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Biomedical subjects

R D Abbott

Publications and source records attributed to R D Abbott.

143 records · Page 8Linked to original sources
PubMedDate not supplied

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.

Aged↗
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On the use of the logistic model in prospective studies.

We describe the usual statistical concepts and consequent appropriate simulations of a prospective study for the simple case of a single risk variable and an assumed logistic model. We examine the simulations of Lilienfeld and Pyne, and show that they are seriously flawed. Contrary to those authors' claims, the estimates of parameters by the Walker-Duncan technique are both accurate and reliable.

Biometry↗
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Sensitivity and reproducibility of the dual-mode actigraph under controlled levels of activity intensity.

The purpose of this study was to test the sensitivity and reproducibility of dual-mode actigraphy as an objective measure of functional performance in healthy adults under controlled levels of activity intensity. Twenty subjects wore the instrument on the nondominant wrist while performing standardized tasks selected to represent day-to-day activities at three levels of intensity (five tasks in each level): light (1-2 metabolic equivalents), moderate (3-4 metabolic equivalents), and heavy (4-6 metabolic equivalents). Upon completion of each intensity level, subjects were asked to rate their level of exertion using Borg's 15-point rating of perceived exertion (RPE) scale. Eighteen subjects repeated the protocol within 7 days. Zero-crossing and time-above-threshold modes successfully differentiated between light and moderate and between light and heavy activity. Reproducibility correlation coefficients (rs) across activity levels were .80 and .66 for the two modes, respectively. Results suggest dual-mode actigraphy may be useful for the study of performance variation and structure in healthy and chronically ill individuals.

Adult↗
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Joint distribution of lipoprotein cholesterol classes. The Framingham study.

During the period 1971 to 1975, the cholesterol content of lipoprotein density classes were measured in 2415 male and female Framingham Heart Study participants and 4342 of their offspring and offspring spouses who were free of coronary heart disease. In this first of three papers, the univariate and bivariate distributions of high density lipoprotein cholesterol, low density lipoprotein cholesterol, and very low density lipoprotein cholesterol are presented. There are differences in the levels of lipoprotein cholesterols by age, gender, and use of hormone preparations. The bivariate cross-tabulations of the three pairs of lipoprotein cholesterol measurements exhibit properties that cannot be appreciated from univariate summary statistics and suggest the importance of joint consideration of different lipoprotein cholesterol patterns for assessing the risk of coronary heart disease.

Adolescent↗
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Factors associated with lipoprotein cholesterol levels. The Framingham study.

Lipoprotein cholesterol determinations in 6328 individuals aged 20 to 79 years in the Framingham Heart Study Cohort and Offspring were related by multiple regression analysis to reported cigarette smoking, alcohol intake, and Quetelet Index (wt/ht2). Cigarette smoking was found to be strongly associated with "atherogenic" lipoprotein cholesterol profiles in young adults, and particularly in women. The associations for alcohol intake were mostly uniform across age groups and lipoprotein cholesterol fractions, while coefficients for Quetelet Index varied considerably. Blood chemistry associations were studied in participants under 50 years, after controlling for smoking, Quetelet Index, and alcohol intake. Significant associations for high density lipoprotein cholesterol (HDL-C) were seen for both sexes with alkaline phosphatase, serum calcium, serum u ric acid, and leucocyte count. Low density lipoprotein cholesterol (LDL-C) associations were observed with calcium, hematocrit, lactate dehydrogenase, and leucocyte count in men and women, while very low density lipoprotein cholesterol (VLDL-C) associations occurred with alkaline phosphatase, glucose, uric acid, and leucocyte count in both sexes. A 1 mg/dl higher calcium corresponded to an HDL-C approximately 4 mg/dl greater and a LDL-C typically 6 mg/dl greater after controlling for 12 other variables. A 1000/ml increase in leucocyte count was typically associated with a decrease in HDL-C by 1 mg/dl and an increase in LDL-C and VLDL-C of 1 mg/dl each.

Adult↗
PubMedDate not supplied

High density lipoprotein cholesterol, total cholesterol screening, and myocardial infarction. The Framingham Study.

The relation between high density lipoprotein cholesterol (HDL-C) and the development of myocardial infarction was examined in 2425 subjects, aged 50 to 79 years, who were enrolled in the Framingham Study from 1969 to 1971. After 12 years of follow-up, men in the bottom three quartiles of HDL-C (less than or equal to 52 mg/dl) experienced a 60% to 70% excess of myocardial infarction as compared to men whose HDL-C levels were higher (p less than 0.05). The effect of HDL-C was especially strong in women. In separate comparisons to the 4th quartile of HDL-C (greater than or equal to 67 mg/dl), the risk of myocardial infarction increased from a fourfold excess in the adjacent 3rd quartile (56 to 66 mg/dl, p less than 0.01) to a nearly sixfold excess in the 1st quartile (less than or equal to 46 mg/dl, p less than 0.001). These results persisted after adjusting for age and other risk factors. In addition, a significant effect of HDL-C remained in subjects who had the lowest concentrations of total cholesterol (less than or equal to 192 mg/dl in men and 211 mg/dl in women) in which 29% had levels of HDL-C (less than or equal to 36 mg/dl in men and 46 mg/dl in women) that were associated with a marked elevation in the incidence of myocardial infarction. We conclude that screening for total cholesterol alone in men and women aged 50 and older may not adequately identify the coronary candidate.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
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High density lipoprotein cholesterol and mortality. The Framingham Heart Study.

In 12 years of follow-up for 2748 Framingham Heart Study participants ages 50 to 79, low levels of high density lipoprotein cholesterol (HDL-C) were associated with increased mortality. For men, the relative risk of death in the first HDL-C quintile (less than 35 mg/dl) as compared to the top quintile (greater than 54 mg/dl) was 1.9 for all causes, and 3.6 and 4.1 for death due to cardiovascular and coronary heart disease (CHD), respectively, after adjustment for standard cardiovascular risk factors. In women, corresponding relative risks, comparing the bottom HDL-C quintile (less than 45 mg/dl) to the top quintile (greater than 69 mg/dl), were 1.5, 1.6, and 3.1. With HDL-C considered as a continuous variable, and after adjustment for standard cardiovascular risk factors, highly significant associations were seen with HDL-C and CHD death in both men and women. In addition, a significant HDL-C effect on total mortality and death due to cardiovascular disease was seen in men. In none of the continuous variable analyses was HDL-C associated with cancer death. We conclude that HDL-C is a potent predictor of CHD death in both sexes and has less consistent associations with other types of death.

Aged↗
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LD and delinquency: rethinking the "link".

Longitudinal data from a 7-year prospective study was examined to investigate whether the presence of learning disabilities (LD) increases a youth's risk of becoming a juvenile delinquent. The sample included 515 students enrolled in the fifth grade in the fall of 1985, 51 (9.9%) of whom were youth with LD. Self-report data on delinquent activity were collected in the spring of 1993. Official court records were obtained for the years 1985 through 1992. Hierarchical multiple regression analyses were performed using a block of three demographic variables (gender, ethnicity, and socioeconomic status) as predictors in the first step and including LD status in a second step. Seven separate analyses were performed, using different measures of delinquency as criterion variables. In no case did LD status account for a significant portion of unique variance in the delinquency variables when the demographic variables were controlled for. The results of this study did not confirm the presence of a direct relationship between LD and delinquency and suggest that the finding of a direct relationship in other studies may have been due to confounding of the LD status with age, ethnicity, or socioeconomic status.

Adolescent↗
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Early intervention for reading disabilities: teaching the alphabet principle in a connectionist framework.

Forty-eight children referred by teachers at the end of first grade for difficulty in reading were randomly assigned to three treatments, all of which modeled connections between written and spoken words but did not teach phonics rules, for eight half-hour individual tutoring sessions. The children were taught 48 words of varying orders of spelling-sound predictability (Venezky, 1995) using a whole-word method, for making connections between a word's name and its constituent letters; a subword method, for making connections between each color-coded spelling unit and its corresponding phonemes; or a combined whole-word and subword method. Regardless of the method used, children improved reliably on standardized reading measures and the taught words, showing that they could make connections between written and spoken words at the whole word and subword levels, even when rules were not taught. By posttest, the subword method showed a reliable advantage on a standardized test of real word reading. Knowledge of sounds associated with both multiletter and single-letter spelling units predicted reading achievement. Order of spelling-sound predictability (easy, moderate, difficult) was correlated with standardized measures of reading at pretest and posttest, and the magnitude of the relationship increased as a result of the intervention. Individual differences in verbal intelligence, rapid automatized naming, and phonological and orthographic skills predicted response to the intervention. Instructional implications of the results are discussed.

Age Factors↗
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The epidemiology of varicose veins: the Framingham Study.

The epidemiology of varicose veins was examined in 3,822 adults in the Framingham Study. Findings indicate that the incidence of varicose veins is higher among women than men, with no clear age differences. Compared to women without varicose veins, women with varicose veins were more often obese (p less than .01), had lower levels of physical activity (p less than .001) and higher systolic blood pressure (p less than .001), and were older at menopause (p less than .001). Women who reported spending eight or more hours in an average day in sedentary activities (sitting or standing) also had a significantly higher incidence of varicose veins than those who spent four or fewer hours a day in such activities (p less than .05). For men, varicose veins coexisted with lower levels of physical activity (p less than .05) and higher smoking rates (p less than .05). While men and women with varicose veins had a higher incidence of atherosclerotic cardiovascular disease than those without varicose veins, only the excess risk of coronary heart disease in women was statistically significant (p less than .05). However, this finding was not significant after controlling for body mass and systolic blood pressure. These results suggest that increased physical activity and weight control may help prevent varicose veins among adults at high risk, and reduce the overall risk of atherosclerotic cardiovascular disease as well.

Adult↗