Australasian Science: Australia's authority on science since 1938


By Stephen Luntz

Brief bites of science news for subscribers only.

Soft Drinks Damage Eyes
Carbohydrate intake, particularly from soft drinks, has been correlated with narrower arteries in the back of children’s eyes. Narrowed arteries in the eyes are associated with a higher risk of heart disease and high blood pressure in future years.

“Children with a high consumption of soft drinks and carbohydrates had a more adverse microvascular profile compared to those who did not drink so many soft drinks or eat so many carbs,” said Dr Bamini Gopinath of Westmead Millennium Institute. The narrowing does not affect vision.

The study of 2000 Sydney students, published in the American Journal of Clinical Nutrition, follows on from research showing that television viewing has similar effects on the eye’s arteries (AS, June 2011, p.43).

The children in the study will be tracked in longitudinal research.

Weight Is a Clot Risk
In an unsurprising but significant finding, obesity in middle-aged women has been correlated with venous thromboembolism (VTE) – the formation of blood clots in the legs that can sometimes travel to the lungs.

In Circulation, Dr Lianne Parkin of the Department of Preventive and Social Medicine at the University of Otago used the UK’s Million Women Study to find that in the 12 weeks after surgery 4.8 women in 1000 with a body mass index of 25 or less experienced VTE, while the rate was 7.0 in 1000 for those with BMIs above 25.

“We also found that women who were overweight or obese were more likely to undergo surgery than those in a healthy weight range,” Parkin says. “So heavier women are more likely to have surgery, and they are more likely to develop blood clots following that surgery.”

Warm-Ups Work
Recent research has suggested that warming-up before exercise is overrated, with one study finding that athletes who warmed up for longer than 5 minutes received no benefit and were more likely to be tired out. However, a paper in the Journal of Strength and Conditioning Research suggests that warm-ups have their place.

Mr Justin Crow of La Trobe University’s School of Physiotherapy put 22 AFL players through low-load muscle exercises and compared this with a control group who did no warm-up and another that did weight-bearing warm-up exercises.

“We found that bodyweight gluteal exercises increase explosiveness in your lower half,” said Crow, by which he apparently means they can jump higher. “Low-load exercises of this nature are likely to be more acceptable to the athlete and coach than are protocols incorporating heavier loads because of a lower risk of athlete fatigue and minimal equipment requirements.”

Back Pain and Work Satisfaction
The link between lower back pain and dissatisfaction at work has been confirmed.

“Everybody has occasional lower back or neck pain but we are concerned about people with continuous non-specific pain for weeks at a time, which has significant socio-economic and personal costs,” said A/Prof Markus Melloh of the University of Western Australia.

Melloh found that in one-third of people with non-specific back pain, the condition worsened to the point where it severely affected their career or social life, and the progress depended on whether they felt valued at work. In most cases tests showed no evidence of physical damage such as a slipped disc.

“Attitude in the workplace and positive thinking have a huge impact on lower back pain,” Melloh said. “If an employee has the option to participate in change in their workplace or have some say in their job design, they can regain a positive attitude and the condition may correct itself.”

Obesity Discriminated Against
A study in the International Journal of Obesity has confirmed that women carrying more weight receive lower starting salaries than those who are thinner.

“Participants viewed a series of résumés that had a small photo of the supposed job applicant attached, and were asked to make ratings of the applicants’ suitability, starting salary and employability,” says Dr Kerry O’Brien of Monash University’s School of Political and Social Inquiry.

Photographs of the same women were provided before and after bariatric surgery. As well as finding that women classified as obese were likely to be offered lower starting salaries, O’Brien found that participants who considered themselves physically attractive were particularly likely to discriminate.

“One interpretation of this finding might be that we feel better about our own bodies if we compare ourselves to, and discriminate against, fatter people, but we need to test this experimentally,” O’Brien said.

Weight Loss Loosens Arteries
People with both obesity and Type 2 diabetes have arteries that are 20% less stiff arteries after losing 6 kg, the Garvan Institute has announced.

A/Prof Katherine Samaras published findings in Diabetes and Vascular Disease Research that the arteries of 14 people who experienced a combination of gastric banding and a calorie-restricted diet showed benefits.

“Obesity, Type 2 diabetes and atherosclerosis are all associated with an inflammatory state involving activation of immune cells in the circulation and in fat tissue, as well as an increase of circulating pro-inflammatory molecules,” Summers said.

“Weight loss reduces immune cell activation and inflammation, which in turn is related to the extent that arteries can relax. To our knowledge, this is the first study to examine the relationships between weight loss-induced improvements in arterial stiffness and the immune response.”

People with more inflammation in their fat tissue gained a smaller benefit than those with lower inflammation.

Asthma Ignorance Endangers Pregnancies
Some women are ceasing their asthma treatment during pregnancy under the misguided belief the medication could prove a threat, Ms Angela Lim of Monash University’s Centre for Medicine Use and Safety has reported in The Journal of Asthma.

Lim says that asthma medications at regular doses do not appear to pose a risk to pregnancy, but many women are assuming there is a problem and not even discussing it with their doctors.

“We have found many women are decreasing or stopping their asthma medication, jeopardising asthma control at a time when it can fluctuate due to pregnancy,” said Lim. “This can lead to negative outcomes for both mother and child, including restricting oxygen flow, which can lead to poor foetal development.”

Skin Damage Done Early
An ultraviolet camera that observes skin damage invisible to the naked eye has confirmed that most of the damage leading to skin cancer is done before people turn 18.

Prof Michael Kimlin of Queensland University of Technology’s AusSun Research Lab said: “We looked at how age impacted on the skin damage we saw and found it’s not a simple one-to-one relationship. The message from this research is to look after your skin when you are a child and teenager to prevent wrinkles and skin damage.”

While skin degradation slows further after the age of 50, Kimlin said that damage could still occur at any age, making whole-of-life sun protection important.

Nevertheless, with vitamin D deficiency among the elderly an increasing concern (AS, July/August 2011, p.10), the research, published in Science of the Total Environment gives people over 50 some additional reasons to spend time in the sun each day.

Woodland Birds Can Be Saved
There is hope for endangered woodland bird species, the Centre of Excellence for Environmental Decisions has found. Monitoring 193 sites on 46 farms across southern NSW revealed that planting of native trees revives bird communities.

“It’s an extremely encouraging result,” said team leader Prof David Lindenmayer. “We’ve seen a big increase in numbers of rare and endangered birds on farms in southern Australia, despite the drought. It’s really good news, and a true credit to all the farmers who have worked so hard to protect and restore native vegetation.”

In PLoS One Lindenmayer revealed that an average of 29 species were detected in new plantings, with 25 in seeding regrowth but only 15 in old growth where all the trees were mature.

“In both new planting and regrowth areas, there is an under-story of young vigorous trees and shrubs which is attractive to many woodland birds,” said Lindenmayer, mentioning “the diamond firetail, hooded robin, flame robin and black-chinned honeyeater.”

Space-Tracked Cassowaries
The world’s largest fruit-eating bird, the cassowary, is under threat but programs to save it are flying blind from lack of knowledge of the bird’s behaviour. The University of Queensland has taken to tagging cassowaries with satellite tracking devices to fill the gap.

“The use of modern satellite telemetry is the only reliable method to monitor the movements of these birds within the rainforest. We can now answer ecological questions about cassowaries which were not possible as little as a decade ago,” says Dr Hamish Campbell of the School of Biological Sciences.

Land is being bought to create wildlife corridors, and fences have been installed, both to keep cassowaries from becoming road kill and to control the movements of dogs.

Food has also been left out after cyclones, but Campbell says there is great dissent as to the effectiveness of these methods, and only greater knowledge of the cassowary’s migration patterns will help.