[Vitamin D in geriatric patients].

Vitamin D deficiency is widespread in geriatric patients. While vitamin D deficiency is prevalent in about 50% of healthy older adults, the prevalence in geriatric patients with hip fracture increases to over 80%. This is partly due to the fact that sunlight is unreliable as the main source of vitamin D. In addition to insufficient sun intensity from November to April, skin aging plays an important role; it causes a 4-fold reduction in the skin's own vitamin D production during sunshine exposure in older adults compared with younger people. Immobility and institutionalization are additional risk factors for vitamin D deficiency in geriatric patients. At the same time, vitamin D deficiency (< 20 ng/ml) increases parathyroid hormone levels and thus promotes bone loss and the risk of fracture. Severe vitamin D deficiency (< 10 ng/ml) may also lead to reversible muscle weakness resulting in an increased risk of falling. Since falls affect at least every second geriatric patient and hip fractures increase exponentially after the age of 75, the correction of vitamin D deficiency is an important medical and public health effort in these patients. Several randomized intervention trials, comparing 800-1000 IU vitamin D/day versus placebo or calcium, showed a significant reduction in falls and hip fractures in adults ≥65 years of age who had an increased risk of vitamin D deficiency and of falls or fractures. In geriatric patients, implementing vitamin D supplementation at this dosage is currently preferred. A bolus dose of over 24,000 IU/month should be avoided due to the increased risk of falls and fractures. These recommendations remain relevant after a critical review of the four most recent meta-analyses.