What the scientists are saying…

Ethnicity and dementia Black people in Britain are much likelier to develop dementia than white people and Asians, scientists have found. The research, led by University College London, is the first nationwide study into how the condition affects different ethnic groups in the UK, analysing data on more than 2.5 million people, including 66,000 diagnosed with dementia. Diagnosed cases were 28% higher for black than white men, and 25% higher for black than white women. But Asian women and men were 18% and 12% less likely to be diagnosed with the disease than white women and men. The researchers believe both genes and environment account for the raised incidence among black people: previous studies have suggested that a gene associated with dementia is more prevalent among black ethnic groups; and various risk factors, including smoking and depression, have higher-than-average rates among the UK’S black population. The results for Asians are harder to explain, especially given that cardiovascular illness – another risk factor – is prevalent among this group. The researchers suspect the stigma associated with dementia makes some Asian people reluctant to seek treatment, masking its true scale.

ADHD drugs “work well” Rather than being over-medicated with Ritalin, British children should be prescribed the drug more, scientists believe. The stimulant is used to treat attention deficit hyperactivity disorder (ADHD), which affects about 5% of children, and is characterised by hyperactivity, impulsive behaviour and an inability to concentrate. But its use is controversial, with some claiming it acts as a “chemical cosh” for badly behaved, but otherwise healthy, children. After analysing 133 studies looking at the effectiveness and tolerability of drugs used to treat ADHD, researchers concluded that Ritalin is the best medication for affected children. “We now have very clear evidence that the brains of children with ADHD are structurally and functionally very different,” David Coghill, professor of child and adolescent psychiatry at The Royal Children’s Hospital in Melbourne, told The Times. He added that there was “strong evidence” to suggest that in many countries, including the UK, ADHD remains “underrecognised and under-diagnosed”.

Is too much sleep risky? Too little sleep is known to adversely affect health – but what about the opposite? A meta-study led by Keele University has found that sleeping more than eight hours a night is associated with a range of health risks, including dying prematurely. Compared with people who sleep seven hours or less, those who average ten hours a night are 30% likelier to have an early death and 56% likelier to suffer a fatal stroke. Poor sleep quality is also associated with a 44% increase in the risk of coronary heart disease. But the researchers don’t think that sleeping a lot directly causes poor health; instead, spending extra hours in bed is often a sign of an underlying health problem. “Abnormal sleep is a marker of elevated cardiovascular risk,” said Dr Chun Shing Kwok, the lead researcher. Writing in the Journal of the American Heart Association, he suggested doctors give greater consideration to sleep duration and quality during consultations.

Heart attacks and sex Women who have heart attacks are likelier to survive if they are treated by female doctors, says the Daily Mail. For a US study, researchers reviewed heart attack cases that occurred in Florida between 1991 and 2010, tallying outcomes not only to the sex of patients, but also to that of the doctors who treated them. Women had slightly worse survival rates than men – a finding consistent with previous research. But the scientists found that this gender gap was considerably greater when male physicians were involved: when patients were treated by a man, 13.3% of women (as against 12.6% of men) died; this closed to 11.8% of men and 12% of women when the physician was female. “Our work corroborates prior research showing that female doctors tend to produce better patient outcomes than male doctors,” said Dr Seth Carnahan, of Washington University in St Louis. “The novel part of what we are doing is showing that the benefit of having a female doctor is particularly stark for female patients.”