The power of two: epigenetics and twins

THG epigenetics blog post

This blog post was written by Jeff Craig

Special Epigenetics issue of Twin Research and Human Genetics

Twins are at the forefront of research into human health and disease. Twin Research and Human Genetics has published a Special Section highlighting how researchers have learned how epigenetics, the molecules that play the symphony of life on our genes, can influence our future health. Never before have such a group of papers been brought together in a single issue.

Papers highlight the power of sampling the same twins over time as their health changes and others detail the ways in which researchers scour the human genome for evidence of epigenetic associations with disease.

Four of the papers focus on the discordant identical twins in which only one twin has an illness. Topics span a wide age range of subjects, from birth weight to hormone replacement therapy (HRT). One even focuses on whether twins are “morning” or “evening” people.

Three papers from the Netherlands Twin Registry highlight the power of collecting biological samples from many hundreds, even thousands, of twin pairs. These are studies of aggressive behaviour, tic disorders and wellbeing and pinpoint specific epigenetic differences linked with each.

The final paper looks at the influences, both genetic and environmental, on how we age epigenetically.

In summary this special section is a clear snapshot of cutting edge twin research that is relevant for our hunt for the genes that influence all of our health.

You can read the articles included in this Special Section free of charge for a limited time here, or using the individual articles linked below.

See below for more details about the papers included in this special issue:

Read the full editorial from Jeff Craig and Richard Saffery, The Power of Two: Epigenetics and Twins

Chiarella et al: “This paper reviews the literature showing how monozygotic twin designs can be used to study epigenetic mechanisms that may explain the impact of early in utero and postnatal environmental factors on the development of psychopathology. “

Tsai et al: “this study of adult identical twins born with different weights found a biological legacy in a gene involved in fetal growth. This suggests that the environment we encounter in the womb can influence us for many year after.”

Bahl et al: “using twins discordant for hormone replacement therapy (HRT) the authors showed that HRT can change the activity of genes in the blood and that many of these genes were associated with sense of smell. This makes sense as HRT is known to improve a woman’s sense of smell.”

Wong et al: “believe it or not, some identical twins are more “day people” while their twin brither or sister are “night people. This study showed that our preference for day or night could be programmed in ‘epigenetic’ factors that stick to our genes and change their activity”

Du et al found an ingenious way to tell which of a pair of identical twins a sample found at a crime scene came from. Identical Twins cannot be distinguished because of their identical DNA but these researchers used “epigenetics”, factors that sit on top of the DNA”.

Bui et al: “identical teenage twins that had separate placentas in the womb may have a greater difference in the activity of their genes than those who shared a placenta. This shows that the environment we encounter in the womb can have long lasting effects”

Zilhao et al and van Dongen et al: “These twin studies of both tic disorders and aggressive behaviour identified changes to gene activity in the blood in genes related to brain function, suggesting that looking at the blood may reveal information about how such disorders are caused.”

Baselmans et al: “study showed that wellbeing in twins is associated with factors that control gene activity.“

Li et al: “study suggests that the variation in methylation acceleration due to unmeasured genetic factors is likely to be even lower that the 40% estimated in previous studies”

More research and regulation needed on e-cigarettes “to protect health of public”

More and more people around the world are switching to electronic cigarettes – known as ‘e-cigarettes’ – as a substitute for conventional cigarettes. An estimated 2.6 million people in the UK alone are using one of the nearly 500 brands of e-cigarettes available from high street shops, petrol stations and via the internet. And yet little is known about the health risks associated with e-cigarettes, which have been in use since they were invented 13 years ago in China.

The authors of a new article point out that – although e-cigarettes are often marketed as using only vapour and nicotine without the carcinogens such as tar found in conventional cigarettes – there have been various chemical compounds found in e-cigarettes that are “either already known to be carcinogens or may well prove to be carcinogenic in the future”. And since e-cigarettes are currently not regulated, users cannot be certain about which chemicals are found within each product.

The three co-authors – who are all experts in the field of respiratory medicine and otolaryngology from hospitals in England – set out to examine the regulations, trends and health risks associated with e-cigarettes, as well as summarising the evidence about the use of e-cigarettes in smoking cessation.

What they found is that many of the elements identified in e-cigarette aerosols are known to cause respiratory distress and disease.  One 2013 study found, for example, that tin, silver, iron, nickel, aluminium and silicate particles have all been found in e-cigarette aerosols. The same study also found that the concentrations of nine out of eleven elements in e-cigarette aerosols were higher than or equal to the corresponding concentrations found in conventional cigarette smoke.

A more recent 2015 study has confirmed that e-cigarettes contain toxic compounds, such as formaldehyde, nitrosamines and nickel, although these were in much lower concentrations than found in conventional cigarettes.

In addition, the authors report that there is limited evidence to prove whether e-cigarettes are an effective method for stopping tobacco smoking. Although several trials suggest that e-cigarettes may be beneficial to some smokers who are looking to quit or reduce smoking, the authors conclude that there is currently not enough long-term data available on the outcomes of using e-cigarettes as smoking cessation devices. At the moment, no e-cigarettes have been approved for smoking cessation purposes by governmental authorities, according to the authors. However, as a result of the European Commission’s Tobacco Products Directive issued in 2014, the Medicines and Healthcare Products Regulatory Agency (MHRA) in the UK is currently considering regulation of e-cigarettes and other nicotine-containing products.

In the meantime, the authors recommend that professionals should not be advocating the use of e-cigarettes as a smoking cessation tool.

“Regulation of e-cigarettes is necessary to establish a scientific basis on which to judge the effects of their use,” they conclude. In addition, they recommend that adequate research is needed on the long-term health effects of e-cigarettes, “firstly so that the public has current and reliable information as to the potential risks and benefits and secondly so that the health of the public is protected.”


The full paper by Miss Nicola Stobbs, Dr Aoife Lillis and Professor Nirmal Kumar is available online in The Journal of Laryngology & Otology (JLO) here.

The dementia difference: Investigating imbalances in the treatment of patients with dementia


The March International Psychogeriatrics Article of the Month is entitled “Healthcare resource utilization and cost in dementia: are there differences between patients screened positive for dementia with and those without a formal diagnosis of dementia in primary care in Germany?” by Bernhard Michalowsky, Tilly Eichler, Jochen René Thyrian, Johannes Hertel, Diana Wucherer, Wolfgang Hoffmann and Steffen Flessa. This blog piece was written for us by one of the paper’s authors, Bernhard Michalowsky.

A precise formal diagnosis of dementia is enormously important to initiate adequate and appropriate treatment and care in dementia. Despite the fact that international standards and evidence based guidelines recommends a precise formal diagnosis, it is well known that dementia is under-diagnosed. Even in high income-countries, fifty to eighty per cent of people with dementia do not receive a formal dementia diagnosis. These persons were unnoticed in most studies, also in cost-of-illness studies. These studies revealed that dementia is associated with substantial and increasing health care costs, which adds to making dementia a serious health care priority. However, are there differences in treatment, in care and in overall healthcare costs between patients formally diagnosed with dementia and those without a formal diagnosis?

We have studied this question in our general-practitioner (GP) based sample of persons who screened positive for dementia and found a significant difference in treatment and care and in medical care cost between patients with and those without a formal dementia diagnosis.

We set out to study this issue within the ongoing DelpHi-MV (Dementia: life- and person-centered help in Mecklenburg-Western Pomerania) trial, a general practitioner-based, cluster-randomized, controlled, intervention trial in the primary care setting. Eligible patients were 70 years or older, living at home and screened in general practitioner (GP) practices for dementia using the DemTect. As published in this month´s issue of the journal we assessed individual data about the utilization of medical and formal health care services of 240 primary care patients. The costs were assessed from the perspective of insurance and the associations between dementia diagnosis and costs were evaluated using multiple linear regression models.

We found that patients formally diagnosed with dementia were treated significantly more often by a neurologist, but less often by all other outpatient specialists, and more often received anti-dementia drugs, but less additional drugs. The higher utilization of anti-dementia drugs and neurologists/ Psychiatrist is in line with the recommendations of evidence-based German guidelines. However, less treatment by outpatient physicians and with additional drugs is out of line with published studies. It is questionable if this corresponds to an inadequate treatment.

Furthermore, we found that diagnosed patients underwent shorter and less frequent planned in-hospital treatments, especially surgeries. This could mean that in hospital a premature discharge is forced and necessary surgeries were possibly omitted or unnecessary surgeries were not conducted because hospitalization is associated with deterioration in health outcomes. Taking all of this into account, dementia diagnosis was significantly associated with less total medical care costs.

What is the take home massage of this research? Actually, it seems to be that there are differences in treatment, care and healthcare cost between persons with dementia and those without a formal dementia diagnosis. Furthermore, dementia diagnosis seems to be beneficial for receiving dementia-specific treatment, but currently insufficient to ensure adequate in-hospital, out-patient specialists and overall medication treatment. This should be validated in further studies and improved in routine care.

The full paper “Healthcare resource utilization and cost in dementia: are there differences between patients screened positive for dementia with and those without a formal diagnosis of dementia in primary care in Germany?” is available free of charge for a limited time here.

The commentary paper “What is the potential for improving care and lowering cost for persons with dementia?” by Karen Davis, Amber Willink and Halima Amjad is also available free of charge here.

Addressing the gender gap in global health leadership – via Global Health, Epidemiology and Genomics

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This post was written by Pascale Allotey andoriginally posted on the Global Health, Epidemiology and Genomics blog – read more at:

In recognition of International Women’s Day 2016, GHEG is inviting submissions for a themed collection on Women in Global Health.

A core mission of global health is to achieve health equity for all people worldwide. Women, particularly in resource-limited settings, experience a disproportionate burden of disease and mortality due to inequities in access to basic health care, nutrition and education.(1) The imbalance in the health burden between genders is therefore a key focus, addressed by both the Millennium Development Goals and more recently, the Sustainable Development Goals.

However, despite this key goal to address gender inequities within the field of global health, women still occupy less than a quarter of global health leadership roles.(1) Ilona Kickbusch’s recent #WGH100 Twitter campaign to identify women leaders working at the forefront of global health, arose from a frustration with the lack of visibility of women in critical public spaces in the field.(2) Like other industries, the reasons for this imbalance include lack of opportunities, family commitments and lack of confidence. Whilst many institutions have attempted to address these issues, tackling the gender gap in leadership still requires a more proactive strategy.

This year’s theme for International Women’s day is Planet 50-50 by 2030: step it up for gender equality. The goal, spearheaded by UN Women, is to achieve gender equality in the next 15 years – by increasing investment in gender equality, striving for parity for women at all levels of decision-making, eliminating discriminatory legislation, and addressing social norms that perpetuate discrimination against women.(3)

The campaign for equality in leadership is important for reasons other than proportional representation. Research in several settings has shown that women in leadership positions are more likely than their male counterparts to invest in infrastructure and programmes that address women’s concerns.(1) Similarly, policies of women in leadership tend to be more responsive to the needs of women and children and recognise women’s responsibility for decision-making when it comes to the health of their families.(1, 2)

In an attempt to address and explore the issues surrounding gender and leadership in global health, GHEG will be publishing a themed collection on Women in Global Health. We invite submissions that explore, among other things, the current landscape, the potential reasons behind the current gender imbalance in global health roles, suggestions for practice and policy that can catalyse change, and descriptions of effective formal partnerships and campaigns on Women in Global Health. The deadline for this call is the 31st May 2016. To find out more visit:

1. Downs JA, Reif LK, Hokororo A, Fitzgerald DW. Increasing women in leadership in global health. Academic medicine : journal of the Association of American Medical Colleges. 2014;89(8):1103-7.
2. Devi S. Twitter campaign highlights top women in global health. Lancet (London, England). 2015;385(9965):318.
3. Press release: World leaders agree: We must close the gender gap [press release]. 2015.

Successful aging at 100 years

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Images: Participants from the PT100 – Oporto Centenarian Study being interviewed

The February International Psychogeriatrics Article of the Month is entitled “Successful aging at 100 years: the relevance of subjectivity and psychological resources” by Lia Araújo, Oscar Ribeiro, Laetitia Teixeira and Constança Paúl. This blog piece was written for us by one of the paper’s authors, Lia Araújo.

Successful aging is a desire that we all aspire for ourselves and for our loved ones. According to Rowe and Kahn’s definition, operationalized through the MacArthur study, individuals who met the three criteria of (i) avoiding disease and disability, (ii) high cognitive and physical functioning and (iii) engagement with life were identified as “successful agers”(1).

Another wish common to many of us is to live longer, why not up to 100!? Indeed, this can be a dream come true for an increasing number of individuals, since the oldest generations are becoming more representative and centenarians are likely to become more common(2).

Both wishes conjointly, a longer and successful aging, motivated the development of the PT100 – Oporto Centenarian Study(3). This population-based study was conducted in the north region of Portugal and included 140 centenarians who were interviewed face-to-face. We began to question ourselves what it means to be “successful” at such an advanced age and quickly got to ask the same question to our study participants. What we found was that sometimes the most relevant outcomes are from the perspective of the subjects themselves; and that together with the concern for problems and needs, we must capitalize on the real strengths of older people.

The criterion of little or no age-related decrements in physiologic function for those aging successfully does not apply to centenarians. However, when considering alternative criteria, based in centenarian´s self-perceptions of health, functional and cognitive capacity, a higher proportion of centenarians might be considered as successful. The paper also presents the influence of the available resources, such as individual strategies and external support, in improving subjective appraisals of successful aging, which confirms that certain internal resources (e.g., self-efficacy and purpose) are not overwhelmed by physical deterioration and may even gain power when corresponding and meaningful perceptions of oneself and one´s life are maintained in late life.

Successful aging at very advanced ages may not mean to stay healthy for even longer but rather to adapt. With that in our minds, as individuals, families, researchers, professionals or policy-makers, longer lives can and will be associated with improved quality of life in all ages and our wishes can become reality for our and next generations.

The full paper “Successful aging at 100 years: the relevance of subjectivity and psychological resources” is available free of charge for a limited time here.

The commentary paper “Success at 100 is easier said than done – comments on Araújo et al: successful aging at 100 years” by Peter Martin and Leonard W. Poon is also available free of charge here.

1. Rowe, J.W., & Kahn, R.L. (1997). Successful aging. Gerontologist, 37, 433-440.
2. Serra, V., Watson, J., Sinclair, D., & Kneale, D. (2011). Living Beyond 100: a report on centenarians. London: International Longevity Centre – UK.

Emotion-processing networks disrupted in sufferers of depression – via UIC News Center

depressed teenage girl

Regions of the brain that normally work together to process emotion become decoupled in people who experience multiple episodes of depression, neuroscientists report. The findings may help identify which patients will benefit from longterm antidepressant treatment to prevent the recurrence of depressive episodes.

The study, led by researchers at the University of Illinois at Chicago, is published in the journal Psychological Medicine.

“Half of people who have a first depressive episode will go on to have another within two years,” says Scott Langenecker, associate professor of psychiatry and psychology at UIC and corresponding author on the study.

Disruptions in the network of areas of the brain that are simultaneously active during problem-solving and emotional processing have been implicated in several mental illnesses, including depression. But in addition, “hyperconnectivity,” or too much connection, within the “resting network,” or areas active during rest and self-reflection, has also been linked to depression.

“If we can identify different network connectivity patterns that are associated with depression, then we may be able to determine which are risk factors for poorer outcomes down the line, such as having multiple episodes, and we can keep those patients on preventive or maintenance medication,” Langenecker explained. “We can also start to see what medications work best for people with different connectivity patterns, to develop more personalized treatment plans.”

In previous research, Langenecker found that the emotional and cognitive brain networks were hyperconnected in young adults who had depression. Areas of the brain related to rumination – thinking about the same thing over and over again – a known risk factor for depression, were also overly connected in adolescents who had experienced depression.

In the new study, Langenecker said he and his coworkers wanted to see if different patterns of network-disruption would show up in young adults who had experienced only one episode of depression versus several episodes.

The researchers used functional magnetic resonance imaging, or fMRI, to scan the brains of 77 young adults (average age: 21.) Seventeen of the participants were experiencing major depression at the time of the scan, while 34 were currently well. Of these 51 patients, 36 had experienced at least one episode of depression in the past, and these individuals were compared  to 26 participants who had never experienced a major depressive episode. None were taking psychiatric medication at the time they were scanned.

All fMRI scans were done in a resting state — to show which areas of the brain are most synchronously active as one relaxes and lets their mind wander.

The researchers found that the amygdala, a region involved in detecting emotion, is decoupled from the emotional network in people who have had multiple episodes of depression. This may cause emotional-information processing to be less accurate, Langenecker said, and could explain “negative processing-bias”  in which depression sufferers perceive even neutral information as negative.

The researchers also saw that participants who had had at least one prior depressive episode — whether or not they were depressed at the time of the scan — exhibited increased connectivity between the resting and cognitive networks.

“This may be an adaptation the brain makes to help regulate emotional biases or rumination,” Langenecker said.

“Since this study provides just a snapshot of the brain at one point in time, longer-term studies are needed, to determine whether the patterns we saw may be predictive of a future of multiple episodes for some patients and might help us identify who should have maintenance treatments and targets for new preventive treatments,” he said.

Rachel Jacobs, Alyssa Barba, Jennifer Gowins, Heide Klumpp, Lisanne Jenkins, Dr. Olusola Ajilore and Dr. K. Luan Phan of the UIC College of Medicine, and Dr. Brian Mickey, Dr. Marta Pecina, Margaret Sikora, Kelly Ryan, David Hsu, Robert Welsh and Jon-Kar Zubieta of the University of Michigan are co-authors on the paper.

This study was funded in part by the UIC Center for Clinical and Translational Science and grants RO1 Q2 601, MH091811 and RO1 MH101487 from the National Institutes of Health. – See more at:

Source: Emotion-processing networks disrupted in sufferers of depression | UIC News Center

The full paper, published in Psychological Medicine, “Decoupling of the amygdala to other salience network regions in adolescent-onset recurrent major depressive disorder” by  S. A. Langenecker et al. can be viewed here free of charge until 31st March 2016.

Free Content about the Zika Virus Now Available


Just 8 days after the public health emergency was declared, this content regarding the Zika virus has been written, reviewed, edited, and released as a freely available resource.

On February 1st, the World Health Organization declared a Public Health Emergency of International Concern related to clusters of microephaly cases in some areas affected by the Zika virus. Like the Ebola virus, there had been very little funding and research on Zika until the recent emergency and associated media and scientific attention – there is therefore a dearth of information and there is neither a vaccine nor prophylactic pharmacotherapy available to prevent Zika virus infection.

In response to concern over the effects of Zika virus infection in pregnant women, the medical publishing team at Cambridge University Press commissioned a brief summary of current evidence and recommendations. Just 8 days after the public health emergency was declared, this content has been written, reviewed, edited and released as a freely available resource. The content has been provided by Professor Bernard Gonik, Fann S. Srere Chair of Perinatal Medicine, Wayne State University School of Medicine.

Released in advance as a freely accessible public resource, this content is part of High-Risk Pregnancy: Management Options – a forthcoming updateable online product from Cambridge University Press. Like all of the content in High-Risk Pregnancy: Management Options, the Zika section will be regularly updated as new information arises.

Read about the Zika Virus Here



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