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, […]
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 […]
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 […]
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 […]
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 […]
Objective: We used quantitative genetic models to assess whether sleep duration modifies genetic and environmental influences on depressive symptoms. Method: Participants were 1,788 adult twins from 894 same-sex twin pairs (192 male and 412 female monozygotic [MZ] pairs, and 81 male and 209 female dizygotic [DZ] pairs] from the University of Washington Twin Registry. Participants self-reported habitual […]
Objective: The population-based University of Washington Twin Registry (UWTR) was used to examine (1) genetic influences on chronobiology and (2) whether these genetic factors influence alcohol-use phenotypes. Methods: We used a reduced Horne-Östberg Morningness-Eveningness Questionnaire (rMEQ) to survey UWTR participants for diurnal preference. Frequency and quantity of alcohol use, as well as binge drinking (6+ drinks per […]
Objective: Using a twin study design, we sought to determine whether an early age at dieting onset is a risk factor for higher adult body mass index (BMI) or use of risky dieting practices, independent of genetic and familial factors. Method: Female twins ages 18-60 years (N=950) from the University of Washington Twin Registry completed 2 surveys […]
Chronic pain is common during adolescence and young adulthood and is associated with poor quality of life, depression, and functional disability. Recognizing that chronic pain has significant consequences, it is important to identify modifiable health behaviors that may place young adults at risk for chronic pain. This study examines associations between chronic musculoskeletal pain and […]
Objective: This study examined if associations between body mass index (BMI) and mental and physical health were independent of genetic and familial factors. Method: Data from 2831 twins (66% female) were used in an epidemiological co-twin control design with measures of BMI and mental and physical health outcomes. Generalized estimating equation regressions assessed relationships between BMI and […]
The University of Washington Twin Registry is a unique community-based registry of twin pairs who join specifically to participate in scientific research. It was founded in 2002 to serve as a resource for investigators throughout the scientific community. Current enrollment exceeds 7,200 pairs, and plans are in place to increase enrollment to 10,000 pairs by […]
Study objectives: To examine whether sleep duration modifies genetic and environmental influences on body mass index (BMI). Design: Genotype-environment interaction twin study. Setting: University of Washington Twin Registry. Patients or participants: A population-based sample of US twins (1,088 pairs, 604 monozygotic, 484 dizygotic; 66% female; mean age = 36.6 yr, standard deviation (SD) = 15.9 yr). Interventions: N/A. Measurements and […]
We used a classical twin design and measures of neighborhood walkability and social deprivation, using each twin’s street address, to examine genetic and environmental influences on the residential location of 1389 same-sex pairs from a US community-based twin registry. Within-pair correlations and structural equation models estimated these influences on walkability among younger (ages 18-24.9) and […]
Background: Data from primary care and community samples suggest higher rates of post-traumatic stress disorder (PTSD) among individuals with chronic fatigue syndrome (CFS). Objective: This study investigated the co-occurrence of CFS, PTSD, and trauma symptoms and assessed the contribution of familial factors to the association of CFS with lifetime PTSD and current traumatic symptoms. Method: Data on lifetime […]
Aims: To determine whether shared genetic influences are responsible for the association between pain from temporomandibular disorders (TMD) and migraine headache. Methods: Data were obtained from 1,236 monozygotic and 570 dizygotic female twin pairs from the University of Washington Twin Registry. TMD pain was assessed with a question about persistent or recurrent pain in the jaw, temple, […]
We used the community-based University of Washington Twin Registry to investigate the genetic association between circadian type and sleep duration. Habitual sleep duration was obtained by self-report and circadian type was measured using a reduced 5-item Horne–Östberg Morningness–Eveningness questionnaire. Univariate and bivariate genetic analyses were fit using structural equation models. We used multinomial logistic regression […]
We investigated the association of restrained eating with BMI and weight gain while controlling for the influence of genes and shared environment. Participants were 1,587 twins enrolled in the University of Washington Twin Registry (UWTR). Restrained eating was assessed by the Herman and Polivy Restraint Scale. Height and weight were self-reported on two occasions. Analyses […]
Background: Studies have found a modest association between depression and obesity, especially in women. Given the substantial genetic contribution to both depression and obesity, we sought to determine whether shared genetic influences are responsible for the association between these two conditions. Methods: Data were obtained from 712 monozygotic and 281 dizygotic female twin pairs who are members […]
Chronic pain and obesity, and their associated impairments, are major health concerns. We estimated the association of overweight and obesity with 5 distinct pain conditions and 3 pain symptoms, and examined whether familial influences explained these relationships. We used data collected from 3,471 twins in the community-based University of Washington Twin Registry. Twins reported sociodemographic data, […]
Objective: Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic pain condition with unclear underlying etiology. Our objectives were to determine whether psychological distress was higher in twins with urological symptoms commonly found in IC/PBS than in twins without, and if so, did familial influences contribute to this association. Method: Data from 1165 female twins in a community-based […]
