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M J Stampfer

Publications and source records attributed to M J Stampfer.

At least 469 records · Page 26Linked to original sources
PubMed1987

The influence of age, relative weight, smoking, and alcohol intake on the reproducibility of a dietary questionnaire.

To evaluate factors that affect the reproducibility of a semi-quantitative food frequency questionnaire used in a large prospective study we compared an extended 99-item questionnaire with a shorter, 61-item form completed by 1497 women with an interval of nine months between. Correlation coefficients for individual items assessed by the two questionnaires were highest for beverages (Spearman r = 0.70). For other foods, coefficients ranged from 0.60 to 0.70 for items eaten frequently (or habitually), to values between 0.34 and 0.45 for foods, such as sweet potatoes and ready made pie, that were eaten less frequently. For food items, the correlation between mean frequency of consumption and the reproducibility coefficient (Spearman r) was 0.51 (p less than 0.01), formally confirming that the reproducibility of measurements was positively associated with frequency of use. Pearson correlation coefficients for calorie-adjusted intakes of nutrients between the two questionnaires ranged from 0.40 for trans-fatty acids to 0.71 for vitamin E (including supplements). These correlation coefficients did not vary materially between subjects in different categories of smoking status or tertiles of age or relative weight. Moderate alcohol use had minimal effect on correlation coefficients, but reproducibility was slightly reduced among heavier drinkers. These data indicate that this self-administered dietary questionnaire can provide reproducible information about individual food and nutrient intakes which is not altered materially by age and a number of important health habits.

Adult↗
PubMed1987

A prospective cohort study of postmenopausal hormone use and risk of breast cancer in US women.

The association between history of postmenopausal hormone use as of 1976 and breast cancer incidence during 1976-1980 was examined prospectively among 33,335 married, postmenopausal registered nurses aged 30-55 years at entry. Half the women reported postmenopausal hormone use, and one fourth had taken these drugs for over five years. During 1976-1980, 221 new cases of breast cancer were identified. The relative risk (RR) for those who had used postmenopausal hormones when compared with women who had never used them was 1.1 (95% confidence limits (CL) 0.8, 1.4); for current and past users, the relative risks were 1.0 (95% CL 0.7, 1.4) and 1.3 (95% CL 0.9, 1.8), respectively. These ratios were not substantially modified by whether or not a woman's ovaries had been removed or by other known breast cancer risk factors. No increase in breast cancer risk was apparent among women who had used postmenopausal hormones for less than five years (RR = 1.0, 95% CL 0.5, 1.6). An apparent effect among the subgroup of women who had used them for five to nine years (RR = 1.5, 95% CL 1.0, 2.2) was not present among the few women with longer-term use (RR = 0.9, 95% CL 0.4, 1.6). These findings are moderately reassuring, but since there are as yet few women in this cohort with long-term durations of use and, particularly, with long intervals since first use, continued follow-up of this and other cohorts will be required before firm conclusions can be drawn, especially among specific subgroups.

Adult↗
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

Effect of dietary fats and carbohydrate on blood pressure of mildly hypertensive patients.

The effect on blood pressure (BP) of replacing dietary saturated fat with either polyunsaturated fat (linoleic acid) or carbohydrate was studied in 21 untreated mildly hypertensive patients. In a randomized, double-blind, crossover protocol, all subjects received dietary supplements of cream, safflower oil, and carbohydrate in random sequence, each prepared in flavored yogurt or milk. Each supplement was administered for 6 weeks and followed by a 4-week washout period of no supplementation. Dietary linoleic acid increased from 4.6 to 13% of energy intake when the safflower oil replaced cream, while saturated fat decreased from 16 to 10%. Total fat intake was 37 to 38% during the cream and safflower oil periods but was 28% during the carbohydrate period. Compliance with the diets was demonstrated by significant changes in fasting plasma fatty acid measurements. Mean clinic BP was 135 +/- 9/93 +/- 6 mm Hg at baseline. There were no significant differences in BP measured in the clinic or at home among the three dietary periods. The protocol had more than 80% power to detect a mean effect of diet of 3 mm Hg systolic or 2 mm Hg diastolic BP. Therefore, replacing dietary saturated fat with carbohydrate or with linoleic acid does not affect BP in subjects with mild hypertension.

Adult↗
PubMed1987

Smoking behavior among participants in the nurses' health study.

We analyzed smoking behavior of 91,651 married female nurses, aged 30-55 years in 1976. The prevalence of smoking was similar among all birth cohorts. The largest percentage increase in starting to smoke occurred between ages 15 and 25 years; by age 25, 50 per cent had started smoking. The cessation rate was lowest in earlier birth cohorts and among nurses starting to smoke at earlier ages. The cessation rate increased substantially between 1963-73 compared with the period 1948-58.

Adult↗
PubMed1987

Reference ranges of retinol, tocopherols, lycopene and alpha- and beta-carotene in plasma by simultaneous high-performance liquid chromatographic analysis.

Using a high-performance liquid chromatographic procedure, age- and gender-based reference ranges for plasma retinol, alpha- and gamma-tocopherol, lycopene, and alpha- and beta-carotene have been established. In addition to confirming higher retinol levels in men than in women (p less than 0.001), this study demonstrates significantly higher plasma levels of both carotenes in women than in men (p less than 0.001). The plasma levels of retinol and beta-carotene showed a positive relationship with age after adjusting for plasma lipids (p less than 0.001 and p less than 0.02, respectively). In contrast to beta-carotene, there was no gender difference for plasma lycopene and a strong (p less than 0.001) inverse relationship of lycopene with age. These results suggest that differences may exist between beta-carotene and lycopene in their intestinal absorption, plasma transport, or tissue metabolism.

Adolescent↗
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

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

Effect of alternate-day regular and enteric-coated aspirin on platelet aggregation, bleeding time, and thromboxane A2 levels in bleeding-time blood.

The effectiveness of low-dose aspirin for primary prevention of cardiovascular mortality is being assessed among the nearly 22,000 United States physicians currently participating in the Physicians' Health Study. Because of occasional reports of gastric irritation among study participants, two enteric-coated aspirin preparations were tested as possible alternatives to regular compressed aspirin for platelet inhibition. Thirty-three volunteers were assigned randomly to one of four treatment groups: regular aspirin (325 mg), placebo, and two enteric-coated aspirin preparations (325 mg). Pills were administered every other day, duplicating the regimen used in the Physicians' Health Study. Bleeding times, platelet aggregation, and thromboxane A2 levels produced by aggregating platelets in vitro, as well as in collected bleeding-time blood, were determined. Measurements were taken before and after a single dose as well as after seven alternate-day doses. Regular and enteric-coated aspirin preparations were equally efficacious in prolonging the bleeding time, inhibiting platelet aggregation, and suppressing thromboxane A2 production. There was virtually complete suppression of thromboxane A2 production (over 99 percent), by platelets in vitro and in collected bleeding-time blood. The levels were still profoundly reduced (89 percent) 48 hours after the last dose. Enteric-coated aspirin may provide an alternative to regular aspirin in a low-dose regimen designed to inhibit platelet activity.

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↗
PubMed1986

Total energy intake: implications for epidemiologic analyses.

Associations between intake of specific nutrients and disease cannot be considered primary effects of diet if they are simply the result of differences between cases and noncases in body size, physical activity, and metabolic efficiency. Epidemiologic studies of diet and disease should therefore be directed at the effect of nutrient intakes independent of total caloric intake in most instances. This is not accomplished with nutrient density measures of dietary intake but can be achieved by employing nutrient intakes adjusted for caloric intake by regression analysis. While pitfalls in the manipulation and interpretation of energy intake data in epidemiologic studies have been emphasized, these considerations also highlight the usefulness of obtaining a measurement of total caloric intake. For instance, if a questionnaire obtained information on only cholesterol intake in a study of coronary heart disease, it is possible that no association with disease would be found even if a real positive effect of a high cholesterol diet existed, since the caloric intake of cases is likely to be less than that of noncases. Such a finding could be appropriately interpreted if an estimate of total caloric intake were available. The relationships between dietary factors and disease are complex. Even with carefully collected measures of intake, consideration of the biologic implications of various analytic approaches is needed to avoid misleading conclusions.

Adult↗
PubMed1986

Low-dose enteric-coated aspirin: a practical approach to continuous-release low-dose aspirin and presystemic acetylation of human platelet cyclooxygenase.

Using a granular enteric-coated aspirin (ECA) preparation, we achieved continuous release of low-dose aspirin and associated inhibition of platelet reactivity. The lowest once-daily dose that produced greater than 90% inhibition of serum thromboxane (TX) A2 after 7 days was 80 mg. The time course of inhibition after the first dose indicated a gradual release of aspirin over a period of 8 hours. We subsequently fractionated this 80 mg dose into three times daily doses of 27 mg that were administered to nine healthy men for 7 days. This regimen resulted in 96% inhibition of serum TXA2 generation (P less than 0.001), inhibition of in vitro platelet aggregation (P less than 0.05), prolongation of the bleeding time by 75% (P less than 0.01), and a threefold increase in inhibition of platelet aggregation by prostacyclin (P less than 0.01) compared with pre-ECA values. In contrast to our previous study using daily 80 mg doses of ECA, after the 27 mg three times daily regimen we found a significant increase in circulating platelet cyclooxygenase activity 24 hours after the final dose (P less than 0.05). This immediate recovery indicates active megakaryocyte cyclooxygenase and suggests that acetylation of platelet cyclooxygenase was restricted to the presystemic circulation. We conclude that long-term dosing with 27 mg ECA three times daily results in profound inhibition of platelet TXA2 production, and diminished in vitro and in vivo platelet reactivity. This regimen provides a practical approach to achieving continuous release of low-dose aspirin and possible presystemic acetylation of platelet cyclooxygenase.

Acetylation↗
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↗