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Biomedical subjects

G A Colditz

Publications and source records attributed to G A Colditz.

At least 487 records · Page 27Linked to original sources
PubMed1987

A prospective study of age at menarche, parity, age at first birth, and coronary heart disease in women.

Reproductive events in women are associated with alterations in blood lipids and blood pressure and may therefore influence determinants of coronary heart disease. To investigate the risk of coronary heart disease in relation to age at menarche, parity, and age at first birth, the authors evaluated prospectively the experience of 119,963 US women aged 30-55 years who were free from coronary heart disease in 1976 and were followed through 1982. During 700,809 person-years of observation, 308 incident cases of nonfatal myocardial infarction or fatal coronary heart disease occurred. Younger age at menarche was weakly associated with coronary heart disease (age-adjusted rate ratio of 1.3 for menarche before age 11 years compared with menarche at age 13 years; chi, Mantel extension test for trend = -1.1, p = 0.2). Nulliparous women experienced only a slightly higher rate of coronary heart disease than parous women (rate ratio = 1.2, 95 per cent confidence interval 0.8-1.8). Among parous women, there was no alteration in risk with increasing number of births. Likewise, there was no significant association between age at first birth and coronary heart disease (chi, Mantel extension test for trend = -0.4, p = 0.4). Established risk factors for coronary heart disease nevertheless showed expected relations. These findings show no important association between reproductive experiences and risk of coronary heart disease.

Adult↗
PubMed1987

Cost effectiveness of labetalol and propranolol in the treatment of hypertension among blacks.

The cost effectiveness of labetalol and propranolol in the treatment of black adults with mild to moderate hypertension was assessed using published reports from US clinical trials of these agents among such patients. Data from these studies suggest that labetalol and propranolol lower diastolic blood pressure among black hypertensive adults by 11.2 mmHg and 8.4 mmHg, respectively. Results indicate that, for a hypothetical cohort of 1,000 patients on monotherapy, patients treated with labetalol would experience two to seven fewer strokes over a ten-year period, depending upon age and sex, and annual drug costs would be reduced by $190. For stepped care, annual costs would be $205 and $212 lower for those treated initially with labetalol. Labetalol therefore may be more cost effective than propranolol among black adults with mild to moderate hypertension.

Aged↗
PubMed1987

Use of permanent hair dyes and risk of breast cancer.

Aromatic amines contained in permanent hair dyes can be absorbed percutaneously and are mutagenic and carcinogenic in some laboratory studies. Concern has been raised that use of these dyes may increase the risk of human cancers. Therefore, the present study examined the relationship between permanent hair dye use and incidence of breast cancer among 118,404 U.S. women aged 30-55 years who were followed prospectively for 6 years. Among women who had ever used permanent hair dyes, 353 developed breast cancer during 246,848 person-years of follow-up, while 505 cases occurred during 397,460 person-years among never users (age-adjusted rate ratio = 1.1; 95% confidence interval = 0.9-1.2). Identical rate ratios were observed when women who had ever used hair dyes were subdivided into current and past users. Adjustment for known determinants of breast cancer in multivariate models did not alter these relationships. The risk of breast cancer did not increase with more frequent use, longer duration of use, or interval since first use. On the basis of these data and previous findings, it appears unlikely that the use of permanent hair dyes causes any important increase in risk of breast cancer.

Adult↗
PubMed1986

Cost-effectiveness of nicotine gum as an adjunct to physician's advice against cigarette smoking.

A nicotine chewing gum has recently become available for use as an aid in giving up cigarette smoking. Although its efficacy has been demonstrated in clinic-based smoking cessation programs, its value in a primary care setting is uncertain. We examined the cost-effectiveness of nicotine gum as an adjunct to physician's advice and counseling against smoking during routine office visits. Our findings indicate that the cost per year of life saved with this intervention ranges from $4113 to $6465 for men and from $6880 to $9473 for women, depending on age. This compares favorably with other widely accepted medical practices, eg, treatment of hypertension or hyperlipidemia. Our study, therefore, suggests that nicotine gum is a cost-effective adjunct to physician's advice against cigarette smoking in a primary care setting.

Adult↗
PubMed1986

Rates of venous thrombosis after general surgery: combined results of randomised clinical trials.

Despite evidence that prophylaxis against deep-vein thrombosis (DVT) is effective, a large proportion of general surgical patients receive no prophylaxis. To determine the extent to which various prophylactic methods reduce the incidence of postoperative DVT, data from randomised controlled trials of these methods were combined by means of meta-analysis. The rates of DVT diagnosed by the fibrinogen uptake test were: control/no therapy 27.0% (95% confidence limits 21.9%, 32.1%); heparin 9.6% (7.2%, 11.9%); gradient compression stockings 11.1% (5.3%, 16.8%); intermittent pneumatic compression 17.6% (6.1%, 29.1%); heparin plus stockings 6.3% (0%, 17.6%); heparin plus dihydroergotamine 9.9% (6.2%, 13.6%); and stockings plus intermittent pneumatic compression 4.5% (1.1%, 8.0%). These results confirm the value of prophylaxis to reduce the incidence of DVT and suggest that combined treatments may be most effective.

Clinical Trials as Topic↗
PubMed1986

Oral contraceptives and breast cancer. A prospective cohort study.

In 1976, information on oral contraceptive (OC) use as well as numerous risk factors for breast cancer was provided by 121,964 married female registered nurses aged 30 to 55 years. Ninety-two percent of women in the cohort completed follow-up questionnaires, and vital records were systematically searched to ascertain deaths among nonrespondents. After four years of follow-up, 592 incident cases of breast cancer were identified. Compared with never users, the age-adjusted relative risk (RR) of breast cancer, regardless of menopausal status, among all women who had ever used OCs was 1.0. Among premenopausal women compared with those who had never used OCs, the RR of breast cancer was 1.5 for current use of OCs in 1976 and 1.0 for past use. Among postmenopausal women, the RR for past use of OCs was 1.0. These estimates were essentially unaltered after controlling for other known risk factors for breast cancer in multiple logistic regression analysis. Furthermore, there was no modification of these effects by family history of breast cancer, age at first use, timing of the first birth, or other breast cancer risk factors. Data on past use of OCs provide substantial reassuring evidence that there is no large excess risk of breast cancer within a few years of cessation of pill use. The observed moderate elevation of breast cancer risk with current use was of borderline statistical significance. However, the observation was based on 29 cases and may reflect the effect of sampling variability, as most other studies have not observed a relationship between current use of OCs and breast cancer in women of this age.

Adult↗
PubMed1986

A prospective study of parental history of myocardial infarction and coronary heart disease in women.

Among 121,964 women aged 30-55 years in 1976, 117,156 who were initially free from coronary heart disease provided information on a number of coronary risk factors including parental history of myocardial infarction and were followed prospectively. In 1976, 31,101 (26.5%) reported that at least one parent had suffered a myocardial infarction. Questionnaires in 1978 and 1980 identified women who had developed nonfatal myocardial infarction (n = 132) and angina pectoris (n = 101). Fatal coronary heart disease cases (n = 42) were ascertained by searches of state vital records. The age-adjusted relative risk of nonfatal myocardial infarction for women with a parental history of myocardial infarction less than or equal to 60 years of age compared with women with no family history was 2.8 (95% confidence limits (CL) 1.8, 4.3). For those with a parental history of myocardial infarction greater than 60 years of age, the age-adjusted relative risk of nonfatal myocardial infarction was 1.0 (CL 0.5, 1.8). The age-adjusted relative risks of fatal coronary heart disease were 5.0 (CL 2.7, 9.2) for parental history before age 61 and 2.6 (CL 1.1, 5.8) for parental history after age 60. The corresponding relative risks of angina pectoris were 3.4 (CL 2.2, 5.2) and 1.9 (CL 1.2, 3.2), respectively. These associations were only slightly altered by adjustment for history of hypertension, diabetes, high cholesterol, use of oral contraceptives, menopause, postmenopausal hormone use, obesity, or smoking, in individual stratified analysis or in multivariate analyses. These data support the hypothesis that parental history of myocardial infarction has an independent effect on risk that is not explained solely by individual risk factors.

Adult↗
PubMed1986

Validation of questionnaire information on risk factors and disease outcomes in a prospective cohort study of women.

To assess the validity of self-reported illnesses, medical records were reviewed for participants reporting major illnesses on the biennial follow-up questionnaires used in a prospective cohort study which began in 1976. In over 90% of cases of cancer of the breast, skin, large bowel, and thyroid, histopathology reports confirmed the subjects' self-report. Lower levels of confirmation were obtained for cancers of the lung, ovary, and uterus. Application of strict diagnostic criteria also gave lower levels of confirmation for myocardial infarction (68%) and stroke (66%). Among random samples of women reporting fractures and hypertension all records obtained confirmed self-reports. For self-reported elevated cholesterol levels 85.7% of self-reports were confirmed. Self-report is a valuable epidemiologic tool but may require additional documentation when the disease is diagnostically complex.

Adult↗
PubMed1985

A prospective study of postmenopausal estrogen therapy and coronary heart disease.

To clarify the possible role of postmenopausal estrogen use in coronary heart disease, we surveyed 121,964 female nurses, aged 30 to 55 years, with mailed questionnaires, beginning in 1976. Information on hormone use and other potential risk factors was updated and the incidence of coronary heart disease was ascertained through additional questionnaires in 1978 and 1980, with a 92.7 per cent follow-up. End points were documented by medical records. During 105,786 person-years of observation among 32,317 postmenopausal women who were initially free of coronary disease, 90 women had either nonfatal myocardial infarctions (65 cases) or fatal coronary heart disease (25 cases). As compared with the risk in women who had never used postmenopausal hormones, the age-adjusted relative risk of coronary disease in those who had ever used them was 0.5 (95 per cent confidence limits, 0.3 and 0.8; P = 0.007), and the risk in current users was 0.3 (95 per cent confidence limits, 0.2 and 0.6; P = 0.001). The relative risks were similar for fatal and nonfatal disease and were unaltered after adjustment for cigarette smoking, hypertension, diabetes, high cholesterol levels, a parental history of myocardial infarction, past use of oral contraceptives, and obesity. These data support the hypothesis that the postmenopausal use of estrogen reduces the risk of severe coronary heart disease.

Adult↗
PubMed1985

Increased green and yellow vegetable intake and lowered cancer deaths in an elderly population.

In a prospective cohort study of 1271 Massachusetts residents 66 years of age or older, we examined the association between consumption of carotene-containing vegetables and subsequent five year mortality. Dietary information was obtained by food frequency questionnaire in 1976. The relative risk of cancer mortality was examined within quintiles of green and yellow vegetable score (calculated from intake of carrots or squash, tomatoes, salads or leafy vegetables, dried fruits, fresh strawberries or fresh melon, and broccoli or brussel sprouts). After controlling for age and smoking behavior, those in the highest quintile of intake of these carotene-containing vegetables had a risk of cancer mortality which was 0.3 (95% confidence limits 0.10-0.96) that of those in the lowest quintile. The trend of decreased cancer risk with increasing intake of carotene containing vegetables was significant (p = .026). This relationship is consistent with the hypothesis that carotene may act as an inhibitor of carcinogenesis.

Aged↗
PubMed1985

Relative weight and risk of breast cancer among premenopausal women.

Although higher relative weight is generally considered to increase the risk of breast cancer, several case-control studies have suggested that the reverse may be true among premenopausal women. The association between Quetelet's index (a measure of relative weight calculated as weight/height) and the subsequent incidence of breast cancer was therefore examined during four years of follow-up among a cohort of 121,964 US women who were 30-55 years of age in 1976. In contrast to women who had experienced natural menopause or bilateral oophorectomy, the incidence of breast cancer among premenopausal women decreased with higher levels of relative weight. Age-adjusted relative risks for increasing quintiles of Quetelet's index were 1.00, 0.90, 0.90, 0.73, and 0.66 (Mantel extension test for trend = -2.82, p = 0.005). This inverse association was not explained by known risk factors for breast cancer and was somewhat stronger when Quetelet's index was computed using reported weight at age 18 years. The excess incidence of breast cancer among lean premenopausal women, however, was limited to tumors that were less than 2.0 cm in diameter, were not associated with metastases to lymph nodes, and were well-differentiated. These findings suggest that the apparent excess risk of breast cancer among lean premenopausal women may result at least in part from easier, and thus earlier, diagnosis of less aggressive tumors.

Adult↗
PubMed1985

The statistical content of published medical research: some implications for biomedical education.

Medical students and doctors need training in biostatistics. The use of analytic statistics in a leading general medical journal is reported. Of 760 consecutive research and review articles, 42% use statistical methods beyond elementary descriptive statistics. Critical reading of the medical literature requires an understanding of many statistical methods. The frequency of use of such methods may help identify those which should receive greater attention in instructional programmes within the medical curriculum. Based on the frequencies and our understanding of the importance of broad statistical concepts, recommendations are developed for the basic course in biostatistics. The integration of several more advanced statistics modules into clinical training is also suggested. The use is recommended of clinically oriented textbooks in biostatistics and current journal articles to help make instruction in statistics more relevant for preclinical students, and to help clinicians appreciate the applications of statistics to their work.

Biometry↗
PubMed1984

The economic costs of smoking and benefits of quitting for individual smokers.

The results of a study that estimated the expected lifetime economic consequences of cigarette smoking for individual smokers are reported herein. The estimates were obtained by combining age- and sex-specific estimates of the incidence-based costs of three smoking-related diseases (lung cancer, coronary heart disease, and emphysema) with estimates of smokers' increased likelihood of developing these illnesses in each remaining year of life relative to nonsmokers. Estimates of the economic consequences of quitting based on these disease cost estimates and on estimates of exsmokers' probability of future disease relative to continuing smokers are also reported. Both the estimates of the economic costs of smoking and the benefits of quitting were calculated separately for men and women between the ages of 35 and 79 who were light, moderate, or heavy cigarette smokers. While the economic costs of smoking varied considerably by sex, age, and amount smoked, they were significant for all groups of smokers. Costs for a 40-year-old man, for example, ranged from $20,000 for a smoker of less than one pack of cigarettes per day to over $56,000 for a smoker of more than two packs of cigarettes per day. The economic benefits of quitting also were found to be sizable for all groups of smokers.

Adult↗