Hyperhomocysteinemia and hypercholesterolemia associated with hypothyroidism in the third US National Health and Nutrition Examination Survey

Hypothyroid (thyroid stimulating hormone (TSH) greater than or equal to 20 mIU/l; N = 32) participants in the third National Health and Nutrition Exam ination Survey, Phase 2 (1991-1994) were compared with non-hypothyroid subj ects (0.5 mIU/l < TSH < 20;mIU/l; N= 6490) to examine the relationship betw een hypothyroidism and hyperhomocysteinemia (serum total homocysteine > 12 mu mol/l) and hypercholesterolemia (serum total cholesterol > 6.2 mmol/l). After controlling for age, gender, and race ethnicity, the odds ratios (95% confidence interval (CI)) relating hypothyroidism to hyperhomocysteinemia and high total cholesterol were 4.9 (1.8-14.0) and 8.0 (2.9-21.9), respecti vely. Based on 26 hypothyroid and 5811 non-hypothyroid subjects with trigly ceride concentration less than or equal to2.82 mmol/l, the odds ratio for t he relationship between hypothyroidism and high low-density lipoprotein (LD L)-cholesterol (> 4.6 mmol/l by the Friedewald equation) was 5.3 (95% CI, 1 .3-20.9). Adding additional terms to the multivariate logistic regression m odel had little effect on the odds ratios relating hypothyroidism to high t otal or LDL-cholesterol, but adding terms for serum creatinine concentratio n > 123.8 mu mol/l and for red blood cell folate and serum vitamin B-12 con centrations resulted in an attenuated, but still significant (P < 0.05), od ds ratio relating hypothyroidism to hyperhomocysteinemia (2.5; 95% CI, 1.0- 6.1). Controlling for cigarette smoking, heart attack/stroke history, body mass index, and serum albumin concentration did not affect the odds ratios. Hyperhomocysteinemia and hypercholesterolemia could help to explain the in creased risk for arteriosclerotic coronary artery disease in hypothyroidism . (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.