Phytoestrogen consumption and risk for cognitive decline and dementia: With consideration of thyroid status and other possible mediators.

It is predicted that around 20% of the worlds population will be age 60 or above by 2050. Prevalence of cognitive decline and dementia is high in older adults and modifiable dietary factors may be able to reduce risk for these conditions. Phytoestrogens are bioactive plant chemicals found in soy, which have a similarity in structure to natural estradiol (the most abundant circulating estrogen). This structural likeness enables phytoestrogens to interact with estrogen receptors in the brain, potentially affecting cognition. However, findings in this domain are largely inconsistent, with approximately 50% of studies showing positive effects of phytoestrogens on cognition and the other half resulting in null/negative findings. This paper provides an updated review of the relationship between consumption of phytoestrogens and risk for cognitive decline and/or dementia. In particular, possible mediators were identified to explain discrepant findings and for consideration in future research. A case can be made for a link between phytoestrogen consumption, thyroid status and cognition in older age, although current findings in this area are very limited. Evidence suggests that inter-individual variants that can affect phytoestrogen bioavailability (and thus cognitive outcome) include age and ability to breakdown ingested phytoestrogens into their bioactive metabolites. Factors of the study design that must be taken into account are type of soy product, dosage, frequency of dietary intake and type of cognitive test used. Guidelines regarding optimal phytoestrogen dosage and frequency of intake are yet to be determined.

Association of coffee and caffeine intake with the risk of Parkinson disease.

CONTEXT: The projected expansion in the next several decades of the elderly population at highest risk for Parkinson disease (PD) makes identification of factors that promote or prevent the disease an important goal. OBJECTIVE: To explore the association of coffee and dietary caffeine intake with risk of PD. DESIGN, SETTING, AND PARTICIPANTS: Data were analyzed from 30 years of follow-up of 8004 Japanese-American men (aged 45-68 years) enrolled in the prospective longitudinal Honolulu Heart Program between 1965 and 1968. MAIN OUTCOME MEASURE: Incident PD, by amount of coffee intake (measured at study enrollment and 6-year follow-up) and by total dietary caffeine intake (measured at enrollment). RESULTS: During follow-up, 102 men were identified as having PD. Age-adjusted incidence of PD declined consistently with increased amounts of coffee intake, from 10.4 per 10,000 person-years in men who drank no coffee to 1.9 per 10,000 person-years in men who drank at least 28 oz/d (P<.001 for trend). Similar relationships were observed with total caffeine intake (P<.001 for trend) and caffeine from non-coffee sources (P=.03 for trend). Consumption of increasing amounts of coffee was also associated with lower risk of PD in men who were never, past, and current smokers at baseline (P=.049, P=.22, and P=.02, respectively, for trend). Other nutrients in coffee, including niacin, were unrelated to PD incidence. The relationship between caffeine and PD was unaltered by intake of milk and sugar. CONCLUSIONS: Our findings indicate that higher coffee and caffeine intake is associated with a significantly lower incidence of PD. This effect appears to be independent of smoking. The data suggest that the mechanism is related to caffeine intake and not to other nutrients contained in coffee. JAMA. 2000;283:2674-2679.

Association of vitamin E and C supplement use with cognitive function and dementia in elderly men.

OBJECTIVE: To determine whether use of vitamin E and C supplements protects against subsequent development of dementia and poor cognitive functioning. METHODS: The Honolulu-Asia Aging Study is a longitudinal study of Japanese-American men living in Hawaii. Data for this study were obtained from a subsample of the cohort interviewed in 1982, and from the entire cohort from a mailed questionnaire in 1988 and the dementia prevalence survey in 1991 to 1993. The subjects included 3,385 men, age 71 to 93 years, whose use of vitamin E and C supplements had been ascertained previously. Cognitive performance was assessed with the Cognitive Abilities Screening Instrument, and subjects were stratified into four groups: low, low normal, mid normal, and high normal. For the dementia analyses, subjects were divided into five mutually exclusive groups: AD (n = 47), vascular dementia (n = 35), mixed/other types of dementia (n = 50), low cognitive test scorers without diagnosed dementia (n = 254), and cognitively intact (n = 2,999; reference). RESULTS: In a multivariate model controlling for other factors, a significant protective effect was found for vascular dementia in men who had reported taking both vitamin E and C supplements in 1988 (odds ratio [OR], 0.12; 95% CI, 0.02 to 0.88). They were also protected against mixed/other dementia (OR, 0.31; 95% CI, 0.11 to 0.89). No protective effect was found for Alzheimer's dementia (OR, 1.81; 95% CI, 0.91 to 3.62). Among those without dementia, use of either vitamin E or C supplements alone in 1988 was associated significantly with better cognitive test performance at the 1991 to 1993 examination (OR, 1.25; 95% CI, 1.04 to 1.50), and use of both vitamin E and C together had borderline significance (OR, 1.18; 95% CI, 0.995 to 1.39). CONCLUSIONS: These results suggest that vitamin E and C supplements may protect against vascular dementia and may improve cognitive function in late life.

Characterization of risk factors for vascular dementia: the Honolulu-Asia Aging Study.

BACKGROUND: The Honolulu Heart Program (HHP) is a prospective study of heart disease and stroke that has accumulated risk factor data on a cohort of 8,006 Japanese American men since the study began in 1965. A recent examination of the cohort identified all patients with vascular dementia (VaD) using the criteria of the California Alzheimer's Disease Diagnostic and Treatment Center. OBJECTIVE: To characterize patients with VaD by stroke subtype and to investigate risk factors for VaD in a cohort of Japanese American men, aged 71 to 93, living in Hawaii and participating in the HHP. METHODS: Sixty-eight men with VaD were compared with 3,335 men without dementia or stroke (NSND). Men with VaD were also compared with 106 men with stroke who were not demented (SND). Candidate risk factors were measured prospectively. RESULTS: Of the 68 men with VaD there were 34 (50%) whose VaD was attributed to small vessel infarcts, 16 (23%) whose VaD was related to large vessel infarcts, and 11 (16%) with both large and small vessel infarcts. The remainder could not be classified. In a multivariate logistic regression model for VaD compared with NSND containing variables found to be associated with VaD in a univariate analysis, age (odds ratio [OR] 1.19, 95% confidence interval [CI] 1.13 to 1.27), coronary heart disease (OR 2.50, 95% CI 1.35 to 4.62), and 1-hour postprandial glucose (OR 1.41, 95% CI 1.06 to 1.88) remained significantly predictive of VaD, whereas preference for a Western diet (OR 0.54, 95% CI 0.30 to 0.98) as opposed to an Oriental or mixed diet and use of supplementary vitamin E (OR 0.32, 95% CI 0.12 to 0.82) were protective. A similar model for the comparison of men with VaD and SND revealed age (OR 1.24, 95% CI 1.14 to 1.35) was predictive of VaD, whereas preference for a Western diet (OR 0.43, 95% CI 0.22 to 0.86) was protective. CONCLUSIONS: The most common stroke subtype associated with VaD was lacunar stroke. Age and traditional vascular risk factors are important contributors to the development of VaD in late life. The antioxidant vitamin E and presently unknown factors related to a Western diet as opposed to an Oriental diet may be protective against developing VaD.

Case-control study of idiopathic Parkinson's disease and dietary vitamin E intake.

A nested case-control study of 84 incident cases of patients with idiopathic Parkinson's disease (PD) detected by June 30, 1994 and 336 age-matched control subjects, compared previously-documented intake of total dietary vitamin E and of selected vitamin E-containing foods. All study subjects had been followed for 27 to 30 years after diet recording in the 8,006-man Honolulu Heart Study cohort. We determined PD outcomes by periodic cohort re-examination and neurologic testing, private physician reports, examination of O'ahu neurologists' office records, and continual death certificate and hospital discharge diagnosis surveillance. Data on vitamin E intake, obtained from three dietary data sets at the time of cohort enrollment (1965 to 1968), included a food-frequency questionnaire and a 24-hour photograph-assisted dietary recall administered by trained dietitians. Although absence of PD was significantly associated with prior consumption of legumes (adjusted OR = 0.27, 95% CI 0.09 to 0.78), a dietary variable preselected for high vitamin E content, neither food categories nor quartiles nor continuous variables of vitamin E consumption were significantly associated with PD occurrence. Though consistent with prior reports of PD protection afforded by legumes, and with speculation on the possible benefits of dietary or supplemental vitamin E in preventing PD, these preliminary data do not conclusively document a beneficial effect of dietary vitamin E on PD occurrence.

Response of bovine alveolar macrophages in vitro to welding fume particles.

Alveolar macrophages (AM) from bovine lungs were exposed in culture to manual metal are (MMA) welding fume particles, chromium (Cr), UICC chrysotile A or anatase for 17-20 hr. All the welding particle samples were more cytotoxic to AM than to anatase. Particles from the welding of mild steel with a rutile-coated electrode were less cytotoxic than those produced with a basic-coated electrode. Particles from the welding of stainless steel were slightly more cytotoxic, and much of this activity was probably due to CrVI. Selective release of N-acetyl-beta-glucosaminidase (beta-NAG) was only detected after exposure of AM to chrysotile. Supplementation of the incubation medium with 10% serum increased the viability of all exposed AM cultures, an effect not produced by serum albumin alone. Incubation of particle samples with dipalmitoyl phosphatidylcholine (DPPC) prior to addition to AM reduced the cytotoxicity of the "rutile" welding particles and of chrysotile.