Inflammatory bowel disease (IBD) is on the rise in New Zealand. We have the third highest rates in the world, following closely behind the USA and Canada and just ahead of Australia. In the 10 years from 2003 to 2013 diagnosis rates in NZ increased by about 80%.
Increasing rates of IBD in children has caused particular concern for New Zealand paediatricians. One specialist in particular, Andrew Day, has initiated research at Otago University into the causes of and potential treatments for IBD.
IBD is in fact an umbrella term that includes both Crohn’s disease and ulcerative colitis – diseases that involve chronic inflammation of the digestive tract. IBD is not to be confused with irritable bowel syndrome (IBS). Although it has certain similar, chronic symptoms, IBS is less severe, far more common, and is not necessarily caused by inflammation.
Symptoms of IBD usually include severe diarrhoea, abdominal pains and cramping, fatigue, blood in stools, loss of appetite and weight loss. Other symptoms can include skin and eye inflammation, joint pain, fever, rectal bleeding and constipation. Some of these symptoms can also lead to further complications such as ulcers, perforated colon, blood clots, severe dehydration and malnutrition.
Inflammatory diseases of the gut can, depending on the severity, be very debilitating and stigmatising for children. There is no cure for IBD, which is usually a lifelong condition that must be managed. For some this means hospitalisation, surgery, special diets, time off school, and potentially embarrassing incidents that children often experience with such a condition.
Is vitamin D a factor?
Professor Andrew Day, a paediatric gastroenterologist at the University of Otago, is heading up a team of researchers to investigate whether there is a link between the high number of New Zealand children with IBD, and vitamin D levels. He suspects vitamin D deficiency may be one of the causes of IBD, as it “is involved in the production of a molecule that plays a key defensive role in the gut.”
An earlier study involving Andrew Day at Otago University found that not only is the rate of IBD in children on the rise, but that the rate is three times higher in children in the South Island than in the North Island. This finding prompted the latest study, which has now secured Cure Kids funding, to explore whether this regional disparity is due to a difference in the amount and quality of available sunlight – and therefore vitamin D levels.
Research in Europe supports the same theory, revealing that IBD is more prevalent in northern European countries than in warmer southern climates. And in terms of vitamin D deficiency, multiple studies internationally have already indicated a link between inflammation in the digestive tract and low levels of vitamin D, some showing improvement in IBD patients following vitamin D supplementation.
Despite the general sun-shy attitudes these days of many New Zealanders, who have been taught to stay out of the sun or smother ourselves in sunscreen, melanoma rates haven’t actually dropped. This sun avoidance may also be responsible for higher rates of vitamin D deficiency, because safe exposure to the sun regularly is your best way to get the vitamin D your body needs. Vitamin D is essential for supporting the immune system against a range of diseases (including inflammatory auto-immune diseases and possibly even cancer), strong bones and muscles, healthy lungs and mood balance, among other things.
IBD rates in children have increased dramatically in many countries in recent decades, with some medical professionals theorising that it’s because children spend less time playing outside, meaning limited exposure to sun and reduced exposure to germs that keep the immune system active. Others have suggested the increase is due to much higher amounts of processed foods eaten by children in developed countries, compared to a few decades ago.
Professor Day hopes his research will help to reduce the number of cases of children falling victim to these often debilitating diseases and improve outcomes for those that do. This in turn would relieve costs to New Zealand’s public health system.
Professor Day is also heading up research to develop less invasive ways of diagnosing and monitoring IBD in children, so as not to add to the stress of the condition. For example, analysing stool samples in place of the usual colonoscopies and blood tests.