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Biomedical subjects

N F Boyd

Publications and source records attributed to N F Boyd.

At least 73 records · Page 4Linked to original sources
PubMed1992

The risk of breast cancer associated with mammographic parenchymal patterns: a meta-analysis of the published literature to examine the effect of method of classification.

The appearance of the breast parenchyma as seen on mammography is known to vary between individuals. The evidence is reviewed that some of the sources of this variation, namely, the densities referred to as "dysplasia", are related to breast cancer risk. We have carried out a meta-analysis of the published literature to determine the magnitude of the risk of breast cancer associated with mammographic densities by calculating summary odds ratios for studies grouped according to their design and the method used to classify mammographic parenchymal patterns. This has shown that subjects with mammographic densities have an increased risk of breast cancer relative to those without densities. Of the studies that used Wolfe's method of classification, cohort studies (n = 8) had a summary odds ratio of 5.19 (95% CI, 3.6 to 7.48); case control studies (n = 13) had a summary odds ratio of 1.8 (95% CI, 1.5 to 2.13); and prevalence surveys had a summary odds ratio of 0.54 (95% CI, 0.4 to 0.7). Other methods of classification, using quantitative estimates of the proportion of the breast occupied by densities, gave substantially higher odds ratios than Wolfe's system. The ability to recognize individuals within the population at different risks for breast cancer could be exploited in studies of potential etiological factors.

Breast↗
PubMed1991

The possible role of lipid peroxidation in breast cancer risk.

Breast cancer remains the commonest cause of death from cancer in women in most of the Western world. There is considerable evidence that breast cancer risk is influenced by environmental factors and can therefore potentially be modified. In this paper we describe evidence suggesting a relationship of lipid peroxidation to breast cancer risk, and propose that the method used to generate this information might usefully be applied to other disease states, and make some suggestions for further work. We have compared the urinary excretion of the mutagen malonaldehyde (MDA) in premenopausal women at different risks for breast cancer as determined by the appearance of the breast parenchyma on mammography. MDA was measured in 24-h urine samples from both groups and excretion in 30 women with mammographic dysplasia (high risk) was found to be approximately double that of 16 women without these radiological changes (p less than 0.02). These results suggest that mammographic dysplasia may be associated with lipid peroxidation. Further study of environmental factors associated with states that precede the development of breast and other cancers may lead to the identification of factors that can be modified and that may prevent the development of malignant disease.

Adult↗
PubMed1990

Evidence of lipid peroxidation in premenopausal women with mammographic dysplasia.

We have compared the urinary excretion of the mutagen malonaldehyde in premenopausal women at different risks for breast cancer as determined by the appearance of the breast parenchyma on mammography. Thirty women with extensive mammographic densities were compared with 16 controls without these radiological changes. Malonaldehyde was measured in 24-h urine samples from both groups and excretion in 30 women with mammographic dysplasia (high risk) was found to be approximately double that of 16 women without these radiological changes (P less than 0.02). These results suggest that mammographic dysplasia may be associated with lipid peroxidation and raise the possibility that mutagenic products generated by this process may influence breast cancer risk.

Adult↗
PubMed1990

Evidence of association between plasma high-density lipoprotein cholesterol and risk factors for breast cancer.

Females in western societies have higher plasma levels of high-density lipoprotein cholesterol (HDL-C) than males. The difference in plasma lipids between the sexes is believed to contribute to differences in risk of heart disease. The evidence reviewed here demonstrates that plasma levels of HDL-C are also associated with factors influencing risk of breast cancer, a leading cause of death in women in western societies. Both breast cancer risk and HDL-C levels are higher in women who live in northern European countries than in those who live in Asia, in women who have never been pregnant compared with those who have, and in women of higher socioeconomic status. HDL-C levels are also affected by several other known or suspected factors in breast cancer risk; these include dietary fat intake, alcohol consumption, endogenous hormones, and premenopausal leanness. Increases in any of these factors are known to increase the level of HDL-C. Preliminary work has also shown HDL-C levels to be higher in subjects with mammographic dysplasia and a family history of breast cancer. Further, in serum-free culture systems, HDL-C appears to possess biologic properties that may be relevant to carcinogenesis. In other areas, evidence of a relationship between increased HDL-C levels and increased breast cancer risk is either incomplete or contradictory. These areas include obesity (in the risk of postmenopausal breast cancer), use of exogenous hormones (oral contraceptives or postmenopausal estrogens), and physical exercise. In addition, both elevated and depressed levels of HDL-C have been reported in women with breast cancer. Our findings suggest an association between high HDL-C levels and the epidemiology of breast cancer risk. We recommend additional studies of plasma lipid level as a possible risk factor for this disease.

Age Factors↗
PubMed1990

Body size and breast cancer prognosis: a critical review of the evidence.

There is currently controversy about the effect of body size on the prognosis of patients with breast cancer. In order to clarify the prognostic importance of body size, and to determine whether the effect varies across subgroups of patients, a critical appraisal of the published literature was undertaken. Thirteen cohort studies and one case-control study were identified that examined the prognostic effect of body size. Methodologic standards were developed that reflected those features of study design considered most important in studies of prognosis in breast cancer, and were independently applied to each report by each of the authors. When the effects of methodologic differences among the studies were controlled, a modest prognostic effect of body size was identified. This effect appeared to be greatest in postmenopausal women, in those with little or no involvement of axillary nodes, and to be independent of other prognostic factors. Additional investigation is recommended to determine the prognostic effects of body size in postmenopausal women with axillary node negative breast cancer and in women receiving systemic adjuvant therapy, and to determine the pathophysiological basis for these effects. Intervention studies to determine the effects of altering body size may also be indicated.

Body Constitution↗
PubMed1990

Ratings of the importance of quality of life variables: therapeutic implications for patients with metastatic breast cancer.

Metastatic breast cancer cannot be cured with currently available therapeutic agents, and the objectives of treatment must, therefore, be directed towards other goals that include the relief of symptoms and the preservation or restoration of function. The main objective of the study reported here was to examine the relative importance of 28 items concerned with general health or with disease and treatment to a group of patients with metastatic breast cancer. All items concerned aspects of quality of life whose relevance and importance to patients with metastatic breast cancer had been shown in previous work. Patients rated items according to importance using two methods, a Q sort and a linear analogue rating. General health items, notably self-care, mobility, and physical activity, appetite, sleep, and family relationships were ranked in the upper quartile of the group of items rated. By contrast, items concerned directly with the common side-effects of chemotherapy were given lower rankings. The ratings were shown to be reproducible. These results emphasize the importance of including in clinical trials of therapy that are palliative in intent, endpoints that include those aspects of quality of life that are of greatest importance to patients.

Adult↗
PubMed1990

Quantitative changes in dietary fat intake and serum cholesterol in women: results from a randomized, controlled trial.

We compared observed and predicted changes in serum cholesterol in women with mammographic dysplasia who participated for 12 mo in a randomized, controlled trial of a low-fat, high-carbohydrate diet, in which total fat intake was reduced from an average of 37% of calories to 21% and carbohydrate intake increased from 44% to 52% of calories. Changes observed in serum cholesterol were greater than those predicted (by the formulas of Hegsted and Keys) for subjects with initial serum cholesterol values in the upper tertile of the population, were not significantly different from those predicted for subjects with baseline values in the middle tertile, and were significantly less than those predicted for subjects with initial values in the lower tertile. These results show that the usefulness of serum cholesterol as a marker of change in dietary fat intake in women depends on the distribution of serum cholesterol values in the population studied.

Adult↗
PubMed1989

Cyclical mastopathy: an evaluation of methods of assessment.

We have evaluated three methods of assessing patients with cyclical breast symptoms (cyclical mastopathy--CM). One method, a screening questionnaire, was used to identify women with CM, and two others, a symptom severity questionnaire and a daily diary, were used prospectively to record the severity of symptoms in relation to the menstrual cycle. The screening questionnaire was assessed for test-retest reliability and for agreement between the recalled severity of symptoms and those recorded during prospective measurement. The symptom severity questionnaire and diary were assessed by examining their ability to discriminate between pre- and postmenstrual phases of the menstrual cycle, differences in symptom severity at these times being the cardinal feature of CM. Test-retest reliability of premenstrual symptoms by the screening questionnaire gave correlation coefficients over 0.70 for 9 of the 11 items assessed. The symptom severity questionnaire showed significant differences between pre- and post-menstrual scores for 8 of the 11 items assessed and the diary for each of the 2 items assessed. Comparison of symptom severity as recalled and as prospectively recorded showed only modest agreement. These results show that the instruments used to assess symptom severity performed satisfactorily but that the screening questionnaire used to identify women with CM, although reliable, correlated only moderately well with prospective measurement.

Adolescent↗
PubMed1989

A review of the methods used by studies of dietary measurement.

Studying the association between diet and disease requires reliable and valid methods for the assessment of diet. The authors reviewed the literature concerned with the assessment of these aspects of the measurement of dietary intake. Studies were examined for the stated purpose and scope of the dietary instrument, for a description of the instrument itself, for any methods employed to train individuals in its use and for the methods used to assess its reliability and validity. Of the 59 studies reviewed, 54% described fully the dietary method used. Of the 39 studies that described the results using questionnaires, 51% gave specific information on questions asked and only 18% included the questionnaire itself. Reliability was assessed in 26 studies and 74% (19) used the test-retest reliability and 22% (6) used proxies to assess reliability. Validity was assessed in 46 studies and 83% (38) used indirect methods that compared the results of one dietary method (e.g. 24 hr recall) with another more extensive one (e.g. diet history). Thirty five percent (16) used biochemical and 15% (7) used other methods. This review suggests several directions that might be usefully followed in conducting and reporting further research in the development of methods to assess diet.

Diet Surveys↗
PubMed1989

Plasma lipids in premenopausal women with mammographic dysplasia.

Epidemiological evidence indicates that mammographic dysplasia is associated with an increased risk of breast cancer, particularly in premenopausal women. To examine biochemical associations with mammographic dysplasia we have compared premenopausal women with different patterns of the breast parenchyma on mammography. One group had extensive radiological dysplasia (n = 30) and the other no dysplasia (n = 16). Both groups were recruited from mammographic units in the same way and then compared according to epidemiological risk factors, anthropometric measures, nutrient intake and plasma levels of oestradiol, progesterone and prolactin obtained in both follicular and luteal phases of the menstrual cycle as well as total plasma cholesterol and lipid fractions. Women with mammographic dysplasia were found to be leaner, more often nulliparous and to consume more alcohol than women without these radiological changes. Mammographic dysplasia and a family history of breast cancer were found to be independently associated with significantly higher levels of high density lipoprotein cholesterol (HDL-C) after taking into account the possible confounding effects of percentage body fat, parity and consumption of alcohol and dietary fat. Triglyceride levels were also independently associated with a family history of breast cancer. We conclude that further investigation is warranted of the role of plasma lipids in relation to breast cancer risk.

Adult↗
PubMed1989

Fish consumption and breast cancer risk: an ecological study.

There is experimental evidence that fish oils protect against mammary carcinogens in animals. However, there has been little investigation of the possible relevance of this finding to breast cancer in humans. We compared breast cancer incidence and mortality rates with estimates of the consumption of fish and other foods and nutrients in the countries for which reliable data are available. The results showed an inverse association between percent calories from fish and breast cancer rates that was consistent with a protective effect. This analysis confirmed the finding of others that dietary fat is strongly associated with international variation in breast cancer rates. It also showed that of the dietary components considered, percent calories from fish was the factor most strongly correlated with breast cancer rates after statistical adjustment for dietary fat intake. This result is therefore in accord with animal experimental data and suggests that the omega-3 fatty acids contained in certain fish may protect against breast cancer.

Analysis of Variance↗
PubMed1988

Clinical trial of low-fat, high-carbohydrate diet in subjects with mammographic dysplasia: report of early outcomes.

Despite evidence that dietary fat intake may influence breast cancer risk, there is little information about the effects of dietary fat on the human breast. We have studied the effects of dietary fat on the breast by examining the influence of dietary fat reduction on mammographic dysplasia (nodular or sheetlike areas of radiological density). Subjects with mammographic dysplasia were randomly allocated to a control group, in which they received advice about maintaining a balanced diet (36% of calories as fat), or an intervention group, in which they were taught to reduce dietary fat to a target of 15% of calories. A total of 295 patients consented to randomization, and after 1 year, 20% of the intervention group and 5% of the control group had dropped out (failed to keep appointments and provide nutrient data). The remaining patients closely adhered to the dietary goals of the study as assessed by food records, chemical analysis of duplicate meals, and serum cholesterol measurements. Comparison of mammograms before and after 1 year of dietary fat reduction shows no significant influence on the extent or density of mammographic dysplasia. Surgical biopsies performed in subjects after entry in the study showed five cancers in the control group and two cancers in the intervention group; this total of seven cancers is four times the number expected. These data show that clinical trials of the effects of dietary fat reduction on breast cancer risk are feasible and that long-term compliance with a low-fat diet can be achieved, and they confirm that the patients selected because they had mammographic dysplasia had increased risk of breast cancer.

Adult↗
PubMed1988

Effect of a low-fat high-carbohydrate diet on symptoms of cyclical mastopathy.

21 patients with severe persistent cyclical mastopathy of at least 5 years' duration were randomised to a control group who received general dietary advice or to an intervention group who were taught how to reduce the fat content of their diet to 15% of calories while increasing complex carbohydrate consumption to maintain caloric intake. Both groups were followed for 6 months with food records and measurement of plasma hormone and lipid levels. Severity of symptoms was recorded with daily diaries and patients were assessed at the beginning and end of the study by a physician who was unaware of their dietary regimen. After 6 months there was a significant reduction in the intervention group in the severity of premenstrual breast tenderness and swelling. Physical examination showed reduced breast swelling, tenderness, and nodularity in 6 of 10 patients in the intervention group and 2 of 9 patients in the control group.

Adult↗
PubMed1988

Cyclical mastopathy: a critical review of therapy.

Because of a recently completed trial which demonstrated that dietary fat reduction improved the symptoms of cyclical mastopathy, we have carried out a critical review of other studies of treatment for this disorder to determine what, if any, mechanisms of action were shared by effective treatments. Therapies were classified as 'definitely effective' if their effectiveness was demonstrated in at least one randomized placebo-controlled study of women with cyclical mastopathy, 'probably effective' if their effectiveness in relieving breast symptoms was demonstrated in at least one study in women with premenstrual syndrome, and 'probably not effective' if they had not been shown to improve breast symptoms in at least two studies in women with premenstrual syndrome. Bromocriptine, danazol, evening primrose oil, tamoxifen and reduction of dietary fat intake were classified as definitely effective and norethisterone and Bellergal as probably effective. Several therapeutic manoeuvres, including reduction of methylxanthine ingestion and the administration of vitamin E or diuretics, have not been adequately evaluated in women with cyclical breast symptoms. A review of the published reports of the physiological effects of therapies that were definitely or probably effective revealed that these agents acted either to alter serum prolactin levels or lipid metabolism, or both. As evidence exists that prolactin influences lipid metabolism it is postulated that cyclical mastopathy may be a disorder of lipid metabolism.

Breast Diseases↗
PubMed1988

Weight gain in women with localized breast cancer--a descriptive study.

A retrospective study was undertaken of weight gain during the first year after diagnosis of breast cancer in three groups of women with localized disease. Group I consisted of 307 women with clinical or pathological node-negative breast cancer and Group II of 139 women with clinical or pathological node-positive breast cancer. Neither of these groups received systemic adjuvant therapy. Group III consisted of 191 women with pathological node-positive breast cancer who received adjuvant cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) (Group IIIA) or CMF plus prednisone (7.5 mg per day) and ovarian ablation (Group IIIB). In the absence of systemic therapy, weight gain was greater in those with involved nodes than in those with uninvolved nodes (p = 0.001). When women with involved nodes were studied, those who received prednisone and ovarian ablation in addition to CMF gained more weight than those who received CMF alone (p less than 0.0001). The use of CMF alone did not significantly affect weight gain. Neither initial weight nor weight gain after diagnosis affected prognosis. It was concluded that the observed weight gain was not due to the use of adjuvant CMF and did not affect prognosis. Further investigation was recommended to replicate the above findings and to determine the cause of weight gain after diagnosis in women with localized breast cancer.

Adult↗