新概念英语第二册外刊精读扩展讲义

新概念英语第二册外刊精读扩展讲义 Rays of hope Exposure to the sun's UV radiation may be good for you For now, though, keep the sun cream handy BASKING IN THE sun has been considered a health hazard for at least four decades. The main risk comes from ultraviolet (UV) light, which the Sun emits alongside visible radiation. This can increase the chances of skin cancer—the number of diagnoses of which are rising—as well as bringing on premature ageing and leading to wrinkles. As a result, most developed countries recommend sunbathers protect their skin in the heat of the day with sun cream, especially in the summer months. The risks UV poses are real, but new research suggests it may be time to consider the benefits. According to a study published recently in Health and Place, increased UV exposure appears to make people significantly less likely to die from cardiovascular disease as well as cancer. The risk of dying from melanoma skin cancer, the deadliest form of skin cancer, did not meaningfully change with UV exposure. Although smaller-scale studies have previously nodded at health benefits, this is the largest study to show a direct correlation between UV exposure and longer lifespans. To conduct their analysis, the researchers from the University of Edinburgh used data from over 360,000 people in the UK Biobank, a database. They identified two cohorts more likely to have high UV exposure: those who claimed to use sunbeds or sunlamps; and those living in sunnier locations. To check that their assumptions about the subjects' UV exposure were correct, the scientists also looked at vitamin D levels in a subset of blood samples. As vitamin D is synthesised in the skin in the presence of certain forms of UV radiation, it is a reliable indicator of solar exposure. The researchers then examined the subjects' death rates while correcting for other confounding factors, including age, gender, smoking and socio-economic status (in Britain, those who live in sunnier climes are typically wealthier). They also corrected for exercise, as some sun-seekers might lead healthier outdoor lives. Their analysis showed that sunbed-users were 23% less likely to die of cardiovascular disease, and 14% less likely to die of cancer, than non-users. Similar trends held depending on where people lived. Someone living in Truro, for example, in the south of Britain, would on average experience about 25% more solar shortwave radiation (a measure that includes UV, visible and some infrared light) in a year than someone living in Glasgow or Edinburgh, which are much further north. The team concluded this translated to a 19% lower risk of dying from cardiovascular disease and 12% lower risk of dying from cancer. Sunbed-users, in other words, lived an average of 48 days longer than non-users over the 15 years during which they were studied. The corresponding figure for those living in sunnier spots was 26 days. According to Richard Weller, who co-led the study, most UV exposure g ... ...