Cholesterol in Menopause: What the SWAN Study Showed

SWAN (the Study of Women's Health Across the Nation) is a prospective cohort study launched in 1996 that has followed more than 3,300 women across multiple US sites through their menopause transition. SWAN is the largest and longest-running study of midlife women in the world, and it is unique in that it tracks women longitudinally through their final menstrual period rather than comparing pre- and post-menopausal women cross-sectionally. SWAN has produced foundational evidence on menopause symptoms, weight gain, sleep, mental health, bone density, and cardiovascular risk.

SWAN cardiovascular substudies, published over multiple years in journals like *Circulation*, *JACC*, and *Journal of Clinical Endocrinology and Metabolism*, found that LDL cholesterol and total cholesterol rise sharply in the year preceding and following the final menstrual period, on average about 10 to 15 mg/dL. Apolipoprotein B, a marker of atherogenic particle number, also rises. Triglycerides trend upward, and the LDL particle size shifts toward smaller, more dangerous particles. HDL cholesterol changes are mixed: levels may rise slightly, but HDL function (its ability to actually remove cholesterol from arteries) often declines, which is not captured by standard tests. These changes are independent of aging and weight gain and have been replicated in several other cohorts.

Estrogen has direct and indirect effects on lipid metabolism. It up-regulates the LDL receptor in the liver, which is the main pathway that clears LDL from the bloodstream. As estrogen falls, LDL receptor activity drops and LDL accumulates. Estrogen also influences cholesterol synthesis pathways, fat distribution (more visceral fat in midlife means more atherogenic particles), and insulin sensitivity. The combination explains why a woman with stable diet and weight can suddenly see her LDL jump from 110 to 140 mg/dL during the menopause transition. The shift is biological, not a sign of new bad habits.

Cardiovascular disease is the leading cause of death in postmenopausal women, exceeding all cancers combined. Heart attacks become much more common in women in the decade after menopause. The combination of rising LDL, smaller LDL particles, more visceral fat, rising blood pressure, and worsening insulin sensitivity tends to compound. The good news: most of this risk is modifiable. Women with low LDL, normal blood pressure, normal blood sugar, no smoking, and regular exercise have very low rates of cardiovascular events even after menopause.

Oral estrogen lowers LDL and raises HDL but also raises triglycerides. Transdermal estrogen (patches, gels) has more neutral lipid effects and a lower risk of blood clots. The WHI 30-year follow-up clarified that women who started HRT within 10 years of menopause had no increased cardiovascular mortality and possibly some benefit, while those starting HRT more than 10 years out had increased risk. HRT is not currently recommended *just* for cardiovascular prevention, but if a woman is starting HRT for vasomotor symptoms, the cardiovascular signal is reassuring when initiated early.

Diet: Mediterranean and DASH eating patterns lower LDL by 5% to 15% in trials. Soluble fiber (oats, beans, psyllium), nuts, fatty fish, olive oil, and vegetables drive most of the benefit. Limiting refined carbohydrates and saturated fat from processed foods helps. Exercise: 150 minutes of moderate cardio plus two strength sessions per week improves LDL particle size, lowers triglycerides, and improves insulin sensitivity. Weight: Even 5% to 10% weight loss meaningfully improves the lipid profile, especially in women with central adiposity. Alcohol: Reducing intake lowers triglycerides and reduces breast cancer risk.

Decisions are based on overall cardiovascular risk, not just cholesterol numbers in isolation. Calculators like the AHA/ACC ASCVD Risk Estimator combine age, sex, blood pressure, cholesterol, smoking, and diabetes. Women with a 10-year ASCVD risk over 7.5%, or those with diabetes, established cardiovascular disease, or LDL persistently over 190 mg/dL, are typically candidates for statin therapy. Newer tools like coronary artery calcium (CAC) scoring can refine risk in women with intermediate scores. Bempedoic acid and PCSK9 inhibitors are options for women who cannot tolerate statins or who need additional LDL lowering. Discuss your individual risk with your healthcare provider.