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C Schairer

Publications and source records attributed to C Schairer.

At least 19 recordsLinked to original sources
PubMed1995

Geographic variation in mortality from breast cancer among white women in the United States.

BACKGROUND: For several decades, mortality from breast cancer has been higher in the northeastern part of the United States than in other regions, particularly the South. Rates have also been somewhat higher in the Midwest and West than in the South, especially among older women. The reasons for these geographic variations are not well understood. PURPOSE: The objective of this study was to evaluate geographic differences in U.S. breast cancer mortality rates in 1987, after taking into account regional differences in the distribution of recognized breast cancer risk factors (e.g., late age at first live birth) and certain prognostic factors (e.g., mammography use). METHODS: The 1987 breast cancer mortality rates for four regions of the country were obtained from the National Center for Health Statistics. Regional data on the distribution of breast cancer risk factors were obtained from 1987 National Health Interview Cancer Epidemiology Supplement interviews with 9778 white women aged 20-79 years. Regional data on the distribution of mammography use were obtained from 1987 National Health Interview Cancer Control Supplement interviews with 3795 white women aged 50-79 years. RESULTS: Age-adjusted mortality ratios (MRs) among women 50 years and older were 1.15, 1.18, and 1.30 in the West, Midwest, and Northeast, respectively, compared with the South. Corresponding MRs among women 20-49 years old were 1.01, 1.08, and 1.07 in the West, Midwest, and Northeast, respectively, compared with the South. After adjustment for recognized risk factors and certain prognostic factors, MRs among older women were 1.13 (95% confidence interval [CI] = 1.04-1.23), 1.08 (95% CI = 1.01-1.16), and 1.13 (95% CI = 1.04-1.23) in the West, Midwest, and Northeast, respectively, compared with the South. Corresponding MRs among younger women were 0.94 (95% CI = 0.76-1.16), 1.05 (95% CI = 0.92-1.18), and 0.99 (95% CI = 0.86-1.14), respectively. CONCLUSION: Before adjustment for regional differences in recognized risk factors and prognostic factors, mortality excesses among younger women in the Northeast, Midwest, and West were less than 10% compared with the South. After adjustment, MRs were near unity for all regions. Among older women, the excess mortality was more substantial before adjustment for relevant factors, ranging from 15% in the West to 30% in the Northeast. Approximately 50% of the excesses in the Northeast and Midwest and 10% of the excess in the West could be explained on the basis of regional differences in the prevalence of recognized breast cancer risk factors and prognostic factors. After adjustment for these factors, the magnitude of excess in breast cancer mortality in the Northeast (13%) was comparable to that in the West (13%) but still slightly higher than that in the Midwest (8%).

Adult↗
PubMed1991

Racial differences in the risk of invasive squamous-cell cervical cancer.

To investigate reasons for the higher rates of invasive squamous-cell cervical carcinoma among Blacks than Whites in the United States, we examined data from a case-control study of cervical cancer conducted in five geographic areas of the US, supplemented by incidence data from the Surveillance, Epidemiology, and End Results (SEER) Program, and hysterectomy prevalence data from the Cancer and Steroid Hormone Study. We observed only minor differences between Blacks and Whites in the magnitude of relative risks associated with a long interval since last Pap smear, multiple sexual partners, cigarette smoking, a higher number of births, and low levels of income and education. Thus, differences in the strength of associations contributed little to the higher incidence rare in Blacks, but the prevalence of these risk factors, except for cigarette smoking, was higher in Blacks than Whites. The SEER incidence rate ratio of 2.3 for Blacks compared to whites was increased to 2.7 when incidence rates utilized denominators corrected for prevalence of hysterectomy, while the rate difference increased from 14.9 to 25.8 cases per 100,000 person-years (PY). We estimated further that, after adjustment for prevalence of hysterectomy, the incidence rate for women at the lowest levels of exposure to the risk factors evaluated was 2.2 times higher in Blacks than Whites, but that the corresponding rate difference was only 2.2 cases per 100,000 PYs. Thus, our results suggest that racial differences in the prevalence of exposure to identified risk factors account for most of the difference in incidence rates. It remains to be determined what, as yet unidentified, aspects of lower socioeconomic status contribute to the higher incidence rate in Blacks.

Adult↗
PubMed1991

Heterogeneity of the effect of family history on breast cancer risk.

We studied the effects of family history on breast cancer risk among 2,908 cases and 3,180 controls, selected from participants in a nationwide screening project. First-degree family history was associated with a twofold risk increase. Second-degree family history effects were minimal, after adjusting for effects of first-degree relatives. Family history effects were not confounded by age at menarche, age at first full-term birth, age at natural menopause, or previous benign breast disease. Risks from mother's and sister's history were independent. The odds ratio (OR) from a maternal history, 1.9 (95% confidence interval [CI]: 1.6-2.3), varied little by the subject's age at diagnosis, menopause status, or disease laterality. Interactions of maternal history effects with multiple breast biopsies and age at menopause were greater than additive, indicating common mechanistic pathways. The OR from a sister's history was 2.3 (95% CI: 1.9-2.8) and was increased among women who were less than 45 (OR = 6.9), had bilateral disease (OR = 4.7), or were premenopausal (OR = 4.4). The effects from a mother's history and a sister's history are modified in different directions by different factors, providing further indication of the separate roles of a mother's and sister's history in breast cancer etiology.

Adult↗
PubMed1990

Case-control study of in situ and invasive carcinoma of the vagina.

A case-control study of 41 patients with carcinoma in situ (CIS) or invasive cancer of the vagina and 97 community controls was undertaken to identify potential risk factors. Although vaginal and cervical cancers often occur as multiple primaries, only a few common risk factors prevailed. Similar to cervical cancer, low education and family income were risk factors for vaginal CIS and invasive cancer. In addition, history of genital warts was strongly related (RR = 2.9), although other sexual factors were not. Previous genital abnormalities related to subsequent cancer risk, with significant associations seen for vaginal discharge or irritation (RR = 6.1), a previous abnormal Pap smear (RR = 3.8), or an early hysterectomy (RR = 6.7). In addition, there was some evidence that vaginal trauma might be involved, with nonsignificant and independent associations relating to regular douching with preparations other than water or vinegar (RR = 2.7) and frequent washing of the genital area (RR = 2.7). Further studies are needed to determine whether our findings persist among a larger series of cases.

Adult↗
PubMed1990

Comparison of jobs, exposures, and mortality risks for short-term and long-term workers.

We compared the jobs, estimates of exposures, and mortality experience of short-term (less than or equal to 1 year) and long-term (greater than 1 year) workers from nine plants producing formaldehyde or formaldehyde products. There were few jobs that were filled solely or primarily by newly hired workers. The estimated median level of formaldehyde exposure experienced by short-term workers on their first job was nearly identical to that for long-term workers, although short-term workers were more likely to be in jobs exposed to particulates than were long-term workers. As duration of employment increased, there was little change in the average estimated exposure level of formaldehyde, but the likelihood of being exposed to particulates decreased. Short-term workers had greater risks than long-term workers of dying from diseases of the circulatory system, arteriosclerotic heart disease, emphysema, diseases of the digestive system, cirrhosis of the liver, motor vehicle accidents, suicide and malignant neoplasms, particularly cancers of the stomach, colon, lung, prostate, and brain.

Cohort Studies↗
PubMed1989

Projecting individualized probabilities of developing breast cancer for white females who are being examined annually.

To assist in medical counseling, we present a method to estimate the chance that a woman with given age and risk factors will develop breast cancer over a specified interval. The risk factors used were age at menarche, age at first live birth, number of previous biopsies, and number of first-degree relatives with breast cancer. A model of relative risks for various combinations of these factors was developed from case-control data from the Breast Cancer Detection Demonstration Project (BCDDP). The model allowed for the fact that relative risks associated with previous breast biopsies were smaller for women aged 50 or more than for younger women. Thus, the proportional hazards models for those under age 50 and for those of age 50 or more. The baseline age-specific hazard rate, which is the rate for a patient without identified risk factors, is computed as the product of the observed age-specific composite hazard rate times the quantity 1 minus the attributable risk. We calculated individualized breast cancer probabilities from information on relative risks and the baseline hazard rate. These calculations take competing risks and the interval of risk into account. Our data were derived from women who participated in the BCDDP and who tended to return for periodic examinations. For this reason, the risk projections given are probably most reliable for counseling women who plan to be examined about once a year.

Adult↗
PubMed1989

Risk of cancer in women receiving hormone replacement therapy.

Cancer risk following treatment with non-contraceptive estrogens was studied in a population-based cohort of 23,244 women. Complete follow-up for an average of 6.7 years revealed 1,087 incident cancers versus 962.5 expected (relative risk/RR/ = 1.13; 95% confidence interval 1.10-1.20). We confirmed the recent findings of a more detailed analysis of the same cohort, based on a 1-year shorter follow-up period, namely: a markedly increased risk of endometrial cancer (RR = 1.8; 1.5-2.1), notably in women receiving potent estrogens, i.e., conjugated estrogens or estradiol (RR = 2.0; 1.6-2.4), and a slightly increased risk of breast cancer (RR = 1.1; 1.0-1.2). A slightly decreased risk of invasive cervical cancer (RR = 0.8; 0.5-1.2) is most likely due to more frequent smear taking than in the background population. There was no increase in the risk of cancer of ovary (RR = 1.0; 0.8-1.2), pancreas (RR = 0.8; 0.5-1.2), large bowel (RR = 1.0; 0.8-1.2) or kidney (RR = 1.0; 0.7-1.4). The risk of developing cancer in liver or biliary tract was lower than expected (RR = 0.4; 0.2-0.7), particularly in women who had used potent estrogens (RR = 0.3; 0.1-0.6), an unexpected finding which warrants further studies. Increased risks of malignant melanoma (RR = 1.5; 1.0-2.1) and lung cancer (RR = 1.3; 0.9-1.7) need cautious interpretation because of their low magnitude, the absence of a biological gradient when subgroups were analyzed and the slightly higher prevalence of smokers in the cohort than in the background population.

Climacteric↗
PubMed1989

The risk of breast cancer after estrogen and estrogen-progestin replacement.

To examine the risk of breast cancer after noncontraceptive treatment with estrogen, we conducted a prospective study of 23,244 women 35 years of age or older who had had estrogen prescriptions filled in the Uppsala region of Sweden. During the follow-up period (mean, 5.7 years) breast cancer developed in 253 women. Compared with other women in the same region, the women in the estrogen cohort had an overall relative risk of breast cancer of 1.1 (95 percent confidence interval, 1.0 to 1.3). The relative risk increased with the duration of estrogen treatment (P = 0.002), reaching 1.7 after nine years (95 percent confidence interval, 1.1 to 2.7). Estradiol (used in 56 percent of the treatment periods in the cohort) was associated with a 1.8-fold increase in risk after more than six years of treatment (95 percent confidence interval, 0.7 to 4.6). No increase in risk was found after the use of conjugated estrogens (used in 22 percent of the treatment periods) or other types, mainly estriols (used in 22 percent of the treatment periods). Although the numbers of women were smaller, the risk of breast cancer was highest among the women who took estrogen and progestin in combination for extended periods. The relative risk was 4.4 (95 percent confidence interval, 0.9 to 22.4) in women who used only this combination for more than six years. Among women who had previously used estrogens alone, the relative risk after three years or more of use of the combination regimen was 2.3 (95 percent confidence interval, 0.7 to 7.8). We conclude that in this cohort, long-term perimenopausal treatment with estrogens (or at least estradiol compounds) seems to be associated with a slightly increased risk of breast cancer, which is not prevented and may even be increased by the addition of progestins.

Adult↗
PubMed1989

Risk of endometrial cancer after treatment with oestrogens alone or in conjunction with progestogens: results of a prospective study.

OBJECTIVE: To determine the relative risk of developing endometrial neoplasia after treatment with oestrogens alone or in conjunction with progestogens. DESIGN: Prospective cohort follow up study, average observation period 5.7 years for each patient. To have a 90% chance of detecting a relative risk of 2.0 with 95% significance the study required 78,000 person years of observation. SETTING: Community based cohort. PATIENTS: Women aged over 35 who were prescribed non-contraceptive oestrogens in the Uppsala health care region during April 1977 to March 1980 were identified from pharmacy records. Of all prescriptions issued, 95% were identified. Patients from the cohort who developed endometrial neoplasia were identified from the cancer registry of the Uppsala health care region. Compliance, sociodemographic data, and lifetime exposures to oestrogen and cyclically added progestogen were assessed by questionnaire in a sample of the cohort. The final cohort consisted of 23,244 patients (133,373 person years). The prevalence of university education, oophorectomy, and hysterectomy was higher in the cohort than the general population; no other confounding factors were identified. MEASUREMENTS: The total number of person years was divided into exposure groups by inference from the data from the questionnaire. Compensation was made for the excess of hysterectomies. Specimens from all cases of endometrial neoplasia in the cohort and 90% of cases in the general population were studied blind histopathologically. Characteristics of treatment of all women who had endometrial neoplasia were assessed by questionnaire. Relative risks and 95% confidence intervals were calculated. RESULTS: Seventy four cases of carcinoma and 33 cases of premalignant lesions occurred in the cohort. The relative risk of endometrial carcinoma was 1.8 (95% confidence interval 1.1 to 3.2) after exposure to any oestrogen compound without progestogen for more than six years; 2.2 (1.2 to 4.4) after more than three years' exposure to conjugated oestrogens without progestogen; and 2.7 (1.4 to 5.1) after more than three years' exposure to oestradiol compounds without progestogen. When carcinoma and premalignant lesions were considered together the results were similar but the relative risk was higher. Risk of carcinoma did not increase when progestogens were cyclically added to oestrogens for the entire treatment period (relative risk 0.9 (0.4 to 2.0]. CONCLUSIONS: Use of oestrogens without progestogens is associated with a twofold to threefold increase in risk of endometrial neoplasia. Use of progestogens either removes this increased risk or delays its onset. A further follow up of the cohort is essential to analyse the risks with greater statistical power.

Adult↗
PubMed1989

Mammographic parenchymal patterns as indicators of breast cancer risk.

Mammographic parenchymal patterns have been suggested as indicators of breast cancer risk. However, few well-controlled studies have used prediagnostic mammograms to determine the pattern classification. The authors studied 266 cases of breast cancer and 301 controls from 25 screening centers of the Breast Cancer Detection and Demonstration Project, a nationwide screening program conducted between 1973 and 1980 to evaluate the risk associated with mammographic patterns using mammograms taken four years before the detection of breast cancer. Mammograms of the cancerous breast of cases and of the ipsilateral breast in the control matched to each case were blindly assessed by one of the investigators (J.N.W.), originator of the mammographic pattern classification. The breast cancer odds ratio among women with the combined P2 + DY patterns, compared with women with the N1 pattern, was 2.8 (95% confidence interval (CI): 1.6-5.1). This estimate of relative risk was comparable with the risk associated with other recognized breast cancer risk factors. The odds ratio among P2 + DY women with a first-degree family history of breast cancer was 5.5 (95% CI: 2.6-11.8) compared with N1 women without a family history. These data provide additional evidence that mammographic patterns are indicators for subsequent development of breast cancer, particularly among women with a first-degree family history of this malignancy.

Adult↗
PubMed1989

Body size and breast cancer risk assessed in women participating in the Breast Cancer Detection Demonstration Project.

In a case-control study that included 2,560 breast cancer cases and 2,679 controls, the authors examined the association between body size and breast cancer with the use of measured height and weight of white US women. The subjects were women aged 26-93 years recruited between 1973 and 1975 for participation in the Breast Cancer Detection Demonstration Project, a nationwide breast cancer screening program. After controlling for the effect of potential confounders, the relative risks of breast cancer across increasing quartiles of height were 1.00, 1.07, 1.15, and 1.27 (p = 0.001, test for trend). The effect of weight independent of height was evaluated using indices of relative weight (e.g., weight/height1.5, weight/height2), and the authors identified excess weight as a risk factor for breast cancer among women who had experienced natural menopause and among women aged 50 years or older at diagnosis. Among women aged 50 years or older, for example, the relative risks of breast cancer for increasing quartiles of weight/height1.5 were 1.00, 1.04, 1.40, and 1.29 (p = 0.0006, test for trend). An inverse association between relative weight and breast cancer risk was suggested for women younger than age 50 years at diagnosis. However, the apparent protective effect of high relative weight was restricted to women with small tumors, suggesting a detection bias.

Adult↗
PubMed1988

Fecapentaenes and their precursors throughout the bowel--results of an autopsy study.

The fecapentaenes are potent mutagens found in the stool of some humans and pigs. These compounds are produced by Bacteroides species in the gut from an uncharacterized family of precursor compounds, and have been postulated to pose a risk of human colorectal cancer. To better understand fecapentaene production in vivo, and to determine if excreted levels measured in epidemiologic studies are representative of the entire colon, fecapentaenes were assayed from multiple sites in the bowel in an autopsy study of 16 humans and 2 pigs. An indirect measurement of fecapentaene precursors was also made. Colonic concentrations of fecapentaenes and precursors varied widely between individuals, but were consistent for each individual throughout the colon. In addition, the measurements of rectal contents, assumed to approximate values in excreted stool, were equivalent to measurements from the colon.

Adult↗
PubMed1988

Risk factors for breast and endometrial cancer in a cohort of women treated with menopausal oestrogens.

A matched case-control study was undertaken with the aim of determining the presence of several risk factors for breast and endometrial cancer in a cohort of women--recruited from a defined geographical area of Sweden--who had received at least one oestrogen prescription for menopausal symptoms. A mailed questionnaire was answered by 653 (88.8%) of 735 women sampled from the cohort (cases) and 952 (76.8%) of 1240 women sampled from the background population (controls) and these respondents formed the basis of the analyses. The prevalence rates of oophorectomy and hysterectomy were significantly higher among oestrogen-treated women than in the background population, 10.7% versus 2.6% (odds ratio (OR) = 5.1, 95% confidence interval (Cl) 3.1-8.5) and 19.0% versus 7.3% (OR = 2.7, Cl 1.9-3.8), respectively. Higher theoretical education entailed a more than twofold increase in the risk of receiving oestrogen treatment, compared with women with less than eight years at school. Women who had a first degree relative with breast cancer ran a relative risk of receiving oestrogen therapy of 0.6 (Cl 0.4-0.9) whereas the risk for women with a prior breast biopsy was 1.4 (Cl 1.0-2.1). For all other variables studied, ie diabetes, hypertension, age at menarche, age at first livebirth, nulliparity, age at menopause, height and weight, there were no statistically significant differences between the cohort of oestrogen-treated women and the background population. We conclude that the difference in the prevalence of hysterectomy has to be taken into account when calculating the risk of endometrial cancer in the cohort.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1988

Racial differences in bladder cancer risk: a case-control study.

To determine why the incidence rate of transitional cell bladder cancer in whites in the United States is approximately twice that in blacks, the authors examined data from a large population-based case-control study of bladder cancer conducted in 1978 involving 2,982 cases and 5,782 controls. The relative risk of transitional cell carcinoma for whites compared with blacks was 1.9 before adjustment for the major bladder cancer risk factors, whereas after adjustment for cigarette smoking and occupation it was 1.6 (95% confidence interval (CI): 1.3-2.1). Further adjustment for other risk factors, including history of a bladder infection and a family history of urinary tract cancer, did not alter this estimate. The elevated risk of white compared with blacks was limited, however, to cases whose disease was confined to the mucosa and submucosa. Among cases whose disease had extended to the bladder musculature or beyond, whites were at slightly reduced risk compared with blacks. This suggests that whites may be diagnosed with conditions that go undetected in blacks but that are unlikely as a group to progress to more extensive disease. Because of the population-based nature of the study, it was possible to determine that if bladder cancer incidence among whites of both sexes was reduced to the level among blacks, total incidence in the United States would fall by 36 per cent.

Adult↗
PubMed1988

Menstrual factors and risk of breast cancer.

A case control study of 2,908 breast cancer cases and 3,180 controls, derived from a nationwide screening program, enabled evaluation of the relationship of breast cancer risk to a variety of menstrual factors. Risk was significantly inversely related to age at menarche, with women who first menstruated at age 15 or later having a 23% lower risk than those with menarche prior to the age of 12. There was a higher relative risk (1.3) for premenopausal than menopausal women. In contrast to previous studies, there was only a slight increase in risk associated with a late age at natural menopause, possibly owing to errors in recall. Bilateral oophorectomy at an early age exerted a protective influence on breast cancer risk, with effects manifested approximately 10 to 15 years after oophorectomy. Women who had both ovaries removed prior to the age of 40 had a 45% reduced risk compared to women with a natural menopause at ages 50 to 54. In addition, bilateral oophorectomy at an early age was associated with a lowered risk relative to natural menopause at a comparable age, which may reflect the more pronounced and sudden decline in endogenous hormones associated with the surgery. Although these results were based on patient reports regarding the types of surgical menopause experienced, validation against medical records showed close correspondence regarding the number of ovaries removed.

Adult↗
PubMed1987

Methylxanthines and breast cancer.

We investigated the relationship between methylxanthine consumption and breast cancer using data from a case-control study which included 1,510 cases and 1,882 controls identified through a nation-wide breast cancer screening program. There was no evidence of a positive association between methylxanthine consumption and risk of breast cancer. In fact, there was some suggestion of a negative association, particularly in women diagnosed after age 50. In addition, there was no evidence of increased risk with past or recent methylxanthine consumption, or with the consumption of caffeine or specific beverages, most notably brewed or instant caffeinated coffee and tea.

Adult↗
PubMed1987

Alcohol consumption and breast cancer.

The association between alcohol consumption and breast cancer was investigated in a case-control study involving 1,524 cases and 1,896 controls identified through a nationwide screening program. Ever drinking alcohol was not associated with any substantial increase in risk [odds ratio (OR) = 1.1; 95% confidence interval (Cl) = 1.0-1.3], but there was a significant trend in risk with increasing average weekly intake (P less than .04). Women who had one or fewer drinks daily (83% of all drinkers) did not experience any excess risk compared to nondrinkers, but significant excess risks were observed among those who drank from 1 to 2 (OR = 1.3; 95% Cl = 1.0-1.7) or more than 2 (OR = 1.7; 95% Cl = 1.2-2.4) drinks a day. An increased risk associated with alcohol consumption was evident only for those who drank at younger ages (less than 30 yr), regardless of current consumption. Alcohol effects were adjusted for a variety of factors, including reproductive history, were adjusted for a variety of factors, including reproductive history, socioeconomic indicators, and obesity, but none exerted any appreciable confounding influence. The results support an association between moderate alcohol consumption in early life and subsequent breast cancer risk, although interpretation should be cautious in the absence of dietary information.

Adult↗