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R B Wallace

Publications and source records attributed to R B Wallace.

At least 73 records · Page 4Linked to original sources
PubMed1997

Asset and Health Dynamics Among the Oldest Old: an overview of the AHEAD Study.

This chapter provides background information for the study of Asset and Health Dynamics Among the Oldest Old (AHEAD), a prospective panel survey of persons born in 1923 or earlier who were residing in the community at the time of the 1993 baseline. Interviews were sought with both spouses in married households, and an overall total of 8,222 were completed. We review the interdisciplinary scientific issues that motivated the study, describe the fundamental design decisions that structured AHEAD, and summarize the content in the core and experimental modules. The study provides unusually detailed data on cognition, family structure and transfers, and assets. Data are presented on sample selections, response rates, and oversamples of minority groups. Basic descriptive data on the demographic, health, and socioeconomic attributes of respondents also are presented. Plans for future waves of AHEAD are described, including a next-of-kin interview for decreased respondents.

Aged↗
PubMed1997

Measures of cognitive functioning in the AHEAD Study.

Decline in cognitive functioning and onset of cognitive impairment are potentially important predictors of elderly persons needing informal assistance and formal health care. This article describes the measures of cognitive functioning that were developed for the Asset and Health Dynamics Among the Oldest Old (AHEAD) study of some 6,500 Americans aged 70 years and older. The study was designed to investigate the impact of health on disbursement of family and economic resources. Evaluation of the cognitive measures in terms of psychometric properties and missing data, telephone administration, and formation of an aggregate index is encouraging. Their construct validity is evidenced by their correlations with sociodemographic characteristics and health indicators that replicate existing findings as well as by their prediction of IADL and ADL functioning that are consistent with theory.

Aged↗
PubMed1997

Change in social ties and subsequent mortality in rural elders.

Prior studies assessing social ties and mortality risk in older persons have not considered the dynamic nature of social ties, health, and functional status in this age group. We evaluated the association between change in social ties (assessed in 1982 and 1985) and subsequent mortality through 1993 in a population-based cohort of 2,575 rural persons ages 65-102 years. The same summary measure of social ties was constructed for both interviews and included marital status, number of close friends and relatives, church attendance, and membership in a group. Compared with persons reporting higher levels of social ties at both interviews, a decrease to a low level of social ties was associated with an increased mortality risk for both men [hazard ratio (HR) = 1.8; 95% confidence interval (CI) = 1.2-2.7] and women (HR = 2.1; 95% CI = 1.5-3.0). Lower levels of social ties at both interviews were also associated with greater mortality risk in men (HR = 2.2: 95% CI = 1.5-3.1) and women (HR = 2.2; 95% CI = 1.6-2.9), whereas an increase to a higher level of social ties was not associated with subsequent mortality risk. Adjustment for age, education, smoking status, cognitive function, onset of a major illness, change in physical function, change in self-perceived health status, and change in depressive symptoms eliminated the association between loss of social ties and survival, but both men (HR = 2.3; 95% CI = 1.5-3.5) and women (HR = 1.8; 95% CI = 1.2-2.6) reporting low levels of social ties at both interviews remained at elevated risk. The lack of an association between loss of social ties and mortality risk after adjusting for demographic, health, and functional status variables indicates that these are either confounding or intervening variables in a social ties and mortality association. In contrast, sustained low levels of social ties appear to influence mortality risk independent of these same variables and imply that continued social isolation may be a more important determinant of mortality risk than recent changes in social ties.

Aged↗
PubMed1997

Cognitive change, medical illness, and crash risk among older drivers: an epidemiological consideration.

This paper reviews selected issues concerning the natural history of cognitive change among older persons and whether the potential effects of such change on the safe operation of a motor vehicle can detected prior to the occurrence of an adverse outcome, such as a crash. Data are reviewed from selected recent, large, population-referent epidemiological studies that have sought direct associations between medical conditions of their treatments and crash risk. Several important medical risk factors have been identified and, if confirmed, these factors must be considered along with the assessment of cognitive decline and dementia when evaluating safety issues in older drivers.

Aging↗
PubMed1997

Apolipoprotein E epsilon 2 allele and risk of stroke in the older population.

BACKGROUND AND PURPOSE: There is evidence for a role of apolipoprotein E (apoE) in atherosclerosis. Coronary heart disease morbidity is higher in persons carrying an epsilon 4 allele and lower in those carrying an epsilon 2 allele, but the effect on cerebrovascular disease is controversial. We estimated the risk of stroke associated with different apoE genotypes in older persons. METHODS: At the sixth annual follow-up of the Iowa cohort of the Established Populations for Epidemiologic Studies of the Elderly, 1664 persons aged > or = 71 years and free of stroke were genotyped for apo E. Occurrence of ischemic strokes was prospectively assessed from subsequent hospital discharge records and death certificates. RESULTS: One hundred fifty persons had an ischemic stroke over the subsequent 5 years (21.2 per 1000 person-years). The presence of epsilon 3 and epsilon 4 did not influence stroke risk. Among persons aged < 80 years at the time of genotyping, epsilon 2 carriers had lower risk of incident stroke, while no effect was detected in the older group. Compared with epsilon 2 carriers aged 70 to 79 years (reference group), those in the same age group and not carrying an epsilon 2 had 2.6-fold higher risk of incident stroke, and those aged > or = 80 years had even higher risk of stroke but without any difference according to presence/absence of epsilon 2 (relative risks 3.6 and 3.3). Results remained substantially unchanged when adjusted for potential confounders and in models estimating the effect of apoE polymorphism on the risk of developing a stroke at ages between 70 and 79 years (56 events) and separately at ages > or = 80 years (94 events). CONCLUSIONS: The conditioning influence of age on the protection conferred by the apoE epsilon 2 allele on stroke risk may account for previous controversies. This hypothesis should be verified in a population with a wider age range.

Aged↗
PubMed1997

Characteristics of older pedestrians who have difficulty crossing the street.

OBJECTIVES: This study examined the sociodemographic and health characteristics and problems of older pedestrians. METHODS: Interviews and assessments were conducted with 1249 enrollees aged 72 or older from the New Haven, Conn, community of the Established Populations for Epidemiologic Studies of the Elderly who agreed to participate in a seventh follow-up. RESULTS: Approximately 11% of the New Haven residents reported difficulty crossing the street. Older pedestrians needing help in one or more activities of daily living were more than 10 times as likely as others, and those with the slowest walking speeds were nearly 3 times as likely as others, to report difficulty crossing the street. Fewer than 1% of these pedestrians aged 72 or older had a normal walking speed sufficient to cross the street in the time typically allotted at signalized intersections (1.22 m/sec). CONCLUSIONS: Crossing times at signalized intersectíons in areas with large populations of elders should be extended, and the recommended walking speed for timing signalized crossings should be modified to reflect the range of abilities among older pedestrians.

Activities of Daily Living↗
PubMed1997

Ligase chain reaction assay for human mutations: the Sickle Cell by LCR assay.

We can detect the beta-globin gene sickle cell mutation by using an assay based on the ligase chain reaction. The simultaneous amplification of the human growth hormone gene in the same reaction serves as a control for the amount of template DNA or amplification efficiency. Ligation products, which are biotinylated at one end and tagged with an arbitrary "tail" sequence at the other, are captured by hybridization to "tail"-complementary oligonucleotides immobilized on polystyrene microwells. The captured ligation products are detected colorimetrically by use of streptavidin-alkaline phosphatase conjugate. In a study of 24 subjects, the assay unequivocally discriminated among normal, carrier, and sickle cell genotypes.

Alleles↗
PubMed1996

Calcium-channel blockade and incidence of cancer in aged populations.

BACKGROUND: Calcium-channel blockers can alter apoptosis, a mechanism for destruction of cancer cells. We examined whether the long-term use of calcium-channel blockers is associated with an increased risk of cancer. METHODS: Between 1988 and 1992 we carried out a prospective cohort study of 5052 people aged 71 years or more and who lived in three regions of Massachusetts, Iowa, and Connecticut USA. Those taking calcium-channel blockers (n = 451) were compared with all other participants (n = 4601). The incidence of cancer was assessed by survey of hospital discharge diagnoses and causes of death. These outcomes were validated by the cancer registry in the one region where it was available. Demographic variables, disability, cigarette smoking, alcohol consumption, blood pressure, body-mass index, use of other drugs, hospital admissions for other causes, and comorbidity were all assessed as possible confounding factors. FINDINGS: The hazard ratio for cancer associated with calcium-channel blockers (1549 person-years, 47 events) compared with those not taking calcium-channel blockers (17225 person-years, 373 events) was 1.72 (95% CI 1.27-2.34, p = 0.0005), after adjustment for confounding factors. A significant dose-response gradient was found. Hazard ratios associated with verapamil, diltiazem, and nifedipine did not differ significantly from each other. The results remained unchanged in community-specific analyses. The association between calcium-channel blockers and cancer was found with most of the common cancers. INTERPRETATION: Calcium-channel blockers were associated with a general increased risk of cancer in the study populations, which suggested a common mechanism. These observational findings should be confirmed by other studies.

Aged↗
PubMed1996

Diet and risk of non-Hodgkin lymphoma in older women.

OBJECTIVE: To test whether high dietary intakes of fat, protein, and milk are associated with the development of non-Hodgkin lymphoma in older women. DESIGN: Prospective cohort study with a 7-year follow-up period. SETTING: General community. PARTICIPANTS: Sample of 35 156 Iowa women aged 55 to 69 years with no prior history of cancer who returned the 1986 baseline questionnaire. MAIN OUTCOME MEASURE: Non-Hodgkin lymphoma (104 incident cases). MAIN RESULTS: After controlling for age, marital status, residence, total energy intake, and transfusion history, the relative risks (RRs) for the highest tertile of intake compared with the lowest were 2.00 (95% confidence interval [CI], 1.21-3.30; P for trend = .01) for animal fat, 1.69 (95% CI, 1.07-2.67; P for trend = .02) for saturated fat, and 1.90 (95% CI, 1.18-3.04; P for trend = .01) for monounsaturated fat, and there was no association with vegetable fat or polyunsaturated fat. Greater intake of animal protein (RR = 1.52; 95% CI, 0.94-2.44; P for trend = .08), but not vegetable protein, was associated with elevated risk, and this was mainly explained by greater consumption of red meat (RR = 1.98; 95% CI, 1.13-3.47; P for trend = .02) and hamburger in particular (RR = 2.35; 95% CI, 1.23-4.48; P for trend = .02). Milk and dairy product consumption were not associated with elevated risk. There was also a decreased risk of non-Hodgkin lymphoma with greater consumption of fruits (RR = 0.64; 95% CI, 0.40-1.05; P for trend = .07). CONCLUSIONS: A high-meat diet and a high intake of fat from animal sources is associated with an increased risk of non-Hodgkin lymphoma in older women.

Aged↗
PubMed1996

A newly identified polymorphism in the apolipoprotein E enhancer gene region is associated with Alzheimer's disease and strongly with the epsilon 4 allele.

Apolipoprotein E allele 4 (apoE epsilon 4) is a major risk factor for late-onset AD. Inheritance of this allele is associated with an earlier age of onset of dementia in individuals with AD. It is unknown whether other polymorphisms in the apoE gene may influence the effect of apoE epsilon 4 on AD. We screened portions of the promoter enhancer element and of the apoE receptor binding domain for other polymorphisms that could affect risk of AD. In particular, a C/G polymorphism at position +113 of the apoE mRNA in the apoE intron 1 enhancer element (IE1) has been recently identified. We found no other polymorphisms. We studied the relationship of the two alleles of the IE1 polymorphism with AD and found an apparent association between IE1 G and AD (n = 94; p = 0.0515). However, the IE1 G allele is also closely associated with apoE epsilon 4 (p < 0.0001). When the presence of apoE epsilon 4 is covaried, the association between the IE1 G allele and AD is no longer statistically significant (odds ratio = 1.29, 95% confidence interval: 0.44, 3.78). In contrast, epsilon 4 is still highly associated with AD when IE1 G is controlled for (odds ratio = 5.91, 95% confidence interval: 3.29, 10.63). Furthermore, there is no significant association between the age of onset of dementia and the inheritance of the G allele. We believe that the apparent association between IE1 G and AD is a consequence of the association between the epsilon 4 and IE1 G alleles.

Adult↗
PubMed1996

Risk factors for occupational injuries among older workers: an analysis of the health and retirement study.

OBJECTIVES: This study examined risk factors for occupational injury among older workers. METHODS: We analyzed data on 6854 employed nonfarmers from the Health and Retirement Study (HRS), a population-based sample of Americans 51 through 61 years old. RESULTS: Occupational injuries were associated with the following: the occupations of mechanics and repairers (odds ratio [OR] = 2.27), service personnel (OR = 1.68), and laborers (OR = 2.18); jobs requiring heavy lifting (OR = 2.75); workers' impaired hearing (OR = 1.60) and impaired vision (OR = 1.53); and jobs requiring good vision (OR = 1.43). Self-employment was associated with fewer injuries (OR = 0.47). CONCLUSIONS: These results emphasize the importance of a good match between job demands and worker capabilities.

Accidents, Occupational↗
PubMed1996

Risk factors for progression to new sites of radiographically defined osteoarthritis in women.

OBJECTIVE: To describe the association between hormonally related risk factors and the progression to new sites of radiographically defined full body (generalized) osteoarthritis (OA) in a cohort of older women. METHODS: A retrospective cohort design was used to study former radium dial painters over the age of 40 years who had minimal radium exposure. At study entry and at varying followup times, clinical examinations were conducted and full body radiographs were taken. Two followup groups were defined: women with a followup radiograph 1-9 years after baseline (n = 75) and 10-19 years after baseline (n = 53). Fifty-five joints (10 joint groups) were independently graded at baseline and followup for OA by the method of Kellgren and Lawrence, and provided the basis for summary full body OA progression scores. Progression was defined as an increase in the number of sites with OA and in separate analyses as an increase in the number of joint groups with OA. RESULTS: Increasing length of followup and lower baseline OA score were associated with greater OA progression, while age at baseline examination showed no clear relation to progression. Beyond these variables, increasing height and having ever smoked were inversely associated with OA progression, while body mass index (BMI) showed a weak positive association. In multivariable modeling for followup 1-9 years, only lower baseline OA score predicted greater OA progression to new sites (partial r2 = 0.13, p = 0.0009). In followup 10-19 years, baseline OA score (partial r2 = 0.12, p = 0.0011), height (partial r2 = 0.057, p = 0.033), and smoking status (partial r2 = 0.09, p = 0.035) were independent predictors of OA progression to new sites, while greater BMI was a positive, weak, and nonsignificant predictor (partial r2 = 0.031, p = 0.29). History of prior cholecystectomy, hysterectomy, dilation and curetage, number of pregnancies, and change in BMI were not significantly related to progression of OA to new sites. Similar results were found for predictors of OA progression to new joint groups. CONCLUSION: Lower baseline level of OA is associated with greater OA progression to new sites or joint groups independent of age, suggesting a "burnout" phenomenon. In addition, shorter height and having never smoked appear to be independent risk factors that predict the progression of radiographic OA to new sites or joint groups.

Adult↗
PubMed1995

HDL cholesterol predicts coronary heart disease mortality in older persons.

OBJECTIVES: To examine the relationship of total cholesterol and high-density lipoprotein cholesterol (HDL-C) with coronary heart disease (CHD) mortality and with occurrence of new CHD events in persons aged 71 years and older. DESIGN: Prospective cohort study with a median of 4.4 years of follow-up. SETTING: East Boston, Mass; New Haven, Conn; and Iowa and Washington counties, Iowa. PARTICIPANTS: A total of 2527 women and 1377 men who completed an interview, had serum lipid determinations, and survived at least 1 year. New CHD events were evaluated in persons with no CHD history or hospitalization. MAIN OUTCOME MEASURES: Death due to CHD (ICD-9 codes 410 through 414 as underlying cause of death); new occurrence of CHD events (fatal CHD or hospitalization with CHD [ICD-9 codes 410 through 414]). RESULTS: After adjustment for established CHD risk factors, the relative risk (RR) of death due to CHD for those with low HDL-C (< 0.90 mmol/L [< 35 mg/dL]) compared with the reference group (HDL-C > or = 1.55 mmol/L [> or = 60 mg/dL]) was 2.5 (95% confidence interval [CI], 1.6 to 4.0). Elevated risk was present in subgroups aged 71 through 80 years (RR, 4.1; 95% CI, 1.9 to 8.8) and over 80 years (RR, 1.8; 95% CI, 0.99 to 3.4), and in men and women. Low HDL-C predicted an increased risk of occurrence of new CHD events (RR, 1.4; 95% CI, 1.1 to 2.0), with similar but nonsignificant results in subgroups of men and women. Total cholesterol was less consistently associated with CHD mortality than HDL-C. When we compared individuals with total cholesterol of at least 6.20 mmol/L (240 mg/dL) with the reference group with total cholesterol of 4.16 to 5.19 mmol/L (161 to 199 mg/dL), a significant risk of CHD mortality was seen for women (RR 1.8; 95% CI, 1.03 to 3.0) but not for men (RR, 1.0; 95% CI, 0.5 to 2.0). In the total population, for each 1-unit increase in the total cholesterol/HDL-C ratio there was a 17% increase in the risk of CHD death that was statistically significant. CONCLUSIONS: Low HDL-C predicts CHD mortality and occurrence of new CHD events in persons older than 70 years. Elevated total cholesterol was not found to be associated with CHD mortality in older men, but may be a risk factor for CHD in older women.

Age Factors↗
PubMed1995

Lower-extremity function in persons over the age of 70 years as a predictor of subsequent disability.

BACKGROUND: Functional assessment is an important part of the evaluation of elderly persons. We conducted this study to determine whether objective measures of physical function can predict subsequent disability in older persons. METHODS: This prospective cohort study included men and women 71 years of age or older who were living in the community, who reported no disability in the activities of daily living, and who reported that they were able to walk one-half mile (0.8 km) and climb stairs without assistance. The subjects completed a short battery of physical-performance tests and participated in a follow-up interview four years later. The tests included an assessment of standing balance, a timed 8-ft (2.4-m) walk at a normal pace, and a timed test of five repetitions of rising from a chair and sitting down. RESULTS: Among the 1122 subjects who were not disabled at base line and who participated in the four-year follow-up, lower scores on the base-line performance tests were associated with a statistically significant, graduated increase in the frequency of disability in the activities of daily living and mobility-related disability at follow-up. After adjustment for age, sex, and the presence of chronic disease, those with the lowest scores on the performance tests were 4.2 to 4.9 times as likely to have disability at four years as those with the highest performance scores, and those with intermediate performance scores were 1.6 to 1.8 times as likely to have disability. CONCLUSIONS: Among nondisabled older persons living in the community, objective measures of lower-extremity function were highly predictive of subsequent disability. Measures of physical performance may identify older persons with a preclinical stage of disability who may benefit from interventions to prevent the development of frank disability.

Activities of Daily Living↗
PubMed1995

Does weight loss from middle age to old age explain the inverse weight mortality relation in old age?

The authors examined body mass index at middle age, body mass index in old age, and weight change between age 50 years and old age in relation to mortality in old age. The study population from the Established Populations for Epidemiologic Studies of the Elderly consisted of 6,387 whites age 70 years or older who experienced 2,650 deaths during the period 1982-1987. Mortality risk was highest for persons in the heaviest quintile of body mass index at age 50 (men, relative risk (RR) = 1.33, 95% confidence interval (CI) 1.13-1.57; women, RR = 1.31, 95% CI 1.12-1.53) compared with persons in the middle quintile. This pattern was reversed for body mass index in old age, with persons in the lowest quintile having the highest mortality risk (men, RR = 1.40, 95% CI 1.19-1.65; women, RR = 1.38, 95% CI 1.17-1.63) relative to persons in the middle quintile. This reversal was explained, in part, by weight change. Compared with persons with stable weight, those who lost 10 percent or more of body weight between age 50 and old age had the highest risk of mortality (men, RR = 1.69, 95% CI 1.45-1.97; women, RR = 1.62, 95% CI 1.38-1.90). Exclusion of participants who lost 10 percent or more of their weight and adjustment for health status eliminated the higher risk of death associated with low weight. The inverse association of weight and mortality in old age appears to reflect illness-related weight loss from heavier weight in middle-age. Weight history may be critical to understanding weight and mortality relations in old age.

Aged↗
PubMed1995

Decreased survival with increasing prevalence of full-body, radiographically defined osteoarthritis in women.

The relation between full-body, radiographically defined osteoarthritis and survival was examined in a cohort of 296 women aged 42-76 years (mean age, 57.1 years). These women were a random sample of women with very low body burdens of radium who were part of a larger cohort of women first employed in the US radium dial-painting industry between 1915 and 1945. At entry into the study between 1957 and 1982, these women had a clinical examination, and full-body radiographs were taken. Fifty-five joints (18 joint groups) of the hands, feet, cervical spine, lumbar spine, pelvis, and knees in each woman were graded for osteoarthritis by the method of J. H. Kellgren and J. S. Lawrence (Ann Rheum Dis 1957; 16:494-502). Through 1985, 18.6% (n = 55) of the women died. Cox regression showed a decreased survival for women with an increasing number of joint groups affected with osteoarthritis after adjusting for age at examination (hazard ratio = 1.45 for each increase in 3.1 joint groups (1 standard deviation) affected with osteoarthritis, 95% confidence interval 1.12-1.87). Further adjustment for a history of diabetes, smoking, alcohol use, and body mass index only slightly altered the risk. Similar results were obtained for the number of joints with osteoarthritis and the number of structures (e.g., left hand and right hand) with osteoarthritis. These results suggest that an increasing prevalence of full-body radiographic osteoarthritis is associated with decreased survival independent of age and several comorbid conditions related to osteoarthritis.

Adult↗
PubMed1995

Effect of recall period on the reporting of occupational injuries among older workers in the Health and Retirement Study.

Studies of injury morbidity often rely on self-reported survey data. In designing these surveys, researchers must chose between a shorter recall period to minimize recall bias and a longer period to maximize the precision of rate estimates. Using data from the Health and Retirement Study, which employed a recall period of 1 year, we examined the effect of the recall period on rates of occupational injuries among older workers as well as upon rate ratios of these injuries for nine risk factors. We fit a stochastic model to the occupational injury rates as a function of time before the interview and used this model to estimate what the injury rates would have been had we used a 4-week recall period. The adjusted occupational injury rate of 5.9 injuries per 100 workers per year was 36% higher than the rate based on a 1-year recall period. Adjustment for recall period had much less effect on rate ratios, which typically varied by < 10%. Our work suggests that self-reported surveys with longer recall periods may be used to estimate occupational injury rates and also may be useful in studying the associations between occupational injuries and a variety of risk factors.

Accidents, Occupational↗