Kuwait Healthy Life Study: Salivary Biomarkers in 10-year old Children

Objective: Metabolic Syndrome (MS) is constellation of symptoms including obesity, high blood pressure, high blood glucose, insulin resistance and high blood lipids leading for increased incidence of diabetes.  The rates of increased body mass index and prevalence of obesity among Kuwaiti adults are higher than in other countries at the Gulf Region.  Although prevalences in children/adolescents (<20 years) are lower than those in adult populations, there is a greater indication that prevalences in younger populations especially in urban areas and among girls are increasing. A longitudinal cohort study was designed to evaluate metabolic status of 10-year old Kuwaiti children using non-invasive methods.

Methods: Prior to main study, a pilot study was conducted with 95 Kuwaiti girls at 10 year-old.  In addition to questionnaires, body measurements and vital signs, an unstimulated saliva sample collected.  Saliva samples were centrifuged and supernatants were collected and frozen until analysis. Luminex 100 was used to analyze salivary levels of insulin, leptin and myeloperoxidase (MPO) as the potential markers of metabolic syndrome.

Results: Salivary levels of insulin, leptin and myeloperoxidase were within our measurement capability.  The mean salivary insulin, leptin and MPO levels were 2,120 ± 677 mg/dl, 4,535 ± 439 mg/dl, and 20,883 ± 8,635 mg/dl, respectively.  Linear regression analysis showed a significant correlation between salivary insulin and leptin levels (r=0.23; p=0.03). Most importantly, an acute phase enzyme, which was shown to be highly correlated with C-reactive protein and increased cardiovascular risk, was found in high levels in 25% of children and was significantly correlated with elevated blood pressure (r=0.26; p=0.01).

Conclusion: Salivary analysis by multiplex methods could be an important tool in evaluating levels of pro-inflammatory cytokines, lipids and hormones that could be predictive of metabolic syndrome in children.  An array of inflammatory analytes and hormones will be further evaluated in the larger study.