1.1 Introduction
Diabetes mellitus (DM) and thyroid dysfunction (TD) are the two most common endocrine disorders seen in adult population(Diezet al., 2011). The prevalence of Type2 diabetes mellitus (T2DM) is rising faster than any other form of diabetes because of increased urbanization which encourages development of obesity due to reduced physical activities, increase consumption of refined foods and snacks globally (Zimmet, 1999; Zimmetet al., 2001). Thyroid hormones, namely Triiodothyronine (T3) and Thyroxine (T4); either or both of which may be elevated or reduced have both direct and indirect effect on blood glucose homeostasis (Udionget al., 2007).
Elevated levels of free circulating thyroid hormones (hyperthyroidism) produce hyperglycemia by causing polyphagia, enhancing glucose absorption from gastro-intestinal tract, accelerating insulin degradation and stimulating glycogenolysis (Webb,2004).Reduced level of the hormones hypothyroidism may cause hypoglycemia (Webb,2004; Cooper, 2003). Hypothyroidism, the most commonly diagnosed thyroid dysfunction has greater implications for Type2 diabetic in whom there is pre-existing dyslipidemia and risk of cardiovascular disease (Cooper, 2003; Rama et al; 2003; Johnson, 2006). Moreover, thyroid hormones have significant effects on the synthesis, mobilization and metabolism of lipid (Dias et al., 2011; Murray et al., 2000).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
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