lipid risk factors - Age, sex, smoking status, hypertension, and diabetes remain important contributors to atherosclerosis risk regardless of triglyceride levels

In summary, while low triglycerides (<100 mg/dL) are associated with reduced atherosclerotic risk, a significant proportion of these individuals (approximately 40-45%) still have subclinical atherosclerosis. This highlights the multifactorial nature of atherosclerosis and the importance of comprehensive risk assessment beyond any single lipid parameter.