Metabolic Syndrome (MetS), a medical condition that is predictive of an increased risk of Type 2 Diabetes Mellitus (T2DM) and cardiovascular disease (CVD), currently affects 47 million U.S. adults. A MetS diagnosis requires that an individual demonstrate three of the following characteristics: central (abdominal) obesity; hypertension (HT); hyperglycemia (HG) and insulin resistance (IR); and dyslipidemia (a low level of HDL cholesterol (HDL-C) and elevated triglycerides).
Three organizations have tried to narrow the definition—The World Health Organization (WHO, 1998); the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP-ATP III, 2001); and the International Diabetes Federation (IDF, 2005). Each report linked the disease to abdominal obesity and IR and CVD risk, but the degree of expression of each component varied. Thus, it may be the identification of genetic determinants that is essential to our understanding of the progression and pathogenesis of MetS (Pollex and Hegele, 2006).
Currently, 34% of U.S. adults are obese (BMI >30) and another 31% are overweight (BMI 25–30), according to statistics from the Centers for Disease Control (CDC, 2007). Data collected and analyzed for U.S. adults from 1985 through 2008 show dramatic increases in both obesity and diabetes (CDC, 2009). New cases of diabetes have nearly doubled since 1997, rising from 4.8/1,000 people in 1997 to 9.1/1,000 people in 2007.
An individual with a BMI >40 demonstrates a 7.4 times greater risk of being diagnosed with diabetes than a person of normal weight (BMI 18.5–24.9).
The relationship between obesity and diabetes is undeniable. Importantly, it has been noted that 80–90% of T2DM adult patients meet the criteria for MetS, as well (Ginsberg et al., 2006).
In addition to the epidemic of obesity in adults, it is important to consider the developing problem of obesity, Met S, and diabetes in children and teens (ages 2–19). As noted among the NHANES studies (www.cdc.gov), a dramatic 2.5–3-fold increase in obesity has occurred within this group in the time span from 1976 to 2003. Obese children and adolescents are more likely to become obese adults (Cook et al., 2003; deFerranti et al., 2004).
As a future concern, 22% of preschool children (ages 2–5) are already overweight (Rocchini, 2002). And 80% of children who were overweight at ages 10–15 became obese adults by age 25 (Hedley et al., 2004).
During their youth, obese children and adolescents are more likely to have risk factors associated with CVD (high blood pressure, high cholesterol) and T2DM (elevated blood glucose) than children and adolescents of normal weight (CDC, 2008). Obese children are more than twice as likely to have diabetes than non-obese children. Although T2DM occurs in the young population (<18 years) at the low rate of 0.32% (Lee, 2006), by the age of 18, the lifetime risk of diabetes increases from 7.6% for underweight children to 70.3% for obese children within the same population.
Cook et al. (2003), using adult criteria, indicated that 6% of the U.S. adolescent population has symptoms of MetS, as well as 28% of overweight teens. Cruz et al. (2004) examined overweight Hispanic youth, since Hispanic adults have the highest rate of MetS, and found 30% of overweight Hispanic youths had three or more components of the MetS diagnostic cluster.
Criteria for children have not been determined, and, therefore, children younger than age 12 have not been properly screened for MetS (Ventura et al., 2006). If, indeed, the continued increase of MetS follows the previous explosion of obesity, a three-fold increase might be projected. Since T2DM increased in parallel with the rapid increase in obesity to make health issues more severe, there is every reason to believe obesity will lead to the same explosive increase in MetS (Ventura et al., 2006). However, early diagnosis of MetS would diminish the secondary complications of T2DM and CVD before reaching epidemic proportions globally.
MetS and other health topics will be discussed at the Nutritional Genomics Conference (http://www.csupomona.edu/nutrigenomics) to be held Nov.12–14, at California State Polytechnic University, Pomona. In Food Technology, the discussion of MetS will continue next month in this column.