Salivary biomarkers as assessment of metabolic function and inflammation in children with obesity

Abstract

Childhood obesity increases adult metabolic and cardiovascular disease risk. Using blood for long-term biomarker analysis in children is problematic because of the discomfort, pain, and anxiety associated with frequent blood draws. Noninvasive methods are vital for predicting childhood obesity complications. This study examined body mass index-for-age percentile scores (zBMI) as a predictor of salivary biomarkers of metabolism and inflammation, including insulin and C-Reactive Protein (CRP), over time. A school sample of 288 adolescents (Mage = 12.1 at study initiation; 46% female; 48% Black, 37% non-Hispanic White, 15% Hispanic or other minorities) were enrolled from greater Birmingham, Alabama. Participants provided salivary samples across four days once per year from 2019–2021. In year 1 of the study, 19% of adolescents were overweight, 18% had obesity, 6.6% had severe obesity, and 7.3% had very severe obesity based on the 2022 CDC Extended BMI-for-Age Growth Charts. Multivariable models showed that lower parental income was associated with an increased risk of obesity (OR = 0.91; 95% CI = 0.85, 0.97; p = 0.009). Greater concentrated poverty, a measure of spatial distribution of socioeconomic deprivation, was associated with an increased risk of severe or very severe obesity (OR = 1.58; 95% CI = 1.01, 2.46; p = 0.043). However, race/ethnicity was not associated with obesity risk. Longitudinal analyses showed that greater zBMI in year 1 was associated with greater salivary CRP ( β = 0.188, SE = 0.058, p = 0.001) and insulin ( β = 0.263, SE = 0.076, p<0.001) in years 2 and 3 of the study after adjusting for year 1 biomarker levels, sex, race/ethnicity, and concentrated poverty. Multivariable models indicated that an accelerated increase in zBMI/year was associated with an accelerated increase in CRP/year ( β = 0.119, SE = 0.048, p = 0.014), but there was no association between the rates of change in zBMI and insulin. Future analyses will incorporate additional hormones, such as adiponectin, and inflammatory cytokines measured in saliva. In conclusion, these results indicate that salivary biomarkers can capture physiological differences associated with zBMI in school-age children. Saliva may constitute a useful non-invasive tool for evaluating markers of inflammation and/or metabolism related to zBMI in children outside clinical settings. This research was supported by an Institute of Education Sciences, U.S. Department of Education Grant (R305A180074) to SM and RE and a National Heart, Lung, and Blood Institute K99R00 Grant (1K99HL165091-01A1) to KMK. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.