Risk factors for uterine leiomyoma: a practice-based case-control study. I. African-American heritage, reproductive history, body size, and smoking

The authors conducted a case-control study among premenopausal women in the Baltimore, Maryland, area to examine the associations of uterine leiomyoma with ethnicity and hormone-related characteristics. Cases of uterine leiomyoma (n = 318) were surgically or sonographically first confirmed between January 1990 and June 1993. A total of 394 controls were selected from women who were visiting their gynecologist for a routine checkup. Data were collected through telephone interviews and abstraction of medical records; 77.8% of eligible cases and 78.0% of eligible controls were interviewed. Positive adjusted associations were observed between risk of uterine leiomyoma and self-described African-American ethnicity (vs. Whites: odds ratio (OR) = 9.4; 95% confidence interval (CI): 5.7, 15.7), early menarche (<11 years vs. >13 years: OR = 2.4; 95% CI: 1.1, 5.6), and high body mass index (upper quartile vs. lower quartile: OR = 2.3; 95% CI: 1.4, 3.8). Inverse associations were observed with use of oral contraceptives (current use vs. never use: OR = 0.2, 95% CI: 0.1, 0.6) and duration of smoking (> or =19 years vs. never: OR = 0.6; 95% CI: 0.4, 1.1). Younger ages at infertility diagnosis and at first and last childbirth were more common among cases; however, analyses of data on tumor location suggested that these associations represent predominantly consequences of uterine leiomyoma. These results suggest that development of uterine leiomyoma is associated with increased exposure to ovarian hormones. Possible reasons for the very elevated risk among African-American women need further investigation.     

Comparative analysis of breast cancer risk factors among African-American women and White women

The authors assessed risk factor profiles among 1,505 African-American and 1,809 White women in the 1993-2001 Carolina Breast Cancer Study. Multiple logistic regression models for case-control data were used to estimate odds ratios for several factors. Racial differences were observed in the prevalence of many breast cancer risk factors among both younger (aged 20-49 years) and older (aged 50-74 years) women. For older women, the magnitude and direction of associations were generally similar for African-American and White women, but important racial differences were observed among younger women. In particular, multiparity was associated with increased risk of breast cancer among younger African-American women (for three or four pregnancies: adjusted odds ratio (OR) = 1.5, 95% confidence interval (CI): 0.9, 2.6; for five or more pregnancies: OR = 1.4, 95% CI: 0.6, 3.1) but not among younger White women (for three or four pregnancies: OR = 0.7, 95% CI: 0.4, 1.2; for five or more pregnancies: OR = 0.8, 95% CI: 0.2, 3.0). The relations with age at first full-term pregnancy and nulliparity also varied by race. Case-only analyses before and after further adjustment for tumor stage and hormone receptor status revealed little effect on results. Hence, racial variations in both prevalences of and risks associated with particular factors may contribute to the higher incidence of breast cancer among younger African-American women.     

Uterine fibroids risk and history of selected medical conditions linked with female hormones

To understand the role of several medical conditions on the risk of uterine fibroids, we analysed the findings of a large case-control study. Cases were 843 women aged 54 or less (median age 43 years, range 21-54) with histologically confirmed uterine fibroids, whose clinical diagnosis dated back no more than 2 years. Indications for surgery were recurrent menorrhagia or ultrasound evidence of fibroids larger than 10 cm in diameter. Controls were 1557 women aged 54 years or less of comparable quinquennia of age (median age 43 years, range 21-54) who had not undergone hysterectomy and were admitted for acute, non-gynecologic, non-hormonal, non-neoplastic conditions to a network of hospitals with a similar catchment area. Clinical history of severe overweight was inversely associated with the risk of fibroids (multivariate odds ratio (OR), OR: 0.6, 95% confidence intervals (CI): 0.5-0.8). An increase in the frequency of fibroids was seen in women with a history of benign breast disease (OR: 1.2, 95% CI: 0.9-1.6) and particularly of breast biopsies (OR: 2.0, 95% CI: 1.2-3.5). The results of this large dataset indicate that medical conditions known or likely to be related to female hormones are not important determinants of the risk of fibroids.     

Tubal sterilization and risk of ovarian, endometrial and cervical cancer. A Danish population-based follow-up study of more than 65 000 sterilized women

BACKGROUND: On the basis of a population-based cohort, we assessed the cancer risk, focusing on gynaecological cancers and pre-malignant lesions, among women with a previous tubal sterilization. METHODS: Using the Danish Hospital Discharge Register we identified 65 232 women who had a tubal sterilization (1977-1993). The cohort was followed for cancer occurrence, and compared with the expected number based on the national cancer incidence rates. RESULTS: The overall risk of ovarian cancer was decreased (standardized incidence ratio [SIR] = 0.82; 95% CI: 0.6, 1.0), and it was still decreased > or =10 years after the sterilization (SIR = 0.65; 95% CI: 0.4, 1.0). The rate of endometrial cancer was also decreased (SIR = 0.66; 95% CI: 0.5, 1.0), the risk continued being moderately reduced during follow-up, although it was not statistically significant. CONCLUSIONS: In this nationwide, population-based study we find that women with tubal sterilization have a decreased risk of subsequent development of ovarian cancer. As the protective effect is not decreasing with years of follow-up, our data do not support that 'screening' bias can explain the protective effect, but indicate that the sterilization itself may convey a reduction in risk. The same pattern is found for endometrial cancer, the association being less strong.     

The intention of adolescents to carry a knife or a gun: a study of low-income African-American adolescents.

PURPOSE: To examine whether African-American inner-city adolescents are independently motivated by a fear of victimization or by delinquency to carry a knife or gun. METHODS: A household sample of 130 female and 93 male African-American adolescents, aged 13-19 years old, were queried about their fear of victimization, history of delinquency, and intention to carry a knife or a gun in the next 3 months. RESULTS: A high intention to carry a knife was reported by 27% of the males and 35% of the females. A high intention to carry a gun was reported by 25% of the males and 9% of the females. The intention to carry a knife was independently associated with a history of delinquency in females (odds ratio [OR] = 3.0; 95% confidence interval [CI] = 1.4-6.2) and males (OR = 4.7; 95% CI = 1.7-13.3). It was not associated with a fear of victimization. The intention to carry a gun was independently associated with fear of victimization in females (OR = 4.5; 95% CI = 1.1-17.7) and males (OR = 3.3; 95% CI = 1.1-9.9). It was also independently associated with a history of delinquency in females (OR = 4.1; 95% CI = 1.1-16.3) and males (OR = 11.7; 95% CI = 3.1-44.7). CONCLUSIONS: Delinquency may play a role in motivating inner-city African-American adolescents to carry a knife, whereas both delinquency and fear of victimization may influence adolescents' motivation to carry a gun.     

Factors associated with contraceptive nonuse among US women ages 35-44 years at risk of unwanted pregnancy

Background

Women ages 35 years and older have the greatest proportion of contraceptive nonuse and unintended pregnancies ending in abortion.

Study Design

We conducted a population-based case-control study among women ages 35-44 years at risk of unwanted pregnancy using the National Survey of Family Growth (NSFG) data to investigate risk factors for contraceptive nonuse.

Results

At last intercourse, 9.8% of women reported not using any contraceptive method. Contraceptive nonusers, as compared to users, were more likely to be ages 40-44 years (OR=2.0, 95% CI 1.1-3.7), foreign-born (OR=4.3, 95% CI 1.9-9.7), black (OR=2.8, 95% CI 1.1-7.0), with household incomes 100-249% of the federal poverty level (FPL) (OR=2.5, 95% CI 1.1-5.8). Women who received contraceptive counseling in the past year had an 80% decreased risk of nonuse (95% CI 0.1-0.5).

Conclusion

Public health strategies to reduce unintended pregnancy, particularly among women ages 35 years and older, should focus on addressing disparities in contraceptive use and promoting contraceptive counseling.     

Race, anthropometric factors, and stage at diagnosis of breast cancer

A recent study suggested that the greater prevalence of severe obesity among African-American women explained almost one third of the observed differences between African-American and White women in stage at diagnosis of breast cancer. The objective of this investigation was to attempt to replicate these findings in a second, larger population and to expand the analyses by including a measure of body fat distribution, the waist:hip ratio. The authors used data from a population-based study in North Carolina comprising 791 breast cancer cases (302 in African-American women and 489 in White women) diagnosed between 1993 and 1996. African-American women were more likely to have later-stage (TNM stage >/=II) breast cancer (odds ratio (OR) = 2.2; 95% confidence interval (CI): 1.6, 2.9). They also were much more likely to be severely obese (body mass index >/=32.3) (OR = 9.7; 95% CI: 6.5, 14.5) and to be in the highest tertile of waist:hip ratio (OR = 5.7; 95% CI: 3.8, 8.6). In multivariate logistic regression models, adjustment for waist:hip ratio reduced the odds ratio for later-stage disease in African-American women by 20%; adjustment for both waist:hip ratio and severe obesity reduced the odds ratio by 27%. These observations suggest that obesity and body fat distribution, in addition to socioeconomic and medical care factors, contribute to racial differences in stage at breast cancer diagnosis.     

Epidemiological models and related simulation results for understanding of contraceptive adoption in India

BACKGROUND: For the first time, models using multilevel analysis of Indian data and related simulation results are reported. They take hierarchical structure into account and incorporate variables from all levels to get correct analysis and proper interpretation of data on current contraceptive use (including sterilization and modern methods). METHODS: The data from an Indian State, Uttar Pradesh (UP), collected by the National Family Health Survey (NFHS) conducted during 10 October 1992 to 22 February 1993 was used. For model I, 7851 currently married women who were neither pregnant nor had continuing post-partum amenorrhoea (PPA) were considered. For model II, these women with at least one child (n = 6748) were used. Two-level logistic regression analysis was carried out for which women's level (level 1) and PSU (Primary Sampling Unit) level (level 2) variables were considered. The results were considered significant at the 5% level of significance. Simulation analysis using each model was also carried out. RESULTS: Model I reveals that those more likely to adopt contraception were women exposed to a TV message (odds ratio [OR] = 1.3; 95% CI: 1.1-1.6); whose houses were pucca (bricks and mortar) (OR = 1.3; 95% CI: 1.1-1.5); who were educated to high school level and above (OR = 2.9; 95% CI: 2.2-3.7); whose husbands were literate with schooling of > or =11 years (OR = 1.7; 95% CI: 1.4-2.1); and who had > or =2 living sons (OR = 2.2; 95% CI: 1.1-4.4). Muslim and other religious women were less likely than Hindu women to adopt contraception (OR = 0.5; 95% CI: 0.4-0.6). Also, the PSU level availability of all weather road was positively associated with contraceptive adoption (OR = 1.4; 95% CI: 1.1-1.7). The PSU level variance, which is the unexplained PSU level variation after controlling for the considered characteristics, was significantly higher. The simulation results revealed that public health education (a TV message) was found to be more effective among less educated women. The PSU level availability of all weather road was as effective as public health education. Similar results were evident from the analysis of second data set (model II) with the noticeable finding that those whose last child is surviving are most likely to adopt contraception (OR = 8.82; 95% CI: 1.01-77.38). CONCLUSIONS: These results reveal that the survival status of the last child has a marked effect on the adoption of contraception in UP. They further support the idea that public health education (a TV message) is more effective among less educated women. Also, the PSU level presence of all weather road is equally effective. Consideration of higher level variables provides not only more accurate results but also important public health clues to help the policy planners.     

Reproductive factors in Hodgkin's disease in women

Reproductive factors have been suggested to have an impact on the development of Hodgkin's disease (HD) in women. In the San Francisco Bay Area, the authors conducted a population-based case-control study addressing the effects of reproductive experience and hormone use on HD risk. Cases were 370 women with HD diagnosed at ages 19-79 years between July 1988 and December 1994. Controls were 450 community women found through random digit dialing. Among the 312 cases and 325 controls interviewed, HD risk was related to parity versus nulliparity but only among never nursers (odds ratio (OR)=2.2, 95% confidence interval (CI): 1.0, 5.0). Risk was marginally related to having uterine fibroids (OR=0.6, 95% CI: 0.5, 1.0) and long-term versus short-term hormone use (OR=0.7, 95% CI: 0.4, 1.0) and was significantly related to recurrent miscarriage (OR=2.8, 95% CI: 1.1, 7.4). Among women aged 35-54 years, for whom the sex difference in incidence is largest, nursing decreased risk; among never nursers, a parity of 1 lowered risk and higher parity increased risk; long-term hormone use lowered risk; and recurrent miscarriage increased risk. Among women under age 35 years, endometriosis lowered HD risk; the lack of significant findings for most other variables may reflect selection bias in controls. Among older women, no significant associations were observed, although hormone use appeared to be protective. These data suggest that steroid hormones may affect HD development.     

Timing of menarche and first full-term birth in relation to breast cancer risk

Ages at menarche and first birth are established risk factors for breast cancer. The interval between these ages may also affect risk, since the breast is more susceptible to carcinogenic insults during this period than during the parous period. However, few investigators have studied this relation. Using logistic regression, the authors evaluated associations between the timing of reproductive events and breast cancer risk among 4,013 cases and 4,069 controls enrolled in a multicenter, population-based US case-control study of White and African-American women (1994-1998). For White, parous premenopausal and postmenopausal women, those who had an interval of > or =16 years between the ages of menarche and first birth had 1.5-fold (95% confidence interval (CI): 1.0, 2.2) and 1.4-fold (95% CI: 1.1, 1.8) increased risks of breast cancer, respectively, in comparison with those who had < or =5 years between these ages. Adjusting for age at first birth altered these risk estimates somewhat, to odds ratios of 1.5 (95% CI: 0.8, 2.9) and 1.0 (95% CI: 0.6, 1.5), respectively. These associations were stronger for lobular and hormone-receptor-positive tumors but were absent among premenopausal African-American women. The authors conclude that the interval between age at menarche and age at first birth is associated with the risk of hormonally sensitive types of breast cancer, particularly among White women.     

Risk factors for uterine leiomyoma: a practice-based case-control study. II. Atherogenic risk factors and potential sources of uterine irritation

In this case-control study, the authors analyzed associations of uterine leiomyoma with atherogenic risk factors and potential sources of uterine irritation. The study included 318 case women with uterine leiomyoma that was first confirmed between 1990 and 1993 in the Baltimore, Maryland, area and 394 controls selected from women visiting the same gynecologists' offices for routine reasons. Telephone interviews were conducted with 77.8% of eligible cases and 78.0% of eligible controls. Compared with participants with no hypertension history, increased risks were observed among participants with any history of hypertension (odds ratio (OR) = 1.7; 95% confidence interval (CI): 1.0, 2.8), hypertension requiring medication (OR = 2.1; 95% CI: 1.1, 4.1), hypertension diagnosed at ages less than 35 years (for hypertension requiring medication, OR = 2.7; 95% CI: 1.0, 7.6), and hypertension of 5 or more years' duration (for hypertension requiring medication, OR = 3.1; 95% CI: 1.2, 8.2). Estimates of associations with diabetes history were very imprecise but followed similar patterns. Adjusted associations were observed with pelvic inflammatory disease (three or more episodes vs. none: OR = 3.7; 95% CI: 0.9, 15.9), chlamydial infection (history vs. no history: OR = 3.2; 95% CI: 0.8, 13.7), and use of an intrauterine device when it caused infectious complications (use vs. no use: OR = 5.3; 95% CI: 1.8, 16.3). Risk of uterine leiomyoma was also associated in a graded fashion with frequency of perineal talc use (daily use vs. no use: OR = 2.2; 95% CI: 1.4, 3.1). The authors conclude that nonhormonal factors may influence risk of uterine leiomyoma.     

Uterine cancer after use of clomiphene citrate to induce ovulation

Clomiphene citrate, a selective estrogen receptor modulator, increases estradiol levels and consequently may increase risk of cancer of the uterine corpus. The authors conducted a retrospective cohort study of 8,431 US women (145,876 woman-years) evaluated for infertility during 1965-1988. Through 1999, 39 uterine cancers were ascertained by questionnaire or cancer and death registries. Poisson regression estimated adjusted rate ratios. Study results suggest that clomiphene may increase uterine cancer risk (rate ratio (RR) = 1.79, 95% confidence interval (CI): 0.9, 3.4) and present evidence of a dose response (p(trend) = 0.07) and latency effect (p(trend) = 0.04). Uterine cancer risk increased with clomiphene dose (RR = 1.93, 95% CI: 0.9, 4.0 for >900 mg), menstrual cycles of use (RR = 2.16, 95% CI: 0.9, 5.2 for >or=6 cycles), and time elapsed since initial use (RR = 2.50, 95% CI: 0.9, 7.2 for women followed for >or=20 years). Risk was more strongly associated with clomiphene among nulligravid (RR = 3.49, 95% CI: 1.3, 9.3) and obese (RR = 6.02, 95% CI: 1.2, 30.0) women, with risk substantially elevated among women who were both obese and nulligravid (RR = 12.52, 95% CI: 1.5, 108.0). Clomiphene may increase uterine cancer risk, with higher doses leading to higher risk. Long-term follow-up of infertility cohorts is necessary to clarify the association between clomiphene use and uterine cancer.     

Obesity and associated coronary heart disease risk factors in a population of low-income African-American and white women: the North Carolina WISEWOMAN project

BACKGROUND: Obesity has been associated with many co-occurring coronary heart disease (CHD) risk factors as well as CHD mortality. These associations have been shown to vary between African-American and white sample populations. METHODS: The authors examined whether obesity co-occurs with several CHD risk factors (diabetes, hypertension, hypercholesterolemia, low high-density lipoprotein cholesterol (HDL-C)), and estimated the 10-year risk for CHD in the North Carolina WISEWOMAN (Well Integrated Screening and Evaluation for Women Across the Nation) study sample. This sample includes low-income African-American and white women (> or = 50 years of age). RESULTS: Among white women (n = 1,284), 34% were overweight (BMI = 25.0-29.99 kg/m(2)) and 35% obese (BMI > or = 30 kg/m(2)); among African-American women (n = 754), 28% were overweight and 59% obese. Among obese and nonobese African-American women, the prevalence of three or more co-occurring risk factors was similar (obese = 17.7% (95% confidence interval (CI): 13.9, 21.6) and nonobese = 13.3% (95% CI: 8.7, 17.8)). By contrast, the prevalence among white women was greater among the obese (26.9% (95% CI: 22.9, 31.0)) than the nonobese (13.0% (95% CI: 9.7, 16.2)). CONCLUSIONS: The differences between and within African-American and white women may be accounted for by the high levels of HDL-C among obese and nonobese African-American women.     

Occupational history and exposure and the risk of adult leukemia in Shanghai

PURPOSE: Evaluation of the association of selected occupational exposures with leukemia risk. METHODS: Population-based case-control study of 486 leukemia subjects and 502 healthy controls residing in Shanghai from 1987 to 1989. Adjusted odds ratios (OR) were calculated for the association between occupational factors and leukemia risk. RESULTS: Significant increase in leukemia risk was observed in chemical manufacturing industry workers (OR=3.1, 95% CI=1.0-9.8). Increased risks for leukemia were observed from self-reported exposures to benzene (OR=1.7, 95% CI=1.1-2.6), radioactive materials (OR=3.7, 95% CI=1.3-10.2), synthetic fiber dust (OR=2.0, 95% CI=1.2-3.5), and toluene (OR=1.6, 95% CI=1.0-2.5). Dose-response relations of leukemia risk was observed with the duration of exposure to benzene (OR=3.3, 95% CI=1.6-6.9 for >or=15 years exposure; p for trend<0.01), radioactive materials (OR=5.2, 95% CI=1.1-24.7 for >or=15 years exposure; p for trend=0.02), paints (OR=2.3, 95% CI=1.2-4.7 for >or=15 years exposure; p for trend=0.09), and toluene (OR=2.9, 95% CI=1.3-6.7 for >or=15 years exposure; p for trend=0.02). CONCLUSIONS: Adult leukemia risk may be associated with working in the chemical industry, and exposure to benzene, synthetic fiber dust, radioactive materials, and toluene in the study population.     

Contraceptive usage, knowledge and correlates of usage among female emergency department patients

OBJECTIVES: For female emergency department (ED) patients, we sought to assess the prevalence of contraceptive usage as well as the extent of contraceptive knowledge and to determine if demographic and sexual health history factors, comprehension of contraceptive methods and moral/religious opinions on contraception were associated with current usage of birth control pills (BCPs), prior usage of emergency contraception (EC) and frequency of condom usage. METHODS: English-speaking female ED patients aged between 18 and 55 years at a northeastern United States urban ED were surveyed on their usage, comprehension and opinions regarding BCPs, EC and condoms. RESULTS: Of the 539 respondents (64.6% were aged 相似文献   

Breast cancer risk and ovariectomy, hysterectomy, and tubal sterilization in the women's contraceptive and reproductive experiences study

Removal or impairment of ovaries before menopause may affect a woman's breast cancer risk by altering her cumulative exposure to ovarian hormones. The Women's Contraceptive and Reproductive Experiences Study, a population-based, multicenter case-control study of incident invasive breast cancer, recruited women aged 35-64 years (4,490 cases and 4,611 controls) who provided data on ovariectomy, hysterectomy, and tubal sterilization during in-person interviews. Controls were frequency-matched to cases by age, race, and study site. Unconditional logistic regression analysis was used. Women who had not undergone premenopausal reproductive surgery were the referent group. Bilateral ovariectomy was associated with reduced breast cancer risk overall (odds ratio (OR) = 0.59, 95% confidence interval (CI): 0.50, 0.69) and among women <45 years of age (ORs ranged from 0.31 to 0.52), but not among those who were older at surgery. It was also associated with a reduced risk for estrogen and progesterone receptor-positive tumors (OR = 0.63, 95% CI: 0.52, 0.75) but not receptor-negative tumors. Hysterectomy with ovarian conservation (OR = 0.83, 95% CI: 0.72, 0.96) and hysterectomy with partial ovary removal (OR = 0.73, 95% CI: 0.59, 0.91) were also associated with lower risk. No association with breast cancer risk was observed with tubal sterilization only or partial ovariectomy without hysterectomy. Reproductive organ surgeries may alter ovarian hormone levels, thereby affecting breast cancer risk.     

Are women with an unintended pregnancy less likely to breastfeed?

OBJECTIVE: To examine the association between unintended pregnancy and the initiation and duration of breastfeeding. STUDY DESIGN: This was a secondary data analysis of the 1995 Cycle 5 of the National Survey of Family Growth. POPULATION: We studied 6733 first singleton live births to US women aged 15 years to 44 years. OUTCOMES: Using the 1995 Institute of Medicine definitions, pregnancies were classified as intended or unintended; unintended pregnancies were further categorized as either mistimed or unwanted. We measured initiation of breastfeeding and duration of nonexclusive breastfeeding for at least 16 weeks. RESULTS: In this study, 51.5% of women never breastfed, 48.5% initiated breastfeeding, and 26.4% of all women continued breastfeeding for at least 16 weeks. US women with unwanted unintended pregnancies were more likely not to initiate breastfeeding (odds ratio [OR] = 1.76; 95% CI, 1.26-2.44) and more likely not to continue breastfeeding (OR = 1.69; 95% CI, 1.12-2.55) than women with intended pregnancies. White women with unwanted unintended pregnancies were more likely not to breastfeed than those with intended ones (initiation: OR = 2.50; 95% CI, 1.54-4.05; continuation: OR = 2.56; 95% CI, 1.34-4.87). This finding was not seen for black or Hispanic women. CONCLUSIONS: In the United States, women with unwanted pregnancies were less likely either to initiate or to continue breastfeeding than women with intended pregnancies. A strong inverse association between unwanted pregnancies and breastfeeding was observed only for white women. Education for women with unintended pregnancies may improve breastfeeding rates and subsequently, the health of women and infants.     

Predisposing and Enabling Factors Associated with Mammography Use Among Hispanic and Non-Hispanic White Women Living in a Rural Area

ABSTRACT:  Context: Women who do not receive regular mammograms are more likely than others to have breast cancer diagnosed at an advanced stage. Purpose: To examine predisposing and enabling factors associated with mammography use among Hispanic and non-Hispanic White women. Methods: Baseline data were used from a larger study on cancer prevention in rural Washington state. In a sample of 20 communities, 537 women formed the sample for this study. The main outcomes were ever having had a mammogram and having had a mammogram within the past 2 years. Findings: Reporting ever having had a mammogram was inversely associated with lack of health insurance (OR = 0.37, 95% CI: 0.16-0.84), ages under 50 years (OR = 0.23, 95% CI: 0.12-0.45), high cost of exams (OR = 0.48, 95% CI: 0.27-0.87), and lack of mammography knowledge (OR = 0.16, 95% CI: 0.07-0.37), while increasing education levels were positively associated (OR = 1.72, 95% CI: 1.09-2.70). Reporting mammography use within the past 2 years was inversely associated with ages under 50 years (OR = 0.49, 95% CI: 0.27-0.88) and over 70 years (OR = 0.47, 95% CI: 0.24-0.94), lack of health insurance (OR = 0.23, 95% CI: 0.10-0.50), and high cost of exams (OR = 0.55, 95% CI: 0.35-0.87). Conclusions: Continued resources and programs for cancer screening are needed to improve mammography participation among women without health insurance or low levels of education.     

Hysterectomy, tubal sterilization, and the risk of breast cancer

Studies suggest that hysterectomy and tubal sterilization may alter the function of the remaining ovaries. Conceivably, this effect could alter breast cancer risk. To investigate whether these surgeries affect breast cancer risk, the authors analyzed data collected between December 1, 1980, and April 30, 1983, in a population-based, case-control study of women aged 20-54 years, the Cancer and Steroid Hormone Study. Compared with never-sterilized women, women with hysterectomy and no remaining ovaries had a decreased risk of breast cancer (relative risk (RR) = 0.7, 95% confidence interval (CI) = 0.6-0.8). Risk was lowest in women who had their surgery before age 40 years or 15 or more years in the past; surgery at an early age provided greater protection than surgery in the distant past. Hysterectomy with one or two remaining ovaries was also inversely associated with breast cancer risk (RR = 0.8, 95% CI = 0.7-0.9), but no relation was found with age at surgery or time since surgery. Women with tubal sterilization had a slightly increased risk of breast cancer, which was of borderline statistical significance (RR = 1.2, 95% CI = 1.0-1.3). However, no relation was found with age at surgery or time since surgery. The data suggest that hysterectomy with bilateral oophorectomy decreases the breast cancer risk in women aged less than 55 years, possibly by curtailing ovarian function at a critical period. However, neither hysterectomy without bilateral oophorectomy nor tubal sterilization appears to substantially alter breast cancer risk in women of this age.     

Age and menopausal effects of hormonal birth control and hormone replacement therapy in relation to breast cancer risk

It is unclear whether breast cancer risk varies by age and menopausal status in relation to use of hormonal birth control (HBC) and hormone replacement therapy (HRT), taken singly or cumulatively. The authors utilized data from 1,478 cases and 1,493 controls aged 20-98 years with known menopausal status, who had participated in a population-based, case-control study conducted on Long Island during 1996-1997. Exogenous hormone use over the lifecourse was assessed by use of memory aids. The authors examined associations among women in these subgroups: premenopausal (n = 968), postmenopausal <65 years (n = 1,045), and postmenopausal > or = 65 years (n = 958). Among premenopausal women, risk was increased for ever use of HBC (odds ratio (OR) = 1.37, 95% confidence interval (CI): 1.04, 1.81) or HRT (OR = 1.81, 95% CI: 1.17, 2.81) and was pronounced among women reporting use of both HBC and HRT (OR = 2.59, 95% CI: 1.50, 4.46), long-term HRT use (OR = 3.93, 95% CI: 1.43, 10.84), or estrogen-plus-progestin therapy (OR = 3.51, 95% CI: 1.45, 8.49). There was no effect of ever HBC use among postmenopausal women aged less than 65 years, but risk was modestly elevated for more than 5 years of HRT use (OR = 1.41, 95% CI: 1.00, 1.99). Among postmenopausal women aged 65 years or more, odds ratios for HBC or HRT use were around the null. These results emphasize that timing of exogenous hormone use is important. Women who used these hormones before menopause had elevated risks, but the harmful effects began to decline with age after menopause.