Calcium supplements can reduce the risk of bone fractures among people over 50 by as much as 24 per cent, according to a University of Western Sydney study of 4,500 elderly people that included an analysis of 17 other studies covering more than 52,500 people. Even when patients failed to take the full dose, the risk fell by 12 per cent, AFP reports. Hip fractures are a serious problem among the elderly.

A river runs through it

Pollution along two of the mainland's major rivers threatens one-sixth of the population, despite a decade of clean-up attempts. Samples from the Huai River and its tributaries in central and eastern China registered grade-five pollution or worse, meaning the water is unfit for human contact and may not be fit even for irrigation, according to a report by Mao Rubai, chairman of the National People's Congress (NPC) environment protection committee. The study was reported by China Daily and on the NPC website, according to Reuters. Mao also said that industrial pollution of the Liao River in the northeast remained too high.

Hearing voices

Researchers have figured out where second thoughts come from - which could have major implications for understanding self-control. That little warning voice inside your head is located just above and between your eyes (the dorsal fronto-median cortex), a German-British team has found. The brain scan study also found that self-control has a cost - not acting on an impulse can be frustrating, WebMD reports.

Life and death behind bars

Who'd have guessed? Bar staff are the workers mostly likely to die of alcohol-related problems, a British study of more than 16,000 deaths has found. Male bar staff are the highest risk group (2.23 times more likely to die from alcohol than the average), followed by seamen (2.16 times more likely). Male farmers are the least at-risk group, BBCi reports.

Jason Sankey is a tennis professional