The Correlation Between Serum Homcysteine Levels And Hypothyroidism- A One Year Case Control Study

Abstract

Background and Objective: Thyroid gland is critical to the proper functioning and regulation of various physiological pathways and processes. It has been postulated that the decreased levels of hepatic enzymes involved in the remethylation pathway of homocysteine and concurrent changes in renal function leads to hyperhomocysteinemia. Also the thyroid hormones affect the metabolism of folic acid and riboflavin, by stimulating flavokinase, and thus reduces the flavin mononucleotides and flavin adenine dinucleotide (FAD). FAD- dependent methylene tetrahydrofolate reductase is reduced in hypothyroidism which leads to hyperhomocysteinemia. Homocysteine has been shown to be a strong independent risk factor for cardiovascular disease. The objectives of the study are to study the incidence of hyperhomocysteinemia in patients with hypothyroidism, and the relation of homocysteine and cholesterol levels to thyroid hormones free T3, free T4 and TSH in newly detected hypothyroid patients. Methodology This was a hospital based case-control study, Which recruited 30 newly detected hypothyroid patients and 30 euthyroid controls, at the KLES Dr Prabhakar Kore Charitable Hospital and Medical Research Center, Belagavi. After initial clinical detection of new hypothyroid patients, the patient was subjected to clinical and blood investigations. Similar method was employed in the control group after matching with the case group. These findings were noted on a predesigned and pretested proforma. Results A total of 30 hypothyroid patients and 30 euthyroid controls were included in the study. In the study the majority of the patients were females,42 (70%) with a male: female ratio of 3:7. the mean age of patients in the hypothyroid group was 40.60 years, and the mean age of patients in the normal group was 41.40 years with a p value of 0.7502, with a study mean age of 41 years. The mean TSH levels in the hypothyroid group was 46.95 mU/L , and that in the normal group was 2.27 mU/L , with a p value of 0.0001. The mean Free T3 levels in the hypothyroid group was 1.41 μg/l , and that in the normal group was 1.80 μg/l, which was not statistically significant ( p value 0.1148). The mean FT4 levels in the hypothyroid group was 4.69 ng/l , and that in the normal group was 5.75 ng/l , which was not statistically significant ( p value 0.2677). The mean serum homocysteine levels in the hypothyroid group was 25.02 mcmol/l , and that in the normal group was 16.65 mcmol/l, which was statistically significant ( p value 0.0064). The mean cholesterol levels in the hypothyroid population was 193.03 mg/dl, and that in the normal group was 165.90 mg/dl, which was statistically significant ( p value 0.0066). On correlating the serum homocysteine levels in the hypothyyroid group with TSH, fT3 and fT4 and serum cholesterol levels, there was no statistically significant correlation (p values of 0.7548,0.4989,0.5590 and 0.8360 respectively) . On correlating the serum homocysteine levels in the normal group with TSH, fT3 and fT4 and serum cholesterol levels, there was no statistically significant correlation ( p values of 0.9356, 0.5106 and 0.9429 respectively). On correlating the serum homocysteine levels with TSH , fT3 and fT3 and cholesterol levels in the total sample, the correlation was not statistically significant ( p values of 0.2278,0.1665,0.9441 and 0.0801 respectively). Conclusion • In conclusion, the study observed elevation of serum homocysteine and total cholesterol levels in hypothyroid patients. Hyperhomocysteinemia and increased cholesterol levels contributes to a greater cardiovascular risk. Hyperhomocysteinemia, along with hypercholesterolemia, can explain the progression of atherosclerosis in hypothyroid patients and we would recommend screening of serum homocysteine levels in hypothyroid patients , in view of the risk of accelerated atherosclerosis and cardiovascular disease. Further studies are needed on large populations