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Polly A Newcomb

Publications and source records attributed to Polly A Newcomb.

At least 37 records · Page 2Linked to original sources
PubMed2005

Differences in breast cancer risk factors by tumor marker subtypes among premenopausal Vietnamese and Chinese women.

We evaluated associations between reproductive and lifestyle risk factors with breast cancer tumor marker status in a case-control study. Cases were premenopausal women living in Vietnam and China who were eligible for a clinical trial of oophorectomy and tamoxifen as treatment for breast cancer (n = 682). Controls were nonrelative hospital visitors, matched on age to the cases (n = 649). Immunohistochemical analysis was used to identify the presence of estrogen receptor (ER) and progesterone receptor and the overexpression of HER-2/neu oncogene. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression, adjusted for known confounders. Overall, 280 (61%) tumor samples were ER positive and 176 (38%) were ER negative. HER-2/neu overexpression was detected in 161 (35%) samples, whereas 286 (26%) samples were HER-2/neu negative. We observed an inverse trend between increasing parity and decreasing breast cancer risk (P = 0.002). Women ages > or =25 years at first birth had increased breast cancer risk compared with women ages <25 years at first birth (OR, 1.53; 95% CI, 1.20-1.95). Women who consumed alcohol had increased risk of breast cancer compared with women who did not (OR,1.85; 95% CI, 1.32-2.61). Compared with controls, OR estimates for breast cancer by parity and age at first birth were significantly associated with ER and/or HER-2/neu tumor status by Wald test (P < 0.05). Family history, age at menarche, cumulative lactation, body mass index, and education were not significantly related to breast cancer risk. Our findings support the hypothesis that some breast cancer risk factors differ by ER and HER-2/neu tumor marker subtypes.

Adult↗
PubMed2005

Correlates of age at menarche among sixth grade students in Wisconsin.

We conducted a cross-sectional, school-based survey of sixth-grade girls living in the Reedsburg, Wis area school district to explore factors associated with age at menarche. Data collection included parent and student questionnaires for demographic, menstrual, physical activity, and nutritional information. School nurses conducted physical examinations to provide anthropometric measurements. Salivary samples were obtained for laboratory analysis of estradiol, estrone, estriol, and progesterone levels. Students (n=59) were an average of 11.9 years of age (range: 10-13). Nineteen students (32%) reported menarche, with an average of 11.4 years of age (range: 8-12). Cycle length of the menstruating students averaged 32.0 days (range: 25-46 days). Students' age at menarche was positively correlated with their mothers' age at menarche (r=0.53, P=0.02). Total caloric intake, macronutrients, hormone levels, birthweight, and family size were not associated with menstrual status. We observed an inverse association between increasing weight and earlier age at menarche (P=0.03). Students past menarche watched more television (P=0.03) and participated in fewer hours of sporting activity (P=0.08) than students who had not yet reached menarche. These preliminary data suggest that further investigation of the determinants of menarche is both feasible and warranted.

Adolescent↗
PubMed2004

STK15 polymorphism and breast cancer risk in a population-based study.

STK15 is considered a potential cancer susceptibility gene owing to its functions in normal cell mitosis. Two common coding region polymorphisms in the gene (F31I and V57I) may affect ubiquitin-dependent degradation and thus the half-life of the encoded protein. There are limited data on the relevance of these polymorphisms to population cancer rates. To examine whether functional variation in STK15 may affect breast cancer risk, we genotyped a large series of incident breast cancer cases (n = 941) and age-matched population controls (n = 830) for the F31I and V57I polymorphisms. Individually, neither the F31I polymorphism [odds ratio (OR) 1.54; 95% confidence interval (CI) 0.96-2.47, comparing 31I with 31F homozygotes] nor the V57I polymorphism (OR 0.92; 95% CI 0.50-1.71, comparing 57I with 57V homozygotes) was significantly associated with breast cancer risk. A relatively common genotype, combining the two polymorphisms (31I-57V/31I-57V, 3% of controls) was related to a significant 2-fold increase in the risk of post-menopausal breast cancer (OR 1.96; 95% CI 1.01-3.79). No interaction was detected between STK15 variants and estrogenic risk factors, although the power of these analyses was limited. These results suggest that STK15 may represent a low penetrance type breast cancer susceptibility gene.

Amino Acid Substitution↗
PubMed2004

The incidence of colorectal cancer following a negative screening sigmoidoscopy: implications for screening interval.

BACKGROUND & AIMS: Current guidelines recommend a 5-year interval for colorectal cancer (CRC) screening by sigmoidoscopy. However, the optimal screening interval is uncertain. We estimated the annual incidence of distal and proximal CRC in the first 5 years following a negative sigmoidoscopy examination to gauge the potential benefit of rescreening in <5 years. METHODS: A cohort of 72,483 participants in the Colon Cancer Prevention program of Kaiser Permanente of Northern California (KP) was defined using computerized databases. Men and women aged 50 years and older who had a negative screening flexible sigmoidoscopy examination between 1994 and 1996 and were considered not to be at high risk for developing CRC were included. Subjects were censored at the time of diagnosis (for cases), death, termination of KP membership, or subsequent colon examination. RESULTS: Thirty cases of distal and 80 cases of proximal CRC occurred. Age-adjusted incidence rates of distal CRC ranged from a low of 2.8 per 100,000 person-years in the first year of follow-up to a high of 13.0 per 100,000 in the fourth year (rate difference, 10.2; 95% confidence interval, 1.1-19.3). However, for the entire follow-up period, incidence of distal CRC remained much lower than age-adjusted rates of 70.6 in the general population (Surveillance, Epidemiology, and End Results registry). The incidence of proximal CRC was also decreased modestly over population rates of disease. CONCLUSIONS: Screening by sigmoidoscopy more frequently than every 5 years would likely lead, at best, to only modest improvements as compared with a 5-year screening interval.

Aged↗
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↗
PubMed2004

Calcium and colorectal cancer: some questions remain.

There is convincing laboratory evidence that calcium reduces the risk of colorectal cancer, but previous epidemiologic studies have reported somewhat inconsistent results. A recent large prospective study confirms that higher calcium intake is associated with a modestly reduced risk of distal colorectal cancer. There was little additional risk reduction associated with consumers of more than 700 mg calcium/day. This study also suggests that certain subgroups, such as males, smokers, and people who consume low levels of vitamin D, may be at differential risk. Because colon cancer is a common disease, even a modest decrease in risk has the potential for preventing a substantial number of cases.

Calcium, Dietary↗
PubMed2004

Potential exposure to PCBs, DDT, and PBDEs from sport-caught fish consumption in relation to breast cancer risk in Wisconsin.

In Wisconsin, consumption of Great Lakes fish is an important source of exposure to polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), polybrominated diphenyl ethers (PBDEs), and other halogenated hydrocarbons, all of which may act as potential risk factors for breast cancer. We examined the association between sport-caught fish consumption and breast cancer incidence as part of an ongoing population-based case-control study. We identified breast cancer cases 20-69 years of age who were diagnosed in 1998-2000 (n = 1,481) from the Wisconsin Cancer Reporting System. Female controls of similar age were randomly selected from population lists (n = 1,301). Information about all sport-caught (Great Lakes and other lakes) fish consumption and breast cancer risk factors was obtained through telephone interviews. After adjustment for known and suspected risk factors, the relative risk of breast cancer for women who had recently consumed sport-caught fish was similar to women who had never eaten sport-caught fish [relative risk (RR) = 1.00; 95% confidence interval (CI), 0.86-1.17]. Frequency of consumption and location of sport-caught fish were not associated with an increased risk of breast cancer. Recent consumption of Great Lakes fish was not associated with postmenopausal breast cancer (RR = 0.78; 95% CI, 0.57-1.07), whereas risk associated with premenopausal breast cancer was elevated (RR = 1.70; 95% CI, 1.16-2.50). In this study we found no overall association between recent consumption of sport-caught fish and breast cancer, although there may be an increased breast cancer risk for subgroups of women who are young and/or premenopausal.

Adult↗
PubMed2004

No evidence of an association of JC virus and colon neoplasia.

JC virus (JCV) is an ubiquitous human polyomavirus that frequently resides in the kidneys of healthy individuals and is excreted in the urine of a large proportion of the adult population. Polyomaviruses are associated with disease largely in immunocompromised individuals (progressive multifocal leukoencephalopathy). Colorectal cancers can show chromosome instability and it was hypothesized that JCV may account for some of this instability. We screened urine from 45 healthy donors and 233 colorectal cancer/normal tissue pairs for the presence of JCV sequences using a Taqman assay. This assay could detect 1 virus genome in 10 human genomes. In the urine samples, we found an infection rate of approximately 70%. The JCV isolates in these samples could be categorized into four JCV types (2B, 4, 7, and 8), none of which had a rearranged regulatory region. Among the colon tissues, one normal tissue (<0.5%) and none of the matched tumors tested positive for JCV. There is no evidence in these data to indicate that JCV is the cause of genetic instability in colorectal cancer.

Adult↗
PubMed2003

Social networks and quality of life among female long-term colorectal cancer survivors.

BACKGROUND: The population of long-term colorectal cancer survivors in the United States continues to increase, but little is known about how they fare-physically, mentally, or socially-in the years after diagnosis. The current study examines female long-term colorectal cancer survivors' health-related quality of life (HRQoL) in relation to social networks. METHODS: A population-based sample of female colorectal cancer survivors (n = 726) residing in Wisconsin was recontacted approximately 9 years after the initial diagnosis. Of 443 women who were alive in 1999, 307 women completed a follow-up questionnaire. Analysis was conducted on 259 participants who completed the Medical Outcomes Study Short Form 36 Health Status Survey and a modified version of Berkman and Syme's Social Network Index. Using multivariate analyses, HRQoL summary scores were tested for associations with individual and composite measures of social networks, including marital/partner status; number of children, relatives, and friends; and the frequency of religious and community participation. RESULTS: After adjusting for age, extent of disease at diagnosis, number of comorbidities, body mass, and education, HRQoL was similar to norms published for the general population. Individual social network measures (including the number of relatives and friends) and composite network measures (including network size, the number of ties seen at least once per month, and overall social connectedness) were associated positively with mental health. CONCLUSIONS: Social networks may have an important relation with HRQoL-particularly mental health-among female long-term colorectal cancer survivors. The results of this study should be of interest to those seeking to understand or improve HRQoL among this growing population.

Adult↗
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

Hormone replacement therapy in relation to survival in women diagnosed with colon cancer.

INTRODUCTION: Colorectal cancer is the second leading cause of cancer death among US men and women. A number of studies report that hormone replacement therapy (HRT) reduces the risk of colorectal cancer, but fewer studies have examined the relation between HRT use and survival after diagnosis and none examined this relation by anatomic location of the primary colon tumor. METHODS: Data from a cohort of 699 women 50-79 years of age diagnosed with colon cancer between 1980 and 1998 in a large Health Maintenance Organization based in Seattle, Washington were analyzed to examine the relation between HRT use prior to diagnosis and survival. Use of HRT was ascertained from a computerized pharmacy database. RESULTS: HRT use was associated with a 41% reduction in risk of death after adjustment for age, stage, and diagnosis year (p= 0.037). The association between HRT use and colon cancer survival was strongest among women with cancer in the distal colon (hazard rate ratio 0.33, 95% confidence interval, 95% CI: 0.13-0.83), while little or no association between HRT use and survival was observed among women with proximal tumors (HRR 0.78, 95% CI: 0.42-1.44). CONCLUSIONS: These findings suggest that HRT use is associated with improved survival from colon cancer. Future observational and laboratory studies should shed light on how hormones may be related to reduced incidence and improved prognosis.

Aged↗