The effect of vitamin D on neurocognitive functions in older vitamin D deficient adults: a pilot longitudinal interventional study.

BACKGROUND: The relationship between vitamin D and cognitive status remains controversial. We aimed to evaluate the effect of vitamin D replacement on cognitive functions in healthy and cognitively intact vitamin D deficient older females. METHODS: This study was designed as a prospective interventional study. A total of 30 female adults aged ≥60 with a serum 25 (OH) vitamin D level of <10 ng/ml were included. Participants were administered 50 000 IU vitamin D3 weekly for 8 weeks followed by a maintenance therapy of 1000 U/day. Detailed neuropsychological assessment was performed prior to vitamin D replacement and repeated at 6 months by the same psychologist. RESULTS: Mean age was 63 ± 6.7 years and baseline vitamin D level was 7.8 ± 2.0 (range: 3.5-10.3) ng/ml. At 6 months, vitamin D level was 32.5 ± 3.4 (32.2-55) ng/ml. The Judgement of Line Orientation Test (P = 0.04), inaccurate word memorizing of the Verbal Memory Processes Test (P = 0.02), perseveration scores of the Verbal Memory Processes Test (P = 0.005), topographical accuracy of the Warrington Recognition Memory Test (P = 0.002), and the spontaneous self-correction of an error in the Boston Naming Test (P = 0.003) scores increased significantly, while the delayed recall score in the Verbal Memory Processes Test (P = 0.03), incorrect naming of words in the Boston Naming Test (P = 0.04), interference time of the Stroop Test (P = 0.05), and spontaneous corrections of the Stroop Test (P = 0.02) scores decreased significantly from baseline. CONCLUSION: Vitamin D replacement has a positive effect on cognitive domains related to visuospatial, executive, and memory processing functions.

Evaluation of paraoxonase 1 polymorphisms in patients with bipolar disorder.

AIM: Bipolar disorder (BD) has a complex genetic etiology, with multiple unidentified genes and environmental factors playing important roles in its pathogenesis. A growing body of evidence suggests that reactive oxygen species (ROS) may be crucially involved in the pathogenesis of psychiatric diseases, including BD. The association between paraoxonase 1 (PON1), an important antioxidant enzyme, and development of BD has been scarcely investigated. We thus attempted to examine genetic variants in the PON1 gene, a putative BD susceptibility gene, in patients with bipolar disease and their first-degree relatives. MATERIALS AND METHODS: The study population consisted of 292 healthy individuals, 199 patients with BD, and 280 unaffected first-degree relatives of the patients. Genotyping of PON1 L55M and Q192R polymorphisms was performed by polymerase chain reaction and restriction enzyme digestion. RESULTS: Patients mostly shared the same PON1 genotypes with their first-degree relatives. The frequency of MM genotype of PON1 L55M polymorphism was lower and that of LM genotype was higher in patients and relatives than healthy controls. PON1 enzyme activities did not differ between patient, relative and healthy control groups but were influenced by PON1 genotype. CONCLUSION: Our findings indicate an association between the genetic variants of PON1 and BD. The PON1 L55M MM genotype seems to be protective against the development of BD.