Sunscreen reduces melanoma risk by 40% in young people

University of Sydney researchers have found that Australians aged 18–40 years who were regular users of sunscreen in childhood reduced their risk of developing melanoma by 40%, compared with those who rarely used sunscreen. Published in JAMA Dermatology, the world-first study analysed data collected from nearly 1700 people who participated in the Australian Melanoma Family Study. “Regular users of sunscreen were more likely to be female, younger, of British or northern European ancestry, and have higher education levels, lighter skin pigmentation, and a strong history of blistering sunburn,” the authors wrote. “People were less likely to use sunscreen if they were male, older, less educated, or had skin that was darker or more resistant to sunburn. Despite sunscreen being widely available and recommended for sun protection, optimising the use of sunscreens remains a challenge and controversies continue to surround its use. This study confirms that sunscreen is an effective form of sun protection and reduces the risk of developing melanoma as a young adult. Sunscreen should be applied regularly during childhood and throughout adulthood whenever the ultraviolet light index is 3 or above, to reduce risk of developing melanoma and other skin cancers. Some population subgroups such as people with sun-sensitive skin or with many moles might get a stronger benefit from using sunscreen.” The Australian Melanoma Family Study was conducted in collaboration with Cancer Council Queensland and the University of Melbourne and funded by the National Health and Medical Research Council, Cancer Council NSW, Cancer Council Victoria, Cancer Council Queensland and the United States National Institutes of Health.

Metabolite puts freeze on obesity in mice

Body temperature, energy expenditure and weight gain in mice can be influenced by the metabolite succinate through a previously unidentified temperature regulation pathway, according to an article from researchers at the Dana–Farber Cancer Institute in the US, published in Nature. There are two ways to lose weight: to eat less, thereby reducing the calories available for metabolism; or to burn more calories, such as by exercising. Calories can also be used as fuel by beige and brown fat. Unlike the energy-storing white fat that amasses with obesity, beige and brown fat cells are rich in mitochondria that generate heat through a variation of the process that normally creates energy-carrying molecules. In mammals, these fats are essential for temperature regulation against the cold. This heat generation burns calories, but activating beige and brown fats on demand has proven difficult. The researchers screened for metabolites that are abundant only in brown fats and whose concentration increases in cold temperatures. This probe highlighted succinate — an intermediate product of a process that unlocks stored energy. Succinate is released into the bloodstream by muscle activities such as shivering, from where it is absorbed into beige and brown fat cells. The authors found that, in mice, succinate can increase the local temperature of these fats — and that drinking succinate-laced water staved off obesity in mice that were fed a high fat diet. In an accompanying editorial the authors note that it will be interesting to see whether succinate also induces calorie burning in humans. Emphasising relevant differences between mice and humans — our relatively lower proportions of brown and beige fats, which also diminish with age — they cautioned that “this could limit the extent to which activation of metabolic processes in brown fat can alter calorie expenditure”.

Alcohol driving liver disease mortality

There has been a rapid rise in deaths due to liver disease in the US since 2009, especially in young people, driven predominantly by alcohol use, according to research published in The BMJ. Cirrhosis and liver cancer carry personal and financial burdens for patients, their families and society, so prevention and early treatment is cost-effective. However, data to guide allocation of resources and preventive efforts are limited, particularly in different groups or regions of the US. The researchers examined death certificate data for nearly 600 000 adults from the Vital Statistics Cooperative and population data from the US Census Bureau between 1999 and 2016. They looked at trends in deaths related to cirrhosis and liver cancer based on age group, sex, race and place of residence. They also looked at trends due to specific complications of cirrhosis, causes other than cirrhosis, and alcohol use disorder. After taking account of several factors that could have influenced the results, the researchers found that deaths due to cirrhosis increased by 65% (from 20 661 in 1999 to 34 174 in 2016) and deaths due to liver cancer doubled (from 5112 in 1999 to 11 073 in 2016). Men had twice as many cirrhosis-related deaths and four times as many liver cancer-related deaths than women. During 2009–16, people aged 25–34 years experienced the highest average annual increase in cirrhosis deaths (10.5%), driven predominantly by alcohol-related liver disease. In contrast, liver cancer deaths decreased in younger people (under 55 years old) and continued to increase in those aged over 55 years. Over the same period, white Americans, Native Americans and Hispanic Americans experienced the greatest increase in deaths from cirrhosis. States in the Western and Southern US experienced the fastest rise in cirrhosis- and liver cancer-related deaths: Kentucky 6.8%, New Mexico 6% and Arkansas 5.7%. Only one state in the northeast region, Maryland, experienced a significant annual decrease in cirrhosis-related deaths (–1.2%). This is an observational study, so no firm conclusions can be drawn about cause and effect.

Telomere discovery could have an impact on cancer, ageing and heart disease

Scientists from the Children’s Medical Research Institute, the University of Sydney, the University of New South Wales, the Walter and Eliza Hall Institute of Medical Research and the University of Adelaide have made a groundbreaking discovery in telomere biology, with implications for conditions ranging from cancer to ageing and heart disease. Telomeres are DNA segments at the ends of every human chromosome. As we age, telomere length naturally decreases. Over the course of a lifetime, telomere shortening instructs ageing cells to stop dividing. This normally functions as a critical barrier to stop cancer. However, some people are born with abnormally short telomeres and may have bone marrow failure, pulmonary fibrosis and high rates of cancer. Telomere length is also an important marker of disease risk for conditions such as cancer, heart disease and diabetes. Telomere shortening causes chromosome ends to resemble broken DNA. However, it has remained a mystery why telomeres change from healthy to unhealthy with age. This research has identified the underlying cause, the authors wrote in Molecular Cell. “Telomeres normally form a loop structure, where the chromosome end is hidden. We found that when the telomere-loop unfolds, the chromosome end is exposed and the cell perceives this as broken DNA. It is not telomere length that matters, but telomere structure. The telomere-loop becomes harder to form as telomeres get short.” In addition, the team identified that telomeres can also change structure in response to some chemotherapeutic agents, which helps kill cancer cells. The advent of super-resolution microscopy, which was awarded the 2014 Nobel Prize in Chemistry, made it possible to see telomere-loops with a microscope. To complete this research, the team used super-resolution microscopes at four Sydney research institutions and purchased the first “Airyscan” super-resolution microscope in Australia.

What’s new online at the MJA

23 July Research letter: Delays in primary percutaneous coronary treatment for patients with ST-elevation myocardial infarction
Dinh et al; doi: 10.5694/mja17.01186
More effort is needed to improve time to reperfusion for patients with STEMI … OPEN ACCESS permanently

23 July Perspective: Rendering visible the previously invisible in health care: the ageing LGBTI communities
Peisah et al; doi: 10.5694/mja17.00896
Recent legislative and policy measures aim to raise awareness of the needs of older LGBTI people … FREE ACCESS for 1 week

23 July Podcast with Samantha Edmonds, National Project Manager of Silver Rainbow … OPEN ACCESS permanently

23 July Research: Differences in management and outcomes for men and women with ST-elevation myocardial infarction
Khan et al; doi: 10.5694/mja17.01109
Women with STEMI are less likely to receive invasive management, revascularisation, or preventive medication at discharge … OPEN ACCESS permanently

23 July Podcast with Professor Clara Chow, Director of the Westmead Applied Research Centre … OPEN ACCESS permanently


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