Completed Studies

Duncan GE, Sun F, Avery AR, Hurvitz PM, Moudon AV, Tsang S, Williams BD. We examined relationships between walkability and health behaviors between and within identical twin pairs, considering both home (neighborhood) walkability and each twin’s measured activity space. Continuous activity and location data (via accelerometry and GPS) were obtained in 79 pairs over 2 […]

Duncan GE, Avery A, Thorson JLM, Nilsson EE, Beck D, Skinner MK. An epigenome-wide association study (EWAS) was performed on buccal cells from monozygotic-twins (MZ) reared together as children, but who live apart as adults. Cohorts of twin pairs were used to investigate associations between neighborhood walkability and objectively measured physical activity (PA) levels. Due […]

Duncan GE, Avery AR, Hurvitz P, Vernez-Moudon A, Tsang S Objectives  Physical activity is a cornerstone of chronic disease prevention and treatment, yet most US adults do not perform levels recommended for health. The neighborhood–built environment (BE) may support or hinder physical activity levels. This study investigated whether identical twins who reside in more walkable […]

Sewaybricker LE, Melhorn SJ, Rosenbaum JL, Askren MK, Tyagi V, Webb MF, De Leon MRB, Grabowski TJ, Schur EA Background Neuroimaging studies suggest that appetitive drive is enhanced in obesity. Objective To test if appetitive drive varies in direct proportion to the level of body adiposity after accounting for genetic factors that contribute to both […]

Boakye KA, Amram O, Schuna JM, Duncan GE, Hystad P. Studies often rely on home locations to access built environment (BE) influences on physical activity (PA). We use GPS and accelerometer data collected for 288 individuals over a two-week period to examine eight GPS-derived BE characteristics and moderate-to-vigorous PA (MVPA) and light-to-moderate-vigorous PA (LMVPA). NDVI, […]

Duncan GE, Hurvitz PM, Moudon AV, Avery AR, Tsang S. This study examined how buffer type (shape), size, and the allocation of activity bouts inside buffers that delineate the neighborhood spatially produce different estimates of neighborhood-based physical activity. A sample of 375 adults wore a global positioning system (GPS) data logger and accelerometer over 2 […]

Floyd K, York C, Ray CD. Using a twin study design, we explored the extent to which affectionate communication is a heritable behavioral trait. Participants (N = 928) were 464 adult twin pairs (229 monozygotic, 235 dizygotic) who provided data on their affectionate communication behaviors. Through ACE modeling, we determined that approximately 45% of the variance in trait expressed […]

Bunning BJ, Contrepois K, Lee-McMullen B, Dhondalay GKR, Zhang W, Tupa D, Raeber O, Desai M, Nadeau KC, Snyder MP, Andorf S. Aging is intimately linked to system-wide metabolic changes that can be captured in blood. Understanding biological processes of aging in humans could help maintain a healthy aging trajectory and promote longevity. We performed […]

Zhu Y, Strachan E, Fowler E, Bacus T, Roy-Byrne P, Zhao J. DNA methylation plays an important role in major depressive disorder (MDD), but the specific genes and genomic regions associated with MDD remain largely unknown. Here we conducted genome-wide profiling of DNA methylation (Infinium MethylationEPIC BeadChip) and gene expression (RNA-seq) in peripheral blood monocytes […]

Sewaybricker LE, Melhorn SJ, Askren MK, Webb MF, Tyagi V, De Leon MRB, Grabowski TJ, Seeley WW, Schur EA. BACKGROUND/OBJECTIVES The salience network (SN) comprises brain regions that evaluate cues in the external environment in light of internal signals. We examined the SN response to meal intake and potential genetic and acquired influences on SN […]

Ramchandani MS, Jing L, Russell RM, Tran T, Laing KJ, Magaret AS, Selke S, Cheng A, Huang ML, Xie H, Strachan E, Greninger AL, Roychoudhury P, Jerome KR, Wald A, Koelle DM. BACKGROUND Orolabial herpes simplex virus type 1 (HSV-1) infection has wide severity spectrum in immunocompetent persons. To study the role of viral genotype […]

Aging is complex process, involving both genetic and non-genetic factors.  Genetics contribute to the rate of change for bodily functions and risk of disease, but these changes can also be influenced by the environment. The goal of this study was to learn more about the genes that are related to healthy aging, and how the […]

Kim S, Wyckoff J, Morris AT, Succop A, Avery A, Duncan GE, Michal Jazwinski S. Variation in healthy aging and lifespan is ascribed more to various non-genetic factors than to inherited genetic determinants, and a major goal in aging research is to reveal the epigenetic basis of aging. One approach to this goal is to […]

Reimann M, Schilke O, Cook KS. Why do people distrust others in social exchange? To what degree, if at all, is distrust subject to genetic influences, and thus possibly heritable, and to what degree is it nurtured by families and immediate peers who encourage young people to be vigilant and suspicious of others? Answering these questions could provide fundamental clues […]

Gasperi M, Herbert M, Schur E, Buchwald D, Afari N. Objective We used quantitative genetic methods to evaluate whether sleep quality, pain, and depression symptoms share a common genetic diathesis, to estimate the genetic and environmental sources of covariance among these symptoms, and to test for possible causal relationships. Methods A community sample of 400 […]

A full understanding of the mechanisms involved in chronic pain could make a significant difference in the quality of life of chronic pain patients, as well as healthcare costs and productivity. Previous clinical studies have found associations between pain conditions and levels of C-Reactive Protein (CRP), a general indicator of inflammation in the body. This […]

This study looked at the relationship between how much sleep a person gets and how it influences metabolism and measures of inflammation, both of which are related to obesity. Fifty five (55) MZ twin pairs were invited to participate in this study. A twin study was done because it is the ideal way to look at […]

Results of a previous pilot study about oral herpes in twins suggested that there are genetic factors in an infected person that strongly influence the reactivation (waking up) of the HSV-1 virus from a dormant (sleeping) state to cause cold sores. The purpose of this study was to understand how the genes of the host, […]

A total of 99 female twin pairs (198 women) participated in this study to understand more about the causes and conditions associated with chronic widespread pain. This study examined perceptions of pain, factors related to sleep, hormones related to the body’s response to stress, and inflammatory markers that might affect sensitivity to pain. A twin […]

Scientists have recently discovered a number of hormones that control appetite and regulate weight. These hormones travel in the bloodstream and some of them change rapidly with every meal. They influence when we get hungry, how full we feel and probably even what foods taste good to us.  The main purpose of this study was […]