**5. Diabetes mellitus and insulin resistance**

Diabetes is an additional cardiovascular risk factor that needs to be addressed in children. Historically, diabetes mellitus type 1 was considered of main importance in children. With increasing obesity, diabetes mellitus type 2 is becoming more prevalent [25]. Other etiologies, causing diabetes mellitus in children, are presented in **Table 3** [26].


#### **Table 3.** *Causes of diabetes mellitus in children.*

#### *Cardiovascular Risk Factors in Children DOI: http://dx.doi.org/10.5772/intechopen.99729*

Regardless of the type of diabetes mellitus, hyperglycemia leads to impaired cardiovascular function, which was demonstrated in type 1 diabetes mellitus with impaired carotid artery structure and function, and decreased elastic properties of the aorta, already in children [27]. Diabetes mellitus is associated with a two-fold increase in the risk of CVD with a premature cardiovascular mortality and further risk increment when other cardiovascular risk factors coexist [28]. Early onset of diabetes mellitus further worsens cardiovascular risk [28].

Studies in the last decades indicate that insulin resistance is the predecessor of type 2 diabetes mellitus and has been associated with obesity, metabolic syndrome, hypertension and heart disease. It is defined as decreased tissue response to insulin and its cellular actions, commonly associated with obesity, however, not always, and not all obese have insulin resistance. Clinically, methods for insulin resistance measurement are scarce and, in many cases, limited to the research environment, however, one of the consequences of insulin resistance is chronic compensatory hyperinsulinemia, which can be demonstrated [29].

The diagnosis of both, diabetes mellitus and insulin resistance, is based on clinical symptoms, blood glucose monitoring, oral glucose tolerance test, and additional optional investigations, such as autoantibodies associated with diabetes or insulin levels [30]. In diabetes mellitus type 1 insulin therapy should be initiated immediately with recommendation of eventual insulin pump application in all small children, in patients with dawn phenomenon, severe hypoglycemia events or severe blood glucose fluctuations, glycated hemoglobin (HbA1c) values outside target range despite intensified conventional therapy, incipient microvascular or macrovascular secondary disease, limitations of the quality of life, in children with great fear of needles, pregnant adolescents and competitive athletes [30]. Treatment of type 2 diabetes mellitus and preceding insulin resistance is similar to treatment in adults. Weight loss and lifestyle change is the cornerstone of initial management. Patients may also be treated with oral agents, most appropriately starting with metformin, the only registered oral agent in children with diabetes mellitus type 2, and some may require administration of insulin to achieve glycemic control [31, 32].
