What the scientists are saying…
Diabetes linked to brain ageing
Type 2 diabetes is already known to have a host of life-threatening complications, including kidney disease and stroke. Now a study has found that the condition may also accelerate brain ageing and cognitive decline. Researchers in New York analysed data on 20,000 adults from the UK Biobank project, who were aged 50 to 80. Around 1,000 of the participants had been diagnosed with type 2 diabetes, and the researchers found that these people tended to perform less well in cognitive tests than the others. On average, they performed 13% worse in tests of their ability to plan complex tasks, and nearly 7% worse in tests that measured their mental-processing speed. Scans also showed that parts of the brains of the diabetics were shrinking at a faster rate than those of the non-diabetics, an effect that tended to be more pronounced the longer the person had had the disease. The study’s authors suspect that the brain cells are not responding to insulin properly, and are therefore not taking in the glucose they need to keep neurons alive. “By the time diabetes is formally diagnosed, this damage may already have occurred,” says Prof Lilianne Mujica-Parodi of Stony Brook University.
Cats really do kill a lot of birds
Pet cats may be claiming the lives of as many as 270 million animals in the UK a year, a study has suggested. Researchers at the University of Reading tracked 79 suburban cats in Berkshire and Hampshire for a year, recording their movements with a GPS device. The pets’ owners kept a log of whenever their cat brought back a dead animal, and noted what kind of animal it was. They found that cats from houses within a 100 metre radius of natural habitat killed an average of 34 animals per year, while cats in more built-up areas that were at least 1km from green space killed 15 per year. Although cats brought home about the same number of birds regardless of whether they lived near green space or not, those in leafier areas killed many more mammals, which raised their total kill rate. Wearing a bell was no deterrent: in fact, the cats with bells tended to kill more animals than those without. “Domestic cats bring great joy and companionship to their owners,” the study concluded, “but they also cause the loss of tens of millions of animals each year.”
Bacteria clings to wet wipes
We know that wet wipes flushed down the toilet are a major cause of the “fatbergs” that block urban sewers. Now scientists at the University of Stirling have found that wet wipes and other sewage-associated waste found on beaches harbour potentially harmful levels of faecal bacteria. Researchers tested wipes, cotton buds and sanitary products gathered on ten beaches in the Firth of Forth, near Edinburgh, as well as natural materials such as seaweed and sand. They found that the litter was a “concentrated reservoir” for faecal bacteria, including E. coli. Bacteria were more likely to bind to plastic-based waste, said the team, which meant the bugs persisted despite exposure to the sand and the sea. High rates of antimicrobial resistance were also detected in the bacteria on wipes and cotton buds. “We all know that sewage waste on our beaches is unsightly, but it could also be a risk to public health,” said research leader Prof Richard Quilliam. He added that he’d been shocked by how many wet wipes his team had found: there were sackfuls of them.
Coffee drinkers may live longer
People who drink coffee have a lower risk of dying early – even if they have it with sugar, a study has indicated. Researchers in China analysed data on more than 171,000 people in the UK Biobank study, tracking participants for seven years from 2009, during which 3,177 people died. After accounting for factors such as age and educational level, the team found that those who drank between 2.5 and 4.5 cups of unsweetened coffee a day had a 29% lower risk of dying than those who didn’t drink it. The reduction for those who added sugar was less, but still significant. Participants were only asked about their coffee habits once, however, and most of those who liked it sugary only added a teaspoon. “While we can’t conclude definitively that drinking coffee lowers your risk of dying, what we can probably say is that drinking coffee with a little bit of sugar probably doesn’t cause much harm,” said Dr Christina Wee, who edited the study.