Controversy pervades the definition of adequate and optimal vitamin D status. The Institutes of Medicine have recommended serum 25(OH)D levels above 50 nmol/L based upon evidence related to bone health, but some experts, including the Endocrine Society and International Osteoporosis Foundation, suggest a minimum serum 25(OH)D level of 75 nmol/L to reduce the risk of falls and fractures in older adults. In a cross-sectional study, we compared vitamin D status in people ≥75 years selected from four groups with a frailty phenotype, combined with a control group free from serious illness, and who considered themselves completely healthy. Only 13% of the 169 controls were vitamin D deficient (S-25(OH)D) < 50 nmol/L), in contrast with 49% of orthopedic patients with hip fractures (n = 133), 31% of stroke patients (n = 122), 39% of patients visiting the hospital's emergency department ≥4 times a year (n = 81), and 75% of homebound adult residents in long-term care nursing homes (n = 51). The mean vitamin D concentration of the healthy control group (74 nmol/L) was similar to a suggested optimal level based on physiological data and mortality studies, and much higher than that of many officially recommended cut-off levels for vitamin D deficiency (<50 nmol/L). The present study provides a basis for planning and implementing public guidelines for the screening of vitamin D deficiency and vitamin D treatment for frail elderly patients.
Keywords: 25-hydroxyvitamin D; Sweden; emergency care; frail older adult; vitamin D.