Association of vitamins, minerals, and lead with lipoprotein(a) in a cross-sectional cohort of US adults

Lipoprotein(a)(Lp[a]) is a low-density lipoprotein-cholesterol (LDL-C)-like particle with potent pro-atherothrombotic properties. The association of Lp(a) with several circulating factors, including vitamins, remains unresolved. We performed an observational analysis using the National Health and Nutrition Examination Survey III cohort, a cohort used to monitor the nutrition status of US-citizens. We used multivariable linear regression to test associations of Lp(a) and LDL-C with levels of serum vitamins and minerals and whole-blood lead. Analyses controlled for factors known to associate with Lp(a) (age, sex, race/ethnicity, statin use, hemoglobin A1c, body mass index, hypertension, diabetes, glomerular filtration rate, alcohol intake, and saturated fat intake). LDL-C was corrected for Lp(a) mass. Multiple sensitivity tests were performed, including considering factors as categorical variables (deficient, normal, elevated). Among 7,662 subjects, Lp(a) correlated (β-coefficient) positively (change per 1 conventional unit increase) with carotenoids (lycopene (0.17(0.06,0.28), p=0.005), lutein (0.19(0.07,0.30), p=0.002), β-cryptoxanthin (0.21(0.05,0.37), p=0.01), β-carotene (0.05(0.02,0.09), p=0.003), and α-carotene (0.15(0.01,0.30), p=0.04)) and lead (0.54(0.03,1.05), p=0.04) levels when tested as continuous variables. LDL-C had similar associations. Lp(a) did not associate with vitamins A, B12, C, or E retinyl esters, folate, RBC-folate, selenium, ferritin, transferrin saturation, or calcium. With factors as categorical variables, Lp(a) but not LDL-C negatively associated with elevated vitamin B12 (-5.41(-9.50, -1.53), p=0.01) and folate (-2.86(-5.09, -0.63), p=0.01). In conclusion, Lp(a) associated similarly to LDL-C when vitamins, minerals, and lead were tested as continuous variables, while only Lp(a) correlated with vitamin B12 and folate when tested as categorical variables. These observations are hypotheses generating and require further studies to determine causality.