Children and Adolescents Diagnosed with Type 2 Diabetes Mellitus. Part 6
Type 2 diabetes in children and adolescents appears to be the result of a combination of factors such as genetic predisposition, obesity, the presence of secondary hyperinsulinemic conditions, physical inactivity, and poor dietary behaviors. While this study is based on a small sample size, the findings are consistent with previous studies that have examined the characteristics of these youth. In regards to ethnicity, studies that have examined the prevalence of type 2 diabetes have also shown higher rates of type 2 diabetes among Hispanic youth compared to other ethnic groups (Fagot-Campagna, et al. 2000). In California, it is reported that Mexican-American children have higher rates of type 2 diabetes than do Caucasian children (Libman & Arslanian, 1999). The present study also demonstrates high rates of type 2 diabetes among Latino youth. In comparison, the youth treated at the Kaiser Santa Teresa pediatric endocrine clinic with type 1 diabetes are predominantly Caucasian.
Since puberty marks a brief period of insulin resistance as compared to prepubertal children or adults, it is not surprising that the mean age at diagnosis for these youth was 12.7 years (± 2.3). Most children who are diagnosed with type 2 diabetes are between 10 to 19 years old, with the majority of diagnoses occurring at 13 years of age or during mid-puberty (Libman & Arslanian, 1999). While pubertal children represent most of the diagnoses for type 2 diabetes among youth, children as young as 10-years-old have been identified with this disease (Fagot-Campagna et al., 2000). In the present study, three children had been diagnosed at age 10 or younger with the youngest diagnosis occurring at age eight-and-one half. Currently, the youngest child diagnosed with type 2 diabetes has been reported as a four-year-old Pima Indian child (Fagot-Campagna et al., 2000).
Physical characteristics such as BMI, revealed that 12 out of 14 subjects (86%) had a BMI greater than 27 kg/m2, indicating a high incidence of overweight and obesity. In comparison, an estimated 13 percent of children between six to 11 years and 14 percent of adolescents ages 12-19 years within the United States are overweight (Centers for Disease Control and Prevention, 2002).
Mexican-American children, in particular, are reported to be susceptible to the development of obesity due to factors such as genetic predisposition, cultural factors, and dietary behaviors (Neufeld, Raffel, Landon, Chen, & Vadheim, 1998). Previous studies have also shown that in Mexican Americans, diabetes incidence increases significantly when combined with an increase in BMI (Haffner, Hazuda, Mitchell, Patterson & Stern, 1991). It is also known that a high BMI in childhood is associated with insulin resistance and that obesity, inactivity, and diets comprised of high-calorie low nutrient dense foods can contribute to the early onset of type 2 diabetes (Cook & Hurley, 1998).
Perhaps as significant as the high incidence of overweight and obesity within these youth with type 2 diabetes was the finding that 10 of the 14 subjects were noted to have acanthosis nigricans, a cutaneous manifestation of hyperinsulinemia resulting in excessive pigmentation and thickening of the skin into soft irregular folds (Glaser, 1997; Stuart, Pate & Peters, 1989). As many as 60 percent to 70 percent of all children diagnosed with type 2 diabetes have acanthosis nigricans (Glaser, 1997). This condition is found in seven percent of school-aged children and is most prevalent among children who are overweight, or from African-American or Hispanic populations (Libman, & Arslanian, 1999). An estimated sixty to seventy percent of children of Hispanic or African-American ethnicity are reported to have acanthosis nigricans (Glaser, 1997). In this study, three of the subjects with acanthosis nigricans also presented with another hyperinsulinemic condition, either PCOS or hirsutism.