Osteomalacia is a disease characterized by softening of bones due to deficiencies in phosphate, calcium, and vitamin D, or from calcium resorption, affecting bone mineralisation. The most common cause of osteomalacia is a deficiency of vitamin D, which is normally mostly derived from exposure to sunlight, and to a lesser extent, from diet. Dietary sources of vitamin D include oily fish, like salmon and sardines, red meat, egg yolk, curd, cheese, and soya beans. Other than fish, meat products pose various health risks and should be consumed in limited quantities. Poor absorption of vitamin D is yet another cause of deficiency. It can occur due to diseases like malabsorption syndrome, Crohn’s disease, TB, chronic kidney diseases, etc. Some drugs like laxatives, steroids, and cholesterol-lowering drugs, also cause a deficiency of vitamin D. Obesity is also a risk factor for vitamin D deficiency and osteomalacia. Some individuals may have osteomalacia due to a hereditary deficiency of vitamin D3. Symptoms include diffuse body pains, muscle weakness, and increased fragility of bones. The spine, pelvis, and legs are particularly affected. Initially, pain occurs during some strenuous activity like climbing stairs or walking long distances. But with the progress of the disease, pain may occur when even walking a small distance or after some minor work. The small bony joints of the backbone can collapse, thus diminishing the stature. The gait of an individual may become waddling. Not only the bones of the body, but even the teeth become brittle. The affected bone can become deformed or break spontaneously, without any trauma (pathologic fracture). Elderly persons, particularly those who are house bound, are more vulnerable to vitamin D deficiency and resultant osteomalacia, as this population has little exposure to sunlight. Besides, the ability to synthesise vitamin D from sunlight and its absorption from the intestine declines with age, thus further aggravating the risk of deficiency in these persons. Other high-risk groups are people who work night shifts and rest during the day, those with surgery involving intestines, people who migrate from warm to cold climates, and women who keep the entire body and face covered with a veil. During pregnancy, the requirement of calcium is increased, if not fulfilled, it makes the bones soft and the newborn prone to rickets. Regular use of alcohol interferes with the metabolism of vitamin D and can result in its deficiency. Osteomalacia is different from osteoporosis, though both cause weakening of the bones. In osteoporosis, the bone mineral density and bone mass reduce, which reduces the strength of the bones. It is a degenerative bone disease, mostly occurring with advancing age, and remains asymptomatic in its early stages. Whereas osteomalacia occurs due to a deficiency of vitamin D, it causes problems with bone formation and softening of the bones. It can occur in children as well when it is called rickets. Diagnosis is made based on clinical features, low blood calcium, vitamin D3, and phosphate levels. X-rays and or scans will show softening of the bones. Nutritional osteomalacia can be treated very well by oral or injectable vitamin D3 supplements. If it is secondary to some disease, treatment of the disease process helps cure osteomalacia as well. Osteomalacia that occurs because of adverse effects of some drugs can be stopped or reversed if the offending drug is stopped in the early stages. Prevention lies in a diet rich in vitamin D and adequate exposure to sunlight. Dietary substances containing vitamin D like fish, egg yolk, cheese, curd, red meat, etc., should be part of daily meals. During pregnancy and the first few months of breastfeeding, it is recommended to take supplements of calcium and vitamin D. This prevents the softening of bones during or after pregnancy and even in the newborn. Alcohol and tobacco are best avoided. Regular physical exercise like walking, running or lifting weights, helps to strengthen muscles and improve strength of limbs. However, strenuous exercise should be avoided. Dr Rachna Pande is a specialist in internal medicine. rachna212002@yahoo.co.uk
