Table 2. Serum 25-hydroxyvitamin D concentrations in healthy subjects, individuals with mild cognitive impairment, Alzheimer’s disease, individuals with mild cognitive impairment after the follow-up examination, and individuals with mild cognitive impairment who progressed to Alzheimer’s disease after the follow-up examination.

Values are given as numbers and percentage in brackets or mean ± standard deviation, 25(OH)D: 25-hydroxyvitamin D, HS: healthy subjects, MCI: individuals with mild cognitive impairment, AD: individuals with Alzheimer’s disease, remained MCI: individuals with mild cognitive impairment after the follow-up examination, MCI to AD: individuals with mild cognitive impairment who progressed to Alzheimer’s disease after the follow-up examination, 95 CI: 95 % confidence interval, aOR: adjusted odds ratio for age, season of blood collection, educational status, sex, body mass index (BMI) and the presence of vascular risk factors included hypertension or/and diabetes.