Studies involving twins have covered just about every aspect of health and medical treatment in Australia:  asthma, autism, Attention Deficit Disorder, anxiety, depression, osteoporosis, dementia, male infertility, premenstrual tension, endometriosis, back pain, epilepsy, diabetes, teeth, heart disease, cancer, diet and stress, tobacco and alcohol use, eating disorders, myopia and blindness, glaucoma, reading ability, growing pains, and transition to school.

Here we highlight some of the recent results from research studies involving the ATR and how twins are making a difference.

If you were involved in a study recently, there may be some information about it below.

• Adult Macular Degeneration (AMD), Glaucoma and Myopia Study
• Impact of Folic Acid on Perinatal Outcome of Twins
• Genetics of Cannabis Use and Mental Health in Australia
• Twins and Sisters Mammographic Density study
• Atrial Fibrillation
• Face Recognition study
• Friendship, Behaviour and Transition to School study
• Molecular Genetics of Inattention study
• The Older Australian Twins Study (OATS)
• OATS Poster
• Tooth Emergence study
• Growing Pains study
• Growing Pains poster
• The Emotional Wellbeing Project
• Syncope and Breath Holding

Twins step up fight against cervical cancer

This study is the next step after the recent release of the cervical cancer vaccine.  It is researching the link between human papillomavirus (or HPV) and cervical cancer, began recruiting in 2007, and now involves over 1700 twins, and more are needed.   The researchers are looking for a very large pool of women to participate in order to gain a clear picture of the effects of lifestyle and genetic factors on a woman’s risk of developing cervical cancer.  It has commenced in Victoria, NSW, Western Australia, Queensland and Tasmania.   

The study needs female twins aged 25 and over, who have had Pap screens within the past 10 years.  Initially participants need only give permission to access their paper-based historical records from the Cervical Cytology Registry in their state.  Involvement is simple, but the scope of this study is huge!

The nature and nurture of a healthy mind

Dementia is an age-related illness, but not everyone suffers from it in old age.   What factors help to prevent dementia? Are they environmental or genetic? If prevention is genetic, what genes are involved?

Researchers are seeking to answer these critical questions in the most comprehensive ageing study with elderly twins ever undertaken in Australia.  Called the Older Australian Twins Study (or OATS), the study began 15-years-ago and continues today. 

Over 450 twin pairs, triplets and siblings are involved in the study – a collaborative effort between the University of NSW, Queensland Institute of Medical Research (QIMR), and the National Ageing Research Institute. 

Emotional wellbeing

One of the largest ATR-supported projects in terms of twin numbers is the Emotional Wellbeing study.  Started in 2007, the study is seeking to identify the risk markers of reduced wellbeing by studying 1500 healthy identical and fraternal twins over the next few years. 

By identifying these markers, individuals could be targeted for early health intervention before developing illnesses.  Researchers at the Brain Dynamics Centre of Westmead Millennium Institute in Sydney plan to test a range of possible factors including saliva analysis (for genetic risk markers); stressful life events; and brain, body and personality risk markers. 

By comparing identical and non-identical twins, they aim to assess the relative contribution of genes versus environment, and how they might provide a focus for future preventative health programs.

Does your heart quiver?

Atrial Fibrillation, or AF, is a heart rhythm disorder associated with irregular electrical activity of the upper chambers of the heart.  AF is the most common heart rhythm abnormality in our community and is a major risk factor for stroke and heart failure. 

Researchers at the Victor Chang Cardiac Research Institute in Sydney are seeking to gain a better understanding of the genetic and environmental factors contributing to increased AF risk.

Started in 2006, the study involves identical and non-identical twins, where one or both of the twins have AF.  Around 330 twin pairs have joined the study but many more are needed.  Participants take a blood test, an electrocardiogram (or ECG) and an echocardiogram.  Tests can be conducted in Sydney or anywhere around Australia.

Unraveling the mysteries of epilepsy and fainting

For more than 20 years, the University of Melbourne’s Epilepsy Research Centre at Austin Health has been studying twin pairs in which one or both have had a seizure, epilepsy or convulsions with a fever when young.  There are now more than 600 twin pairs enrolled in this study.

The researchers have found that twins do not have a greater chance of having epilepsy than the general population.  They have also discovered which types of epilepsy have an inherited component; new forms of inherited epilepsy; demonstrated the importance of non-inherited factors found in some epilepsies; and used the insights provided by twins to discover new genes for epilepsies.

Most recently, researchers have begun investigating another phenomenon whereby people have fainting (syncope) or breath-holding attacks rather than epileptic seizures. By studying twins and their families, the researchers are looking to identify the genes that underlie fainting and breath-holding. These findings will assist diagnosis and treatment in severe cases.

The study continues to seek twin pairs where one or both have had a seizure, epilepsy, febrile convulsions, fainting or breath-holding.

Care for Healthy Bones in an Ageing Population

The ageing of Australia’s population is leading to an increasing focus on prevention programs and improving treatment for bone and muscoskeletal conditions.  The ATR is at the forefront of this national focus, supporting a number of studies that are helping to better understand factors in bone health. 

A seven-year study involving twins at the Royal Melbourne Hospital is investigating the link between the use of anti-epileptic medication and increased risk of bone fracture.   Data from 50 twin or sibling pairs, where one is taking anti-epileptic medication and the other is not, shows that early commencement of medication (before age of 18) reduces bone density, particularly of the hip.

The same team is undertaking another study into muscoskeletal health, investigating how genes and lifestyle factors affect the risk of developing certain joint diseases.

Meanwhile, a study at the Austin and Repatriation Medical Centre in Melbourne is seeking to better understand how bone structure changes during menopause and how hormonal factors contribute to bone loss and bone fragility.

All of these studies are seeking more twins to join in the search for improved treatments for many debilitating bone conditions.  

Mammographic density

Started in 1994, the Australian Twins and Sisters Mammographic Density Study, is now the biggest family study in the world of mammographic density, a strong and heritable risk factor for breast cancer.

It is also the first study to show a clear association between mammographic density and some of the common genetic variants that are known to be associated with breast cancer risk.  The researchers have also identified other potential genetic variants that are associated with mammographic density using genome-wide scan data.

The team is collaborating with international researchers to maximize the potential of this valuable resource.   Today, there are 1221 Australian twins and their sisters involved in this ongoing study. 

Is there a link between diabetes and dementia?

Researchers from Melbourne’s Monash University are investigating the link between type 2 diabetes mellitus and dementia, two diseases common in older people. 

Previous research has shown that people with type 2 diabetes may be at increased risk of dementia.  It is possible that brain blood vessels and other structure are more vulnerable to the effects of diabetes mellitus, but this is as yet unknown.

Started in 2006, the study has recruited 20 twin pairs but needs more -- identical and fraternal twin pairs over the age of 50 years where one twin has type 2 diabetes mellitus and the other does not. Twin pairs undertake an MRI scan and perform memory skills.

Familiar faces

Since 2008, the international team behind the popular website www.testmybrain.org has collaborated with ATR members to answer fascinating questions behind human psychology.

Recently, the team completed a study on face recognition and found genes play an important part in our ability to recognize faces, while environmental factors (for example, our formal schooling) contribute surprisingly little.  It also found that face recognition ability is quite separate from other abilities, such as memory for words or abstract art.  These results provided valuable insight into one of most intensely studied and socially advantageous of our cognitive traits.

As a next step, the team is undertaking a study, Beauty and the Eye of the Beholder, investigating the differences between individuals in what they find beautiful.  The study is seeking to answer the question: are our differences in taste more likely due to the genes that we are born with, or to our experiences?

The study is a collaboration between psychology schools from University of Western Australia, and the USA’s Wellesley College, Harvard University and Gettysburg College.

The dilemma of growing pains

Since 2007, the Sydney Children’s Hospital has studied twin pairs aged 3-12 years in which one (or both) has experienced growing pains, and more twins are needed.  Studies have found that identical twins are more likely to experience growing pains compared to non-identical twins, indicating there is a strong genetic component to this condition.

They also found remarkable relationships between growing pains and ‘restless legs syndrome’.  These results may ultimately help in defining genes for vulnerability to growing pains and, in turn, to childhood risk for other pain disorders.

Teeth and faces of young Australians

For more than 30 years, the University of Adelaide has been studying twins to learn more about the role of genetic factors in dental health and facial structures.  Results from this research have led to developments in prevention and treatment for various dental and jaw problems.

Most recently, these researchers have involved twin babies and children in charting the order and timing of emerging teeth.  They have found a strong genetic influence in the emergence of baby teeth and their various findings are leading to new guidelines in dental health for all Australian children.