When I was a resident we learned about the typical presentation of a child with diabetes — polydipsia, polyuria, polyphagia and weight loss. Usually these children presented acutely ill with dehydration, ketoacidosis and very high blood sugars. Diabetes type 2 was reserved for adults and we really never thought about it in kids.

How the picture has changed! Today we’re looking at a new epidemic of type 2 diabetes in the pediatric population with growing alarm and it’s a major reason why we need to be on the frontline in the fight against childhood obesity. There are several population based studies from Japan, Thailand, Argentina and the United States¹ showing the dramatic increase in type 2 diabetes in the pediatric population coinciding with a similarly alarming increase in obesity. One study in the U.S. showed a 10-fold increase in children and adolescents from age 10-19 years between 1982 and 1994.²

The presentation of type 2 diabetes can vary from frank ketoacidosis to asymptomatic individuals picked up on routine screening. Adolescents with type 2 diabetes presenting with ketoacidosis (the rate varies from 5-25%)³ can be distinguished from type 1 diabetes by certain clinical characteristics although sometimes this may be difficult. Symptomatic presentations other than ketoacidosis can include polyuria, polydipsia and nocturia and in teenage girls, monilial vaginal infections. Asymptomatic individuals may be diagnosed through screening of obese adolescents. Who do we screen in our community offices? What is the best screening test?

Obesity ought to be number one in our sights. It should be defined using the BMI. A caveat is in order when speaking of BMI in children. As well as calculating the BMI, it’s important to plot the BMI. Growth curves have BMI percentiles according to age and this is important. For example a BMI of 23, certainly normal for an adult would plot above the 97^th percentile for any child up to age 9! Overweight is defined as a child with a BMI plotting between the 85^th and the 95^th percentiles. Above the 95^th percentile is defined as obesity in kids.

Ethnic groups that are at higher risk include First Nations and Metis. In the U.S., ethnic groups at risk include African Americans, Hispanics and Asian-Americans.

Girls have a slightly higher risk (1.3-1.7), perhaps related to polycystic ovarian disease (PCO).

Insulin resistant conditions include PCO, as mentioned. Puberty itself is a risk factor, as insulin sensitivity decreases during puberty due to increased activity of growth hormone and insulin-like growth factor-1.⁴ The Barker hypothesis states that intrauterine conditions are critical for the later development of adult diseases such as diabetes and cardiovascular disease. Infants small for gestational age, in particular, are at risk for the development of type 2 diabetes in adult life.⁵

Children should be screened from the age of 10 every three years if they fit the screening criteria. Screening recommendations include: BMI > 85^th percentile for age and gender, plus two of the following risk factors: family history in a 1^st- or 2^nd- degree relative, high-risk ethnic group, or signs of insulin resistance on physical examination (acanthosis nigricans, hypertension, dyslipidemia, polycystic ovarian syndrome, small for gestational age birth weight).

Once you’ve decided to screen your overweight adolescent, which is the best test to use? One can use either fasting blood glucose (after an 8-hour fast), hemoglobin A1c⁶ or an oral glucose tolerant test. Of the three, the most convenient is either a fasting glucose or the HbA_1c. HbA_1c ≥ 6.5%, on two occasions is diagnostic, as is a fasting glucose > 7 mmol/L. Fasting glucose between 5.6 and 6.9 mmol/L is considered prediabetic.

Of course, having made the diagnosis, the real challenge for the physician and the patient is the treatment, which inevitably requires some major lifestyle challenges! But I will leave that to you, dear reader.

References

1. Pinhas-Hamiel O et al. The global spread of type 2 diabetes mellitus in children and adolescents. J Pediatr 2005;146:693.

1. Urakami T et al. Annual incidence and clinical characteristics of type 2 diabetes in children as detected by urine glucose screening in the Tokyo metropolitan area. Diabetes Care 2005;28:1876.

2. Pinhas-Hamiel, O et al. Increased incidence of non-insulin-dependent diabetes mellitus among adolescents. J Pediatr 1996;128:608.

3. Scott CR et al. Characteristics of youth-onset noninsulin-dependent diabetes mellitus and insulin-dependent diabetes mellitus at diagnosis. Pediatrics 1997;100:84.

4. AMiel SA et al. Impaired insulin action in puberty. A contributing factor to poor glycemic control in adolescents with diabetes. NEJM 1986;315:215.

5. Barker DJP et al. Type 2 (non-insulin-dependent) diabetes mellitus, hypertension and hyperlipidaemia (syndrome X): relation to reduced fetal growth. Diabetologiae (1993) 36:62-7.

6. Shah S et al. Screening for type 2 diabetes in obese youth. Pediatrics 2009;124;573-9.