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PubMed1992

Characteristics relating to ovarian cancer risk: collaborative analysis of 12 U.S. case-control studies. VI. Nonepithelial cancers among adults. Collaborative Ovarian Cancer Group.

Nonepithelial ovarian cancers are rare, and little is known about their etiology. Of particular interest are the effects of oral contraceptive use and pregnancy, both of which are associated with large decreases in risk for epithelial ovarian cancer. We examined the risk factors for nonepithelial ovarian tumors by combining data from four case-control studies conducted in the United States. We compared personal characteristics of 38 germ cell cases and 45 stromal cases, respectively, with 1,142 and 2,617 general population controls. All subjects were over age 18 years. For germ cell tumors, there was a weak negative association with parity but no consistent pattern of decreasing risk with increasing parity. In contrast, relative to nulligravid women, gravid nulliparous women were at increased risk of developing a germ cell cancer [odds ratio (OR) = 4.8, 95% confidence interval (CI) = 1.2-18.6]. The use of oral contraceptives was also associated with elevated risk (OR = 2.0, 95% CI = 0.77-5.1); however, no clear trends in risk were observed. For stromal tumors, oral contraceptive use was associated with decreased risk (OR = 0.37, 95% CI = 0.16-0.83), whereas pregnancy was associated with a small elevation in risk. A trend of increasing risk with increasing age at first term pregnancy was observed, with an odds ratio of 3.6 (95% CI = 1.0-12.5) for a first birth after age 29 years. Risk factors for nonepithelial ovarian cancers do not appear to parallel each other or those for epithelial ovarian cancer.

Adolescent↗
PubMed1996

Seasonal variation in the time to pregnancy: avoiding bias by using the date of onset.

To study seasonality in human fecundability, measured indirectly by time to the first pregnancy, we used data from 18,970 French-Canadian women who married for the first time during the 17th or 18th century. The time to pregnancy was approximated by the interval between marriage and first birth minus 38 weeks. We used the week of marriage and the week of conception as references to study seasonality. We found a minor seasonal pattern in time to pregnancy when using the week of marriage as a reference. The proportions of women with a short time to pregnancy were highest during December-January and June-July, indicating that these may be the most fecund periods. In contrast, we found an obvious seasonal pattern when using the date of conception as a reference. This pattern can be largely explained by a strong seasonal pattern in pregnancy planning (in this case, in marriages). When studying seasonal variation in the time to pregnancy, the date of onset of the time to pregnancy should be used as reference, not the date of conception. Otherwise, results will be biased owing to seasonality in pregnancy planning. The same is true for studies on seasonally bound exposures in relation to time to pregnancy.

Adolescent↗
PubMed1997

Reproductive factors, oral contraceptive use, and risk of colorectal cancer.

Multiparity and use of oral contraceptives are hypothesized to reduce risk of colorectal cancer. Among 57,529 women, 31-90 years of age, who volunteered for a nationwide breast cancer screening program from 1973 to 1980, we observed 154 pathologically confirmed cases of colon cancer and 49 cases of rectal cancer in up to 10 years of follow-up (388,555 person-years). Parity was not associated with risk of colorectal cancer [age-adjusted rate ratio for > or = 4 children vs no children = 1.0; 95% confidence interval (CI) = 0.72-1.5], although decreases in proximal colon cancer and increases in distal colon cancer were observed among parous women. The effect of parity did not vary by age at diagnosis. We found no strong or consistent association for age at menarche, age at first birth, or age at natural menopause. In addition, oral contraceptive use, reflecting mainly past use, was unrelated to risk of colorectal cancer (rate ratio = 1.0; 95% CI = 0.75-1.4). These findings do not corroborate the hypothesis that reproductive events or oral contraceptives influence the development of colorectal cancer.

Adult↗
PubMed1999

Fecundability in relation to body mass and menstrual cycle patterns.

Few studies have investigated the association between body mass index and fecundability, that is, the ability to conceive in a menstrual cycle, among fertile women with normal menstrual cycle pattern. We examined the independent and combined effects of duration and regularity of the menstrual cycle, body mass index, and fecundability from records on pregnant women attending antenatal care at Odense University Hospital, Denmark, between 1972 and 1987. We included only the first birth of each woman who had planned pregnancies and no pre-pregnancy disease (N = 10,903). We estimated the fecundability odds ratio (FR) as the odds of conception in a menstrual cycle. After adjusting for confounders, the fecundability for women with a body mass index >25 kg/m2 was lower than for women with a body mass index of 20-25 kg/m2 [FR = 0.77; 95% confidence interval (CI) = 0.70-0.84]. FR was lower for women with long (>35 days) (FR = 0.74; 95% CI = 0.63-0.87) or irregular cycles (FR = 0.78; 95% CI = 0.70-0.87), even when their body mass index was within the normal range (20-25 kg/m2) and/or their cycles were regular.

Body Mass Index↗
PubMed2001

Declining HIV prevalence and risk behaviours in Zambia: evidence from surveillance and population-based surveys.

OBJECTIVE: To examine trends in HIV prevalence and behaviours in Zambia during the 1990s. METHODS: The core Zambian system for epidemiological surveillance and research has two major components: (i) HIV sentinel surveillance at selected antenatal clinics (ANC) in all provinces; and (ii) population-based HIV surveys in selected sentinel populations (1996 and 1999). The former was refined in 1994 to improve the monitoring of prevalence trends, whereas the latter was designed to validate ANC-based data, to study change in prevalence and behaviour concomitantly and to assess demographic impacts. RESULTS: The ANC-based data showed a dominant trend of significant declines in HIV prevalence in the 15--19 years age-group, and for urban sites also in age-group 20--24 years and overall when rates were adjusted for over-representation of women with low education. In the general population prevalence declined significantly in urban women aged 15--29 years whereas it showed a tendency to decline among rural women aged 15-24 years. Prominent decline in prevalence was associated with higher education, stable or rising prevalence with low education. There was evidence in urban populations of increased condom use, decline in multiple sexual partners and, among younger women, delayed age at first birth. CONCLUSIONS: The results suggested a dominant declining trend in HIV prevalence that corresponds to declines in incidence since the early 1990s attributable to behavioural changes. Efforts to sustain the ongoing process of change in the well-educated segments of the population should not be undervalued, but the modest change in behaviour identified among the most deprived groups represents the major preventive challenge.

Adolescent↗
PubMed2000

Characteristics of a population of women with breast implants compared with women seeking other types of plastic surgery.

Several previous studies have shown that breast implant patients demonstrate a number of differences compared with the general population. However, studies have not compared patients with breast implants with women receiving other types of plastic surgery, of interest because this latter group has been proposed as a comparison group for assessing the long-term health effects experienced by breast implant patients. Questionnaire data obtained from 7447 breast implant patients and 2203 patients with other types plastic surgery were collected during the course of a retrospective cohort study, to determine whether implant patients demonstrate different characteristics compared with a more restricted group of patients. In contrast to previous investigations that compared implant patients with the general population, distinctive differences with respect to family income, number of pregnancies, alcohol consumption, cigarette smoking, or histories of previous gynecologic operations or operations for benign breast disease were not found. However, implant patients were significantly more likely than other plastic surgery patients to be white, have low levels of education, have early ages at first birth, be thin, and be screened frequently for breast disease. Furthermore, implant patients reported somewhat greater use of exogenous hormones and familial histories of rheumatoid arthritis. These results support the notion that other plastic surgery patients are a more appropriate comparison group than women in the general population for studies of the health effects of breast implants; however, there continue to be distinctive characteristics possessed by breast implant patients, which need to be taken into account in an assessment of what disease effects can be uniquely attributed to silicone breast implants.

Adult↗
PubMed1993

Mammographic patterns and breast cancer risk factors among women having elective screening.

We assessed the association between Wolfe mammographic patterns and breast cancer risk factors among 239 women who attended the Breast Evaluation Unit screening program of the Comprehensive Cancer Center of Alabama, University of Alabama at Birmingham, from November 1984 through April 1986. Evaluation consisted of a breast cancer risk assessment based on a questionnaire concerning commonly accepted breast cancer risk factors, along with a physical breast examination and mammogram. Increased age, weight, and parity were associated with a low-risk pattern; late age at first birth, alcohol consumption, and oral contraceptive use were associated with a high-risk pattern. Our findings support those of previous studies, except for those concerning use of oral contraceptives. Further exploration is needed to ascertain whether the association of oral contraceptive use with high-risk patterns indicates a pathway through which estrogens may increase the risk of breast cancer.

Adult↗
PubMed1994

Correlations of choriocarcinoma mortality with alcohol drinking and reproductive factors in China.

This country-based correlation study examined associations of choriocarcinoma mortality with reproductive characteristics and lifestyle factors using data from an ecological survey in 49 Chinese rural counties. Univariate correlation and multivariate regression analyses showed that choriocarcinoma mortality rates among Chinese women were significantly related to alcohol consumption, number of pregnancies and age at menopause, and inversely associated with age at first birth. No clear association was seen between choriocarcinoma mortality and smoking, body mass index, dietary factors and levels of serum nutrients, sex hormones, and antibodies to herpes simplex virus. Limitations of these ecological data preclude causal inferences, but the findings add to the limited evidence of the role of reproductive characteristics in choriocarcinoma risk and provide additional clues to other risk factors for this rare and seldom examined cancer.

Adult↗
PubMed1996

Breast size and breast cancer risk.

The relationship between brassière size, as an indicator of breast size, and breast cancer risk was considered in a case--control study conducted between 1991 and 1994 in six Italian centres. Cases were 2,557 women, below age 75, with histologically confirmed breast cancer, and controls were 2,566 women admitted to hospital for a wide spectrum of acute, non-neoplastic, non-hormone-related diseases. Odds ratio (ORs) of breast cancer and their 95% confidence intervals (CIs) were obtained from multiple logistic regression equations including terms for study centre and age, as well as main breast cancer risk factors. A slight inverse relationship was observed between breast size and the risk of breast cancer, with an OR of 1.37 (95% CI 1.05-1.80) for the smallest brassière size compared with the largest; the increase in risk disappeared after adjustment for main recognized breast cancer risk factors, with an OR of 1.16 (95% CI 0.87-1.54) for brassière size < or = 1 compared with > or = 5. No significant heterogeneity in risk of breast cancer with breast size was found in strata of age at diagnosis, parity, age at first birth, age at menopause, family history of breast cancer, benign breast disease, ever use of oral contraceptives and/or hormone replacement therapy. Thus, this study, based on large number of caucasian women, provides conclusive evidence of a lack of appreciable association between breast size and breast cancer risk in this Italian population.

Adult↗
PubMed2002

Oral contraceptive use and mammographic patterns.

High-risk mammographic patterns represent an increased risk of contracting breast cancer and may be used as a surrogate endpoint for the disease. We examined the relationship between oral contraceptive (OC) use and mammographic patterns among 3218 Norwegian women, aged 40-56 years. Information on ever OC use, duration, and age of first OC use and other epidemiological data were obtained through questionnaires. The mammograms were categorized into five groups. Patterns I-III were combined into a low-risk group and patterns IV and V into a high-risk group. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression and adjusted for age, menopausal status, parity, age at first birth, and body mass index. Women who reported ever having used OCs were 20% more likely (OR 1.27, 95% CI 1.0-1.6) to have high-risk mammographic patterns compared with those reporting never having used OCs. There was no dose response between different measures of OC use and high-risk patterns. Among nulliparous women, ever OC users were four times more likely (OR 4.65, 95% CI 2.1-10.3) to have high-risk patterns compared with never users. Our findings suggest that, especially among nulliparous women, ever OC use may exert its effect on breast cancer risk through changes in breast tissue, which can be observed on a mammogram.

Adult↗
PubMed2002

Can physical trauma cause breast cancer?

The objective of this study is to explore the effect of lifestyle on the risk of invasive breast carcinoma in women aged 50-65 years. A case-control study using a questionnaire and a semi-structured interview. Cases (n = 67) and controls (n = 134) were closely matched on known risk factors for breast cancer including age, family history, age at menarche, parity, age at first birth and menopausal status. Controls were chosen from a pool of 5600 women who attended for breast screening and filled in a questionnaire giving details to allow matching with cases. The study took place at the North Lancashire Breast Screening Service. Women were aged 50-65 years and presented with breast cancer or attended for breast screening. Women with breast carcinoma were more likely to report physical trauma to the breast in the previous 5 years than were the controls (odds ratio (OR) 3.3, 95% confidence interval (CI) 1.3-10.8, P < 0.0001). There were no significant differences in a wide range of other lifestyle indicators including factors relevant to social class, education, residence, smoking and alcohol consumption. In conclusion, recall bias is an unlikely explanation for these results in view of the nature and severity of physical trauma. Models of epithelial cell generation indicate that a causal link between physical trauma and cancer is plausible. A latent interval between cancer onset and presentation of under 5 years is also plausible. The most likely explanation of the findings is that physical trauma can cause breast cancer.

Aged↗
PubMed1994

Danish Cancer Registry as a resource for occupational research.

With its long tradition of population registration, Denmark has outstanding possibilities for occupational health research. The municipality registers date back to 1924, the national death and cancer registers to 1943, and unique personal identification numbers were introduced in 1968. For studies on occupational cancer, the cancer register has been linked with census data, pension data, and personnel files from various companies. Suspected associations between occupational exposures and cancer have been studied. For example, women in dry cleaning exposed to tetrachloroethylene had an excess risk of liver cancer (observed = 14; expected = 5.2; standardized incidence ratio (SIR) = 2.7; 95% CI = 1.5-4.5), and oncology nurses handling antineoplastic drugs had an excess risk of leukemia (SIR = 10.7), based on two cases. The linked registers have also been used to systematically search for associations between occupations and cancer risks (eg, female hairdressers). Cancer patterns differ greatly across countries and across main occupational groups within countries. Future efforts should focus not only on traditional approaches to occupational cancer research but also incorporate indirect influences of the work environment (eg, smoking, parity, age at first birth) and labor market participation on cancer risk.

Denmark↗
PubMed1995

Cancer incidence among Icelandic nurses.

This study investigated cancer incidence among Icelandic nurses, with a special focus on breast cancer. Cancer incidence in the study group was compared with that of the general female population. Elevated standardized incidence ratios (SIRs) were seen for some cancer sites, including breast cancer. For all cancers, breast cancer, and selected cancer sites, SIR increased with increasing length of time intervals allowed to elapse before the study period began. The nurses with a shorter employment time had a higher incidence of cancer than those with a longer one. Known confounding factors--parity and age at first birth--do not appear to be a convincing explanation of the excess of breast cancer. The possibility cannot be excluded that the nursing occupation constitutes an independent risk factor for breast cancer.

Adult↗
PubMed2006

Hormonal and reproductive factors are associated with chronic low back pain and chronic upper extremity pain in women--the MORGEN study.

STUDY DESIGN: Cross-sectional study of 11,428 women aged 20-59 years who were included in a postal questionnaire survey in the Dutch general population. OBJECTIVE: To examine how hormonal and reproductive factors are associated with chronic low back pain (LBP) and chronic upper extremity pain (UEP) in women. SUMMARY OF BACKGROUND DATA: Although LBP is suggested to be linked to hormonal and reproductive factors in women, results from previous studies are inconclusive. In addition, the association with chronic UEP is unknown. METHODS: Multivariate logistic regression models were used to examine associations between hormonal and reproductive factors (independent variables) and, respectively, chronic LBP, chronic UEP and combined chronic LBP/UEP. Associations were adjusted for age, level of education, working status, smoking, and overweight. RESULTS: Past pregnancy, young maternal age at first birth, duration of oral contraceptive use, and use of estrogens during menopause were associated with chronic LBP, while young age at menarche was associated with chronic UEP. Irregular or prolonged menstruation and hysterectomy were associated both with chronic LBP and chronic UEP. No positive associations were found for current pregnancy and number of children. CONCLUSIONS: In adult women, hormonal and reproductive factors are associated with chronic musculoskeletal pain in general. Factors related to increased estrogen levels may specifically increase the risk of chronic LBP.

Adult↗
PubMed2004

Socioeconomic risk factors for breast cancer: distinguishing individual- and community-level effects.

BACKGROUND: Women are at higher risk of breast cancer if they have higher socioeconomic status (SES) or live in higher SES or urban communities. We examined whether women living in such communities remained at greater risk of breast cancer after controlling for individual education and other known individual-level risk factors. METHODS: Data were from a population-based, breast cancer case-control study conducted in Wisconsin from 1988 to 1995 (n = 14,667). Data on community SES and urbanicity come from the 1990 census, measured at the census tract and zip code levels. We evaluated relationships between individual- and community-level variables and breast cancer risk using multilevel logistic regression models with random community intercepts. RESULTS: After controlling for individual education and other individual-level risk factors (age, mammography use, family history of breast cancer, parity, age at first birth, alcohol intake, body mass index, hormone replacement use, oral contraceptive use, and menopausal status), women living in the highest SES communities had greater odds of having breast cancer than women living in the lowest SES communities (1.20; 95% confidence interval = 1.05-1.37). Similarly, the odds were greater for women in urban versus rural communities (1.17; 1.06-1.28). CONCLUSIONS: Community SES and urbanicity are apparently not simply proxies for individual SES. Future research should examine why living in such communities itself is associated with greater risk of breast cancer.

Adult↗
PubMed2005

Mathematical models of ovarian cancer incidence.

BACKGROUND: Pike has proposed "protected time" as one summary method for modeling reproductive risk factors in relation to ovarian cancer incidence. We evaluate this and other approaches to summarizing risk for ovarian cancer. METHODS: We identified 472 incident cases of ovarian cancer during 2,298,068 person-years of follow-up of 24- to 55-year-old premenopausal women at cohort inception. Reproductive exposures, use of oral contraceptives, and history of tubal ligation were evaluated. RESULTS: Age at menopause is directly related to cumulative risk of ovarian cancer up to age 70 years (age 55 vs. age 45, risk increase = 62%; 95% confidence interval = 36 to 96%) and age at menarche is inversely related to risk (age 15 vs. 11, risk reduction = 31%; 27-34%). Use of oral contraceptives for 5 years before age 30 decreases risk of ovarian cancer to age 70 by 37% (32 to 41%). Tubal ligation reduces risk up to age 70 by 21% (-2 to 38%). Parity reduces risk, independent of age at first birth and age at last birth. A model summarizing years of ovulation offers a fit comparable to a more complex modeling of reproductive variables. The model fit is good, with a concordance statistic of 0.60 (0.57 to 0.62) indicating reasonable ability to differentiate those who will develop ovarian cancer from those who will remain disease free. CONCLUSION: This model may be applied in the identification of women at high risk for ovarian cancer, for example, in selecting candidates for prevention trials.

Adult↗
PubMedDate not supplied

Prevention of congenital dislocation of the hip in the newborn.

Routine examination and early treatment of any instability in the hips of newborns has recently been called into question after a period of universal agreement. The hips of 49,937 neonates were prospectively studied by a general hip screening. Every unstable hip--449 in 317 children--was immediately treated with a Von Rosen splint for a 3-month-period. Overall, satisfactory reduction of the incidence of established congenital dislocation of the hip (CDH) was achieved. Risk factors leading to unstable hips (sex, first birth, and breech birth) and the development of CDH (time of stabilization) were considered.

Diagnostic Errors↗
PubMed2006

Signal content of red facial coloration in female mandrills (Mandrillus sphinx).

Studies of secondary sexual ornamentation and its maintenance by sexual selection tend to focus on males; however, females may also possess showy ornaments. For example, female mandrills possess facial coloration that ranges from black to bright pink. We used fortnightly photographs of 52 semi-free-ranging females aged above 3years over 19 months to evaluate whether colour conveys information concerning female competitive ability, reproductive quality, age or reproductive status. Colour was not related to female rank or quality (body mass index, age at first birth or mean inter-birth interval); however, colour did increase significantly with age and primiparous females were darker than multiparous females. Colour may therefore signal reproductive quality, as younger females are less fertile and produce smaller offspring. Colour was brighter during the follicular phase than during the luteal phase, suggesting that it may signal fertility. Colour also varied across gestation and peaked at four and eight weeks post-parturition, suggesting that it may signal approaching parturition and lactation. Future studies should examine the relationship between colour and the menstrual cycle in more detail, the hormonal basis of female colour, and determine experimentally whether mandrills of both sexes attend to differences in colour between and within females.

Aging↗