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Biomedical subjects

A B Miller

Publications and source records attributed to A B Miller.

At least 217 records · Page 12Linked to original sources
PubMed1989

Risk of bladder cancer by source and type of tobacco exposure: a case-control study.

The association between tobacco use and risk of bladder cancer was investigated in a population-based case-control study conducted in Alberta and south-central Ontario, Canada, between 1979 and 1982. In all, 826 histologically-confirmed cancer cases and 792 randomly selected controls, individually matched to cases for age, sex, and area of residence, were recruited into the study. Compared to those who had never smoked cigarettes, males and females who had ever smoked cigarettes had a statistically highly significant 2-fold increase in risk of bladder cancer; for ex-smokers, the risk was intermediate between that for current smokers and never-smokers. There was a dose-dependent increase in risk of bladder cancer with total lifetime cigarette consumption, of similar magnitude for males and females. In males, risk increased with self-reported degree of inhalation in ex-smokers and in current smokers (statistically significant trend), while in females there was no association in current smokers, and a statistically significant inverse association in ex-smokers. Overall, risks of bladder cancer associated with lifetime consumption of plain and filter cigarettes were similar, and there was little evidence to suggest that switching from plain to filter cigarettes was beneficial. Neither passive smoking nor other forms of tobacco consumption (pipes, cigars, chewing tobacco, or snuff) were associated with altered risk of bladder cancer. The population attributable risk for cigarette smoking was about 47% in males and about 33% in females.

Adult↗
PubMed1989

Physical examination. Its role as a single screening modality in the Canadian National Breast Screening Study.

Although often recommended as an important component in screening for breast cancer, physical examination of the breasts (PE) by medical professionals has not been well evaluated. The Canadian National Breast Screening Study (NBSS) permits estimation of sensitivity, specificity, and positive predictive value (PPV) of PE alone as performed by screen-examiners because 50% of the 89,835 NBSS participants did not receive mammography. There were 19,965 women aged from 50 to 59 years who were eligible to receive four or five annual PEs from 77 nurse-examiners, in 12 screen centers outside Quebec province and 58 physician-examiners in three screen centers in Quebec. The gold standard was histologically proven breast cancer. When a test was positive the participant was referred to the study surgeon for review. For screens one to five, sensitivity was 83, 71, 57, 83, and 77; specificity was 88, 94, 96, 96, and 96; and PPV was 3, 3, 4, 3, and 4, respectively. For 25,620 women aged 40 to 49 years who were eligible to receive only one PE, sensitivity was 71, specificity 84, and PPV 1.5. Using a binomial regression model, X2 for heterogeneity suggested there was no difference between nurse and physician examiners (P = 0.6879). Similar estimates made for the surgeons who performed 8914 reviews showed that sensitivity and PPV were higher than for the screen examiners and specificity was lower. These results support the conclusion that physical examination of the breasts by trained nurses is a useful component in screening for breast cancer.

Adult↗
PubMed1989

Separation of afterload reduction and a direct beneficial cardiac effect of nifedipine in congestive cardiomyopathy.

To assess whether the calcium antagonist nifedipine has a specific, direct effect on left ventricular diastolic function separate from its vasodilatory action, we studied 10 patients with idiopathic congestive cardiomyopathy (ages 28-69, New York Heart Association Class III or IV) at 30 min, 2 h, and 6 h after administration of 10 mg of sublingual nifedipine. Hemodynamic parameters were assessed with Swan-Ganz catheter and two-dimensional echo images were processed with computer-assisted analysis (Quantic 1200) to obtain left ventricular chamber areas and an index of rapid diastolic filling. Indices of left ventricular systolic performance (cardiac index and left ventricular area change fraction) improved during the early (30 min and 2 h) observation periods as afterload (estimated by systolic blood pressure and systemic vascular resistance) was reduced (p less than .05 vs. baseline). Pulmonary capillary wedge pressure fell from 17 mmHg to 11 mmHg and rapid diastolic filling index increased from .28 (% area change/ms) to .37 (% area change/ms) (p less than .05 vs. baseline) during the early observation periods. Indices of left ventricular systolic performance and afterload had returned to baseline at the late (6 h) observation period. However, pulmonary capillary wedge pressure remained reduced significantly at 10 mmHg after 6 h (p less than .05 vs. baseline). Preload (estimated by left ventricular end-diastolic chamber area) did not vary throughout the study period. Reduction of pulmonary capillary wedge pressure at 6 h, despite return of afterload reduction to baseline and no change in preload, suggests improved left ventricular chamber compliance after sublingual nifedipine, not related to alteration of left ventricular loading conditions.

Adult↗
PubMed1989

A study of repeatability of dietary data over a seven-year period.

A repeatability study of dietary intake has been carried out using 94 control subjects from a previously reported case-control study of diet and colorectal cancer. Dietary histories readministered on average seven years after an initial interview were used to estimate intake of various macro- and microdietary components. Comparisons of current intake with intake of seven years previously yielded good reliability for macrocomponents among subjects reporting no dietary change during the time period. Reliability was poorer for microcomponents and for subjects reporting a dietary change. Comparisons were also made between diet measured seven years previously with subjects' recall of that diet. It is concluded that current diet is at least as reliable a measure of past diet as that assessed by a questionnaire addressed to the past period.

Aging↗
PubMed1989

Cigarette smoking and breast cancer: case-control studies of prevalent and incident cancer in the Canadian National Breast Screening Study.

Two case-control studies of Canadian women aged 40-59 years are reported investigating the relation of cigarette smoking with initial visit (prevalent) and subsequent visit (incident) breast cancer detection, respectively, within the Canadian National Breast Screening Study. The analysis of prevalent breast cancer (1982-1985), which involved 254 cases and 762 controls, showed no evidence of an elevated risk for women with a history of cigarette smoking, with odds ratios of 0.9 (95% confidence interval (Cl) 0.6-1.5) and 1.2 (95% Cl 0.8-1.8) in premenopausal and postmenopausal subjects, respectively. Similarly, in the incident breast cancer analysis (1981-1987) based on 317 cases and 951 controls, women with a history of cigarette smoking had odds ratios of 1.2 (95% Cl 0.8-2.0) and 1.2 (95% Cl 0.9-1.7) in the premenopausal and postmenopausal categories, respectively. No evidence of dose response or of elevated risk in ex-smokers or current smokers was found in either study. These results persisted despite adjustment for several important variables. The present data demonstrate no association between smoking and prevalent or incident breast cancer in either menopausal category, contradicting the authors' previous finding of a positive association with premenopausal prevalent disease earlier in this screening study. The relation of smoking and breast cancer remains controversial. Further study is required to determine whether an association truly does not exist or whether smoking might have both protective and harmful effects that are mediated through different pathways, thus accounting for the paradoxical findings in the literature to date.

Adult↗
PubMed1989

Demand analysis of mental health service use among ethnic subpopulations.

This paper estimates demand for mental health services by blacks, Hispanics, and whites, as well as males and females, using a three-part regression model. It examines the probability of mental health use and the level of outpatient and inpatient use. The data base is the high option Blue Cross/Blue Shield Federal Employee Health Benefits Plan for the 1979 to 1981 period. All user subpopulations sharing this plan have the same coverage, so differences in demand and utilization are related to ethnic and racial background, age, salary, outpatient visit copayment and market area characteristics, including the supply of psychiatrists. Results show vast differences in demand for care by ethnic, racial, and gender groups with identical insurance coverage. Alternative explanations for the differences are suggested.

Black or African American↗
PubMed1989

Mammography: a critical evaluation of its role in breast cancer screening, especially in developing countries.

Screening for breast cancer using mammography alone, or mammography plus physical examination of the breasts, reduces mortality from breast cancer in women age 50-69. The evidence for effectiveness in older women is less clear. If effective in younger women, benefit is delayed compared to that seen in women age 50 or more. The increasing incidence of breast cancer in developing countries, and the late stage at diagnosis of most disease, supports efforts to introduce screening for breast cancer. However, the requirements of mammography in terms of technology and skilled personnel make it difficult to apply in most developing countries at present. There is a need to evaluate simpler screening tests, such as physical examination of the breasts and breast self-examination, as they can be applied by existing health personnel, and more readily integrated into medical care.

Adult↗
PubMed1988

The reliability of passive smoking histories reported in a case-control study of lung cancer.

A test-retest design has been used to examine the reliability of passive smoking histories reported in personal interviews. A total of 117 control subjects initially interviewed in a lung cancer case-control study conducted in metropolitan Toronto, Canada, between 1983 and 1984 were reinterviewed on average six months later. Responses to initial screening questions used to detect a person's exposure to passive smoke were more reliable for residential than for occupational exposure. Respondents also more reliably reported residential exposure to spouse's passive smoke than to the passive smoke of others at home. Quantitative measures of exposure to passive smoke, i.e., number and duration of exposure, were even less reliably reported. Nonsmoking respondents gave the most reliable information. The low reliability of self-reported duration of exposure to passive smoke is consistent with the inability of several studies to detect a significant dose-response relation with lung cancer risk when measures of dose that depend solely on duration are used.

Data Collection↗
PubMed1988

Dietary factors and the incidence of cancer of the urinary bladder.

A case-control study of diet and bladder cancer was conducted during 1979-1982 in Edmonton, Calgary, Toronto, and Kingston, Canada. A total of 826 histologically verified cancer cases were individually matched by age, sex, and area of residence to 792 randomly selected population controls. Subjects were interviewed concerning their histories of exposure to a number of dietary factors, including table-top artificial sweeteners, low calorie foods and drinks, beverages containing caffeine or ethanol, and certain other food items. Also, subjects provided information on their past medical, occupational, and residential histories, in addition to their exposures to tobacco and other life-style factors. For the analysis, conditional logistic regression methods were used. Under adjustment for cumulative lifetime amount of cigarette smoking, the dietary factors, with little exception, were not associated with significant alteration of risk for bladder cancer. In particular, ever regular use of artificial sweeteners did not appear to be associated with increased risk, either among men (odds ratio = 0.95, p = 0.70) or among women (odds ratio = 1.15, p = 0.53). However, daily intake of cholesterol, calculated from reported frequencies of consumption of nine relevant food items, suggested a mild increase in risk; the odds ratio estimate of trend was 1.07/100 mg average daily intake (i.e., 1.07(5.5) = 1.45 for 550 mg cholesterol per day, as might be consumed in one egg; p = 0.009). A history of diabetes mellitus of onset after age 20 years also seemed to be associated with increased risk of bladder cancer (odds ratio = 1.65, p = 0.019), but this increase did not appear to be the result of use of insulin or other medications, or use of artificial sweeteners or low calorie foods. Thus, this study tends to confirm reports of a lack of association between use of artificial sweeteners and subsequent risk of bladder cancer.

Adult↗
PubMed1988

Risk factors for spontaneous abortion and its recurrence.

Pregnancy histories of women interviewed as normal population controls during 1974-1981 in four case-control studies in the US and Canada were examined to identify risk factors for the occurrence of miscarriage. In total, 2,068 ever-gravid women aged 20-79 years at interview (mean age, 50.3 years) described 6,282 pregnancies, including 805 miscarriages. The roles of previous pregnancy history, age at pregnancy, and other factors were evaluated using relative risk binomial regression methods (similar to logistic regression). Risk of miscarriage during a given pregnancy was found to increase directly with the number of previous miscarriages (the risk was closely approximated by (1 + number of prior miscarriages)1.01), but appeared to be unrelated to the order of miscarriages within all previous pregnancies. Maternal age was also highly related to risk after controlling for gravidity and previous miscarriages, with doubled risk (compared with age 20 years) seen for pregnancies in women older than age 40 years. Risk of miscarriage did not appear to be associated with years since previous pregnancy, height, weight or obesity, use of oral contraceptives within one year before pregnancy, or duration of oral contraceptive use. A slight increase in risk was seen for women who had ever regularly smoked cigarettes (relative risk = 1.14, 95 per cent confidence limits = 1.00, 1.30). Thus, the levels of risk of miscarriage found in this analysis are similar to those of previous studies, and the analytic methods suggest how age, obstetric history, and other factors can be simultaneously examined for associations with such risk.

Abortion, Spontaneous↗
PubMed1988

Occupational factors and the incidence of cancer of the bladder in Canada.

During 1979-82, a case-control study of occupational factors and urinary bladder cancer was conducted in Edmonton, Calgary, Toronto, and Kingston, Canada. A total of 826 histologically verified cases of cancer were individually matched by sex, age, and area of residence to 792 randomly selected population controls. Subjects were specifically asked about employment in several industries thought relevant to risk of bladder cancer. Information was also obtained on lifelong occupational history, with special attention given regarding exposures to fumes, dusts, smoke, and chemicals. In addition, subjects provided data on past medical and residential history, on intake of certain dietary items, and on exposure to tobacco and other lifestyle factors. Conditional logistic regression methods were used for the analysis. Under adjustment for cumulative lifetime cigarette consumption, it appeared that for both men and women, most of the occupational factors examined were not associated with significant alteration in risk of bladder cancer. For exposures during the period eight to 28 years before diagnosis, however, raised risk was suggested for men employed at least six months in the chemicals industry (odds ratio = 2.37, p = 0.004), in dye manufacturing or the dyeing of cloth (OR = 3.62 and 4.63, p = 0.041 and 0.035, respectively), as tailors (OR = 3.85, p = 0.015), or in jobs in which contact with diesel or traffic fumes occurred (OR = 1.69, p = 0.0008). Increased risk was also seen for men occupationally exposed to tars or asphalt (OR = 3.11, p = 0.019). This study then, at least for men, supports perhaps a few of the suspect industries as related to risk of bladder cancer.

Adult↗
PubMed1988

Sensitivity and specificity of first screen mammography in 15 NBSS centres.

We report the sensitivity and specificity of first screen mammography in a 15-centre randomized screening trial. Of 44,718 women who received mammography and physical examination at first screening, 238 were diagnosed with breast cancer at first screen, 34 in the 12-month interval after the first screen, and 98 at the second screen. Seventeen of the interval cases and 47 of the second-year cancers were defined as potentially detectable at first screening. Interpretations of first screen mammograms by radiologists at the screening centres were matched to known histological outcomes. Simultaneous blind review of 2908 cases, which included all cancers detected at first and second screenings as well as interval cancers, was done by a single reference radiologist. The sensitivity of the technique as carried out at all NBSS centres was 0.75, the specificity 0.94, the positive predictive value 0.07, and the negative predictive value 0.998.

Breast Neoplasms↗
PubMed1988

Screening for cancer.

Screening has proved effective for only two cancer sites, the breast and the cervix uteri. Only for these, therefore, should screening be a part of routine clinical practice. The degree to which screening is effective depends on whether appropriate groups are screened. For cancer of the breast, current evidence justifies mammographic screening every two years only from the age of 50, continuing at least to the age of 70. The place of breast self-examination and physical examination of the breasts is under investigation, but these procedures should probably be used in all women after the age of 40. For cancer of the cervix, nearly maximal efficacy is obtained by screening sexually active women every three years from the age of 25 to 60. Older women who have not been screened regularly should be screened. Other screening techniques to detect cancers, such as the rectal examination, sigmoidoscopy, and fecal occult blood tests for colorectal cancer, are still experimental. Organizational and other difficulties will prevent screening programs from making a major contribution to reducing overall cancer mortality by the year 2000. If organizational problems can be overcome, however, screening may control invasive cancer of the cervix and make a major contribution in reducing breast cancer mortality in the future.

Adult↗