# Vitamin D and Rehabilitation after Stroke: Status of Art
## 5 Vitamin D and Post Stroke Recovery: Focus on Rehabilitation
### Vitamin D and Rehabilitation after Stroke  
There is only a relatively old review [3] in which the authors report that vitamin D deficiency is rarely documented in the rehabilitation literature. This study was done on 107 articles, narrowedto 51, focusing on vitamin D levels and musculoskeletal manifestations, like musculoskeletal pain and muscle weakness. Musculoskeletal pain is often seen in rehabilitation settings, where patients arrive after a long hospitalization and in a poor nutritional status, often including vitamin D deficiency. As reported by the authors, numerous studies have shown improvements in muscle strength after supplementation of vitamin D, with an improvement in outcome measurements of lower-extremity functions like walking tests or sit-to-stand tests [3].  
[PERSON] et al. [12] determined the association between vitamin D status, baseline function, and short-term inpatient recovery after rehabilitation in 100 heterogeneous patients (including 15 post-stroke patients). At admission, 80% of patients were highly vitamin-D-deficient (25(OH)D \(<\) 0.8 ng/mL or) with 94% below the recommended minimum of 32 ng/mL. Moreover, a weak but significant association with a low total Functional Independence Measurement (FIM) score at admission and at discharge was found. Patients with a 25(OH)D greater than median value of 16.5 ng/mL had a significantly higher mean FIM score than patients with values below the median. Authors suggest that, in patients that underwent rehabilitation treatment, suboptimal vitamin D should be evaluated by means of routine analysis, and should be corrected by supplementation [12].  
[PERSON] et al. [13] came to the same conclusions, reporting that high levels of 25(OH)D were associated with greater functional gain during the rehabilitation protocol treatment.  
A very recent multi-center study is the \"Safari study\", on a population of 420 Italian and Spanish older adults admitted to three geriatric rehabilitation unit, after orthopedic events or stroke (n= 138) [15]. Patients were divided in quartiles based on the 25(OH)D levels, and the outcomes of rehabilitation were: absolute functional gain (variation of Barthel index between discharge and admission) and ability to walk both 3 months after admission. A non-linear relationship between vitamin D and absolute functional gain was found, with a stronger association for 25(OH)D concentration \(<\)16 ng/mL. In particular, patients in the third quartile Q3 (serum 25(OH)D: 11.5-18.2 ng/mL) had the best absolute functional gain and ability to walk compared to patients in the first quartile Q1 (serum 25(OH)D: \(\leq\) 6 ng/mL). Authors suggested the importance of considering a non-linear relationship between 25(OH)D and functional outcomes; therefore, using linear models as a continuous variable may be not correct, as in the study of [PERSON] et al. [14].  
Finally a recent meta-analysis from [PERSON] et al. [74] reported malnutrition as an important risk factor for stroke that can influence the general status of patients during post-stroke rehabilitation, and the rehabilitation outcome. Stroke patients, in fact, undergo a long period of rehabilitation, in some cases for 1 year after the onset. Motor disability, cognitive impairment, psychological aspects and dysphagia contribute to a general status of malnutrition. Low vitamin D levels can be also due to reduced nutrition, influencing the outcome of rehabilitation and contributing to a poor recovery (Table 1).