Apolipoprotein E and Paraoxonase 1 polymorphisms are associated with lower serum thyroid hormones in postmenopausal women

Summary Objective Autoimmune thyroiditis and overt or subclinical hypothyroidism have been associated with increased prevalence of cardiovascular disease (CVD). Design Cross‐sectional investigation of the association between gene polymorphisms related to CVD with thyroid function and autoimmunity. Patients In total 84 healthy postmenopausal women aged 49–69 years. Measurements FT3, FT4, anti‐TPO and anti‐TG were assessed in the sera of participants. The following polymorphisms were assessed from peripheral lymphocyte DNA: Apolipoprotein E E2/E3/E4, paraoxonase 1 A/B, Glycoprotein IIIa leu33pro, MTHFR ala222val, ApoBarg3500gln, plasminogen activator inhibitor 1 4G/5G, cholesterol 7‐α hydroxylase A204C and cholesterol ester transfer protein B1/B2. Results A statistically significant correlation was found between Apolipoprotein E and paraoxonase1 polymorphisms and serum thyroid hormones: carriers of the E2 or E4 allele of the ApoE gene had lower levels of FT4 (P = 0·0005) than women with the E3/E3 genotype. Carriers of the B allele of paraoxonase 1 gene had lower levels of FT3 compared to women with the wild‐type genotype (P = 0·047). A statistically significant positive association (P = 0·049) was also observed between anti‐TG antibodies and the presence of the E2 allele of the Apolipoprotein E gene. Conclusions Polymorphisms of apolipoprotein E and paraoxonase 1 are associated with different levels of thyroid hormone and anti‐Tg antibody levels in the study population in this pilot study. The mechanism underlying this association remains to be elucidated.