T136. DO VITAMIN D SUPPLEMENTATION DURING THE FIRST YEAR OF LIFE PREDICT COGNITION IN PSYCHOSES DURING MIDLIFE?

Abstract

Background: Schizophrenia (SCZ) has been associated with cognitive impairment. The lack of vitamin D was associated with over 2-fold risk for mild cognitive impairment, and vitamin D could also associate with cognitive performance which may be explained by the role of vitamin D in the development of central nervous system or in neuroprotection. Vitamin D supplementation during the first year of life has been associated with a reduced risk of SCZ in males within the Northern Finland Birth Cohort 1966(NFBC 1966), but no studies have examined it's possible association with cognition in SCZ during midlife. The aim of this study was to examine the association of vitamin D supplementation during the first year of life with the cognition at the age of 43 years separately among those having psychosis and among non-psychotic controls in prospective NFBC 1966. Methods: The study is based on the NFBC 1966 concerning 12.058 liveborn children in 1966 in Northern Finland. The final study population of this study (N= 257) consisted of 60 persons with schizophrenia spectrum disorder (SSD) and of 26 individuals with non-schizophrenic psychoses (NSSD) while 171 non-psychotic participants formed the reference group. The daily dose of vitamin D was calculated based on the concentration of vitamin D in the product used and the reported amount of the product consumed. At the time when cohort was born, the recommended dose of vitamin D was 2000 IU/day. Based on maternal interviews in the year after birth, two measures of vitamin D supplementation were available: (a) frequency of intake (coded as regularly or irregularly/none) and (b) dose of vitamin D (1600 IU/day, 1601-2000 IU/day, or 2000 IU/day. The following tests were performed at the age of 43 years: California Verbal Learning Test (CVLT), Abstraction Inhibition and Working Memory Task (AIM), Visual Object Learning Test (VOLT), Vocabulary (WAIS-III), Visual Series (WMS-III), Digit Span (WAIS-III), Grooved Pegboard, Matrix Reasoning and Verbal Fluency. Results: The study population (N= 2579 included 60 subjects with SSD, 26 persons had NSSD, and 171 non-psychotic controls formed the reference group. There were more men among those having psychosis (52.3% vs. 47.7%, respectively while the control group had more women (49.7 vs. 50.3, respectively). Only 13.2% of participants in the entire study population had received vitamin D supplementation irregularly or not at all. On the other hand, 5.1% had taken vitamin D supplementation more than the recommended dose. Because the number of those who got vitamin supplementation under recommended dose (2000IU/day) was not more than 3 persons (1.2% of the whole study population), the association of the dose vitamin D supplements with later cognition was not analyzed. Therefore, the frequency of vitamin D supplementation (coded as regular or irregular/none) was utilized in final analyses. The frequency of vitamin D supplementation was not associated with cognition in midlife either among those having psychosis or in the control group (p-values for global cognitive performance in psychoses and controls were 0.89 and 0.61, respectively). Discussion: The main finding of this study was that no association was found between the frequency of vitamin D supplementation during first year of life and cognition in midlife either among those having psychosis or in the control group. The only earlier study (N=9.114) evaluating a link between the use of nutritional supplements during early life and risk of SCZ was carried out in NFBC 1966. In males, the use of either irregular or regular vitamin D supplements was associated with a reduced risk of SCZ compared with no supplementation.