What is Dyslipidemia in PCOS?
Dyslipidemia in PCOS is an abnormal lipid profile characterized by elevated triglycerides, low HDL cholesterol, and increased small dense LDL particles—a pattern called atherogenic dyslipidemia that significantly increases cardiovascular disease risk even in young women with normal BMI. 1, 2
Core Lipid Abnormalities in PCOS
The lipid profile in PCOS patients differs substantially from healthy women, with specific quantitative and qualitative changes:
Quantitative Changes
- Triglycerides are elevated by approximately 26 mg/dL compared to women without PCOS 3, 4
- HDL cholesterol is reduced by approximately 6 mg/dL, removing the cardioprotective effect of this lipoprotein 3, 4
- LDL cholesterol is elevated by approximately 12 mg/dL on average 3
- Non-HDL cholesterol levels are higher by approximately 19 mg/dL, indicating increased atherogenic particle burden 4
Qualitative Changes
- Small dense LDL particles are increased, which are more atherogenic than normal-sized LDL particles 5, 3
- ApoB levels are elevated, tracking with the increased number of atherogenic particles 4
- Lipoprotein(a) is consistently elevated, representing an independent cardiovascular risk factor 3
- ApoC-III/ApoC-II ratios are elevated, indicating impaired triglyceride metabolism 4
- ApoC-I levels are increased even in non-obese women, potentially representing the earliest lipid abnormality in PCOS 3, 4
- ApoA-I levels are reduced, further diminishing cardioprotective mechanisms 3
Why This Occurs in PCOS (Even with Normal BMI)
Insulin resistance is intrinsic to PCOS itself and occurs independently of obesity, affecting both lean and overweight women equally. 2 This is critical to understand—your patient's normal BMI does not protect her from these metabolic abnormalities.
Pathophysiologic Mechanisms
- Insulin resistance drives the dyslipidemia through increased hepatic VLDL production and impaired lipoprotein lipase activity 6, 4
- Hyperandrogenism contributes to the adverse lipid profile through direct effects on hepatic lipid metabolism 5, 4
- Estrogen dominance (as in your patient) can paradoxically worsen triglycerides through increased hepatic VLDL synthesis, though this effect varies by individual 1
Clinical Significance
This atherogenic lipoprotein phenotype substantially increases cardiovascular disease risk despite the patient's young age and normal weight. 1, 5
Cardiovascular Risk Context
- Women with PCOS develop endothelial dysfunction and subclinical atherosclerosis even before traditional risk factors fully manifest 1
- The dyslipidemia pattern in PCOS mirrors that seen in established metabolic syndrome, conferring similar cardiovascular risk 6, 4
- East Asian women with PCOS have the highest prevalence of metabolic syndrome despite lower BMI, suggesting ethnic variation in risk expression 1
Required Screening and Monitoring
All women with PCOS require comprehensive lipid screening regardless of BMI or weight. 1, 2, 7
Specific Testing Requirements
- Obtain a complete fasting lipid panel including total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides at diagnosis 1, 7
- Repeat lipid panels at least annually as part of ongoing cardiovascular risk monitoring 1, 7
- Consider advanced lipid testing (ApoB, lipoprotein[a], LDL particle size) in patients with borderline standard lipid values to better characterize risk 3, 4
- Screen for diabetes with 2-hour oral glucose tolerance test (75g glucose load) at diagnosis and every 2 years, as insulin resistance drives the dyslipidemia 2, 7
Additional Monitoring Parameters
- Monitor weight and calculate BMI every 6-12 months even if currently normal, as weight gain will exacerbate lipid abnormalities 1, 7
- Measure waist circumference and waist-hip ratio to assess central adiposity patterns that predict cardiovascular risk 7
- Check blood pressure at least annually, as hypertension clusters with dyslipidemia in PCOS 1, 6
Common Pitfall to Avoid
Do not assume normal BMI equals normal metabolic health in PCOS—the insulin resistance and dyslipidemia are intrinsic to the syndrome and require screening and management regardless of body weight. 2, 3 Many clinicians mistakenly defer lipid screening in lean PCOS patients, missing the opportunity for early cardiovascular risk modification.