Search

Objective: Although many studies have shown that higher weight increases the risk of postmenopausal breast cancer, some aspects of this association are unclear. In order to examine the risk associated with different patterns of weight change, we analyzed data from a large case-control study of postmenopausal breast cancer.Methods: Participants included women aged 50 79 years (n = 5031) who are newly diagnosed with invasive breast cancer in Massachusetts, New Hampshire, and Wisconsin. Similarly-aged population controls (n = 5255) were selected at random from driver's license files and Medicare beneficiary lists. Height, weight, and information on other breast cancer risk factors were ascertained by structured telephone interviews from 1992 to 1995, and logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI).Results: Women in the top quintile groups for height at age 20, recent weight, and recent body mass index had significantly increased risks of breast cancer. Among women who reached their highest adult weight at younger ages (<45 years), increasing weight loss since that age was associated with a reduced risk of postmenopausal breast cancer (OR 0.90, CI 0.84 0.98, per 5 kg). However, weight loss among women whose highest weight occurred after age 45 was not associated with risk (OR 1.00, CI 0.95 1.05, per 5 kg). Weight gain since the lowest adult weight increased risk by 8% for each 5 kg of gain (OR 1.08, CI 1.06-1. 11). Temporary weight cycling (weight loss followed by weight gain) was not associated with increased risk.Conclusions: Weight gain clearly increased risk of postmenopausal breast cancer. These data lend further support to efforts aimed at helping women avoid weight gain as they age. [ABSTRACT FROM AUTHOR]

Ingestion of arsenic-contaminated drinking water is associated with an increased risk of several cancers, including skin and bladder malignancies; but it is not yet clear whether such adverse effects are present at levels to which the U.S. population is exposed. In New Hampshire, detectable levels of arsenic have been reported in drinking water supplies throughout the state. Therefore, we have begun a population-based epidemiologic case-control study in which residents of New Hampshire diagnosed with primary squamous cell (n = 900) and basal cell (n = 1200) skin cancers are being selected from a special statewide skin cancer incidence survey; patients diagnosed with primary bladder cancers (n = 450) are being identified through the New Hampshire State Cancer Registry. Exposure histories of these patients will be compared to a control group of individuals randomly selected from population lists (n = 1200). Along with a detailed personal interview, arsenic and other trace elements are being measured in toenail clipping samples using instrumental neutron activation analysis. Household water samples are being tested on selected participants using a hydride generation technique with high-resolution inductively coupled plasma mass spectrometry. In the first 793 households tested arsenic concentrations ranged from undetectable (0.01 microgram/l) to 180 microgram/l. Over 10% of the private wells contained levels above 10 microgram/l and 2.5% were above 50 microgram/l. Based on our projected sample size, we expect at least 80% power to detect a 2-fold risk of basal cell or squamous cell skin cancer or bladder cancer among individuals with the highest 5% toenail concentrations of arsenic.

Background: There is considerable interest in the possibility of an infectious etiology for human breast cancer. Although studies have shown that certain strains of mice transmit mammary tumor virus via breast milk, few epidemiologic studies have addressed this topic in humans., Methods: We evaluated the relationship between having been breast-fed as an infant and breast cancer risk among 8299 women who participated in a population-based, case-control study of breast cancer in women aged 50 years or more. Case women were identified through cancer registries in three states (Massachusetts, New Hampshire, and Wisconsin); control women were identified through statewide driver's license lists (age <65 years) or Medicare lists (ages 65-79 years). Information on epidemiologic risk factors was obtained through telephone interview. We used multiple logistic regression to assess having been breast-fed and maternal history of breast cancer in relation to breast cancer occurrence both in premenopausal women (205 case women; 220 control women) and in postmenopausal women (3803 case women; 4071 control women)., Results: We found no evidence that having been breast-fed increased breast cancer risk in either premenopausal women (odds ratio [OR] = 0.65; 95% confidence interval [CI] = 0.41-1.04) or postmenopausal women (OR = 0.95; 95% CI = 0.85-1.07). In addition, breast cancer risk was not increased by having been breast-fed by a mother who later developed breast cancer., Conclusion: Our results do not support the hypothesis that a transmissible agent in breast milk increases breast cancer risk. Because premenopausal women were not well represented in our study population, our findings with regard to this group may not be generalizable and should be viewed with caution.

We have used data from a large population-based case-control study in the United States to evaluate the effect of occupational physical activity on breast cancer risk. Women diagnosed with breast cancer identified from four state cancer registries, and controls randomly selected from lists of licensed drivers or Medicare beneficiaries, were interviewed by telephone for information on usual occupation and other factors. We classified usual occupation into one of four categories of physical activity. After excluding subjects for whom a strength rating could not be assigned, we had a final sample size of 4,863 cases and 6,783 controls. Using conditional logistic regression models, we calculated adjusted odds ratios (OR) and 95 percent confidence intervals (CI) for occupations having light, medium, and heavy activity compared with sedentary ones. Women with heavy-activity occupations had a lower risk of breast cancer than women with sedentary jobs (OR = 0.82, CI = 0.63-1.08), as did women with jobs with medium activity (OR = 0.86, CI = 0.77-0.97) or light activity (OR = 0.92, CI = 0.84-1.01). There was a significant decreasing trend in the ORs from sedentary to heavy work (P = 0.007). Although limited by exposure misclassification, these data are consistent with the hypothesis that physical activity reduces the risk of breast cancer.

Data from a population-based case control study were used to estimate occupation-specific relative risks for female breast cancer, adjusted for established breast cancer risk factors. Breast cancer cases under age 75 were identified from tumor registries in four states. Controls were randomly selected from driver's license and Medicare beneficiary lists. Information on usual occupation and risk factors was obtained by telephone interview. Odds ratios from logistic regression adjusted for age, state, body mass index, benign breast disease, family history of breast cancer, menopausal status, age at menarche, parity, age of first birth, lactation history, education, and alcohol consumption were calculated for each of 26 occupational groups. Complete occupational information was obtained for 6,835 cases and 9,453 controls. Of 26 occupational groups, only "administrative support occupations" had a statistically significantly increased risk of breast cancer (OR = 1.15, 95% CI 1.06-1.24). In these data, no specific occupational group had an unusual risk of breast cancer. Increased risks reported elsewhere for nurses and teachers were not corroborated.

A priori hypotheses suggest that cigarette smoking could either increase or decrease breast cancer incidence. To clarify these competing hypotheses, we used data from a very large population-based breast cancer case-control study to investigate the impact of smoking on breast cancer risk. Breast cancer patients less than 75 years old were identified from statewide tumor registries in Wisconsin, Massachusetts, Maine, and New Hampshire; controls were randomly selected from driver's license lists (age less than 65) or lists of Medicare beneficiaries (age 65-74). Information on reproductive history, medical history, and personal habits including cigarette smoking was obtained by telephone interview. A total of 6,888 cases and 9,529 controls were interviewed. There was virtually no relationship between current smoking and breast cancer risk (multivariate odds ratio, 1.00; 95% confidence interval, 0.92-1.09), and former smokers had a barely increased risk (odds ratio, 1.10; 95% confidence interval, 1.01-1.19). Similar results were observed among both premenopausal and postmenopausal women. There was no suggestion that heavy or long-term smoking increased or decreased risk, nor were there indications that women who began smoking at an early age were at increased risk, as has been hypothesized. The results of this large population-based study indicate that smoking does not influence the risk of breast cancer, even among heavy smokers who began smoking at an early age.

One of the goals of our medical school is to teach our students how to learn. In theory, this is a noble goal, but, in practice, our style is often to "impart" our knowledge to the students without allowing them to question it, to practice with it, and to really understand it. To address this problem, we are developing a vertically integrated four-year program in medical decision making funded by the Culpeper Foundation. The curriculum begins with classic epidemiology in year one. In year-two courses, principles of clinical epidemiology (diagnosis, variability, etc) and the elements of quantitative decision making are woven into our organ system courses. In year three, these skills are practiced in clerkships, and critical thinking sessions occur in several clerkships. The curriculum culminates in year four with sessions on expected value decision analysis in one of our required courses. Built into this experience are computer interactive programs, faculty and housestaff development sessions, and availability of consultation from a medical decision making team. We are developing competency-based exams in which students will have to demonstrate skills in medical decision making, critical thinking, and problem solving. We hope this will help teach our students "how to" make decisions and understand such things as critical thinking, probability, uncertainty, and variability. Through this, we hope the decisions they will help their patients make will lead to the "best" outcomes for these patients.

We reviewed 1808 hospital charts representing virtually all patients given a diagnosis of non-small-cell lung cancer in New Hampshire and Vermont between 1973 and 1976 and found that the treatment of patients varied according to their marital status, medical insurance coverage, and proximity to a cancer-treatment center. Patients were more likely to be treated with surgery if they were married (odds ratio, 1.67; 95 percent confidence interval, 1.08 to 2.57) or had private medical insurance (1.52; 1.03 to 2.26). Among patients who did not have surgery, those with private insurance were more likely to receive another form of anticancer therapy--either radiation or chemotherapy (1.57; 1.18 to 2.09). Residing farther from a cancer-treatment center was associated with a greater chance of having surgery. Patients 75 years of age and older were less likely to have surgery (0.16; 0.08 to 0.35) or any other tumor-directed therapy (0.32; 0.19 to 0.54). The relation between the type of treatment and a patient's characteristics was not based on apparent differences in tumor stage or functional status, although both these factors were also strongly predictive of the type of treatment. Despite the fact that privately insured and married patients were more aggressively treated, they did not survive longer after diagnosis. We conclude that for non-small-cell lung cancer, socio-economic as well as medical factors determine treatment.

Identified were 1,906 cases of confirmed lung cancer that occurred among all residents of New Hampshire and Vermont over a 4-year period. Medical records, pathologists' reports, and, when possible, pathology slides were obtained and reviewed to assign cases to a specific histologic diagnosis. The diagnosis made by the original pathologist was generally confirmed upon review, except for the large cell undifferentiated cell type which appeared to be an unreliable classification. Among men at all ages incidence rates for squamous cell cancer far exceeded those for adenocarcinoma and small cell undifferentiated carcinoma, and the three age-incidence curves showed a similar pattern, rising until the eighth decade of life and then declining. Among women these three major cell types occurred about equally often, but the age-incidence curves differed in shape with adenocarcinoma reaching a peak incidence at an earlier age.