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Polly A Newcomb

Publications and source records attributed to Polly A Newcomb.

17 recordsLinked to original sources
PubMed2003

Oral contraceptive use and risk of breast cancer by histologic type.

We examined the association between oral contraceptive use and risk of specific breast cancer histopathologies in a large, multi-center, population-based, case-control study. Women younger than age 75 with a new diagnosis of invasive breast cancer were identified from 4 statewide tumor registries. We compared women with lobular (n = 493) and ductal carcinoma (n = 5,510) to randomly selected controls (n = 9,311). Odds ratios (OR) and 95% confidence intervals (CI) for each histologic type were estimated using polytomous logistic regression, adjusted for other breast cancer risk factors. Current oral contraceptive use was associated with increased risk of lobular carcinoma (OR = 2.6, 95%CI = 1.0-7.1) and there was a significant trend (p = 0.017) of increased risk with more recent use. Oral contraceptive use was not clearly associated with ductal carcinoma (OR = 1.2, 95%CI = 0.8-1.9). These results suggest that the association between oral contraceptive use and risk of breast cancer may vary by histologic type.

Adult↗
PubMed2003

Selection bias in the assessment of gene-environment interaction in case-control studies.

Selection bias is a common concern in epidemiologic studies, particularly case-control studies. Selection bias in the odds ratio occurs when participation depends jointly on exposure and disease status. General results for understanding when selection bias may affect studies involving gene-environment interactions have not yet been developed. In this paper, the authors show that the assessment of gene-environment interactions will not be subject to selection bias under the assumption that genotype does not influence participation conditional on exposure and disease status. This is true even when selection, including self-selection of subjects, is jointly influenced by exposure and disease and regardless of whether the genotype is related to exposure, disease, or both. The authors present an example to illustrate this concept.

Bias↗
PubMed2003

Long-term efficacy of sigmoidoscopy in the reduction of colorectal cancer incidence.

Screening sigmoidoscopy is associated with a reduction in both the incidence and mortality of colorectal cancer. Although current guidelines recommend sigmoidoscopy screening every 5 years, the duration of risk reduction is not known. We conducted a population-based case-control study to examine the association between sigmoidoscopy screening and colorectal cancer incidence. We collected information on screening history and risk factors from case patients with distal (n = 1026) and proximal (n = 642) colorectal cancer and from 1294 control subjects from October 1998 through February 2002. Screening sigmoidoscopy was associated with a statistically significant reduction in the incidence of distal colorectal cancer (odds ratio [OR] = 0.24, 95% confidence interval [CI] = 0.17 to 0.33). These reductions were sustained for up to 16 years with little attenuation. We also observed strong inverse associations between cancer incidence and sigmoidoscopy in analyses that included subjects with symptom-related tests. Current recommendations regarding the frequency of sigmoidoscopy screening may be unnecessarily aggressive.

Adult↗
PubMed2003

Early life risk factors in cancer: the relation of birth weight to adult obesity.

The intrauterine environment appears to play a role in the development of adult diseases, including several prominent cancers. Our study aims to characterize the relationship between birth weight, a measure of the intrauterine environment, and adult obesity. A population-based sample of women aged 50-79, living in the states of Massachusetts, New Hampshire or Wisconsin, were randomly selected from lists of licensed drivers and Medicare beneficiaries to participate as controls in a case-control study of breast cancer. Information on birth weight, adult height and adult weight were collected through structured telephone interviews from 1992-1995. Our analysis was based on 1,850 interviews. A U-shaped relationship between birth weight and adult BMI was observed. Median adult BMI for the birth weight categories (in kilograms) <2.3, 2.3<2.5, 2.5<3.2, 3.2<3.9, 3.9<4.5 and > or =4.5 were 26.6, 24.4, 25.1, 25.5, 25.4 and 26.6 kg/m respectively. Compared to women 2.5<3.2 kg at birth, women in highest birth weight category (> or =4.5 kg) had an odds ratio of 1.99 (95% CI 1.13-3.48) of being obese (> or =30 kg/m(2)) as adults. The odds ratio for women in the <2.3 kg birth weight category was 1.67 (95% CI 1.01-2.76). These data suggest that both low and high birth weights are associated with higher adult BMI and support the hypothesis that fetal experience may influence adult obesity with potential consequences for risk of several major cancers.

Aged↗
PubMed2003

Association of NAT2 and smoking in relation to breast cancer incidence in a population-based case-control study (United States).

OBJECTIVE: To evaluate the potential interaction between N-acetyltransferase 2 (NAT2) and smoking in breast cancer incidence. METHODS: The data are derived from a population-based case-control study of women aged 20-69 years who were residents of Massachusetts or Wisconsin during 1997-1998. Incident cases of invasive breast cancer were identified through state tumor registries and age-similar controls were selected at random from population lists. Telephone interviews were conducted to obtain information on known and suspected risk factors including smoking history. Women provided oral mucosal DNA through the mail for genetic studies. RESULTS: A total of 791 cases and 797 controls were included in the analysis. Overall, smoking was modestly associated with breast cancer risk (multivariate odds ratio (OR) for ever smoking: 1.37; 95% confidence interval (CI): 1.12-1.69), and there was a trend in risk for greater pack-years of smoking among postmenopausal women (p for trend = 0.02). Overall, NAT2 was not related to invasive breast cancer (multivariate OR: 1.1 1; 95% CI: 0.90-1.36). Associations of smoking with breast cancer tended to be somewhat stronger among the women with the slow acetylator genotype for NAT2: when compared to those who never smoked and were rapid acetylators, the OR for ever smoking was 1.50 (95% CI: 1.11-2.02) in slow acetylators, and OR: 1.24 (95% CI: 0.91-1.70) in rapid acetylators. However, tests for multiplicative interaction were not significant in case-control comparisons, or in case-only analyses. CONCLUSION: Results of the study are compatible with the majority of previous studies that indicate little or no association of NAT2, smoking, or their interaction with the occurrence of breast cancer.

Adult↗
PubMed2003

Patterns of postmenopausal progestin use with estrogen in relation to endometrial cancer (United States).

OBJECTIVE: To investigate the risk of endometrial cancer associated with various regimens of postmenopausal hormone therapy. METHODS: Data from a population-based case-control study were analysed that included 591 women newly diagnosed with endometrial cancer, aged 40-79, and who were reported to Wisconsin's statewide tumor registry in 1991-1994. Similarly aged population controls (n = 2045) were randomly selected from lists of licensed drivers and Medicare beneficiaries. Information on hormone use and other factors was obtained through telephone interviews. RESULTS: Ever use of estrogen-progestin hormones was associated with increased endometrial cancer compared to women who had never used hormones; the increase per year of use was 7% (95% confidence interval 1-13%). Both cyclic (<10 days per month) and continuous progestin used with estrogen were associated with comparable twofold increases in risk relative to non-users. There was no increased risk associated with progestin used for 10-21 days per month. CONCLUSIONS: Both continuous and cyclic progestin regimens are associated with a much lower risk of endometrial cancer than estrogen alone. However, many women using these regimens remain at significantly increased risk of endometrial cancer.

Adult↗
PubMed2003

Postmenopausal hormone therapy and risk of breast cancer by histologic type (United States).

OBJECTIVE: Postmenopausal hormone use and risk of breast cancer by histopathology was examined in a large multi-centered population-based case-control study. METHODS: Women younger than 75 years newly diagnosed with invasive breast cancer between 1988 and 1991 were identified from statewide tumour registries in Wisconsin, Massachusetts, New Hampshire, and Maine. Only postmenopausal women were included in this analysis. Breast cancer cases (lobular (n = 219), ductal, NOS (n = 2172), and specific ductal subtypes (n = 242)) were compared with randomly selected population controls (n = 3179) using adjusted multi-variable polytomous logistic regression to estimate odds ratios (OR) and 95% confidence intervals (95%CI) for each histology. RESULTS: Lobular carcinoma was associated with recent (within 2 years) estrogen therapy (OR: 1.8, 95% CI: 1.0-3.4) and recent use of combined estrogen-plus-progestin therapy (OR:3.6, 95%CI: 1.8-7.6). Risk of ductal carcinoma was not associated with recent use of either estrogen alone (OR: 0.9, 95% CI: 0.7-1.2) or combined therapy (OR:0.9, 95% CI: 0.6-1.3). No associations were found with ductal subtypes. CONCLUSIONS: The association between postmenopausal hormone use and risk of breast cancer may depend on histopathology. Of particular interest is the association between combined hormone therapy and increased risk of lobular carcinoma. This lesion is increasingly common but, nonetheless, comprises fewer than 10% of invasive breast cancers.

Aged↗
PubMed2003

Geocoding addresses from a large population-based study: lessons learned.

BACKGROUND: Geographic information systems (GIS) and spatial statistics are useful for exploring the relation between geographic location and health. The ultimate usefulness of GIS depends on both completeness and accuracy of geocoding (the process of assigning study participants' residences latitude/longitude coordinates that closely approximate their true locations, also known as address matching). The goal of this project was to develop an iterative geocoding process that would achieve a high match rate in a large population-based health study. METHODS: Data were from a study conducted in Wisconsin using mailing addresses of participants who were interviewed by telephone from 1988 to 1995. We standardized the addresses according to US Postal Service guidelines, used desktop GIS geocoding software and two versions of the Topologically Integrated Geographic Encoding and Referencing street maps, accessed Internet mapping engines for problematic addresses, and recontacted a small number of study participants' households. We also tabulated the project's cost, time commitment, software requirements, and brief notes for each step and their alternatives. RESULTS: Of the 14,804 participants, 97% were ultimately assigned latitude/longitude coordinates corresponding to their respective residences. The remaining 3% were geocoded to their zip code centroid. CONCLUSION: The multiple methods described in this work provide practical information for investigators who are considering the use of GIS in their population health research.

Data Collection↗
PubMed2002

Detection method and breast carcinoma histology.

BACKGROUND: The association between method of detection and breast carcinoma histopathology has not been assessed adequately in a population-based setting. METHODS: Among women who were included in a population-based, case-control study of breast cancer, patients who were newly diagnosed with invasive breast carcinoma were identified from Wisconsin's statewide tumor registry. Only women age > or = 50 years were analyzed, because screening by mammography was not recommended before age 50 years at the time of the study. The breast tumors among these women (n = 2341 tumors) included the following histopathologies: lobular carcinoma (n = 206 tumors); ductal carcinoma, not otherwise specified (n = 1920 tumors); papillary carcinoma (n = 15 tumors); medullary carcinoma (n = 36 tumors); mucinous adenocarcinoma (n = 56 tumors); tubular adenocarcinoma (n = 41 tumors); invasive comedocarcinoma (n = 24 tumors); scirrhous adenocarcinoma (n = 15 tumors); and mixed ductal/lobular carcinoma (n = 28 tumors). RESULTS: Overall, women reported that 41% of tumors were detected by mammography, 48% of tumors were self detected, and 11% of tumors were detected by clinical breast examination (CBE). Detection by mammography was significantly more likely for women who had tubular carcinoma (83%; P < 0.001) and invasive comedocarcinoma (67%; P = 0.23) compared with women who had ductal carcinoma (40%). Mammography was significantly less likely to detect medullary carcinoma (17%) than ductal carcinoma (40%; P = 0.01). Lobular carcinoma was the only histopathology that, compared with ductal carcinoma, was detected significantly more often by CBE than by self detection. Mammography detected lobular carcinoma (42%) as frequently as ductal carcinoma (40%). However, the use of postmenopausal hormones may have modified these detection patterns: Among current users, mammography discovered a greater percentage of ductal carcinomas (51%) and fewer lobular carcinomas (36%) than nonusers. CONCLUSIONS: Among women age > or = 50 years, breast cancer detection by mammography, self detection, and CBE varied according to tumor histopathology.

Adenocarcinoma↗
PubMed2002

Endometrial cancer incidence in relation to electric blanket use.

Endometrial cancer is associated with endogenous and exogenous estrogen excess. Some investigators have posited that electromagnetic fields may influence cancer risk through estrogenic hormonal mechanisms; however, there have been no studies reporting on electric blanket exposure in relation to endometrial cancer. The authors examined this possible association between endometrial cancer risk and electric blanket or mattress cover use as part of a population-based, case-control study. This analysis included incident endometrial cancer cases 40-79 years of age, interviewed during 1994 (n = 148; response rate, 87%) and identified from the Wisconsin tumor registry. Female controls of similar age were randomly selected from population lists (n = 659; response rate, 85%). Information regarding electric blanket and mattress cover use and endometrial cancer risk factors was obtained through structured telephone interviews approximately 1 year after diagnosis. After adjustment for age, body mass index, and postmenopausal hormone use, the risk of endometrial cancer was similar among ever users (odds ratio = 1.04, 95% confidence interval: 0.70, 1.55) and among current users (odds ratio = 0.87, 95% confidence interval: 0.49, 1.54) as compared with never users. Despite its small size and potential misclassification of exposure, this study provides evidence against an association between electric blanket or mattress cover use and endometrial cancer.

Adult↗
PubMed2002

Recreational physical activity and ovarian cancer in a population-based case-control study.

Results from epidemiologic studies of physical activity and ovarian cancer have been inconsistent, with 2 prospective studies reporting a modest positive association. We evaluated this relationship in a population-based case-control study conducted in Massachusetts and Wisconsin. Incident cases diagnosed between 1991 and 1994 were identified through statewide tumor registries. Community controls were selected randomly from lists of licensed drivers and Medicare recipients. Participation in moderate and vigorous recreational physical activity at age 12, age 20 and 5 years prior to diagnosis was assessed by telephone interview. Data were available for 327 cases and 3,129 controls. Results were adjusted for age, parity and other ovarian cancer risk factors. Total and vigorous physical activity were not associated with a substantial decrease in ovarian cancer risk at any age. The relative risk (RR) for women reporting > or = 7 vs. 0 hr/week of recent vigorous activity was 0.85 [95% confidence interval (CI) = 0.39-1.86; p for trend = 0.31]. When metabolic equivalent task (MET) hours of activity were estimated, only women in the highest category had any reduction in risk (RR for > 42 MET-hours/week at the reference age = 0.70; 95% CI = 0.36-1.35; p for trend = 0.41). Overall, our results provide only limited support for an inverse association between recreational physical activity and risk of ovarian cancer.

Adult↗
PubMed2002

Prevalence and treatment of menopausal symptoms among breast cancer survivors.

Women diagnosed with breast cancer often experience early menopause secondary to treatment effects, yet physicians may be reluctant to prescribe hormone replacement therapy (HRT) because of the potential increased risk of recurrence. To assess the burden of menopausal symptoms, HRT use, and alternative treatments in recent breast cancer survivors, a population-based, case-control study was conducted among breast cancer survivors and age-matched controls. Wisconsin women 18-69 years old with a new diagnosis of breast cancer 8-11 months prior to interview (n = 110) and control subjects randomly selected from population lists (n = 73) responded to a standardized telephone questionnaire that elicited information on menopausal symptoms, estrogen and alternative therapies (prescription medications, vitamins, herbal preparations, soy products, acupuncture, chiropractic) used to alleviate symptoms. We used multivariate logistic regression to obtain odds ratios and 95% confidence intervals (CI) for symptoms of menopause, use of estrogen, and use of alternative therapies. Breast cancer survivors were 5.3 (95% CI 2.7-10.2) times more likely to experience symptoms, 25 (95% CI 8.3-100) times less likely to use estrogen, and 7.4 (95% CI 2.5-21.9) times more likely to use alternatives than controls. Soy, vitamin E, and herbal remedies were the most common alternative therapies reported by participants; use was greater in cases compared to controls. Most soy users reported increasing soy products specifically to reduce the chances of a diagnosis of recurrent breast cancer. Among cases, tamoxifen users (n = 62) reported a higher prevalence of symptoms and a higher prevalence of alternative treatments. This is the first population-based survey of menopausal symptoms and treatments that compares breast cancer cases with disease-free controls. Cases are both more likely to experience menopausal symptoms and less likely to use HRT than controls. Instead, cases treat menopausal symptoms with vitamin E and soy products, even though the safety and efficacy of these therapies are unproven. The increased use of soy products in this population has not been previously documented.

Adolescent↗
PubMed2002

Early life factors in relation to breast cancer risk in postmenopausal women.

We evaluated the role of early life factors in a large, population-based, case-control study of breast cancer risk in postmenopausal women. Case women in Massachusetts, New Hampshire, and Wisconsin were ascertained through state cancer registries; control women were randomly selected from drivers license lists (50-65 years of age) or Medicare beneficiary lists (65-79 years of age). Information concerning factors of interest was obtained through structured telephone interviews. Overall, 83% of eligible cases and 78% of eligible controls participated, and data from more than 2900 women were available for this analysis. We observed a weak J-shaped relationship between birth weight and breast cancer risk; the increased risk was not statistically significant for either the lowest or the highest birth weight. Parental smoking during the pregnancy was not associated with risk of breast cancer in the adult daughter. Breast cancer risk increased significantly with father's education (P = 0.01). Risk also increased with greater age of the mother at the time of the subject's birth (P = 0.04). The subject's birth rank was inversely associated with risk (P = 0.03), as was the number of older sisters (P = 0.03), but the number of older brothers, number of younger siblings, sibship gender ratio, and total sibship size were unrelated to risk. Overall, our results are consistent with previous studies and suggest that these early life factors have a modest influence on breast cancer risk in postmenopausal women.

Aged↗
PubMed2002

Postmenopausal estrogen and progestin use in relation to breast cancer risk.

Epidemiological evidence now consistently supports a modest increase in breast cancer risk among women using postmenopausal hormones, usually estrogens. Less is known regarding how the addition of progestin affects breast cancer risk. The objective of this study was to investigate the type and duration of postmenopausal therapy and breast cancer risk. We performed a multicenter population-based case-control study set in Massachusetts, New Hampshire, and Wisconsin. The subjects were 5298 postmenopausal women (age range, 50-79 years) with a new diagnosis of invasive breast cancer from statewide tumor registries. For comparison, 5571 controls were randomly selected from population lists. Participants completed a structured telephone interview covering hormone use and breast cancer risk factors. Multivariable regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). The RR for breast cancer increased with longer durations of hormone use, about 2%/year for estrogen alone (RR, 1.02; 95% CI, 1.01-1.03) and 4%/year for estrogen-progestin use (RR, 1.04; 95% CI, 1.01-1.08). Estrogen-progestin use that was both recent and long term (>5 years in duration) was more strongly associated with breast cancer risk (RR, 1.57; 95% CI, 1.15-2.14) than similar use of estrogen alone (RR, 1.39; 95% CI, 1.17-1.65). In estrogen-progestin users, risks were similar for sequential and continuous use regimens but perhaps stronger for lobular than ductal breast cancer. Use of progestin alone was associated with a doubling of risk (RR, 2.09; 95% CI, 1.07-4.07 for ever use versus nonuse). Estrogen-progestin use, both sequential and continuous, appears to be more strongly associated with risk of breast cancer than use of estrogen alone.

Age Distribution↗
PubMed2002

Risk factors for hyperplastic and adenomatous polyps: evidence for malignant potential?

Recent studies have suggested that hyperplastic polyps may be benign precursor lesions for a distinct subset of colorectal tumors. We conducted a clinic-based case-control study to evaluate risk factors for hyperplastic polyps. Cases with hyperplastic polyps (n = 219), adenomas (n = 437), and both types of polyps (n = 138), along with colonoscopy-negative controls (n = 708), were identified at a gastroenterology practice in the Minneapolis area during 1991-1994. A self-administered questionnaire was used to collect risk factor information. Risk factors for hyperplastic and adenomatous polyps were generally similar to those for colorectal cancer. Male sex, smoking, and alcohol consumption were associated with increased risk of all polyp groups; nonsteroidal anti-inflammatory drug use, hormone replacement therapy use, and calcium intake were associated with reduced risk. There was no apparent association between increasing age and hyperplastic polyp risk (P = 0.21) in this analysis, although it was a strong risk factor for adenoma (P < 0.001). The odds ratio (OR) for hyperplastic polyps associated with >25 pack-years of smoking was 4.1 [95% confidence interval (CI), 2.2-7.6], whereas the OR for adenoma alone was 1.3 (95% CI, 0.8-2.3). The OR estimate for individuals diagnosed with both polyp types was 4.2 (95% CI, 1.9-9.3). These results suggest, as one possibility, that the consistent association of adenoma and smoking observed in previous studies may be partially attributable to the inclusion of individuals with both adenomas and hyperplastic polyps in the adenoma case group. To the contrary, individuals with both polyp types may be expressing a phenotype distinct from those who have only adenomas and should be considered separately. Further studies are necessary to establish which polyp phenotypes are related to smoking. Overall, the similarity of the risk profiles of colorectal hyperplastic polyps, adenoma, and cancer provides additional support for the growing body of evidence that some hyperplastic polyps may have neoplastic potential.

Adenomatous Polyps↗