Diseases and medications – special issues for nutrition and bone health
Inflammatory bowel disease
Two of the most common disorders are Crohn’s disease and ulcerative colitis. Symptoms of these disorders tend to occur intermittently, and include diarrhoea, abdominal cramps and pains, fever and weight loss. Patients with these disorders are at increased risk for bone loss and osteoporotic fractures, due to a variety of factors including: poor food intake and nutritional status; poor absorption of nutrients by the damaged intestine (including calcium, vitamin D, protein and calories); surgery to remove parts of the intestine; treatment with glucocorticoid medications to reduce the inflammation; hormonal modifications induced by the gastrointestinal disease; and the release of compounds called cytokines (chemical messengers) as part of the inflammatory process, which increase the loss of calcium from bone. Osteoporosis prevention measures need to be included in the overall care strategy for patients with these disorders, including ensuring an adequate calcium and vitamin D intake either through diet or supplements. Other measures to prevent bone loss include avoidance of excessive alcohol intake and smoking, and taking regular weight-bearing exercise. Osteoporosis medications may be recommended for some patients, for example older patients taking long-term glucocorticoid therapy and those with prior fragility fractures.
Celiac disease
People with celiac disease may be at increased risk of osteoporosis if the disorder goes undiagnosed or is poorly controlled, due to inadequate nutrient absorption from food (including calcium and vitamin D), sometimes leading to frank malnutrition. Rates of celiac disease are commonly found to be higher among patients with osteoporosis than those without osteoporosis. Sometimes the celiac disease has no symptoms, and is ‘discovered’ when a patient who is vitamin D-deficient shows no response to being given a large therapeutic dose of vitamin D. By following a gluten-free diet, the damage to the gut surface is reversed, nutrients can be absorbed properly again, and the symptoms should abate.
Glucocorticoid medications
Commonly prescribed glucocorticoids include cortisone, hydrocortisone, prednisone and dexamethasone. Glucocorticoid use is an extremely important risk factor for osteoporosis and related fractures, as they can induce substantial bone loss, early in the course of treatment. A rate of bone loss of over 15% per year has been reported in patients receiving doses of prednisone at 30 mg/day. The predominant effect of the glucocorticoids is a reduction in bone formation, due to direct detrimental effects on osteoblasts, although there is also evidence that they increase the activity of osteoclasts. They can also interfere with calcium metabolism, and adversely affect the levels of sex hormones. In addition to the glucocorticoid treatment, the primary disease itself might also predispose to bone loss, through factors such as nutritional deficiencies (e.g. in gastrointestinal diseases) or the increased production of inflammatory cytokines which enhance bone loss (e.g. in rheumatoid arthritis). Patients taking glucocorticoids long-term (more than 3 months) should be evaluated for osteoporosis risk. The decision to initiate treatment with an osteoporosis medication (often a bisphosphonate) would depend on the glucocorticoid dose, and the patient’s other risk factors for fracture (46). In addition, those initiating long-term glucocorticoid treatment should be counselled on preventive lifestyle changes, such as good nutrition, ensuring adequate calcium and vitamin D intake (supplements are usually required), and weight-bearing exercise.
References
- Reid IR (2000) Glucocorticoid-induced osteoporosis. Baillieres Best Pract Res Clin Endocrinol Metab 14:279-98.
