Vitamin D status and impact of vitamin D3 and/or calcium supplementation in a randomized pilot study in the Southeastern United States.

Objective: Vitamin D supplementation may be required for certain subgroups in the United States in whom status and intake are inadequate, but the impact of various doses, and whether calcium administration jointly or independently influences vitamin D metabolite levels, is unclear.

Methods: In a pilot chemoprevention trial of biomarkers of risk for colorectal adenoma, we measured the impact of vitamin D supplementation and/or calcium supplementation on plasma vitamin D metabolite concentrations. Ninety-two adult men and women living in the southeastern United States were randomized to 800 IU vitamin D(3), 2000 mg elemental calcium, both, or placebo daily for 6 months.

Allelic variation of a functional polymorphism in the serotonin transporter gene and depression in Parkinson's disease.

A genetic susceptibility to depression in PD, acting via the serotonergic system, has been suggested. We examined the influence of allelic variation (L/S) in a functional polymorphism in the serotonin transporter (5-HTTLPR) gene upon mood in 108 PD patients and 82 controls. Using a logistic regression model we found no evidence for an association between 5-HTTLPR genotypes, or the presence of the S allele, and depression.

Mitochondrial DNA haplogroup cluster UKJT reduces the risk of PD.

There is increasing evidence that genetic variants of mitochondrial DNA have an important role in the cause of idiopathic Parkinson's disease. We determined the mitochondrial DNA haplogroup of 455 Parkinson's disease cases, 185 Alzheimer's disease cases, and 447 healthy English control subjects. The UKJT haplogroup cluster was associated with a 22% reduction in population-attributable risk for Parkinson's disease.