Association between Thyroid Dysfunction and Type II Diabetes Mellitus among Adults in Benghazi City
1.1. Diabetes Mellitus Diabetes mellitus is a chronic metabolic disease characterized by hyperglycemia. Normally when levels of glucose are elevated in the blood, the insulin is released from pancreatic cells and acts to increase the cells’ uptake of glucose; where it’s used to release energy (muscle cells) or stored for later use (liver and fat cells). In diabetes , it is caused by either a defect in insulin secretion or an insufficient response from the target cells (Dean and McEntyre, 2004). Chronic hyperglycemia causes a long-term and possibly life-threatening complications which include retinopathy, nephropathy and neuropathy (Association, 2014). It also causes an increased risk of heart disease ranging from to 2-to-4 folds. Diabetic patients are classified according to the pathogenicity of the disease. Most are classified into two types: either there is a complete absent of insulin due to autoimmune destruction of pancreatic beta cells, referred to as type 1 diabetes mellitus (T1DM); or there is a resistance to insulin action, referred to as type 2 diabetes mellitus (T2DM). It is common for insulin resistance to be accompanied by defects in its secretion (Olokoba, Obateru and Olokoba, 2012). Symptoms of hyperglycemia include polyuria, polydipsia and polyphagia. If left untreated, uncontrolled diabetes could lead to ketoacidosis or non-ketotic hyperosmolar syndrome. The early symptoms are mild and hyperglycemia could go untreated for years; especially in T2DM (Olokoba, Obateru and Olokoba, 2012). Diabetes mellitus is considered one of the most common endocrine disorders worldwide. The region of the Middle East and North Africa has a prevalence of 10.9% (Kharroubi, 2015). T1DM occurs mostly among children under 15 years with a higher incidence in people of European descent. T2DM has a much higher prevalence, and its incidence increases with age. However, it is becoming more common in children due to increased rate of obesity (Forouhi and Wareham, 2019).
Diabetes mellitus is one of the most common endocrine disorders and is often classified as type 1 and type 2 according to its pathogenicity. Type 2 is due insulin resistance, which is when the target cells don’t respond to insulin. It is seen more in older age groups and associated with obesity. Insulin and thyroid hormones influence one another, if the thyroid function is disturbed in diabetic patients; the glycemic control is negatively affected. The aim of the study was to assess the frequency and pattern of thyroid dysfunction in type 2 diabetic patients. The participants (n=90) included diabetic patients (n=71) and control (n=19). Thyroid status was evaluated and 8.45% of diabetic patients were shown to have subclinical hypothyroidism, while in the control group, the prevalence of subclinical hypothyroidism was 10.53%. No other types of thyroid disorders were found. Statistical analysis was performed and showed no significant relationship between thyroid dysfunction and the following: gender, age, BMI, duration of diabetes, usage of insulin and oral hypoglycemic agents or hypertension, in either diabetic or control group. The prevalence of thyroid autoimmunity among the patients was 14.08%. The prevalence was higher in females than males (20.51% vs. 6.25%) in the diabetic group as well as in the control group (16.67% vs. 14.29%).