Category Archives: For Twins

Study of Air Pollution in Twins (R33 phase)

This study seeks to understand how the environment influences our health by using a new device (the Portable Particle Monitor, PUWPM) that measures toxins in the environment, which was built and tested during the first phase of this study. These toxins include air pollution, noise, and allergens.

Exposure to particle pollution can result in increased hospital admissions, emergency room visits, absences from school or work, and restricted activity days, especially for those with pre-existing heart or lung disease, older people, and children. The size of particles is directly linked to their potential for causing health problems. Fine particles (PM2.5) pose the greatest health risk. The following is an example of what we are able to observe from collected data. Both maps show a morning walk in the summer. However, the walk on the right took place after major forest fires had broken out in the greater Pacific Northwest area. We can see that the PM2.5 this individual was exposed to was much lower before the fires broke out (map on left). By comparing twins, we can better understand how exposures to toxins in the unique environment may influence health.

Identical twins living apart within the State of Washington will be considered for this study. Eligible pairs will come to the Roosevelt Clinic in the University District of Seattle to receive the study materials. The study coordinator will record vital measurements and conduct a spirometry (lung function) test. At the end of the visit, participants will have their blood drawn. Biological specimens will be used to measure the amount of inflammation in the body, which may be related to environmental exposures. Data is then collected at home for two weeks. Participants will carry a GPS and wear an activity monitor that is similar to a pedometer or a Fitbit, as well as carry the PUWPM from the time they wake up until they go to sleep at night. They will also complete questionnaires. At the end of the two-week period, everything is returned to the study coordinator in a prepaid FedEx box.

Physical Activity in Twins (PAT) follow-up study

This study continues on work conducted from 2012-15 exploring the role of the built environment in supporting healthy lifestyles. The built environment is defined as human-made surroundings, such as buildings, streets, and transportation systems, which support or hinder human activity. Although this topic has gained increasing attention from many researchers over the last several years, the influence of the environment on behaviors and health is not fully understood.

In this follow-up study, twin pairs who participated in the PAT study are contacted to participate in one week of follow-up data collection. All data collection is done entirely at home, and participants do not have to live within the Puget Sound to be eligible. Participants wear a GPS and an activity monitor, and complete questionnaires.

Familial factors predicting recovery and maintenance of physical activity in people with low back pain: insights from a population-based twin study.

Zadro JR, Shirley D, Duncan GE, Ferreira PH.

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Hypothalamic Gliosis by MRI and Visceral Fat Mass Negatively Correlate with Plasma Testosterone Concentrations in Healthy Men.

Berkseth KE, Rubinow KB, Melhorn SJ, Webb MF, De Leon MRB, Marck BT, Matsumoto AM, Amory JK, Page ST, Schur EA.

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DNA methylation associated with healthy aging of elderly twins.

Kim S, Wyckoff J, Morris AT, Succop A, Avery A, Duncan GE, Michal Jazwinski S.

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Gene Expression and the Microbiome in Twins (GEMsTone)

Cells in the human body contain DNA. Each cell expresses, or turns on, a fraction of its genes in a process known as gene regulation. Genes can be expressed depending on your genetic history, your lifestyle, and your environment. Microbes are very small life forms such as bacteria that exist on or in the human body. The human microbiome is the full collection of genes of all of the microbes. In this study, we are interested in learning more about the relationship between your genes and your microbiome. The gut microbiome changes over time, but can also change when your diet changes or when your health in general changes. As a twin and a member of the WSTR, you can make a unique contribution to understanding the relationship between the gut microbiome and gene expression.

Eligible twin pairs are sent the collection materials to collect data at home. Data collection materials include three questionnaires, measuring waist circumference, using a soft brush to collect buccal (cheek) cells for epigenetic analysis, and collecting a stool sample for the gut microbiome analysis.

Twin Breast Cancer Study

Dr. Thomas Mack of the USC California Twin Program is reaching out to twins diagnosed with breast cancer in order to understand why some women remain free from breast cancer when other women with the same genetics and upbringing are affected.

What we know:
  • As a group, twin women of any age, including identical twin women, are at the same risk of breast cancer as their friends and neighbors.
  • Even though inheritance seems to play at least some role in most cases of breast cancer, most of the healthy co-twins of women who are diagnosed with breast cancer remain free, for years, decades or permanently.
  • That suggests that some causal elements are acquired, probably long before the appearance of the disease, possibly as early as childhood.
What does the study entail?

We will ask each participant to provide a sample of saliva. From such samples we can find cells containing the unique inherited DNA code and identify any genetic breast cancer risk factors.

What questions will be asked?
  1. Generally: Participants will be asked questions relating to known predictors of breast cancer risk, most of which relate to reproductive history.
  2. Twin comparisons: Twins have compared each other since childhood, and are uniquely able to recall and agree on early differences, even after decades. Questions will be especially directed at early differences.
  3. We will ask breast cancer cases to help us obtain Pathology Reports and samples of tumor tissue from providers.

The questions should take you one-half to one hour. The more twins who participate, especially as pairs, the more likely that we can find answers to these important questions about a dreaded disease.

The study is supported by the National Cancer Institute of the National Institutes of Health. There is no cost to volunteers, except the time it takes to mark your responses and send your specimen. You will never be asked for money (your cooperation is more valuable). You may always refuse to answer any question, and you may withdraw cooperation at any time. All information will be held in complete confidence. No outside persons will have access to your identity without your permission. Results will only be released in statistical form, and no persons will ever be identified.


Click here to send an email to the study coordinator. If you would prefer to speak to someone by phone, please call 1-323-865-0828.

FTO genotype impacts food intake and corticolimbic activation.

Melhorn SJ, Askren MK, Chung WK, Kratz M, Bosch TA, Tyagi V, Webb MF, De Leon MRB, Grabowski TJ, Leibel RL, Schur EA.

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Examination of Cross-Sectional Associations of Neighborhood Deprivation and Alcohol Outlet Density With Hazardous Drinking Using a Twin Design.

Rhew IC, Kosterman R, Duncan GE, Mair C.

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Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts.

Silventoinen K, Jelenkovic A, Hopper JL, Busjahn A, Cozen W, Mack TM, Sumathipala A, Harris JR, Goldberg JH, Harden KP, Duncan GE, Buchwald D, Turkheimer E, Kaprio J, et al.

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Cross-sectional association between soda consumption and body mass index in a community-based sample of twins.

Eney AE, Tsang S, Delaney JA, Turkheimer E, Duncan GE.

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Differences in genetic and environmental variation in adult body mass index by sex, age, time period, and region: an individual-based pooled analysis of 40 twin cohorts.

Silventoinen K, Jelenkovic A, Cozen W, Mack T, Sumathipala A, Christensen K, Busjahn A, Duncan GE, Buchwald D, Goldberg JH, Hopper JL, Sung J, Turkheimer E, Kaprio J, et al.

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Genetic and Environment Influences on Sleep, Pain, and Depression Symptoms in a Community Sample of Twins.

Gasperi M, Herbert M, Schur E, Buchwald D, Afari N.

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Neighborhood walkability moderates the association between low back pain and physical activity: A co-twin control study.

Zadro JR, Shirley D, Pinheiro MB, Bauman A, Duncan GE, Ferreira PH.

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Does the sex of one’s co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts.

Bogl LH, Jelenkovic A, Christensen K, Cozen W, Mack TM, Duncan GE, Buchwald D, Hopper JL, Silventoinen K, Kaprio J, et al.

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Neighborhood deprivation and depression in adult twins: genetics and gene×environment interaction.

Strachan E, Duncan G, Horn E, Turkheimer E.

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