What the scientists are saying…

Blood pressure and dementia People aged 50 with only moderately raised blood pressure still have a significantly higher chance of developing dementia, a new study has found. The link between hypertension – defined in the UK as a reading of 140/90 mmhg or more – and dementia is well established, but this is the first evidence to suggest that more modest spikes increase the risk. Drawing on a cohort study of 10,000 British civil servants who were subjected to a range of health tests in the mid-1980s and followed up over subsequent decades, researchers found that a systolic blood pressure reading of just 130 mmhg at the age of 50 was associated with a 45% greater risk of developing dementia. The findings, which were reported in the European Heart Journal, add weight to the argument that the level at which hypertension is diagnosed should be reduced from 140 mmhg to 130 mmhg – a change that America made last year. However, many experts oppose the move (which would lead to about 14% more adults in the UK being diagnosed with hypertension) citing – among other things – evidence that just being diagnosed with high blood pressure raises people’s risk of depression and anxiety.

A metal “seed” to kill tumours Hard-to-access tumours – such as those in the brain – could be eradicated by using a tiny metal “seed” to heat them up, reports The Daily Telegraph. For the therapy, developed at University College London, patients have the magnetic seed injected into their bloodstream. In an MRI scanner, doctors locate the tumour, guide – with maximum precision – the seed to the sight of the cancer, then use the scanner’s radio waves to heat it up to the point where it destroys the surrounding cancer cells. So far, the technique has effectively treated brain tumours in pigs and the team hope to trial it on humans within two years. As well as killing fewer healthy cells than other treatments, the therapy is extremely quick. “We can get through a tumour in ten minutes,” said Professor Mark Lythgoe, launching the technology at the Cheltenham Science Festival.

Our IQ levels are gradually falling Younger people today are not as clever as previous generations, if IQ tests are an accurate gauge of intelligence. Scientists in Norway analysed scores achieved by 730,000 young men, born between 1962 and 1991, who did IQ tests as part of their national service. They found that for many years, the IQ levels of entrants rose, by about 0.3 points a year on average. This is consistent with the Flynn effect, the steady rise of IQ scores, by about three points a decade, observed across the developed world in the 20th century, a phenomenon put down to massive improvements in education, diet and healthcare over that period. However, IQ levels peaked among the cohort born in 1975, and then began to fall, at a rate equivalent to seven points per generation. The researchers speculate that changes to teaching methods and the shift to screen-based entertainment could be responsible for the change.

A closer look at myopia There’s a downside to being highly educated: it can make you short-sighted. Scientists have long known that myopia is more common among those who spend longer in education, but they weren’t sure whether bookishness was a causal risk factor for short-sightedness – or vice versa. Now researchers at Bristol and Cardiff universities have used a form of analysis known as Mendelian randomisation to find the answer. Drawing on earlier research, the team identified genetic variants associated with being shortsighted and with spending longer in education. They then cross-checked them against data held on 68,000 adults in the UK Biobank. Their analysis revealed that while those with a genetic predisposition to spend longer in education were more likely to be myopic, the reverse was not true: there was little evidence that people predisposed to be short-sighted spend longer in education. The researchers thus conclude that education leads to myopia, probably because people who spend a long time in the classroom tend to spend less time outdoors, in natural light. Levels of myopia are rising globally, and have reached epidemic levels in countries like South Korea and China, where up to 90% of school leavers are now short-sighted.