Insomnia raises risk of having a stroke People who have trouble sleeping may have a much higher risk of stroke than people who don't, according to new research based on the health records of 85,000 Taiwanese. Published in the American Heart Association journal Stroke , the study found that insomnia raised the likelihood of subsequent hospitalisation for stroke by 54 per cent over four years. The risk was far greater in young adults: the incidence of stroke was eight times higher among those with insomnia aged between 18 and 34. Beyond age 35, the risk continually decreased. Insomnia may alter cardiovascular health via systematic inflammation, impaired glucose tolerance or increased blood pressure. Study links obesity and cognitive function Obese children are slower than healthy-weight children to recognise an error and correct it, finds a new study by the University of Illinois. Scientists measured the behavioural and neuroelectric responses of 74 pre-adolescent children - half obese, half of healthy weight - while the children completed an action monitoring activity. The obese subjects were considerably slower to respond to stimuli during the activity. Healthy-weight children were better at evaluating their need to change their behaviour to avoid future errors. Spotty connection Not sure if that piece of chocolate is going to make your skin break out? There's an iPhone app for that. Researchers at Chicago's Northwestern University have created a free "Diet & Acne" app that uses data from a systematic analysis of peer-reviewed research studies to show the scientific evidence linking acne to foods such as chocolate, fat, sugar and whey protein. "Users may be surprised to learn that there is no conclusive evidence from large randomised controlled trials that have linked chocolate and acne," says Dr Diana Cohen, the app's creator. "Although one small study found that eating 100 per cent cocoa could worsen acne symptoms." Details about the use of the app were published online in this month's issue of JAMA Dermatology .