Estimates of diet-disease relative risks (RRs) suffer from inaccuracies introduced by dietary measurement errors. Using the "method of triads," by which the validity coefficient (VC) of the dietary assessment method and "true" long-term intake could be estimated from 3 pairwise correlations between the FFQ, the reference method, and the biomarker, the authors evaluated the performance of a newly developed FFQ. Over a period of 13 mo (September 2000 to September 2001), 161 participants completed 3 FFQs and six 24-h recalls (24HRs), and supplied 2 blood samples and three 24-h urine collections. For protein, beta-carotene, and folic acid, the VCs of the FFQ with the "true intake" (0.77, 0.65, and 0.72, respectively) were relatively higher than the VCs of 24HRs (0.68, 0.60 and 0.39, respectively). Among the biomarkers, the VCs of serum beta-carotene and folic acid with the "true intake" (0.65 and 0.65) were higher than the VCs of urinary nitrogen and alpha-tocopherol (0.44 and 0.34, respectively). The DEARR study showed that the newly developed FFQ is a valid and reproducible instrument for assessing dietary intake. The VCs obtained can be used for future adjustment of diet-disease RR estimates in this population.
Background
Parkinson’s disease [PD] is a degenerative process affecting the striato nigral system [SN]. Its etiology, although obscure may involve oxidative damage. Selenium, an anti-oxidant, was shown to protect the SN in animal models. In the current study we investigate the association between plasma selenium concentrations and the presence of “soft” neurological signs related to the SN.
Methods
Plasma selenium concentration was assessed in participants age ≥65y in the InCHIANTI study, a population-based cohort study in Tuscany, Italy. PD was defined based on standard criteria. “Soft” neurological signs were ascertained by physical examination.
Results
A total of 1012 participants were included. No association was found between the presence of PD and plasma selenium. There was, however, a strong association between plasma selenium and timed performance-based assessments.
Conclusions
Lower levels of selenium were significantly associated with decreased performance in neurological tests of coordination among older adults. Prospective studies are needed to further investigate the effects of selenium on SN dysfunction.
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