Soltalk December 2018 | Page 46

Doctor’s notes Dr Rik Heymans is a general practitioner in Nerja and writes on developments in the world of medicine Vitamin D more outdoors life, walking about, or enjoying the sun on a terrace! There appears to be a growing discrepancy between the observational studies on the benefits of having sufficient levels of vitamin D, and the randomised clinical trials of vitamin D intake. For example, the observational studies are showing a fairly consistent relationship between low blood levels of vitamin D and an increased risk for heart disease, cancer, diabetes, and many other chronic diseases. Contact lens use and infections Most adult contact lens wearers in the United States who took part in an online survey from the Centers for Disease Control and Prevention (CDC) reported at least one type of hygienic behaviour that put them at risk for an eye infection in 2014. In addition, approximately one-third of them reported at least one healthcare visit for a red or painful eye while wearing contact lenses, researchers reported recently. The survey found that approximately 40.9 million US adults (an estimated 1 in 6 adults in the United States) wear contact lenses. Nearly all (93.0%) of them wear soft contact lenses. Yet, the randomised clinical trials of vitamin D supple- mentation to date have been generally disappointing. This includes several randomised trials published over the past few months, including a large analysis of randomised trials of vitamin D supplementation showing minimal, if any, benefit on lowering blood pressure; a trial of high-dose vitamin D supplementation showing no clear benefit for muscle strength, bone mineral density, or even the risk for falls; and, most recently, a randomised trial of vitamin D supplementation with and without calcium showing no clear benefit in reducing the risk for colorectal adenomas. Of the respondents to this survey, approximately 99% reported at least one risky hygiene behaviour, including ever doing any of the following: sleeping overnight in contact lenses (50.2%), napping in contact lenses (87.1%), diluting the disinfecting solution (55.1%), extending the recommended replacement frequency of lenses (49.9%) or cases (82.3%), showering (84.9%) or swimming (61.0%) whilst wearing contact lenses, rinsing lenses in tap water (35.5%), or even storing lenses in tap water (16.8%). Of all contact lens wearers, 30.2% reported ever having a red or painful eye while wearing lenses that required a doctor’s visit. Vitamin D is one of these vitamins which is stored in the body, and accumulates there - unlike Vitamin C or B, where any excess ingested is easily washed out; so when taking in too high doses Vitamin D will have toxic effects. The Institute of Medicine (IOM) and the US Preventive Services Task Force do not endorse routine universal screening for vitamin D deficiency. They also recommend more moderate intakes of vitamin D. For example, the IOM recommends 600-800 IU a day for adults and also recommends avoiding daily intakes above 4000 IU, which has been set as the tolerable upper intake level. The frequent exposure of contact lenses to water, including storing or rinsing the lenses in tap water and showering or swimming while wearing lenses, is especially concerning. Exposure of lenses to water raises the risk for infection because bacteria or viruses living in this water can be transferred to the eye. Even household tap water, although treated to be safe for drinking, is not sterile and contains microorganisms that can contaminate lens cases and contact lenses and cause eye infections. And although some contact lenses have approval from the US Food and Drug Administration for overnight wear, sleeping in any type of contact lens increases risk for eye infection, as obviously does noncompliance with lens and case replacement schedules. However, some patients may have higher vitamin D requirements. This may include patients with bone health problems (osteoporosis, osteomalacia) or poor diets; those who spend minimal time outdoors; those with malabsorption syndromes; or those who take medications that may interfere with vitamin D metabolism (long-term cortisone, anticonvulsant medications, and antituberculosis drugs). All in all, here in sunny Spain there would be little need for additional Vitamin D supplements, since one tends to live a The final message should be: focus on keeping all water away from contact lenses; discarding used disinfecting solution from the case and cleaning with fresh solution each day; and replacing contact lens case every three months, the authors conclude. © Dr RIK HEYMANS c/ Angustias 24, Nerja. Tel: 95 252 6775 44 Dr Rik Heymans "running in the rain" in the Vélez Half Marathon last month. Not deterred by the weather apparently, he plans to run the Half Marathon in Cordoba next...