PUBLISHED : Monday, 28 August, 2006, 12:00am
UPDATED : Monday, 28 August, 2006, 12:00am

Weighty issue

As many as one in every five people in China is overweight or obese - and the problem is rapidly worsening, according to a report in the British Medical Journal that blames western diets, increasing affluence, sedentary lifestyles and a traditional belief that being fat indicates health and prosperity. 'China once [had] one of the leanest populations, but it is fast catching up with the west,' says lead author Wu Yang-feng of the Chinese Academy of Medical Sciences in Beijing. Nationwide, 215 million people out of a population of 1.3 billion are overweight or obese, according to a 2002 survey using WHO definitions, although the report says the figure would be 281 million using stricter, non-Caucasian measures. Weight gains during the past 20 years have been most marked in children, Reuters reports.

Mass protest

Then again ... body-mass index (BMI), the widely used, 100-year-old measure of obesity and cardiovascular risk, is seriously flawed and should be replaced, according to analysis by Mayo Clinic researchers of 40 studies involving more than 250,000 patients. Their report in the Lancet says that people with low BMI typically have a higher risk of fatal heart disease than those with normal BMI. Unlike measures such as waist-hip ratio, BMI doesn't distinguish between muscle and fat, reports.

Aids test success

An unspecified number of volunteers in preliminary trials of China's first Aids vaccine developed immunity to HIV within 15 days, and none had severe adverse reactions, according to the State Food and Drug Administration. Team leader Kong Wei of Jilin University told China Daily the initial results, using 49 healthy men and women, were 'truly inspiring', although it was too early to claim success. Further trials, using 800 volunteers, are expected to take years, AFP reports.

A cut above

Circumcision could help prevent millions of HIV infections, according to research presented at an inter-national Aids conference in Toronto, bolstering previous findings that circumcised heterosexual men are at least 60 per cent less likely to contract the virus than their uncircumcised counterparts. It's not clear why circumcision makes a difference, but WHO official Kevin De Cock says it may be because the foreskin is covered with a thinner layer of cells than the penis, which could facilitate invasion by the virus, WebMD reports.

Toon in, less pain

Television - particularly cartoons - can be even better than a mother's hug for children having blood taken, according to a small Italian study of about 70 children. University of Siena researchers found that those who were allowed to watch cartoons while having needles inserted rated the pain as lower than those whose mothers tried to distract and soothe them, AP reports.

DNA link may be found

A multinational research team may have found key missing links in human genetic evolution - key areas of DNA that changed dramatically after the human division from chimpanzees, having been almost unchanged for millennia. Scientists from the US, France and Belgium have identified 49 so-called human accelerated regions that show a lot of genetic activity. In one, 18 out of the 118 nucleotides had changed since the evolutionary separation about six million years ago, whereas only two had changed during the 310 million years previously. 'We have very suggestive evidence that it might be involved at a critical step in brain development,' says team leader David Haussler. Nonetheless, he says it's most likely that a series of changes was involved, rather than 'evolution of just one region in the genome', Reuters reports.

Spray goodbye to bacteria

US health officials have approved the first bacteria-killing virus spray for food - particularly so-called ready-to-eat luncheon meat - that may prevent the deaths of hundreds of people a year from an infection called listeriosis. The bacteriophage spray - the first time a virus mixture has been approved by the US Food and Drug Administration as a food additive - is used before packaging. The maker is also seeking approval of a spray to kill E. coli bacteria on beef before it is ground.

Jason Sankey is a tennis professional