Poster #14 - Association Between Obesity-Related Brain Volume and Genomic Propensity for Late Puberty in Youth

• In Event: 3-003 - Poster Session 09
  In Poster Session: PS 09 Section - Biological Processes: Neuroscience and Genetics

Integrative Statement

Obesity is one of the most prevalent diseases in adults (39.8%), possibly leading to the pathological conditions such as heart disease, stroke, and type 2 diabetes (Centers for Disease Control and Prevention, 2018). In a longitudinal study, obese and overweight youth showed a relatively high prevalence of the early pubertal maturation compared with youth of normal and lean-weight group (Zhai et al., 2015), showing that obesity is related to the pubertal timing, especially in girls (Shalitin & Kiess, 2017).
There is also evidence that obese participants showed an increased neural activity in the orbitofrontal cortex (OFC) and postcentral gyrus (PG) in response to the food-related cues (Feldstein Ewing et al., 2017; Luo et al., 2018). Thus, neural activity in these regions may correlate with propensity toward obesity. OFC activation is strongly tied to the reward salience in the brain (Lichtenberg et al., 2017), and obese groups showed smaller OFC volumes relative to the controls (Shott et al., 2015; Smucny et al., 2012). PG is a part of the somatosensory system of the brain and underlies sensation as touch (Ploner, Schmitz, Freund, & Schnitzler, 2000). These studies may indicate that morphological features of OFC and PG may not only be relevant to better understand obesity but perhaps changes affected by obesity such as pubertal timing.
Profound brain morphological changes occur across childhood and adolescence, with most studies using age as a marker of maturation (Koolschijn & Crone, 2013). However, it is yet unknown whether the volume of OFC or PG is related to the pubertal timing. During adolescence, the onset of puberty is affected by genetic and epigenetic factors (Livadas & Chrousos, 2016) that may also affect morphological brain development (Fjell et al., 2015), especially during puberty (Giedd et al., 2006).
This study examines the relationship between the genetic propensity of late puberty and volume of the OFC and PG. Data from 915 typically developing population (457 females; ages 3-21) were downloaded from the Pediatric Imaging Neurocognition, and Genetics (PING) dataset and processed using FreeSurfer. Regions of interest included OFC and PG, because they have been related to the obesity-related neural functioning and the neural connectivity during adolescence (Spielberg et al., 2015). Based on Day and colleagues (Day et al., 2017), a polygenetic risk score (PRS), M=.03, SD = .06, was estimated (McGrath, 2018; Mooney & Wilmot, 2015), serving as a probabilistic indicator for genetic propensity of having relatively later pubertal onset.
The volume of right medial OFC was positively predicted by age, β=23.65, p=.046, and negatively predicted by PRS, β=-5258.18, p=.044 (Fig. 1). The interaction between age and PRS was not significant, β=2613.76, p=.109, indicating that age and PRS were independently related to t medial OFC volume. Furthermore, PRS significantly predicted the volume of right PG, β=-4046.37, p=.030, but age failed to do so, β=23.56, p=.452. Gender moderated the association between the volume of right PG and PRS, β=2654.77, p=.024 (Fig. 2), implying that PRS is a useful indicator predicting the volume of PG in a gender specific way.

Authors

• Yoojin Lee, Iowa State University
  Presenting Author

• Auriel Willette, Iowa State University
  Non-Presenting Author

• Kristine Marceau, Purdue University
  Non-Presenting Author

• Elizabeth A Shirtcliff, Iowa State University
  Non-Presenting Author