The Study of Anemia in Hypothyroidism with Reference to Vitamin B12 Deficiency

Abstract

INTRODUCTION: Hypothyroidism is a condition caused due to decreased synthesis, metabolism or decreased action of thyroid hormone which can be due to various causes. Hypothyroidism is the most common of thyroid disorders in India, affecting one in ten adults. The prevalence of hypothyroidism is 11% in India, compared with U.K & U.S.A, which is only 2% and 4·6% respectively. Despite the known fact that anemia and thyroid dysfunction often occur simultaneously, the pathophysiology remains unclear. Hypothyroid patients often present with symptoms of numbness, paresthesia, poor memory and weakness, despite being on adequate replacement doses of thyroxin. Only few studies have been conducted to assess the cause of anemia and specifically role of Vitamin B12. So, we planned this study to see for prevalence of anemia in thyroid patients and to see if there is any association between vitamin B12 deficiency and anemia in patients with hypothyroidism either new or in already diagnosed cases that present to our hospital. METHODOLOGY: It was an observational study. It was carried out in the Department of Medicine, SBKS Medical Institute & Research Centre. All hypothyroid patients attending the medicine OPD or admitted to medicine wards were enrolled for the study. The patients already diagnosed as hypothyroid >18 years in age and those who give consent for participation in the study were included. Total 60 patients of hypothyroidism were included in the study. A detailed history was taken from all participants. All were subjected to CBC, thyroid function test, S. Vitamin B12. xi Sickling, Urine RM, renal function test, liver function test. S. ferritin, retic count was recorded only if required. Data was analysed to assess the burden of B12 deficiency in hypothyroids and to find out any correlation between TSH level, anemia and vitamin B12 deficiency. RESULT: Majority of the patients of hypothyroidism belong to > 50 years’ age group of 51 to 60 years. Females are more prone to develop hypothyroidism as compared to the opposite gender. About one third of hypothyroids had decreased vitamin B 12 levels. Fatigue and lethargy were the most commonly reported symptoms, followed by breathlessness and generalized swelling. TSH levels of our study population correlated well with hemoglobin levels and MCV values. However, no clinical symptom correlated with TSH levels. Similarly, no blood indices or physical symptom correlated with vitamin B12 levels. TSH levels itself did not correlate with vitamin B12 levels in our patients. However, 28% of the hypothyroid patients had vitamin b12 deficiency. CONCLUSION: Our findings suggest that anemia is common among patients with hypothyroidism as is vitamin b12 deficiency, however we could not establish any significant correlation of TSH with vitamin B12. Data published previously demonstrates the role of thyroxin in anemia that could not be corrected by iron alone. Therefore, based on these results, we would recommend testing for TSH levels in anemic patients and testing for vitamin B12 def. anemia in hypothyroid patients. Further studies are required to understand the pathophysiology and mechanisms involved in xii hypothyroidism and vitamin B12 deficiency anemia. A multicentric randomized controlled study will help us in elucidating the role of TSH in vitamin B12 deficiency anemia and overall impact on the clinical outcome in these patients. This study didn’t show any significant correlation of vitamin B12 as a cause of anemia in hypothyroid patients.