Ally Avery

Familial Contributions to Self-Reported Sleep and Pain in Female Twins

Objective: The relationship between sleep quality and pain has been studied in populations with chronic pain and in nonclinical populations using experimental paradigms. Little is known about the familial contributions to this relationship. This study examines self-reported sleep quality and pain in a nonclinical sample and to explore familial (i.e., shared genetic and common family environment) […]

Allergy & Asthma in Twins

This study is being conducted by Dr. Kari Nadeau, an allergist and immunologist at Stanford University, and Dr. Rebecca Bauer, a postdoctoral researcher in Dr. Nadeau’s laboratory. The purpose of this study is to better understand how exposure to tobacco smoke affects immunity and diseases of the immune system such as asthma. Researchers will assess […]

Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age: A Study of the CODATwins Project

A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to […]

Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic 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% […]

In adult twins, visceral fat accumulation depends more on exceeding sex-specific adiposity thresholds than on genetics

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, […]

The CODATwins Project

The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic […]

Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins

Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around […]

Behavioral and Environmental Modification of the Genetic Influence on Body Mass Index: A Twin Study

Body mass index (BMI) has a strong genetic basis, with a heritability around 0.75, but is also influenced by numerous behavioral and environmental factors. Aspects of the built environment (e.g., environmental walkability) are hypothesized to influence obesity by directly affecting BMI, by facilitating or inhibiting behaviors such as physical activity that are related to BMI, […]

Access to green space, physical activity and mental health: a twin study

Increasing global urbanisation has resulted in a greater proportion of the world’s population becoming exposed to risk factors unique to urban areas, and understanding these effects on public health is essential. The aim of this study was to examine the association between access to green space and mental health among adult twin pairs. We used a […]

Validation and Application of Portable Particulate Device in the UW Twin Registry

PI: Edmund Seto and Glen DuncanProject number: 5R21ES024715Project dates: 3/1/2015–2/28/2017 This research addresses the mission of the National Institutes of Environmental Health Sciences by increasing our understanding of how the environment influences human health through validation of a new wearable device that measures multiple environmental toxicants in real-time and space, called the Portable University of Washington […]

Heritability of Pain Catastrophizing and Associations with Experimental Pain Outcomes: A Twin Study

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 […]

Quasi-causal associations of physical activity and neighborhood walkability with body mass index: A twin study

Objective: Physical activity, neighborhood walkability, and body mass index (BMI, kg/m(2)) associations were tested using quasi-experimental twin methods. We hypothesized that physical activity and walkability were independently associated with BMI within twin pairs, controlling for genetic and environmental background shared between them. Methods: Data were from 6376 (64% female; 58% identical) same-sex pairs, University of Washington Twin […]

Clinical and evoked pain, personality traits, and emotional states: Can familial confounding explain the associations?

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 […]

International Network of Twin Registries (INTR): Building a Platform for International Collaboration.

The International Network of Twin Registries (INTR) aims to foster scientific collaboration and promote twin research on a global scale by working to expand the resources of twin registries around the world and make them available to researchers who adhere to established guidelines for international collaboration. Our vision is to create an unprecedented scientific network of […]

TwinFest a Huge Success!

Over 300 people gathered on Saturday, June 7, 2014 for our first annual TwinFest! Attending this joyful celebration of twins were about 120 pairs of twins and their family and friends. The event was emceed by Shawn Dietrich, a fraternal twin who is a member of the UW Twin Registry. As a child, he and […]

Stepping towards causation in studies of neighborhood and environmental effects: How twin research can overcome problems of selection and reverse causation

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 […]

A twin study of differences in the response of plasma ghrelin to a milkshake preload in restrained eaters

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 […]

Does caregiving cause psychological distress? The case for familial and genetic vulnerabilities in female twins

Background: Informal caregiving can be deleterious to mental health, but research results are inconsistent and may reflect an interaction between caregiving and vulnerability to stress. Methods: We examined psychological distress among 1,228 female caregiving and non-caregiving twins. By examining monozygotic and dizygotic twin pairs discordant for caregiving, we assessed the extent to which distress is directly related […]

Salivary cortisol and cold pain sensitivity in female twins

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 […]

Moderation of Genetic and Environmental Influences on Diurnal Preference by Age in Adult Twins

Diurnal preference changes across the lifespan. However, the mechanisms underlying this age-related shift are poorly understood. The aim of this twin study was to determine the extent to which genetic and environmental influences on diurnal preference are moderated by age. Seven hundred and sixty-eight monozygotic and 674 dizygotic adult twin pairs participating in the University of […]