饮食中添加抗氧化剂与年龄相关性黄斑变性患病风险的关系

背景:发达国家中,年龄相关性黄斑变性(AM D)是导致不可逆盲的最主要原因。近期研究发现,添加高剂量的β-胡萝卜素,维生素C、维生素E以及锌均可延缓AM D的进展。目的:研究日常摄入抗氧化剂能否减少罹患AM D的风险。设计:基于鹿特丹郊区中产阶级聚集区所有55岁以上的居民人群的研     

Dietary intake of antioxidant nutrients and the risk of incident Alzheimer disease in a biracial community study

Context  Oxidative processes have been suggested as elements in the development of Alzheimer disease (AD), but whether dietary intake of vitamin E and other antioxidant nutrients prevents its development is unknown. Objective  To examine whether intake of antioxidant nutrients, vitamin E, vitamin C, and beta carotene is associated with incident AD. Design, Setting, and Participants  Prospective study, conducted from 1993 to 2000, of individuals selected in a stratified random sample of community-dwelling residents. The 815 residents 65 years and older were free of AD at baseline and were followed up for a mean of 3.9 years. They completed food frequency questionnaires an average of 1.7 years after baseline. Main Outcome Measure  Incident AD diagnosed in clinical evaluations with standardized criteria. Results  Increasing vitamin E intake from foods was associated with decreased risk of developing AD after adjustment for age, education, sex, race, APOE 4, and length of follow-up. Relative risks (95% confidence intervals [CIs]) from lowest to highest quintiles of intake were 1.00, 0.71 (0.24-2.07), 0.62 (0.26-1.45), 0.71 (0.27-1.88), and 0.30 (0.10-0.92) (P for trend = .05). The protective association of vitamin E was observed only among persons who were APOE 4 negative. Adjustment for other dietary factors reduced the protective association. After adjustment for baseline memory score, the risk was 0.36 (95% CI, 0.11-1.17). Intake of vitamin C, beta carotene, and vitamin E from supplements was not significantly associated with risk of AD. Conclusion  This study suggests that vitamin E from food, but not other antioxidants, may be associated with a reduced risk of AD. Unexpectedly, this association was observed only among individuals without the APOE 4 allele.      

Dietary sodium intake and subsequent risk of cardiovascular disease in overweight adults

CONTEXT: Dietary sodium is positively associated with blood pressure, and ecological and animal studies both have suggested that high dietary sodium intake increases stroke mortality. OBJECTIVE: To examine the risk of cardiovascular disease associated with dietary sodium intake in overweight and nonoverweight persons. DESIGN: Prospective cohort study. SETTING: The first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study, conducted in 1982-1984, 1986, 1987, and 1992. PARTICIPANTS: Of those aged 25 to 74 years when the survey was conducted in 1971 -1975 (14407 participants), a total of 2688 overweight and 6797 nonoverweight persons were included in the analysis. MAIN OUTCOME MEASURES: Dietary sodium and energy intake were estimated at baseline using a single 24-hour dietary recall method. Incidence and mortality data for cardiovascular disease were obtained from medical records and death certificates. RESULTS: For overweight and nonoverweight persons, over an average of 19 years of follow-up, the total number of documented cases were as follows: 680 stroke events (210 fatal), 1727 coronary heart disease events (614 fatal), 895 cardiovascular disease deaths, and 2486 deaths from all causes. Among overweight persons with an average energy intake of 7452 kJ, a 100 mmol higher sodium intake was associated with a 32% increase (relative risk [RR], 1.32; 95% confidence interval [CI], 1.07-1.64; P = .01) in stroke incidence, 89% increase (RR, 1.89; 95% CI, 1.31-2.74; P<.001) in stroke mortality, 44% increase (RR, 1.44; 95% CI, 1.14-1.81; P = .002) in coronary heart disease mortality, 61% increase (RR, 1.61; 95% CI, 1.32-1.96; P<.001) in cardiovascular disease mortality, and 39% increase (RR, 1.39; 95% CI, 1.23-1.58; P<.001) in mortality from all causes. Dietary sodium intake was not significantly associated with cardiovascular disease risk in nonoverweight persons. CONCLUSIONS: Our analysis indicates that high sodium intake is strongly and independently associated with an increased risk of cardiovascular disease and all-cause mortality in overweight persons.     

Participation in cognitively stimulating activities and risk of incident Alzheimer disease

Context  Frequent participation in cognitively stimulating activities has been hypothesized to reduce risk of Alzheimer disease (AD), but prospective data regarding an association are lacking. Objective  To test the hypothesis that frequent participation in cognitive activities is associated with a reduced risk of AD. Design  Longitudinal cohort study with baseline evaluations performed between January 1994 and July 2001 and mean follow-up of 4.5 years. Participants and Setting  A total of 801 older Catholic nuns, priests, and brothers without dementia at enrollment, recruited from 40 groups across the United States. At baseline, they rated frequency of participation in common cognitive activities (eg, reading a newspaper), from which a previously validated composite measure of cognitive activity frequency was derived. Main Outcome Measures  Clinical diagnosis of AD by a board-certified neurologist using National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria and change in global and specific measures of cognitive function, compared by cognitive activity score at baseline. Results  Baseline scores on the composite measure of cognitive activity ranged from 1.57 to 4.71 (mean, 3.57; SD, 0.55), with higher scores indicating more frequent activity. During an average of 4.5 years of follow-up, 111 persons developed AD. In a proportional hazards model that controlled for age, sex, and education, a 1-point increase in cognitive activity score was associated with a 33% reduction in risk of AD (hazard ratio, 0.67; 95% confidence interval, 0.49-0.92). Results were comparable when persons with memory impairment at baseline were excluded and when terms for the apolipoprotein E 4 allele and other medical conditions were added. In random-effects models that controlled for age, sex, education, and baseline level of cognitive function, a 1-point increase in cognitive activity was associated with reduced decline in global cognition (by 47%), working memory (by 60%), and perceptual speed (by 30%). Conclusion  These results suggest that frequent participation in cognitively stimulating activities is associated with reduced risk of AD.      

Current Alzheimer disease research highlights: evidence for novel risk factors

Alzheimer disease (AD) is the most common type of dementia characterized by the progressive cognitive and social decline. Clinical drug targets have heavily focused on the amyloid hypothesis, with amyloid beta (Aβ), and tau proteins as key pathophysiologic markers of AD. However, no effective treatment has been developed so far, which prompts researchers to focus on other aspects of AD beyond Aβ, and tau proteins. Additionally, there is a mounting epidemiologic evidence that various environmental factors influence the development of dementia and that dementia etiology is likely heterogenous. In the past decades, new risk factors or potential etiologies have been widely studied. Here, we review several novel epidemiologic and clinical research developments that focus on sleep, hypoxia, diet, gut microbiota, and hearing impairment and their links to AD published in recent years. At the frontiers of AD research, these findings and updates could be worthy of further attention.     

Dietary fiber intake and risk of colorectal cancer: a pooled analysis of prospective cohort studies

Context  Inconsistent findings from observational studies have continued the controversy over the effects of dietary fiber on colorectal cancer. Objective  To evaluate the association between dietary fiber intake and risk of colorectal cancer. Design, Setting, and Participants  From 13 prospective cohort studies included in the Pooling Project of Prospective Studies of Diet and Cancer, 725 628 men and women were followed up for 6 to 20 years across studies. Study- and sex-specific relative risks (RRs) were estimated with the Cox proportional hazards model and were subsequently pooled using a random-effects model. Main Outcome Measure  Incident colorectal cancer. Results  During 6 to 20 years of follow-up across studies, 8081 colorectal cancer cases were identified. For comparison of the highest vs lowest study- and sex-specific quintile of dietary fiber intake, a significant inverse association was found in the age-adjusted model (pooled RR = 0.84; 95% confidence interval [CI], 0.77-0.92). However, the association was attenuated and no longer statistically significant after adjusting for other risk factors (pooled multivariate RR = 0.94; 95% CI, 0.86-1.03). In categorical analyses compared with dietary fiber intake of 10 to <15 g/d, the pooled multivariate RR was 1.18 (95% CI, 1.05-1.31) for less than 10 g/d (11% of the overall study population); and RR, 1.00 (95% CI, 0.85-1.17) for 30 or more g/d. Fiber intake from cereals, fruits, and vegetables was not associated with risk of colorectal cancer. The pooled multivariate RRs comparing the highest vs lowest study- and sex-specific quintile of dietary fiber intake were 1.00 (95% CI, 0.90-1.11) for colon cancer and 0.85 (95% CI, 0.72-1.01) for rectal cancer (P for common effects by tumor site = .07). Conclusions  In this large pooled analysis, dietary fiber intake was inversely associated with risk of colorectal cancer in age-adjusted analyses. However, after accounting for other dietary risk factors, high dietary fiber intake was not associated with a reduced risk of colorectal cancer.      

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.