If you don't get enough sunshine, your risk of developing rheumatoid arthritis (RA) rises. A new study has discovered that people who live in northerly climes - which see less sunshine - are more likely to suffer from a vitamin D deficiency as a result, and this can lead to RA. The study has discovered that higher rates of RA have been recorded among women in the north-eastern states of America, such as Vermont, New Hampshire and southern Maine, which have less sunshine than more southerly states. RA is one of a range of auto-immune diseases that can be triggered by a vitamin D deficiency, and sunshine is one of the major sources of the vitamin. The researchers made the discovery when they profiled 461 women with RA and compared them to 9,220 healthy controls. Lead researcher Dr Veronica Vieira, from the Boston University School of Public Health, said: "The results were unexpected. Prior to the analysis, we were more interested in the relationship with air pollution. I hadn't given latitudes much thought." Earlier studies have also drawn a link between vitamin D, and a lack of sunshine, with other auto-immune diseases such as Crohn's disease and multiple sclerosis (MS). (Source: Environmental Health Perspectives, 2010; doi: 10.1289/ehp.0901861).