Osteomalacia is most often caused by a prolonged lack of vitamin D, which is produced naturally by your body when your skin is exposed to sunlight and can also be obtained from some foods, e. g oily fish. You are more at risk of this illness if you cover up extensively with clothing, don't spend much time outdoors, use too much sunscreen, are aged 65 years or more and, have a poor diet, lacking in vitamins and nutrients, or a restrictive diet, e. g vegetarian or vegan.
Attribution: BUPA