What the scientists are saying…

Are there five types of diabetes? To divide adult-onset diabetes into two types is probably too simplistic: according to a new study, there may actually be five. Traditionally, sufferers have been classed as having either type 1 diabetes, which occurs when the body’s immune system attacks insulin cells in the pancreas, leaving it unable to produce any insulin at all, or type 2, a condition that appears (often in adulthood) when the body stops producing enough insulin or stops responding to it properly, and which is often linked to lifestyle factors. The vast majority of those with diabetes – about 90% – are diagnosed as having this latter condition. But based on their analysis of the medical records of thousands of adults with diabetes in Scandinavia, the authors of the new study have suggested that it is more accurate to divide diabetes into five “clusters”. The first of these, severe autoimmune diabetes, corresponds to type 1, while the rest are “subtypes” of type 2. Two are “mild” forms, while the others are “severe” and display some of the symptoms of type 1. This diagnostic refinement, say the researchers in The Lancet, would enable treatment to become more tailored, and help doctors identify patients at risk of specific complications, such as diabetic eye disease. However, more research is still needed to establish whether their findings apply to non-scandinavian populations.

Learning to “see” like a bat Being blind doesn’t necessarily mean you can’t “see”. A small proportion of visually impaired people are able to build a picture of their surroundings using a process similar to that employed by bats. Known as echolocation, it involves making sounds – usually mouth clicks – and listening to the echoes created when these waves hit nearby objects. Some skilled practitioners have become so adept at building a picture of their environment using echolocation that they can ride bikes on unfamiliar paths. Now, a new study has given a fresh insight into how echolocation works. Researchers at Durham University asked eight echolocators to try to detect a 17.5cm disc positioned at various angles a metre away. When the disc was in front of them, they all managed to locate it; this fell to 80% when it was slightly behind them and 50% when it was right behind them. The researchers found that while they only needed one or two clicks to “spot” the object when it was in front of them, when it was moved to the side or behind them, they used more and louder clicks (as bats do). The study’s lead author, Dr Lore Thaler, said this insight should make it easier to teach more blind people to use echolocation as a navigational aid. “It’s very learnable,” she told The Guardian. Prostate screening “doesn’t work” Routine PSA screening for prostate cancer produces no discernible benefits and may do harm, a study of more than 400,000 men in the UK has suggested. Currently, men over 50 are entitled to request a PSA test, which measures levels of prostatespecific antigens in their blood. If levels are raised, this can be a sign of the disease and patients are then given a biopsy. With 11,000 men dying of prostate cancer each year in the UK, there have been calls for a full screening programme – but the wisdom of this has long been debated. Not only does the test miss some fast-growing cancers, it also leads to many patients receiving treatment – the side effects of which include impotence and incontinence – for slow-growing tumours that are unlikely to harm them. For the latest research, 573 GP practices were asked either to offer PSA tests to all men aged 50-69, or to carry on giving them only on request. When the results were compared ten years later, the team found that while a slightly higher proportion of men in the screening group had been diagnosed with the cancer (4.3% as opposed to 3.6%), this didn’t affect rates of death from the disease, which were three per 1,000 in both groups. “The PSA test is a blunt tool missing the subtleties of the disease and causing harm,” said Dr Richard Roope of Cancer Research UK, which funded the study. “We need to develop more accurate tools if we want to save men’s lives.”

Health statistics Half of UK adults believe that stress causes cancer, although most studies have found that it does not. By contrast, more than half of adults are unaware that processed meats and lack of exercise can increase the risk of cancer, a Yougov poll has found.