The purpose of this study was to examine the Geriatric Depression Scale (GDS) translated into Turkish for its reliability, discriminant validity, and factor structure in a sample of 276 community-dwelling elderly and 30 patients with major depression. One item (Item 5) was discovered to have conceptual difficulty for Turkish elderly and was transformed to negative form. Item 2 was transformed to positive form to keep the number of positive and negative items equal to that in the original GDS. A reasonable time stability with 1-week interval (r:.74) and a high level of internal consistency (α = .91) were observed. Student's t test resulted in a significant discriminant validity for the scale total score. Factor study with principal component analysis and varimax rotation gave rise to a structure with seven factors. Results of the same analysis with two factors were found to be easier to interpret. The first factor was composed of 19 items reflecting “depressive affect and thought content.” The other 11 items representing “decrease in motivation and cognitive functions” loaded in the second factor. In conclusion, the Turkish GDS was found to have reasonable time reliability, high internal consistency, and discriminant validity for Turkish elderly. Its two-factor structure can be used as an informative instrument for epidemiological studies, reflecting two main dimensions of depression in the elderly.

Vitamin D 3 is known to be involved in neuroprotection and exert its neuroprotective effects by modulating neuronal calcium homeostasis and production of neurotrophins. The single nucleotide polymorphisms (SNP) in vitamin D receptor (VDR) gene which can influence the affinity of vitamin D 3 to its receptor may be related to neurodegenerative diseases and neuronal damage by altering the vitamin D-mediated pathways. In this study, our aim was to determine whether there is an association between VDR gene and lateonset Alzheimer's disease (AD) in order to see if vitamin D contributes to AD or not. One hundred and four cases of dementia of Alzheimer type and 109 age-matched controls were genotyped according to ApaI (a: + restriction site and A: no restriction site) and TaqI (t: + restriction site and T: no restriction site) sites in intron 8 and exon 9 of the ligand-binding site of VDR gene. When the controls and patients were compared for their ApaI genotypes, the frequency of the patients with Aa genotype was significantly higher than the frequency of the healthy individuals with the same genotype ( p = 0.008, χ 2 = 9.577, OR = 2.30). Thus, the "Aa" genotype may increase the risk of developing AD 2.3 times when compared with the "AA" genotype. On the other hand, the "AT" haplotype was significantly higher in controls ( p = 0.006) indicating a protective role of the "AT" haplotype in AD. Consequently, this study provides evidence for a possible link between AD and vitamin D. vitamin D; VDR; Alzheimer's disease; SNP; haplotype © 2007 Tohoku University Medical PressThe most common form of degenerative dementia is Alzheimer's disease (AD) constituting approximately 60-70% of cases (Emilien et al. 2004). It is a chronic, degenerative, dementing illness with typically insidious onset (Rocca et al. 1991). The key aims in therapeutic strategies of AD are to decrease the neuronal damage, provide maintenance or regeneration of neu r o n s

The objective of this study was to investigate reliability and validity of the self rated 30 item Geriatric Depression Scale (GDS) in screening and diagnosis of depression in Parkinson's disease (PD). The study sample comprised 109 non-demented patients with PD admitted to the movement disorders outpatient unit. The reference diagnosis of depression was made according to DSM-IV criteria. Discriminant validity and internal consistency of the total scale were studied. Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated for different cutoff scores. Receiver operating characteristics (ROC) analysis was also carried out. The sample comprised 56 patients with and 53 without depression. In the discriminant validity analysis, the mean total GDS score of subjects with depression was significantly higher compared with those without depression. The Cronbach's a score was 0.92 and the split half correlation coefficient 0.91. The cutoff score of 13/14 provided the highest sum of sensitivity and specificity level. The sensitivity of this cutoff score was 0.78 and specificity 0.85, while PPV was 0.84 and NPV 0.79. The area under the curve value in the ROC analysis was 0.891. Sensitivity and specificity analysis showed that cutoff scores of 8/9 or 9/10 could be useful for screening and 14/15 or 15/16 for diagnostic purposes. This study showed that the 30 item GDS, with its high discriminant validity, internal consistency, and reasonably clear cutoff scores, could be a useful screening or diagnostic self rated depression scale in patients with PD.

Vitamin D 3 is a neurosteroid that mediates its effects via the vitamin D receptor (VDR). The VDR gene is located on chromosome 12q13 and consists of 9 exons. VDR contains the DNA-binding site encoded by exons 2 and 3 and the ligand-binding site encoded by exons 4 -9. Our earlier study showed that the ApaI polymorphic site of the VDR gene is associated with late-onset Alzheimer's disease (AD). Here, we investigated the association between additional polymorphisms of the VDR gene and AD using the same samples. Two single nucleotide polymorphisms (SNPs) in intron 8 (BsmI and Tru9I polymorphisms) and one in exon 2 (FokI polymorphism) of the VDR gene were examined in up to 108 AD patients and 115 age-matched controls. Genotypes were determined with polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. Haplotype analysis also included the previously studied polymorphic sites that were recognized by TaqI (in exon 9) and ApaI (in intron 8) restriction enzymes. There was no significant difference between AD patients and controls when their genotypes for BsmI, Tru9I and FokI polymorphic sites were compared. However, the frequency of "TaubF" haplotype (alleles of TaqI, ApaI, Tru9I, BsmI and FokI, respectively), which was determined by analyzing 5 polymorphisms together, was significantly higher in the AD patient group, suggesting that this haplotype is a risk factor in AD. Our results point out a possible link between AD and certain VDR polymorphisms and indicate that individuals with these polymorphisms might be vulnerable to AD.