For Twins

Study objectives: Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Setting: Academic clinical research center. Participants: 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% […]

Half-identical twins are also called polar body twins. At the end of the normal process of ovulation, the developing egg divides into two cells. Each cell has the same number of chromosomes in the nucleus, but different amounts of cytoplasm. The bigger cell (with most of the cytoplasm) is the egg, and the much smaller […]

Objective: We recently reported sex-specific percent body fat (%BF) thresholds (males=23%, females=38%) above which, visceral adipose tissue (VAT) significantly increases. Using monozygotic (MZ) and dizygotic (DZ) twins, we examined the influence of genetics on regional fat distribution measured by dual-energy X-ray absorptiometry, above and below these sex-specific thresholds for VAT accumulation. Methods: Fifty-eight twin pairs (44 MZ, […]

This study used a twin paradigm to examine genetic and environmental contributions to pain catastrophizing and the observed association between pain catastrophizing and cold-pressor task (CPT) outcomes. Male and female monozygotic (n = 206) and dizygotic twins (n = 194) from the University of Washington Twin Registry completed a measure of pain catastrophizing and performed […]

Objectives: Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample. Methods: 99 female twin pairs were evaluated for clinical and evoked pain using […]

No causal evidence is available to translate associations between neighborhood characteristics and health outcomes into beneficial changes to built environments. Observed associations may be causal or result from uncontrolled confounds related to family upbringing. Twin designs can help neighborhood effects studies overcome selection and reverse causation problems in specifying causal mechanisms. Beyond quantifying genetic effects […]

Background: Genetic, physiological, and psychological factors can affect food intake, but twin studies can distinguish inherited from environmental contributors. We examined the influence of attempted cognitive control of eating (“restrained eating”) on levels of appetite-regulating hormones. Methods: Sixteen female, monozygotic twin pairs, discordant for Restraint Scale score (i.e., one twin a restrained eater with score>15 whereas the […]

Background: There is a dearth of knowledge about the link between cortisol and pain sensitivity. Purpose: We examined the association of salivary cortisol with indices of cold pain sensitivity in 198 female twins and explored the role of familial confounding. Methods: Three-day saliva samples were collected for cortisol levels and a cold pressor test was used to collect […]

Precise measurement of physical activity is important for health research, providing a better understanding of activity location, type, duration, and intensity. This article describes a novel suite of tools to measure and analyze physical activity behaviors in spatial epidemiology research. We use individual-level, high-resolution, objective data collected in a space-time framework to investigate built and […]

To examine the relationship between adverse childhood experiences (ACE) and health perception in adulthood, and to explore the contribution of shared familial factors to these associations. Data were collected from 180 female twins (90 pairs) from the community-based University of Washington Twin Registry. Participants completed questionnaires including the modified ACE Questionnaire, Traumatic Life Events Questionnaire, […]

We studied whether self-reported intent to exert cognitive control over eating was associated with differences in brain response to food cues, independent of genetic background. Subjects were ten pairs of identical twins in which one twin was a restrained eater and the co-twin was unrestrained, as classified by the Herman and Polivy Restraint Scale. Before […]

Background: Systemic inflammation and pain sensitivity may contribute to the development and maintenance of chronic pain conditions. Purpose: We examined the relationship between systemic inflammation as measured by C-reactive protein (CRP) and cold pain sensitivity in 198 female twins from the University of Washington Twin Registry. We also explored the potential role of familial factors in this […]

PI: Nathaniel WatsonProject Number: 5K23HL083350Project Dates: 5/01/2007–3/31/2012 This K23 award will allow Dr. Watson to become an investigator proficient in genetic epidemiology and the design and conduct of interdisciplinary research on gene-environment interactions in sleep medicine. The training and research activities will focus on complex environmental and genetic influences on habitual sleep duration and the impact […]

PI: Niloofar AfariProject Number: 5R01AR051524Project Dates: 9/25/2005–7/31/2011 Chronic widespread pain (CWP) occurs in 4-13% of people and is one of the defining characteristics of Fibromyalgia (FM). Although tender points were originally considered as essential to the diagnosis of FM, it is now felt that they reflect pain severity and distress, and that FM lies at one […]

PI: Ellen SchurProject Number: 1K23DK070826Project Dates: 6/15/2005–5/31/2010 This K23 award will allow Dr. Schur to become an independent investigator proficient in the design and conduct of interdisciplinary research on eating behavior and weight regulation. The training and research activities focus on complex environmental and genetic influences on eating habits and appetite regulation. The application proposes an […]