Sitting down affects men’s health

University of Western Sydney

Sitting down for more than four hours a day increases men’s risk of developing chronic diseases such as diabetes and hypertension, a new study revealed. Image: Yuri Arcurs/Shutterstock Office workers, truck drivers and couch potatoes beware: a University of Western Sydney study has found that that men who spend more than four hours of each day sitting down are more likely to experience chronic disease such as cancer, diabetes, heart disease and high blood pressure. Emma George, a PhD researcher from the UWS School of Science and Health, worked in collaboration with Professor Gregory Kolt, Dean of Science and Health at UWS, and Dr Richard Rosenkranz from the Department of Human Nutrition at Kansas State University to conduct the study of 63,048 Australian males aged 45-64. Study participants from the NSW 45 and Up Study were asked to report on a range of health-related variables including the presence or absence of chronic diseases, and their daily sitting time. Sitting time was divided into four categories: less than four hours, four to six hours, six to eight hours, and more than eight hours. Ms George says, compared with those who spent four hours or less sitting down each day, participants reporting higher amounts of sitting were much more likely to report serious health conditions. "The rates of chronic diseases reported by the participants exponentially increased in proportion with the amount of time the participants spent sitting down,” says Ms George. Independent of factors such as age, BMI and level of physical activity, the amount of time men spent sitting each day was significantly associated with chronic disease and diabetes – indicating that, despite how active people may be outside of work hours, the amount of time spent sitting during the day may still have a significant impact. "Despite your levels of physical activity, the more time you spend sitting the less time your body has to stay active and expend energy,” says Ms George. Ms George says the study is highly relevant to office workers and anyone whose daily job requires them to sit down for long periods of time, such as truck drivers. “The results of this study suggest that there is potential for people to improve their overall health if they found more opportunities to move around during the day and reduce the amount of time spent sitting,” she says. “People should consider ways that they can integrate movement into their daily routines. Perhaps arranging  ‘active’ meetings rather than a teleconference, or walk around during your lunch break rather than sitting at your desk.” The research is part of the 45 and Up Study, the largest long-term study of ageing in Australia, involving more than 267,000 people. The results have been published in the International Journal of Behavioral Nutrition and Physical Activity. Editor's Note: Original news release can be found here.

'Junk DNA' regulates cancer gene

The University of New South Wales

Many cancers occur when genes that suppress tumours are not functioning properly, but the study found that what was once considered 'junk DNA' can re-activate these tumour suppressor genes.  Image: enot-poloskun/iStockphoto Research revealing that genetic sequences once considered as "junk DNA" can regulate cancer genes could lead to the development of new cancer drugs to re-activate tumour suppressor genes. Researchers led by UNSW's Associate Professor Kevin Morris have discovered a new mechanism,  which re-activate genes that have been switched off. Many cancers occur when genes that suppress tumours are not functioning properly, allowing the cancer to grow unchecked. The study by the international team is published in the journal Nature Structural and Molecular Biology. It reveals how a tumour suppressor gene called PTEN, which is shut down in many cancers including skin cancer, is controlled. And it shows how DNA sequences long considered “junk” can influence disease genes. “We show that there are multiple layers of complexity in the regulation of this PTEN gene, but also that it might be possible to switch it back on in cancer,” Dr Morris says. The researchers hope this would make tumours more sensitive to chemotherapy and prevent the development of resistance to cancer drugs. Less than 2 per cent of DNA in the human genome is made up of genes, which carry the blueprint for the production of proteins. Most of the other 98 per cent of the genetic code - known as noncoding DNA – was dismissed in the past as “junk”, because it does not make proteins. Some short stretches of noncoding DNA are called pseudogenes, because of the similarity of their sequences to known genes. Dr Morris, of the School of Biotechnology and Biomolecular Sciences in the Faculty of Science, says their research shows that a pseudogene regulates the activity of the PTEN tumour suppressor gene, and the “big deal” is that they found the pseudogene uses two different mechanisms to do this. “This is the first time bimodal functionality of a pseudogene has been shown,” he says. He says the exciting prospect is that small molecules could be used to de-activate the pseudogene in cancer. “When you knock out the pseudogene you get activation of the tumour suppressor gene, which would be a good thing.” Co-author, Per Johnsson, of the Karolinska Institute in Sweden, says: “This means that we might one day be able to reprogram cancer cells to proliferate less, become more normal, and that resistance to chemotherapy can hopefully be avoided.” Much more research will be needed before this approach is available for clinical use. Although the work was carried out on just one gene, it could be applicable to many more. “There is speculation now that there is one pseudogene for each gene,” says Dr Morris. Last year researchers in the ENCODE public consortium showed that most noncoding DNA is active: it is transcribed into RNA molecules, although mostly of unknown function. The two mechanisms the pseudogene uses to regulate the PTEN gene are: the pseudogene’s RNA  controls whether PTEN is active and produces any RNA itself; it also controls whether the gene’s protein is made, or not, elsewhere in the cell. The team includes researchers from the Karolinska Institute and the Scripps Research Institute in the US. Editor's Note: Original news release can be found here.

The problem with maths

The University of Sydney

Why aren’t Australian girls studying maths? Only 1.5% of girls go on to study science or maths for their HSC; 4.4% of boys undertake advanced maths with physics and/or chemistry components. Image: Sergey Nivens/Shutterstock The percentage of girls studying no maths for their HSC has more than doubled in the past decade, a report co-authored by University of Sydney researchers shows. Honorary Professor John Mack from the Faculty of Education and Social Work and Barry Walsh examined data of all Year 8 students in NSW to show the proportion who go on to study maths-science subject combinations for their HSC. The data revealed there was a substantial increase in the number of girls studying no maths at all in the HSC, and also showed a substantial drop overall in the number of boy and girl students undertaking at least one maths and one science subject in the HSC. "The decline in maths and science participation coincided with the removal in 2001 of the HSC requirement for undertaking English and at least one course in maths or science," says Dr Rachel Wilson from the Faculty of Education and Social Work, who helped prepare the report. "It is not a requirement in New South Wales, Victoria and Western Australia; although it is compulsory in SA, and to a small extent in Queensland and the Northern Territory. The study calls for policy change to make these subjects mandatory in order to lift participation in high school and to attract more girls to maths and science." The figures show that in 2001, 9.5 percent of girls undertook no mathematics course for their HSC. In 2011, this figure was 21.8 percent - more than double that of 10 years previously. Furthermore, in the same period the total proportion of Year 8 girls who went on to study intermediate or advanced maths dropped from 25 percent to 18 percent. In terms of undertaking science and maths the study also showed that only 1.5 percent of girls and 4.4 percent of boys go on to study advanced maths with both physics and chemistry. In 2001 some 19.7 percent of boys and 16.8 percent of girls studied a math-science combination in the HSC. In 2011 these figures had dropped to 18.6 percent of boys and 13.8 percent of girls. The decline has occurred despite the fact HSC participation increased by 5 percent over the period. This analysis suggests there is an urgent need to address declining female participation and stagnated male participation in intermediate/advanced maths-and-science combinations of study. The proportion of girls studying such combination subjects has dwindled since 2001 and there is now a greater gender disparity in maths/sciences participation than there was in the 1980s. Editor's Note: Original news release can be found here.