Interestingly, among the poststroke patients 56.0% of those with 25(OH)D < 50 nmol/L had SHPT, whereas in the nonstroke group elevated PTH was observed only in 36.0% of subjects with vitamin D insufficiency (P = 0.007, χ2 test), indicating that in the former group in addition to low vitamin D levels other mechanisms contribute to the excess of PTH. This evidence concerns the gene PTH and vitamin D deficiency.