Women in thoracic surgery and the Thoracic Surgery Foundation for Research and Education.
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Fellowships and Scholarships↗
Biomedical subjects
R B Wallace
Publications and source records attributed to R B Wallace.
Is this a practical approach?
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Ethics, Medical↗
Consumption of carrageenan and other water-soluble polymers used as food additives and incidence of mammary carcinoma.
This study examined the hypothesis that the increasing incidence of mammary carcinoma in the USA in the twentieth century may be related to the consumption of carrageenan and possibly other water-soluble polymers. Widely used as food additives in the Western diet, the water-soluble polymers, also known as gums, are generally regarded as inert. However, the gum carrageenan which is comprised of linked, sulfated galactose residues has potent biological activity and undergoes acid hydrolysis to poligeenan, an acknowledged carcinogen. A time-trend analysis using age-adjusted incidence data and consumption data from established sources tested the hypothesis that increased consumption of the gums may be associated with increased incidence of mammary carcinoma. Correlations were determined using Pearson and Spearman correlation coefficients, incorporating lag intervals of 10 to 35 years. This analysis demonstrated that increasing consumption of several gums correlates positively with increased incidence of breast carcinoma.
Breast Neoplasms↗
Persistent, consistent, widespread, and robust? Another look at recent trends in old-age disability.
OBJECTIVE: The purpose of this study was to provide new evidence on disability trends among elderly persons from 1982 to 1996. METHODS: The sample includes 124,949 participants aged 70 and older in the 1982-1996 National Health Interview Surveys. Logistic analysis was used to estimate the trend in disability prevalence after controlling for various sociodemographic factors. RESULTS: We found that: (a) the prevalence of disability has declined, but the gains did not persist throughout the entire period or accelerate over time; (b) only routine care disability has declined, whereas more severe personal care disability shows no improvements; (c) estimates are robust to the exclusion of the nursing home population but may be sensitive to growth in the assisted living population; (d) estimates of decline in disability prevalence are fairly consistent across five national surveys; (e) gains have been concentrated among the most educated elderly persons; and (f) gains in education appear to be an important confounder of the improvements. DISCUSSION: Evidence from several surveys using various measures indicates that disability has declined among elderly persons. Determining the causes of the improvements should be a high priority in future research efforts.
Age Distribution↗
Changes in driving patterns and worsening depressive symptoms among older adults.
OBJECTIVES: This study examined whether changes in driving patterns-driving cessation and reduction-have negative consequences for the depressive symptoms of older Americans and whether these consequences are mitigated for people with a spouse who drives. METHODS: The project used data from 3 waves of the Asset and Health Dynamics Among the Oldest Old (AHEAD) study. Depressive symptoms were assessed with an abbreviated Center for Epidemiologic Studies-Depression scale. Using 2 models, the project examined how driving cessation and reduction that occurred between Waves 1 and 2 contributed to increases in depressive symptoms between Waves 2 and 3. The first model included the entire sample (N = 5,239), and the second model focused on drivers only (n = 3,543). A third model added interaction terms to the analysis to consider whether respondents who stopped driving but had a spouse who drove were less at risk of worsening depressive symptoms. RESULTS: Respondents who stopped driving had greater risk of worsening depressive symptoms. Drivers who restricted their driving distances before the study began also had greater risk of worsening depressive symptoms, but seemingly less so than the respondents who stopped driving altogether. For respondents who stopped driving, having a spouse available to drive them did not mitigate the risk of worsening symptoms. DISCUSSION: Changes in driving patterns can be deleterious for older people's depressive symptoms. Initiatives for assisting older people should focus on strategies that help them retain driving skills, that prepare them for the possible transition from driver to ex-driver, and that ensure that they have access to mental health therapies if driving changes are imminent.
Activities of Daily Living↗
Assisted suicide: a few answers--many questions.
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Adult↗
National estimates of the quantity and cost of informal caregiving for the elderly with dementia.
OBJECTIVE: Caring for the elderly with dementia imposes a substantial burden on family members and likely accounts for more than half of the total cost of dementia for those living in the community. However, most past estimates of this cost were derived from small, nonrepresentative samples. We sought to obtain nationally representative estimates of the time and associated cost of informal caregiving for the elderly with mild, moderate, and severe dementia. DESIGN: Multivariable regression models using data from the 1993 Asset and Health Dynamics Study, a nationally representative survey of people age 70 years or older (N = 7,443). SETTING: National population-based sample of the community-dwelling elderly. MAIN OUTCOME MEASURES: Incremental weekly hours of informal caregiving and incremental cost of caregiver time for those with mild dementia, moderate dementia, and severe dementia, as compared to elderly individuals with normal cognition. Dementia severity was defined using the Telephone Interview for Cognitive Status. RESULTS: After adjusting for sociodemographics, comorbidities, and potential caregiving network, those with normal cognition received an average of 4.6 hours per week of informal care. Those with mild dementia received an additional 8.5 hours per week of informal care compared to those with normal cognition (P < .001), while those with moderate and severe dementia received an additional 17.4 and 41.5 hours (P < .001), respectively. The associated additional yearly cost of informal care per case was 3,630 dollars for mild dementia, 7,420 dollars for moderate dementia, and 17,700 dollars for severe dementia. This represents a national annual cost of more than 18 billion dollars. CONCLUSION: The quantity and associated economic cost of informal caregiving for the elderly with dementia are substantial and increase sharply as cognitive impairment worsens. Physicians caring for elderly individuals with dementia should be mindful of the importance of informal care for the well-being of their patients, as well as the potential for significant burden on those (often elderly) individuals providing the care.
Aged↗
Bridging epidemiology and demography: theories and themes.
Epidemiology and demography, although both encumbering several theoretical constructs, are generally applied, problem-solving disciplines concerned with the nature and trajectories of defined groups. There are differences between the two disciplines in substantive interests and methodological traditions, however both have comprehensive perspectives and both are deeply concerned with the health, social, and economic well-being of human populations. One way to promote productive interdisciplinary research is to apply or develop scientific theories that exploit the complementary interests and methods of the two disciplines. Several candidate theories and themes are suggested here, including (1) the life course approach as applied to the biology of longevity; (2) the "modernized" Malthusian dilemma; (3) the demographic transition within developing countries; (4) the theory of evolution and its social and biological implications; (5) reciprocal effects of ecological and environmental characteristics on population health and well-being; and (6) systems theory as an approach to population complexity. Other approaches to fostering interdisciplinary investigation between these disciplines include joint course work, specifically targeted research funding initiatives and collaborative development of new population theory. The latter may be particularly important from several perspectives: uniting disciplines to jointly approach common and important scientific problems, providing existing frameworks with which to generate new scientific questions, and promoting enhanced scientific rigor by more tightly linking methods with hypotheses.
Biological Evolution↗
Advocacy in epidemiology and demography.
This paper is a summary of a panel discussion at the Conference on Epidemiology and Demography held at Georgetown University, in Washington D.C. on February 8-9, 2001. The participants were Al Hermalin, Linda Martin, Mike Stoto, Robert Wallace, Douglas Weed, and Rose Li (who chaired the session). A list of questions similar to the section headings in this paper was prepared in advance of the conference, and each of the participants was asked to address specific issues, although the presentations typically covered a range of topics. This summary also includes comments from the floor.
Consumer Advocacy↗
Linked linear amplification: a new method for the amplification of DNA.
BACKGROUND: Linked Linear Amplification (LLA) is a new nucleic acid amplification method that uses multiple cycles of primer extension reactions. The presence of nonreplicable elements in LLA primers renders primer extension products unusable as templates for further amplification, leading to linear accumulation of products. Through the use of nested primers, linear reactions can be "linked", providing total amplification yields comparable to those obtained by PCR. METHODS: The LLA model predicts (a) that amplification yield will approach that of PCR as the number of primers increases and (b) that the unique composition of LLA products will give lower carryover amplification efficiency compared with PCR. To test these hypotheses, the human ss-globin gene was amplified by 10-, 14-, or 18-primer LLA and the yield was compared with PCR. Carryover contamination was simulated by reamplifying a dilution series of LLA or PCR products. To demonstrate the clinical utility of the method, LLA coupled with allele-specific oligonucleotide (ASO) capture was used to detect the factor V Leiden mutation in a panel of 111 DNA samples. RESULTS: Fourteen- and 18-primer LLA gave amplification yields comparable to PCR. However, LLA carryover amplification efficiency was four orders of magnitude lower than that of PCR. The LLA-ASO assay detected the correct factor V Leiden genotype in all 111 samples. CONCLUSIONS: LLA is a robust target amplification method that is comparable to PCR in yield. However, LLA is more resistant to false results caused by carryover amplicon contamination.
DNA↗
Blood transfusions and risk of non-Hodgkin's lymphoma subtypes and chronic lymphocytic leukemia.
Allogeneic blood transfusion has been suggested as a risk factor for non-Hodgkin's lymphoma (NHL), possibly specific to certain NHL subtypes, or chronic lymphocytic leukemia (CLL). Self-reported transfusion history and risk of NHL subtypes and CLL were examined in a cohort of 37,934 older Iowa women, using data from a questionnaire mailed in 1986. Through 1997, 229 cases of NHL and 57 cases of CLL in the cohort were identified through linkage to the Iowa Surveillance, Epidemiology and End Results Cancer REGISTRY: Women who reported ever receiving a blood transfusion were at increased risk for all NHLs [age adjusted relative risk (RR), 1.6; 95% confidence interval (CI), 1.2-2.1). On the basis of the Working Formulation classification, blood transfusion was positively associated with low-grade NHL (RR, 2.7; 95% CI, 1.7-4.5) but not with intermediate-grade NHL (RR, 1.1; 95% CI, 0.7-1.6); there were only 8 cases of high-grade NHL. Blood transfusion was positively associated with follicular (RR, 2.8; 95% CI, 1.6-5.1) and small lymphocytic (RR, 3.4; 95% CI, 1.5-7.9) NHL subtypes but not with diffuse NHL (RR, 1.0; 95% CI, 0.7-1.5). There was also a positive association with CLL (RR, 1.7; 95% CI, 1.0-3.0). Finally, transfusion was associated with nodal (RR, 1.8; 95% CI, 1.3-2.5) but not extranodal (RR, 1.2; 95% CI, 0.7-2.1) NHL. Further adjustment for marital status, farm residence, diabetes, alcohol use, smoking, and red meat and fruit consumption did not alter these associations. In conclusion, prior blood transfusion was associated with NHL and CLL, and the strongest associations were seen for low-grade NHL, particularly follicular and small lymphocytic NHL.
Aged↗
Constrictive pericarditis.
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Cardiac Catheterization↗
Lifestyle and anthropometric risk factors for prostate cancer in a cohort of Iowa men.
PURPOSE: Several lines of evidence suggest that prostate cancer has a hormonal etiology. We evaluated factors known to modulate the endocrine system, including alcohol and tobacco use, physical activity, and obesity as risk factors for prostate cancer. METHODS: Cancer-free controls who participated in a population-based case-control study from 1986-1989 (81% response rate) were followed through 1995 for cancer incidence by linkage to the Iowa Cancer Registry; 101 incident prostate cancers were identified. RESULTS: Compared with non-users of alcohol, men who consumed <22 grams alcohol per week (relative risk [RR] = 1.1; 95% Confidence Interval [CI] 0.6-2.1), 22-96 grams alcohol per week (RR = 2.6; 95% CI 1.4-4. 6) and >96 grams alcohol per week (RR = 3.1; 95% CI 1.5-6.3) were at increased risk of prostate cancer after adjustment for age, family history of prostate cancer, body mass index, total energy, and intake of carbohydrate, linoleic acid, lycopene, retinol, and red meat (p for trend < 0.0001). The respective RRs were similar when assessing type of alcohol consumed (beer, wine or liquor) or when well-differentiated, localized tumors were excluded. Body mass index was only weakly and positively associated with prostate cancer after adjustment for age, but this association strengthened after multivariate adjustment and exclusion of well-differentiated, localized tumors. For the latter tumors, men with a BMI of 24.1-26.6 kg/m(2) and >26.6 kg/m(2) were at elevated risk compared to men with a BMI <24.1 kg/m(2). Tobacco use (cigarettes, cigar/pipe, chewing tobacco and snuff use), height, weight, and both leisure and occupational physical activity were not associated with risk of prostate cancer in this cohort. CONCLUSIONS: These data suggest that in white men obesity is a risk factor for more clinically significant prostate cancer and confirm limited previous reports showing that alcohol consumption is positively associated with prostate cancer and that this risk is not limited to any specific type of alcohol.
Adult↗
Lower extremity function and subsequent disability: consistency across studies, predictive models, and value of gait speed alone compared with the short physical performance battery.
BACKGROUND: Although it has been demonstrated that physical performance measures predict incident disability in previously nondisabled older persons, the available data have not been fully developed to create usable methods for determining risk profiles in community-dwelling populations. Using several populations and different follow-up periods, this study replicates previous findings by using the Established Populations for the Epidemiologic Study of the Elderly (EPESE) performance battery and provides equations for the prediction of disability risk according to age, sex, and level of performance. METHODS: Tests of balance, time to walk 8 ft, and time to rise from a chair 5 times were administered to 4,588 initially nondisabled persons in the four sites of the EPESE and to 1,946 initially nondisabled persons in the Hispanic EPESE. Follow-up assessment for activity of daily living (ADL) and mobility-related disability occurred from 1 to 6 years later. RESULTS: In the EPESE, compared with those with the best performance (EPESE summary performance score of 10-12), the relative risks of mobility-related disability for those with scores of 4-6 ranged from 2.9 to 4.9 and the relative risk of disability for those with scores of 7-9 ranged from 1.5 to 2.1, with similar consistent results for ADL disability. The observed rates of incident disability according to performance level in the Hispanic EPESE agreed closely with rates predicted from models developed from the EPESE sites. Receiver operating characteristic curves showed that gait speed alone performed almost as well as the full battery in predicting incident disability. CONCLUSIONS: Performance tests of lower extremity function accurately predict disability across diverse populations. Equations derived from models using both the summary score and the gait speed alone allow for the estimation of risk of disability in community-dwelling populations and provide valuable information for estimating sample size for clinical trials of disability prevention.
Activities of Daily Living↗
Age, medical conditions, and gender as interactive predictors of cognitive performance: the effects of selective survival.
The interaction of age, medical conditions, and gender on free-recall and mental status test performance was analyzed in two large survey samples of older adults. Age, gender, and the presence of medical conditions interacted with recall and mental status in Study 1 (n = 2,695) and mental status in Study 2 (n = 6,299). For men, those with one or more medical conditions declined more steeply with age than those with no conditions. For women, this relationship was reversed. The findings suggest survival effects, whereby those who lived to old age with medical conditions and were selected into the sample had high levels of cognitive functioning. The age at which these effects are seen vary with gender because women survive longer than men.
Aged↗
Memory complaint in a community sample aged 70 and older.
OBJECTIVES: The ability of older people to estimate their own memory, often referred to as "metamemory," has been evaluated in previous studies with conflicting reports regarding accuracy. Some studies have suggested that an older person's metamemory is mostly accurate, whereas others have demonstrated little relationship between memory complaint and actual impairment. This study examines memory complaint in a large national sample of older people aged > or = 70. DESIGN: A longitudinal cohort study with two waves of data collection spaced 2 years apart. SETTING: A nationwide random sample of community-dwelling older persons. PARTICIPANTS: A total of 5,444 community-dwelling persons aged > or = 70 and their spouses. MEASUREMENTS: Participants were asked if they believed their memory was excellent, very good, good, fair, or poor. They were then administered a cognitive assessment derived from the Mini-Mental Status Exam. RESULTS: In general, people's assessment of their memory corresponded with their actual performance on cognitive measures. However, large portions of the sample inaccurately assessed their memory skills. People who reported depressive symptoms and had impairment in activities of daily living were more likely to state that their memory was impaired, although they performed very well on cognitive measures. CONCLUSIONS: The conditions that skew people's self-assessment are the ones most likely to bring them into contact with healthcare professionals. This may give clinicians the general impression that older people cannot assess their own cognitive skills. However, poor metamemory appears to be a characteristic of a specific subgroup of older persons, not necessarily characteristic of the general population.
Activities of Daily Living↗
The role of antihypertensive agents in preventing cognitive impairment.
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Antihypertensive Agents↗
Smoking and risk of non-Hodgkin lymphoma subtypes in a cohort of older women.
Although non-Hodgkin lymphoma (NHL) has not been considered to be a smoking-related malignancy, recent investigations suggest otherwise. We evaluated this association in a cohort of 37,336 women, aged 55-69 years, who reported in a mailed questionnaire in 1986 information regarding smoking history as well as demographic, medical history and dietary factors. Cancer and mortality experience through 1996 was determined by linkage to the Iowa Cancer Registry and other databases; there were 200 incident cases of NHL during the 380,231 total person-years of follow-up. Compared to never smokers, former (age-adjusted RR = 1.0; 95% CI 0.8-1.5) and current smokers (age-adjusted RR = 1.0; 95% CI 0.7-1.5) were not at elevated risk of NHL, and there was no trend with pack-years smoked (Ptrend = 0.3). Multivariate adjustment for other NHL risk factors did not alter these findings. Age-adjusted analysis by NHL subtype revealed a suggestive positive association of smoking with follicular NHL [(RRformer = 1.3; 95% CI 0.6-2.8), (RRcurrent = 1.8; 95% CI 0.8-3.8)], which strengthened after multivariate adjustment [(RRformer = 1.6; 95% CI 0.7-3.4), (RRcurrent = 2.3; 95% CI 1.0-5.0)]; there was no association for diffuse or small cleaved-cell NHL. Our study findings, which are consistent with other recent investigations, suggest that smoking may be associated with an increased risk of follicular NHL.
Age Factors↗