Biologic markers as predictors of risk in aerodigestive tract cancers.
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Antigens, Neoplasm↗
Biomedical subjects
B Trock
Publications and source records attributed to B Trock.
The logistic modeling of sensitivity, specificity, and predictive value of a diagnostic test.
A method is described for modeling the sensitivity, specificity, and positive and negative predictive values of a diagnostic test. To model sensitivity and specificity, the dependent variable (Y) is defined to be the dichotomous results of the screening test, and the presence or absence of disease, as defined by the "gold standard", is included as a binary explanatory variable (X1), along with variables used to define the subgroups of interest. The sensitivity of the screening test may then be estimated using logistic regression procedures. Modeled estimates of the specificity and predictive values of the screening test may be similarly derived. Using data from a population-based study of peripheral arterial disease, the authors demonstrated empirically that this method may be useful for obtaining smoothed estimates of sensitivity, specificity, and predictive values. As an extension of this method, an approach to the modeling of the relative sensitivity of two screening tests is described, using data from a study of screening procedures for colorectal disease as an example.
Arterial Occlusive Diseases↗
Psychological and behavioral implications of abnormal mammograms.
OBJECTIVE: To evaluate women's psychological responses to abnormal mammograms and the effect on mammography adherence. To identify psychological responses and other factors that predict mammography adherence in women with normal or abnormal mammograms. DESIGN: Survey study with prospective analysis of factors associated with mammography adherence. SETTING: Health Maintenance Organization of Pennsylvania and New Jersey (HMO PA/NJ). PATIENTS: Study patients, members of HMO PA/NJ who were 50 years of age or older, and who had had mammography done 3 months earlier, included women with normal mammograms (n = 121), women with low-suspicion mammograms (n = 119), and women with high-suspicion mammograms (n = 68), but not women with breast cancer. MEASUREMENTS: Psychological responses 3 months after mammography and adherence to subsequent annual mammography were assessed. MAIN RESULTS: Women with high-suspicion mammograms had substantial mammography-related anxiety (47%) and worries about breast cancer (41%). Such worries affected the moods (26%) and daily functioning (17%) of these women, despite diagnostic evaluation excluding malignancy. For each variable, a consistent trend (P greater than 0.05) was seen with degree of mammogram abnormality. Sixty-eight percent of women with normal results, 78% of women with low-suspicion results, and 74% of women with high-suspicion results obtained their subsequent annual mammograms (P greater than 0.05). The number of previous mammograms (odds ratio, 3.2; 95% CI, 1.6 to 6.2) and the effect of the previous results on concerns about breast cancer (odds ratio, 0.5; CI, 0.2 to 1.0) were independent predictors of adherence in logistic regression analyses (P less than 0.05). CONCLUSIONS: A substantial proportion of women with suspicious mammograms have psychological difficulties, even after learning that they do not have cancer. Such sequelae do not appear to interfere with subsequent adherence.
Aged↗
Regression methods for estimating attributable risk in population-based case-control studies: a comparison of additive and multiplicative models.
A regression method that utilizes an additive model is proposed for the estimation of attributable risk in case-control studies carried out in defined populations. In contrast to previous multivariate procedures for the estimation of attributable risk, which have utilized logistic regression techniques to adjust for confounding factors, the model assumes an additive relation between the covariates included in the regression equation. As an empirical example, additive and logistic models were fitted to matched case-control data from a population-based study of childhood astrocytoma brain tumors. Although both models fitted the data well, the additive model provided a more satisfactory estimate of the risk attributable to multiple exposures, in the absence of significant additive interaction. In contrast to the results from the logistic model, the adjusted estimates of the risk attributable to each factor included in the additive model summed to the overall estimate for all of the factors considered jointly. Thus, the additive approach provides a useful alternative to existing procedures for the multivariate estimation of attributable risk when the additive model is determined to be appropriate on the basis of goodness-of-fit.
Astrocytoma↗
Psychological side effects of breast cancer screening.
Evaluated the impact of receiving abnormal mammogram results on women's anxiety and breast cancer worries and on their breast self-examination (BSE) frequency and intentions to obtain subsequent mammograms. A telephone survey was conducted with 308 women 50 years old and older approximately 3 months following a screening mammogram. Subjects included women with suspicious abnormal mammograms, nonsuspicious abnormal mammograms, and normal mammograms. Women with suspicious abnormal mammograms exhibited significantly elevated levels of mammography-related anxiety and breast cancer worries that interfered with their moods and functioning, despite the fact that diagnostic work-ups had ruled out breast cancer. Women with moderate levels of impairment in mood or functioning were more likely to practice monthly BSE than women with either high or low levels of impairment. Breast cancer worries, perceived susceptibility to breast cancer, and physician encouragement to get mammograms all exhibited independent positive relationships to mammogram intentions.
Adaptation, Psychological↗
Dietary fiber, vegetables, and colon cancer: critical review and meta-analyses of the epidemiologic evidence.
Whether colon cancer risk can be modified by a diet rich in vegetables, grains, and fruit, and, if so, whether the protective factor is dietary fiber or other biologically active components correlated with a high-fiber diet are questions of active research interest. Because studies on diet are susceptible to bias from a number of sources, in this review we evaluated the adequacy of study methodology as well as study results to clarify how much protection, if any, is conferred by a high-fiber diet. The review consisted of an aggregate assessment of the strength of evidence from 37 observational epidemiologic studies as well as meta-analyses of data from 16 of the 23 case-control studies. Both types of analyses revealed that the majority of studies gave support for a protective effect associated with fiber-rich diets; an estimated combined odds ratio (OR) of 0.57 (95% confidence interval = 0.50, 0.64) was obtained when the highest and lowest quantiles of intake were compared. Risk estimates based on vegetable consumption (OR = 0.48) were only slightly more convincing than those based on an estimate of fiber intake (OR = 0.58), but the data do not permit discrimination between effects due to fiber and nonfiber effects due to vegetables.
Case-Control Studies↗
Factors associated with repeat adherence to breast cancer screening.
This study identified barriers and facilitators of repeat participation in mammography and breast physical examination among women ages 50 years and over. Telephone interviews were conducted with 910 women in this age group. Forty percent of respondents had never had a mammogram. Only 38% had had one in the past 12 months. Of women who had a prior mammogram, 43% had had only one. Only 60% of women had had a breast exam in the past 12 months. A physician recommendation was the single best predictor of adherence to mammography. However, only 60% of women reported that their physicians had ever recommended mammography. Several other barriers to mammography were revealed, including anxiety, embarrassment, and concerns about cost and radiation. Both a family history of breast cancer and heightened perceived vulnerability to breast cancer were associated positively with repeat mammography participation; anxiety about screening reduced the likelihood of this outcome. These findings suggest that physicians can play a powerful role in motivating women to participate in initial and subsequent breast cancer screening. Reassurance may reduce women's anxiety and embarrassment and increase utilization further.
Age Factors↗
How valid are mammography self-reports?
We compared mammography reports in medical records to self-reports obtained during a 1989 telephone interview survey for a sample of 100 women members of a health maintenance organization (HMO) who indicated they had mammograms within the past year and 100 who said they had not had mammograms within the past year. Of the women reporting they had not had mammograms within the past year, none had mammogram reports in the HMO data center. Of the 100 women reporting they had mammograms within the past year, 94 had confirmatory radiology records.
Aged↗
Interactions and public health decisions.
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Decision Making↗
Why do some women get regular mammograms?
One in nine American women will be diagnosed with breast cancer at some time in their lives. Although mammography is a proven technology for diagnosing early, curable breast cancer, most women do not obtain regular mammograms. The purpose of this study was to identify the characteristics of women who received more than one mammogram. Such information is needed to develop health education programs aimed at fostering adherence to routine mammographic screening. The data were obtained from a 1989 random telephone survey of 910 women 50-74 years of age. The survey is part of the evaluation strategy for a five-year breast screening study. Two-thirds of the respondents reported having had mammograms. Most of these women had one or two mammograms. We report two logistic regression models which describe women who had mammograms in the past year and those who had one versus two or more mammograms. The most important variable in the models was physician support. Other consistently significant variables included being willing to pay $75-$100 (although most women did not pay this amount), visiting the doctor at least annually when healthy, being a nonsmoker, and recognizing that women older than 50 are at greater risk for breast cancer. The results indicate that two-pronged educational strategies aimed at both women and their physicians are needed to increase the percentage of women who obtain regular mammograms.
Aged↗
Breast screening practices among primary physicians: reality and potential.
Increased use of regular screening mammograms and clinical breast examinations (CBE) among women aged 40 years and more could have a dramatic impact on mortality from breast cancer, but patient and physician barriers to mammography impede its acceptance. We conducted a survey of 300 primary care physicians to assess their knowledge, attitudes, beliefs, and breast screening practices. Our results show that only 71 percent of the respondents ordered mammograms for all women aged 50 to 75 years, which is the recommendation by the National Cancer Institute and American Cancer Society. Approximately 46 percent of respondents performed CBE on all women patients aged 50 to 75 years. Inadequate patient insurance coverage, equivocal radiology reports, patient reluctance or worry, and patient embarrassment all appear to be barriers to physicians' utilization of breast screening.
Adult↗