Category Archives: Completed Studies

Global metabolic profiling to model biological processes of aging in twins.

Bunning BJ, Contrepois K, Lee-McMullen B, Dhondalay GKR, Zhang W, Tupa D, Raeber O, Desai M, Nadeau KC, Snyder MP, Andorf S.

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Genome-wide profiling of DNA methylome and transcriptome in peripheral blood monocytes for major depression: A Monozygotic Discordant Twin Study.

Zhu Y, Strachan E, Fowler E, Bacus T, Roy-Byrne P, Zhao J.

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Salience network connectivity is reduced by a meal and influenced by genetic background and hypothalamic gliosis.

Sewaybricker LE, Melhorn SJ, Askren MK, Webb MF, Tyagi V, De Leon MRB, Grabowski TJ, Seeley WW, Schur EA.

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Viral genetics modulate orolabial HSV-1 shedding in humans.

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.

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The Genetics and Epigenetics of Healthy Aging in Twins

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 aging process is influenced by environmental factors. By looking at genetic information, physical condition, family history, medical history, and life experiences across participants, researchers may be able to determine how these factors work together to create the overall aging experience.

This study collected data from 2013 to 2014. 275 same-sex twins 65 and older participated, with more of a focus on fraternal twins. The average age of participants in this study was 75, and the oldest participants were 91. All data collection was completed at home. Twins completed a packet of questionnaires, provided a saliva sample, and provided a small sample of blood collected by a finger stick.

Published research from this study

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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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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Multilevel Pain Phenotyping (SIP2)

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 study examined the relationship between underlying pain sensitivity and CRP and other inflammatory markers.

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Sleep Duration and Metabolism in Twins (Sleep)

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 how genes and environmental factors influence how much sleep we need. This is an important area of research that may help us better understand what controls how much sleep we need, and what impact getting too little sleep has on overall health.

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Personality, Stress and Cold Sores: A Twin Study

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, and environmental factors such as stress and personality, contribute to how a person’s body responds to oral herpes infections. A twin study was done because it is the ideal way to understand how genetic and environmental factors contribute to a condition.

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Chronic Widespread Pain (CWP)

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 study was done because one of the aims of the study was to discover if familial or environmental factors have a role in chronic pain.

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An Interdisciplinary Study of Eating Behavior in Twins

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 to find out how genes and environmental factors contribute to the hormones controlling appetite and weight. This is an important area of research and may eventually help in finding new ways to help people avoid obesity or lose weight. A twin study was done  because it is the ideal way to study the relative contribution of genes and the environment to a health condition.

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Gut Bacteria in Inflammation and Obesity

Obesity increases the risk of many diseases, including diabetes, heart disease, and cancer. There is evidence that there may be a link between obesity and inflammation (irritation) in the body and the kinds of bacteria found in the gut. The goal of this study was to better understand how body weight in adults and the composition of their gut bacteria interact, and what role genetics and environment may play in this interaction.  A twin study was done because it is the ideal way to study how genetics and the environment contribute to a condition.

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Heritability of Innate Immune Inflammatory Responses

There are big differences in how people respond to severe bacterial infection.  The inflammatory response of white blood cells to harmful bacteria that invade the body may play an important role in determining how well a patient will be able to fight the infection. The purpose of this study was to better understand how genetic factors control the amount of inflammation of white blood cells when exposed to bacteria that cause serious diseases.  This is an important area of research and may eventually help in the development of new ways to diagnose and treat patients with severe infections.

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Physical Activity in Twins (PAT)

This study explored 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.

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HSV Pilot

Oral herpes is a very common infection of the mouth area. It is caused by the herpes simplex virus type-1 (HSV-1). When they are first infected, some people have symptoms while others do not.  After the first infection, the virus becomes dormant (goes to sleep) in nerve tissues in the face for life.  Periodically the virus is reactivated (wakes up) and causes cold sores in the mouth area.  Cold sores (also called fever blisters) are small painful blisters of the lips, mouth or gums. The severity of the cold sores, and how often they recur, vary greatly between individuals. This suggests that the immunity of the infected person plays an important role.

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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 how tobacco smoke exposure alters the genes of immune cells in the blood that contribute to asthma and allergy. The researchers are recruiting twin pairs for this study because twin pairs provide a unique way to look at the genetics of immune responses.

If you decide to participate, you will be asked to commit to one study visit, and, if needed, a follow-up visit at ASTHMA, Inc. in Seattle, WA. During the visit you will complete a questionnaire, and the research team will collect blood, cheek swabs, urine, and saliva samples. They will also measure your height, weight, and blood pressure. They will be conducting two breathing tests (spirometry and a measurement of exhaled nitric oxide) and will administer a skin prick test for allergies. At the end of the visit, they will give you a stool collection kit to assess your microbiota (the bacteria in your digestive track) that you can complete in clinic or at home and then send the stool kit in the mail at your earliest convenience. The entire visit should last from 1.5 to 2 hours.

Published Research