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Background:It is unclear whether circulating insulin or glucose levels are associated with increased risk of colorectal cancer. Few prospective studies have examined this question, and only one study had repeated measurements.Methods:We conducted a prospective study of colorectal cancer risk using the subsample of women in the Women's Health Initiative study whose fasting blood samples, collected at baseline and during follow-up, were analysed for insulin and glucose. Cox proportional hazards models were used to assess associations with colorectal cancer risk in both baseline and time-dependent covariates analyses.Results:Among 4902 non-diabetic women with baseline fasting serum insulin and glucose values, 81 incident cases of colorectal cancer were identified over 12 years of follow-up. Baseline glucose levels were positively associated with colorectal cancer and colon cancer risk: multivariable-adjusted hazard ratio (HR) comparing the highest (99.5 mg dl−1) with the lowest tertile (<89.5 mg dl−1): 1.74, 95% confidence interval (CI) 0.97-3.15 and 2.25, 95% CI: 1.12-4.51, respectively. Serum insulin and homeostasis model assessment were not associated with risk. Analyses of repeated measurements supported the baseline results.Conclusion:These data suggest that elevated serum glucose levels may be a risk factor for colorectal cancer in postmenopausal women. [ABSTRACT FROM AUTHOR]

Objectives: To explore the relationship between serum homocysteine, a sensitive biomarker for folate inadequacy and problems in one-carbon metabolism, and invasive cervical cancer.Methods: A large case-control study was conducted in five US areas with up to two community controls, obtained by random-digit dialing, individually matched to each case. Cervical cancer risk factors were assessed through at-home interview. Blood was drawn at least 6 months after completion of cancer treatment from 51% and 68% of interviewed cases and controls. Serum homocysteine was measured by high-performance liquid chromatography, and exposure to human papillomavirus (HPV) type 16, the most prevalent oncogenic type, was assessed using an enzyme-linked immunosorbent assay. Cases with advanced cancer and/or receiving chemotherapy were excluded, leaving 183 cases and 540 controls.Results: Invasive cervical cancer risk was substantially elevated for women in the upper three homocysteine quartiles (> 6.31 micromol/L); multivariate-adjusted odds ratios ranged from 2.4 to 3.2 (all 95% CIs excluded 1.0). A trend was apparent and significant (p = 0.01). When cases were compared with HPV-16 seropositive controls only, odds ratios were comparable.Conclusions: Serum homocysteine was strongly and significantly predictive of invasive cervical cancer risk. This association could reflect folate, B12 and/or B6 inadequacy, or genetic polymorphisms affecting one-carbon metabolism. [ABSTRACT FROM AUTHOR]

Objective: Human papilloma virus (HPV) is frequently detectable in cancers of the cervix, vagina, and vulva, but its role in endometrial and ovarian cancers is less certain. This analysis aimed to examine the association of presence of HPV type 16 (HPV-16) antibodies with subsequent risk of cervical, endometrial, and ovarian cancers.Methods: In a prospective study enrolling over 15,000 pregnant women, pre-cancer sera from women who developed cervical (n = 83), endometrial (n = 34), and ovarian (n = 35) cancers were compared with sera from 172 control women frequency-matched by age group and race.Results: HPV-16 seropositivity (OR = 2.0, 95% CI 1.0-3.4) was associated with cervical cancer, with the association more prominent for cancers occurring within 10 years of serum sampling (OR = 2.3, 95% CI 1.0-5.3) than cancers occurring later (OR = 1.6, 95% CI 0.75-3.6). Overall, the associations between HPV-16 seropositivity and endometrial (OR = 1.6, 95% CI 0.64-3.8) and ovarian cancers (OR = 1.1, 95% CI 0.43-2.8) were not significant, although the odds ratios for those cancers occurring within 20 years after serum sampling were similar to that for cervical cancer (OR = 2.2 for both).Conclusions: Our results confirm that HPV-16 infection precedes the development of cervical cancer. Predictability of HPV-16 seropositivity for risk of other female cancers warrants further investigation. [ABSTRACT FROM AUTHOR]

Context: Poliovirus vaccine contaminated with live simian virus 40 (SV40), a macaque polyomavirus that is tumorigenic in rodents, was used extensively in the United States between 1955 and 1963. Simian virus 40 DNA has recently been detected in several rare human tumors, including ependymomas, osteosarcomas, and mesotheliomas.Objective: To determine the risk of ependymoma, osteosarcoma, and mesothelioma among Americans who as children received SV40-contaminated poliovirus vaccine.Design: Retrospective cohort study using data from the Surveillance, Epidemiology, and End Results program (1973-1993) and the Connecticut Tumor Registry (1950-1969), as well as national mortality statistics (1947-1973).Setting: United States.Participants: Birth cohorts that were likely to have received SV40-contaminated poliovirus vaccine as infants, born 1956 through 1962 (60 811730 person-years of observation); as children, born 1947 through 1952 (46430953 person-years); or that were unexposed, born 1964 through 1969 (44959979 person-years).Main Outcome Measures: Relative risk (RR) of each cancer among exposed compared with unexposed birth cohorts.Results: Age-specific cancer rates were generally low and were not significantly elevated in birth cohorts exposed to SV40-contaminated vaccine. Specifically, compared with the unexposed, the relative risk of ependymoma was not increased in the cohorts exposed as infants (RR, 1.06; 95% confidence interval [CI], 0.69-1.63), or as children (RR, 0.98; 95% CI, 0.57-1.69) nor did the exposed have an increased risk of all brain cancers. Osteosarcoma incidence also showed no relation to exposure as infants (RR, 0.87; 95% CI, 0.71-1.06) or children (RR, 0.85; 95% CI, 0.59-1.22). Last, mesotheliomas were not significantly associated with exposure, although the cohorts studied have not yet reached the age at which these tumors tend to occur.Conclusions: After more than 30 years of follow-up, exposure to SV40-contaminated poliovirus vaccine was not associated with significantly increased rates of ependymomas and other brain cancers, osteosarcomas, or mesotheliomas in the United States. [ABSTRACT FROM AUTHOR]