The prevalence of overweight/obesity and obesity-related chronic diseases such as hypertension has more than doubled during the past several decades in the U.S. and Mexico. Emerging evidence suggests that in adults, subclinical inflammation may mediate the relationship between obesity and high blood pressure and other cardiovascular and metabolic conditions. However, this issue has not been well investigated in young children. This cross-sectional study investigated the hypothesized association of child overweight/obesity with sub-clinical inflammation, as measured by serum C-reactive protein (CRP) levels, and blood pressure.

The subjects were 175 children (x=8.3 ± 1.3 yrs) enrolled in a Ciudad Juarez, Mexico, public elementary school located in a working class neighborhood. A structured interview administered to parents was used to collect medical history data on the children. The subjects underwent a comprehensive physical exam that included blood pressure measurements. They also underwent anthropometric assessment to determine their body mass index (BMI) and mid-upper-arm fat area (MUFA). Child BMI was categorized using both the CDC (2000) and International Obesity Task Force (IOTF, 2000) classification schemes in order to compare our results with previous studies. In addition, subjects donated a small blood sample for measuring serum CRP. Bivariate and multivariate statistical techniques were used to analyze the data.

The results revealed that a high proportion of the study children, approximately one-third, had a high BMI. Using the CDC reference standard, 9.7% were classified as at-risk for overweight and 23.4% as overweight, and using the IOTF reference standard, 17.8% as overweight and 17.2% as obese. The multivariate analysis results indicated that children classified with a high BMI using either the CDC or IOTF reference standards exhibited significantly higher mean systolic (SBP), diastolic (DBP), and mean arterial pressures (MAP) compared to their normal weight counterparts (P<0.004). The multivariate results also showed that children identified as having a high BMI by the CDC (P=0.015) or IOTF (P=0.009) reference standards exhibited significantly higher mean serum CRP values. Furthermore, detectable CRP levels (≥ 0.11mg/dL vs. < 0.11 mg/dL) were associated with higher SBP (P<0.042), DBP (P<0.017), and MAP (P<0.026) in the multivariate statistical analyses.

Subclinical inflammation appears to be an early complication of childhood overweight in young children and may presage an elevated risk for hypertension and other obesity-related conditions. Future studies should investigate and provide information about the inflammatory mechanisms linking childhood overweight/obesity and high blood pressure. Additional studies are required to define the impact of these associations on the cardiovascular health of future adults.