In multivariate analysis models, adjusted for age, sex, infarct volume, BMI, NIHSS score, season of samples included, time from onset to blood collection, stroke syndrome, stroke etiology, treatment, vascular risk factors and blood levels of cholesterol, HDL, HCY, FBG, CRP, PTH, and calcium, vitamin D deficiency was associated with poor functional outcomes, and the risk increased by 200% (OR: 3.0; 95% CI: 1.6–4.1, P<0.001). Here, PTH is linked to vitamin D deficiency.