Our objective was to explore the utility of salivary telomere length (sTL) as an early indicator of neighborhood-level social environmental risk during child development. We therefore tested the hypothesis that sTL would be associated with markers of social stress exposure in children. Children age 4–14 from 87 neighborhoods were recruited through five urban schools in New Orleans, Louisiana, U.S. Data were collected at the level of the child, family/household, and neighborhood. DNA was obtained from saliva using commercially available kits and sTL was determined for 104 children using quantitative PCR. Analysis was performed on 99 children who had complete data including sTL, social environmental stress, and additional covariates. The mean sTL value was 7.4 T/S (telomere signal/single-copy signal) ratio units (±2.4, range = 2.5–18.0), and 4.7% of the variance in sTL was attributed to differences across neighborhoods. Children living in neighborhoods characterized by high disorder had an sTL value 3.2 units lower than children not living in high disordered environments (p < 0.05) and their odds of having low relative sTL (defined as <1 standard deviation below standardized Z-score mean) values was 3.43 times that of children not living in high disorder environments (adjusted OR = 3.43, 95% CI = 1.22, 9.62). Our findings are consistent with previous studies in adults demonstrating a strong link between psychosocial stress and sTL obtained from peripheral blood, consistent with previous studies in youth demonstrating an association between early life stress and sTL obtained from buccal cell DNA and offer increased support for the hypothesis that sTL represents a non-invasive biological indicator of psychosocial stress exposure (i.e., neighborhood disorder) able to reflect differences in stress exposure levels even in young children.
The American Academy of Pediatrics recently emphasized the need to increase the understanding of the early roots of health disparities. They proposed the incorporation of an eco-biodevelopmental (EBD) framework that underscores the need to identify the biological indicators of exposure to early adversity, track these indicators across development, and use these indicators to unravel the underlying mechanisms, improve health outcomes, and minimize health disparities (Committee on Psychosocial Aspects of Child and Family Health, Committee on Early Childhood Adoption and Dependent Care, Section on Developmental and Behavioral Pediatrics, & American Academy of Pediatrics, 2012). This extension of the allostasis framework, and other more recent models, including the adaptive calibration model, together with the need to define the biological changes associated with potentially “toxic” early life stress requires the development of novel biomarkers that: reflect salient environments (Essex et al., 2011), are sensitive to changes across developmental time points (Buss, Davis, & Kiel, 2011), validated in individuals of all ages including young children, and, ideally, obtainable via non-invasive methods (Bush, Obradovic, Adler, & Boyce, 2011; Buss et al., 2011; Essex et al., 2011).
