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Biomedical subjects

G J Petot

Publications and source records attributed to G J Petot.

7 recordsLinked to original sources

Plasma total homocysteine levels, dietary vitamin B6 and folate intake in AD and healthy aging.

PURPOSE: To study the association between Alzheimer s disease (AD) and plasma total homocysteine (tHcy), dietary folate and vitamin B6. METHODS: 64 AD patients were matched by gender, age, and smoking status to 64 healthy controls. tHcy was determined using an automated immunoassay. Dietary patterns for three age periods (20-39, 40-59, and 60 + yrs) were assessed using a questionnaire adapted from the Block Health Habits and History Questionnaire. Respondents (cases by proxy) reported food frequencies, which were translated into estimated daily nutrient intakes. APOE genotype, cognitive performance (CDR, MMSE), blood lipids, and albumin were obtained for patients and controls. RESULTS: tHcy did not differ significantly between controls (11.5 +/- 3.7 mmol/L) and AD patients (12.3 +/- 4.3 mmol/L)(p=0.25). tHcy levels were not related in AD patients or controls to education, CDR, MMSE, blood lipids, albumin or ApoE genotype (p>0.15). There was a negative correlation between plasma tHcy and triglyceride levels in AD patients (p=0.023), but not in controls. AD patients consumed significantly less dietary vitamin B6 (p=0.05) and folate (p=0.001) after age 60 than controls. CONCLUSIONS: Although plasma tHcy levels were higher in cases than controls, this difference was not significant. tHcy levels were not related to cognitive status. Plasma tHcy was inversely correlated with triglyceride levels in AD patients but not in controls.

Adult↗

Patients with Alzheimer's disease have reduced activities in midlife compared with healthy control-group members.

The development of Alzheimer's disease (AD) later in life may be reflective of environmental factors operating over the course of a lifetime. Educational and occupational attainments have been found to be protective against the development of the disease but participation in activities has received little attention. In a case-control study, we collected questionnaire data about 26 nonoccupational activities from ages 20 to 60. Participants included 193 people with probable or possible AD and 358 healthy control-group members. Activity patterns for intellectual, passive, and physical activities were classified by using an adaptation of a published scale in terms of "diversity" (total number of activities), "intensity" (hours per month), and "percentage intensity" (percentage of total activity hours devoted to each activity category). The control group was more active during midlife than the case group was for all three activity categories, even after controlling for age, gender, income adequacy, and education. The odds ratio for AD in those performing less than the mean value of activities was 3.85 (95% confidence interval: 2.65-5.58, P < 0.001). The increase in time devoted to intellectual activities from early adulthood (20-39) to middle adulthood (40-60) was associated with a significant decrease in the probability of membership in the case group. We conclude that diversity of activities and intensity of intellectual activities were reduced in patients with AD as compared with the control group. These findings may be because inactivity is a risk factor for the disease or because inactivity is a reflection of very early subclinical effects of the disease, or both.

Activities of Daily Living↗

On the use of surrogate respondents for controls in a case-control study of Alzheimer's disease.

OBJECTIVE: To examine the presence and extent of bias introduced by using surrogate respondents for healthy controls in a case-control study of Alzheimer's disease (AD). DESIGN: Comparative study of matched responses to questionnaire ascertaining lifestyle issues. SETTING: University Hospitals/Case Western Reserve University Alzheimer Center. PARTICIPANTS: Controls (n = 50) were identified through the Research Registry. Surrogates (n = 50) were their healthy relatives or friends. MEASUREMENTS: Answers in the areas of demographic and occupational history, smoking habits, medical history, dietary intake, and leisure and work activities were recorded. The analysis was based on methods for paired data. Continuous variables were analyzed, focusing on paired differences between self and surrogate responses. RESULTS: For occupations and exposures, over 80% of the surrogates agreed with the subjects on over 80% of the questions. On smoking history, over 90% of the surrogates agreed with the subjects on over 70% of the questions. On leisure and work activities, over 70% of the surrogates agreed with the subjects on over 50% of the questions. There was less agreement regarding medical history. For continuous variables, most paired t-tests of zero mean difference between self and surrogate responses resulted in nonrejection of this hypothesis. Computed mean differences were not always positive or always negative. CONCLUSION: We did not find systematic under- or overreporting by the surrogates of the controls. Therefore, if there are biases in the responses of surrogates of the AD cases in our case-control study, they would not be canceled out by using surrogates for the controls.

Aged↗

An artificial intelligence system for computer-assisted menu planning.

Planning nutritious and appetizing menus is a complex task that researchers have tried to computerize since the early 1960s. We have attempted to facilitate computer-assisted menu planning by modeling the reasoning an expert dietitian uses to plan menus. Two independent expert systems were built, each designed to plan a daily menu meeting the nutrition needs and personal preferences of an individual client. One system modeled rule-based, or logical, reasoning, whereas the other modeled case-based, or experiential, reasoning. The 2 systems were evaluated and their strengths and weaknesses identified. A hybrid system was built, combining the best of both systems. The hybrid system represents an important step forward because it plans daily menus in accordance with a person's needs and preferences; the Reference Daily Intakes; the Dietary Guidelines for Americans; and accepted aesthetic standards for color, texture, temperature, taste, and variety. Additional work to expand the system's scope and to enhance the user interface will be needed to make it a practical tool. Our system framework could be applied to special-purpose menu planning for patients in medical settings or adapted for institutional use. We conclude that an artificial intelligence approach has practical use for computer-assisted menu planning.

Artificial Intelligence↗

Validity of portion-size measurement aids: a review.

A review of research studies that focus on the validity of portion-size measurement aids (PSMAs) was undertaken because guidelines for the use of PSMAs in studies of food intake have not been developed. Also, the accuracy of food quantity estimates may greatly influence the quality of dietary intake data. Generally, the review indicated that differences between the food quantity estimates obtained from different PSMAs were not statistically significant. Research on PSMA accuracy was lacking in several areas. Additional information is needed on the validity of PSMAs, particularly as it relates to PSMA use by different socio-demographic groups. Little research has focused on the specific effects that PSMAs have on quantity estimates or on subject perceptions of PSMA use. Improved reporting of PSMAs in the literature is also needed. Future research should be directed toward these issues so that PSMA guidelines can be developed. Until there is a more complete research base, it is not possible at this time to establish guidelines for use of PSMAs in clinical practice or in research settings.

Diet↗

Effects of educational attainment on the clinical expression of Alzheimer's disease: results from a research registry.

The "reserve" hypothesis suggests that education should affect the clinical expression of Alzheimer's disease (AD), but results from studies examining this idea are not consistent. In a single study, we evaluated the effects of educational attainment on three aspects of the clinical expression of AD: age at symptom onset, rate of cognitive decline, and survival. Subjects were 258 persons with mild- or moderate-stage Alzheimer's, drawn from our AD Research Registry. With statistical adjustment for confounding variables present in a clinic-based design, we found that higher educational attainment was associated with slightly earlier reports of symptom onset and a slower rate of cognitive decline on the Mini-Mental State Exam (MMSE). Education did not affect time of survival until death. We conclude that, for subjects in our sample, education had modest effects on aspects of the clinical expression of AD. These effects were not fully consistent with predictions derived from the "reserve" hypothesis.

Aged↗