25 results on '"Helzlsouer, K. J."'
Search Results
2. Null association between insulin-like growth factors, insulin-like growth factor-binding proteins, and prostate cancer in a prospective study.
- Author
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Lacey JV Jr, Hsing AW, Fillmore CM, Hoffman S, Helzlsouer KJ, and Comstock GW
- Subjects
- Age Distribution, Aged, Aged, 80 and over, Case-Control Studies, Confidence Intervals, Humans, Incidence, Male, Middle Aged, Odds Ratio, Probability, Prospective Studies, Reference Values, Risk Assessment, Risk Factors, Sensitivity and Specificity, Biomarkers, Tumor analysis, Insulin-Like Growth Factor Binding Protein 3 analysis, Prostatic Neoplasms diagnosis, Prostatic Neoplasms epidemiology, Somatomedins analysis
- Published
- 2001
3. The repeatability of serum carotenoid, retinoid, and tocopherol concentrations in specimens of blood collected 15 years apart.
- Author
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Comstock GW, Burke AE, Hoffman SC, Norkus EP, Gross M, and Helzlsouer KJ
- Subjects
- Aged, Arteriosclerosis etiology, Biomarkers analysis, Blood Banks, Case-Control Studies, Female, Humans, Hypertension complications, Male, Middle Aged, Reproducibility of Results, Risk Assessment, Sensitivity and Specificity, Specimen Handling, Carotenoids blood, Retinoids blood, Vitamin E blood
- Abstract
Community-wide programs to collect blood for a research serum bank were carried out in Washington County, Maryland in 1974 and 1989. Of the 8395 persons who participated in both programs, 64 were controls in a nested case-control study of the association of antioxidant micronutrients with subsequent breast cancer, and 30 and 166 were controls in similar studies of lung and prostate cancer. Assay results for five carotenoids, two retinoids, and two tocopherols in samples of blood collected 15 years apart were thus available for comparisons of micronutrient concentrations. The mean Spearman rank order correlation coefficient for all comparisons was 0.44, with two coefficients greater than 0.60 and two less than 0.30. Blood pressure readings at the two blood collections had a mean rank order correlation coefficient of 0.46. Because blood pressure readings in 1974 were shown to be significantly predictive of atherosclerosis 15-18 years later, the present results suggest that ranked concentrations of antioxidant micronutrients from a single sample are sufficiently representative to be used as predictors of subsequent concentrations and are thus suitable for assessment as risk factors for subsequent illnesses.
- Published
- 2001
4. Catechol-O-methyltransferase polymorphism is not associated with ovarian cancer risk.
- Author
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Goodman JE, Lavigne JA, Hengstler JG, Tanner B, Helzlsouer KJ, and Yager JD
- Subjects
- Case-Control Studies, Female, Genotype, Humans, Middle Aged, Ovarian Neoplasms genetics, Catechol O-Methyltransferase genetics, Glutathione Transferase genetics, Ovarian Neoplasms enzymology, Polymorphism, Genetic
- Abstract
A valine-108-methionine polymorphism in exon 4 of the catechol-O-methyltransferase (COMT) gene causes a 3- to 4-fold reduction in enzyme activity and has been associated with an increased risk of breast cancer. This increased risk may be attributable to a decreased ability of the protein encoded by the low-activity allele (COMT(L)) to methylate and inactivate catechol estrogens, which have been implicated in estrogen carcinogenesis. Because estrogens have also been implicated in the etiology of ovarian cancer, we analyzed 108 cases and 106 controls from a case-control study conducted in Mainz, Germany, to test the hypothesis that COMT(L) is associated with ovarian cancer risk. No significant association was found between the COMT genotype and ovarian cancer risk (for the intermediate-activity COMT genotype versus the high-activity COMT genotype, OR, 1.29; 95% CI, 0.63-2.64; for the low-activity COMT genotype versus the high-activity COMT genotype, OR, 1.17; 95% CI, 0.52-2.61). We also hypothesized that women who were both low-activity COMT genotype- and glutathione S-transferase (GST) M1- and/or T1 null would be at higher risk for ovarian cancer because the combination of these genotypes could theoretically lead to higher catechol estrogen exposure. However, the association between the COMT polymorphism and ovarian cancer risk was similar across GSTM1 and GSTT1 genotypes (Ptrend > 0.40, for all strata). Because of the small sample size of this study population, odds ratios of a small magnitude could not be completely ruled out; however, the results presented do not support a strong association between the COMT polymorphism and the risk of ovarian cancer.
- Published
- 2000
5. The risk of cervical cancer in relation to serum concentrations of folate, vitamin B12, and homocysteine.
- Author
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Alberg AJ, Selhub J, Shah KV, Viscidi RP, Comstock GW, and Helzlsouer KJ
- Subjects
- Adult, Case-Control Studies, DNA Repair, Female, Humans, Odds Ratio, Risk Assessment, Uterine Cervical Neoplasms etiology, Folic Acid blood, Homocysteine blood, Uterine Cervical Neoplasms epidemiology, Vitamin B 12 blood
- Abstract
Due to its role in the synthesis and repair of DNA, folate may protect against the development of cervical cancer. Prospective data on the possible association between folate and cervical cancer have been lacking. There is also a paucity of prospective evidence concerning the possible associations between cervical cancer and vitamin B12, which shares pathways with folate, and homocysteine, a marker of low B vitamin concentrations. A nested case-control study was conducted to prospectively evaluate the associations between cervical cancer and serum concentrations of folate, vitamin B12, and homocysteine. Among a community-based cohort of women who donated blood in 1974 for a serum bank in Washington County, Maryland, 39 cases of cervical cancer diagnosed between 1975 and mid-1990 were included in the study (13 cases of invasive cervical cancer and 26 cases of carcinoma in situ). Two controls were matched to each case by age, race, and sex. Stored serum from the cases and controls was assayed for folate, B12, and homocysteine concentrations. For folate, adjusted odds ratios were 1.0, 0.62, and 0.60 for the low to high thirds of the serum concentrations, respectively, a trend in the protective direction that was not statistically significant (P for trend = 0.42). Overall, the results for vitamin B12 tended to mimic those for folate, whereas the associations for homocysteine tended to be in the opposite direction. None of the results of this study were statistically significant, but patterns of the associations are in accord with hypothesized mechanistic pathways concerning B vitamins and cervical cancer.
- Published
- 2000
6. The effects of vitamin C and vitamin E on oxidative DNA damage: results from a randomized controlled trial.
- Author
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Huang HY, Helzlsouer KJ, and Appel LJ
- Subjects
- 8-Hydroxy-2'-Deoxyguanosine, Aged, Antioxidants therapeutic use, Ascorbic Acid therapeutic use, Cell Transformation, Neoplastic, Chemoprevention, Deoxyguanosine urine, Double-Blind Method, Female, Humans, Life Style, Male, Middle Aged, Oxidative Stress, Vitamin E therapeutic use, Antioxidants pharmacology, Ascorbic Acid pharmacology, DNA Damage, Deoxyguanosine analogs & derivatives, Vitamin E pharmacology
- Abstract
Oxidative DNA damage may be important in mutagenic, carcinogenic, and aging processes. Although it is plausible that antioxidant vitamins may reduce oxidative DNA damage, evidence from human studies has been sparse and inconsistent. We determined the short-term effects of vitamin C (500 mg/day) and vitamin E (400 IU d-alpha-tocopheryl acetate/day) supplements on oxidative DNA damage in a double-masked, placebo-controlled, 2x2 factorial trial in 184 nonsmoking adults. Mean duration of supplementation was 2 months. Oxidative DNA damage was measured by 24-h urinary excretion of 8-hydroxy-2'-deoxyguanosine (8-OHdG). At baseline, urinary 8-OHdG (mean +/- SE; ng/mg creatinine) was associated with race (15.6 +/- 0.8 in African Americans versus 20.3 +/- 1.2 in Caucasians, P = 0.001), prior antioxidant supplement use (18.6 +/- 0.8 in users versus 13.8 +/- 1.5 in non-users, P = 0.007), and regular exercise (19.2 +/- 1.1 in exercisers versus 16.6 +/- 0.9 in non-exercisers, P = 0.04). Fruit and vegetable intake and serum ascorbic acid were inversely associated with urinary 8-OHdG (P-trend = 0.02 and 0.016, respectively). The benefits of fruit and vegetable intake became evident with the consumption being at least three servings/day. At the end of supplementation, change from baseline in urinary 8-OHdG (mean +/- SE; ng/mg creatinine) was -0.6 +/- 1.4 (P = 0.61), 0.6 +/- 1.1 (P = 0.59), 0.5 +/- 1.0 (P = 0.61), and 1.6 +/- 1.4 (P = 0.27) in the placebo, vitamin C alone, vitamin E alone, and combined vitamins C and E groups, respectively. In overall and subgroup analyses, there was no significant main effect or interaction effect of the supplements on urinary 8-OHdG. In conclusion, supplementation of diet with vitamin C (500 mg/day) and vitamin E (400 IU d-alpha-tocopheryl acetate/day) had no significant main effect or interaction effect on oxidative DNA damage as measured by urinary 8-OHdG in nonsmoking adults. However, several aspects of a healthy lifestyle were associated with lower oxidative DNA damage.
- Published
- 2000
7. Serum dehydroepiandrosterone and dehydroepiandrosterone sulfate and the subsequent risk of developing colon cancer.
- Author
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Alberg AJ, Gordon GB, Hoffman SC, Comstock GW, and Helzlsouer KJ
- Subjects
- Adult, Age Factors, Aged, Case-Control Studies, Colonic Neoplasms blood, Colonic Neoplasms etiology, Disease Susceptibility blood, Humans, Male, Middle Aged, Prospective Studies, Risk Factors, Sex Factors, Colonic Neoplasms epidemiology, Dehydroepiandrosterone blood, Dehydroepiandrosterone Sulfate blood
- Abstract
This purpose of this study was to evaluate whether serum dehydroepiandrosterone (DHEA) and its sulfate conjugate, dehydroepiandrosterone sulfate (DHEAS), are associated with the likelihood of developing colon cancer. A nested case-control study was conducted using the serum bank and cancer registry in Washington County, Maryland. From a population of 20,305 county residents who donated blood in 1974, incident cases of colon cancer that occurred from 1975 to 1991 (n = 117) were matched to one cancer-free control by age, race, and sex. Serum specimens that were stored at -70 degrees C since 1974 were assayed for DHEA and DHEAS. Compared with the controls, the mean serum concentrations of cases were 3% lower for DHEA (P = 0.90) and 13% lower for DHEAS (P = 0.60). When DHEA levels were analyzed according to fourths, no noteworthy associations were observed. Compared with the lowest fourth, the highest fourth of serum DHEAS was nonsignificantly associated with a halving in the risk of colon cancer (odds ratio, 0.50; 95% confidence limits, 0.18, 1.37; Ptrend = 0.22), and further analyses showed the potential protective association was confined largely to males (highest-versus-lowest fourth odds ratio, 0.26; 95% confidence limits, 0.06, 1.16; Ptrend = 0.06). This prospective study does not provide strong evidence that circulating DHEA and DHEAS concentrations are associated with the risk of colon cancer. Among men, DHEAS was associated with a decreased risk of colon cancer, but the association was within the bounds of chance. Further studies are needed to either support or refute the potentially promising lead hinted at by the results for DHEAS.
- Published
- 2000
8. Serum concentrations of organochlorine compounds and the subsequent development of breast cancer.
- Author
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Helzlsouer KJ, Alberg AJ, Huang HY, Hoffman SC, Strickland PT, Brock JW, Burse VW, Needham LL, Bell DA, Lavigne JA, Yager JD, and Comstock GW
- Subjects
- Adult, Aged, Blood Banks, Case-Control Studies, Female, Humans, Maryland, Middle Aged, Prospective Studies, Risk Factors, Surveys and Questionnaires, Time Factors, Breast Neoplasms blood, Breast Neoplasms chemically induced, Carcinogens adverse effects, Carcinogens metabolism, DDT adverse effects, DDT blood, Dichlorodiphenyl Dichloroethylene adverse effects, Dichlorodiphenyl Dichloroethylene blood, Environmental Pollutants adverse effects, Environmental Pollutants blood, Polychlorinated Biphenyls adverse effects, Polychlorinated Biphenyls blood
- Abstract
A nested case-control study was conducted to examine the association between serum concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the primary metabolite of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), and polychlorinated biphenyls (PCBs) and the development of breast cancer up to 20 years later. Cases (n = 346) and controls (n = 346) were selected from cohorts of women who donated blood in 1974, 1989, or both, and were matched on age, race, menopausal status, and month and year of blood donation. Analyses were stratified by cohort participation because median DDE and PCB concentrations among the controls were 59 and 147% higher in 1974 than 1989, respectively. Median concentrations of DDE were lower among cases than controls in both time periods [11.7% lower in 1974 (P = 0.06) and 8.6% lower in 1989 (P = 0.41)]. Median concentrations of PCBs were similar among cases and controls [P = 0.21 for 1974 and P = 0.37 for 1989 (Wilcoxon signed rank test)]. The risk of developing breast cancer among women with the highest concentrations of DDE was roughly half that among women with the lowest concentrations, whether based on concentrations in 1974 [odds ratio (OR), 0.50; 95% confidence interval (CI), 0.27-0.89; P(trend) = 0.02] or in 1989 (OR, 0.53; 95% CI, 0.24-1.17; P(trend) = 0.08). The associations between circulating concentrations of PCBs and breast cancer were less pronounced but still in the same direction (1974: OR, 0.68; 95% CI, 0.36-12.9; P(trend) = 0.2; and 1989: OR, 0.73; 95% CI, 0.37-1.46; P(trend) = 0.6). Adjustment for family history of breast cancer, body mass index, age at menarche or first birth, and months of lactation did not materially alter these associations. These associations remained consistent regardless of lactation history and length of the follow-up interval, with the strongest inverse association observed among women diagnosed 16-20 years after blood drawing. Results from this prospective, community-based nested case-control study are reassuring. Even after 20 years of follow-up, exposure to relatively high concentrations of DDE or PCBs showed no evidence of contributing to an increased risk of breast cancer.
- Published
- 1999
9. A prospective study on folate, B12, and pyridoxal 5'-phosphate (B6) and breast cancer.
- Author
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Wu K, Helzlsouer KJ, Comstock GW, Hoffman SC, Nadeau MR, and Selhub J
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Breast Neoplasms prevention & control, Case-Control Studies, Cohort Studies, Confidence Intervals, Female, Homocysteine blood, Humans, Incidence, Maryland epidemiology, Menopause, Middle Aged, Odds Ratio, Postmenopause, Prospective Studies, Reproductive History, Risk Factors, Breast Neoplasms epidemiology, Folic Acid blood, Pyridoxal Phosphate blood, Pyridoxine blood, Vitamin B 12 blood
- Abstract
To investigate the incidence of breast cancer and prediagnostic serum levels of folate, B12, and pyridoxal 5'-phosphate (B6), we conducted a nested case-control study using resources from the Washington County (Maryland) serum bank. In 1974, 12,450 serum specimens were donated, and in 1989, 14,625 plasma specimens were donated by female residents of Washington County. One hundred ninety-five incident breast cancer cases and 195 controls were matched by age, race, menopausal status at donation, and cohort participation as well as by date of blood donation. In both cohorts and all menopausal subgroups, median B12 concentrations were lower among cases than controls. Differences reached statistical significance only among women who were postmenopausal at donation (1974 cohort, 413 versus 482 pg/ml, P = 0.03; 1989 cohort, 406 versus 452 pg/ml, P = 0.02). Among women postmenopausal at blood donation, observed associations of B12 suggested a threshold effect with increased risk of breast cancer in the lowest one-fifth compared to the higher four-fifths of the control distribution [lowest versus highest fifth: 1974 cohort, matched odds ratio = 4.00 (95% confidence interval = 1.05-15.20); 1989 cohort, matched odds ratio = 2.25 (95% confidence interval = 0.86-5.91)]. We found no evidence for an association between folate, B6, and homocysteine and breast cancer. Findings suggested a threshold effect for serum B12 with an increased risk of breast cancer among postmenopausal women in the lowest one-fifth compared to the higher four-fifths of the control distribution. These results should stimulate further investigations of potentially modifiable risk factors, such as these B-vitamins, for prevention of breast cancer.
- Published
- 1999
10. Association between CYP17 polymorphisms and the development of breast cancer.
- Author
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Helzlsouer KJ, Huang HY, Strickland PT, Hoffman S, Alberg AJ, Comstock GW, and Bell DA
- Subjects
- Case-Control Studies, Female, Gene Frequency, Genetic Predisposition to Disease genetics, Genotype, Humans, Maryland, Menarche, Menopause, Middle Aged, Odds Ratio, Risk Factors, White People genetics, Breast Neoplasms genetics, Polymorphism, Genetic genetics, Steroid 17-alpha-Hydroxylase genetics
- Abstract
A nested case-control study was conducted to determine whether a genetic polymorphism in the CYP17 gene, which encodes for an enzyme that mediates steroid hormone metabolism, was associated with an increased risk of breast cancer. No association was found between the presence of an A2 allele and the subsequent development of breast cancer [A1/A2 odds ratio, 0.61 (95% confidence interval, 0.33-1.14); A2/A2 odds ratio, 0.89 (95% confidence interval, 0.41-1.95)]. No significant association was observed with risk factors presumed to be surrogates for endogenous estrogen exposure, nor was there an association observed with the stage of disease at diagnosis. Genotype frequencies in this Caucasian population were similar to those reported for African-American, Asian, and Latino women. Additional studies of larger size are needed to achieve a consensus regarding the relevance of CYP17 genotypes to the risk of developing breast cancer.
- Published
- 1998
11. Oltipraz chemoprevention trial in Qidong, People's Republic of China: modulation of serum aflatoxin albumin adduct biomarkers.
- Author
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Kensler TW, He X, Otieno M, Egner PA, Jacobson LP, Chen B, Wang JS, Zhu YR, Zhang BC, Wang JB, Wu Y, Zhang QN, Qian GS, Kuang SY, Fang X, Li YF, Yu LY, Prochaska HJ, Davidson NE, Gordon GB, Gorman MB, Zarba A, Enger C, Muñoz A, and Helzlsouer KJ
- Subjects
- Adult, Aged, Anticarcinogenic Agents administration & dosage, Biomarkers blood, China, Dose-Response Relationship, Drug, Genotype, Glutathione Transferase genetics, Humans, Middle Aged, Pyrazines administration & dosage, Radioimmunoassay, Risk Assessment, Thiones, Thiophenes, Aflatoxins analysis, Albumins analysis, Anticarcinogenic Agents therapeutic use, Carcinoma, Hepatocellular prevention & control, Liver Neoplasms prevention & control, Pyrazines therapeutic use
- Abstract
In 1995, 234 adults from Qidong, People's Republic of China, were enrolled and followed in a Phase IIa 4-methyl-5-(N-2-pyrazinyl)-1,2-dithiole-3-thione (oltipraz) chemoprevention trial. Residents of this area are at high risk for development of hepatocellular carcinoma, in part due to consumption of aflatoxin-contaminated foods. The intervention was a randomized, placebo-controlled, double-blind study. Elements of the study design and clinical outcomes have been recently published (Jacobson et al, Cancer Epidemiol. Biomark. Prev., 6: 257-265, 1997). The primary objective was to conduct a preliminary assessment of the ability of oltipraz to modulate levels of a validated biomarker of aflatoxin exposure and of the risk of hepatocellular carcinoma by determining levels of aflatoxin-albumin adducts in sera. Healthy eligible individuals were randomized into three arms to receive p.o. 125 mg of oltipraz daily, 500 mg of oltipraz weekly, or placebo for 8 weeks. There were no consistent changes in biomarker levels in the placebo arm over the 16-week observation period, nor was any apparent effect observed in the arm receiving 125 mg of oltipraz each day. However, individuals receiving 500 mg of oltipraz once a week for 8 weeks showed a triphasic response to oltipraz. No effect was observed during the 1st month of the intervention, whereas a significant (P = 0.001) diminution in adduct levels was observed during the 2nd month of active intervention and during the lst month of follow-up. A partial rebound in adduct levels toward baseline values was observed during the 2nd month postintervention. Linear regression models up to week 13 confirmed a significant (P = 0.008) weekly decline of biomarker levels in the group receiving 500 mg of oltipraz once a week. However, despite these effects relative to baseline values within the 500-mg weekly arm, there were no statistically significant differences in biomarker trajectories between treatment arms. The genotype for glutathione S-transferase M1, an oltipraz-inducible isoform involved in the detoxification of aflatoxin B1, did not appear to affect either baseline levels or rates of decline in the biomarker. A follow-up Phase IIb trial with a longer intervention period will be necessary to determine the full extent to which aflatoxin biomarker burden can be reduced and whether diminution of biomarkers can be sustained over the long term.
- Published
- 1998
12. An association between the allele coding for a low activity variant of catechol-O-methyltransferase and the risk for breast cancer.
- Author
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Lavigne JA, Helzlsouer KJ, Huang HY, Strickland PT, Bell DA, Selmin O, Watson MA, Hoffman S, Comstock GW, and Yager JD
- Subjects
- Aged, Breast Neoplasms epidemiology, Case-Control Studies, DNA genetics, DNA, Neoplasm genetics, Female, Genotype, Humans, Middle Aged, Polymerase Chain Reaction, Polymorphism, Genetic, Polymorphism, Restriction Fragment Length, Risk Factors, Alleles, Breast Neoplasms enzymology, Breast Neoplasms genetics, Catechol O-Methyltransferase genetics, Catechol O-Methyltransferase metabolism
- Abstract
Mounting evidence suggests that catechol metabolites of estradiol may contribute to the development of estrogen-induced cancers. O-Methylation, catalyzed by catechol-O-methyltransferase (COMT), inactivates catechol estrogens. COMT is polymorphic in the human population, with 25% of Caucasians being homozygous for a low activity allele of the enzyme (COMT(LL)). We hypothesized that low activity COMT may be a risk factor for human breast cancer and designed a PCR-based RFLP assay to determine COMT genotype in a cohort of 112 matched, nested case-control samples. In the total study population, the odds ratios for the association of breast cancer risk with COMT(HL) and COMT(LL) genotypes were 1.30 [confidence interval (CI), 0.66-2.58] and 1.45 (CI, 0.69-3.07), respectively. Postmenopausal COMT(LL) women had a greater than 2-fold increased risk of developing breast cancer [odds ratio (OR), 2.18; CI, 0.93-5.11]. The association of COMT(LL) with the development of postmenopausal breast cancer was stronger and statistically significant in those women with a body mass index >24.47 kg/m2 (OR, 3.58; CI, 1.07-11.98). When COMT(LL) was combined with either glutathione S-transferase (GST) M1 null or with GSTP1 Ile-105-Val/Val-105-Val (intermediate/low activity, respectively) genotypes, the risk for developing postmenopausal breast cancer was also significantly increased. Our findings suggest that the allele encoding low activity COMT may be an important contributor to the postmenopausal development of breast cancer in certain women.
- Published
- 1997
13. The risk of developing lung cancer associated with antioxidants in the blood: ascorbic acid, carotenoids, alpha-tocopherol, selenium, and total peroxyl radical absorbing capacity.
- Author
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Comstock GW, Alberg AJ, Huang HY, Wu K, Burke AE, Hoffman SC, Norkus EP, Gross M, Cutler RG, Morris JS, Spate VL, and Helzlsouer KJ
- Subjects
- Adult, Aged, Biomarkers blood, Case-Control Studies, Female, Free Radicals, Humans, Linear Models, Male, Middle Aged, Oxidation-Reduction, Risk Factors, Smoking metabolism, Tobacco Smoke Pollution, Antioxidants metabolism, Ascorbic Acid blood, Carotenoids blood, Lung Neoplasms blood, Lung Neoplasms epidemiology, Selenium blood, Vitamin E blood
- Abstract
Lung cancer cases diagnosed during the period 1975 through 1993 and matched controls were identified in the rosters of Washington County, Maryland residents who had donated blood for a serum bank in 1974 or 1989. Plasma from participants in the 1989 project was assayed for ascorbic acid; serum or plasma was assayed for participants in either project for alpha- and beta-carotene, cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Among the total group of 258 cases and 515 controls, serum/plasma concentrations were significantly lower among cases than controls for cryptoxanthin, beta-carotene, and lutein/zeaxanthin with case-control differences of -25.5, -17.1, and -10.1%, respectively. Modest nonsignificant case-control differences in a protective direction were noted for alpha-carotene and ascorbic acid. There were only trivial differences for lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Findings are reported for males and females and for persons who had never smoked cigarettes, former smokers, and current smokers at baseline. These results and those from previous studies suggest that beta-carotene is a marker for some protective factor(s) against lung cancer; that cryptoxanthin, alpha-carotene, and ascorbic acid need to be investigated further as potentially protective factors or associates of a protective factor; and that lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity are unlikely to be associated with lung cancer risk. Until specific preventive factors are identified, the best protection against lung cancer is still the avoidance of airborne carcinogens, especially tobacco smoke; second best is the consumption of a diet rich in fruits and vegetables.
- Published
- 1997
14. Antibodies to human papillomavirus 16 and subsequent in situ or invasive cancer of the cervix.
- Author
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Shah KV, Viscidi RP, Alberg AJ, Helzlsouer KJ, and Comstock GW
- Subjects
- Adult, Aged, Cell Transformation, Neoplastic immunology, Cell Transformation, Neoplastic pathology, Cervix Uteri immunology, Cervix Uteri pathology, Female, Follow-Up Studies, Humans, Middle Aged, Neoplasm Invasiveness, Papillomavirus Infections diagnosis, Papillomavirus Infections pathology, Risk, Smoking adverse effects, Tumor Virus Infections diagnosis, Tumor Virus Infections pathology, Uterine Cervical Neoplasms diagnosis, Uterine Cervical Neoplasms pathology, Uterine Cervical Dysplasia diagnosis, Uterine Cervical Dysplasia pathology, Antibodies, Viral blood, Papillomaviridae immunology, Papillomavirus Infections immunology, Tumor Virus Infections immunology, Uterine Cervical Neoplasms immunology, Uterine Cervical Dysplasia immunology
- Abstract
Our objective was to examine whether past infection with human papillomavirus (HPV)-16, as determined by an antibody assay, is a risk factor for subsequent cervical cancer. Incident cases of in situ or invasive cervical cancer occurring between 1975 and 1990 in a cohort of over 11,000 healthy women in Washington County, MD, were identified. The baseline sera of cases and of matched controls, collected in 1974, were examined for IgG antibodies reactive with virus-like particles of HPV-16, a cancer-associated HPV, and HPV-6, a low-risk HPV. Postdiagnosis sera of 11 cases were also assessed similarly. Fourteen cases of invasive and 28 cases of in situ cervical cancer and 83 matched controls were evaluated. The main outcome measure was the risk of cervical cancer in women who had HPV-16 or HPV-6 antibodies in prediagnostic sera. Antibodies to HPV-16 but not to HPV-6 were a marker for subsequent occurrence of cervical cancer. Case sera were reactive more often and more strongly with HPV-16 virus-like particles than were sera of matched controls. The presence of antibodies to HPV-16 was significantly associated with an increased risk of cervical cancer (odds ratio, 3.9; 95% confidence limits, 1.4, 10.7); high antibody levels to HPV-16 were associated with an even greater risk of cervical cancer (odds ratio = 7.5, 95% confidence limits 1.5, 36.3). The association with cervical cancer was strengthened after adjustment for smoking and years of education. In tests of 11 pairs of pre- and postdiagnostic sera, HPV-16 antibodies did not decline markedly over a 7-13-year time period, and seroconversion to HPV-16 appeared to have occurred in 2 cases. The serological data indicate that HPV-16 infection is associated with future risk of cervical cancer and strengthen the evidence for the etiological role of HPVs in cervical cancer.
- Published
- 1997
15. Oltipraz chemoprevention trial in Qidong, People's Republic of China: study design and clinical outcomes.
- Author
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Jacobson LP, Zhang BC, Zhu YR, Wang JB, Wu Y, Zhang QN, Yu LY, Qian GS, Kuang SY, Li YF, Fang X, Zarba A, Chen B, Enger C, Davidson NE, Gorman MB, Gordon GB, Prochaska HJ, Egner PA, Groopman JD, Muñoz A, Helzlsouer KJ, and Kensler TW
- Subjects
- Adult, Aflatoxins, Aged, Anticarcinogenic Agents adverse effects, Carcinoma, Hepatocellular chemically induced, China, Dose-Response Relationship, Drug, Drug Administration Schedule, Drug Monitoring, Female, Hepatitis B complications, Hepatitis B drug therapy, Humans, Liver Neoplasms chemically induced, Male, Middle Aged, Pyrazines adverse effects, Thiones, Thiophenes, Anticarcinogenic Agents administration & dosage, Carcinoma, Hepatocellular prevention & control, Liver Neoplasms prevention & control, Pyrazines administration & dosage
- Abstract
In 1995, 234 adults from Qidong, Jiangsu Province, People's Republic of China, where hepatocellular carcinoma is the leading cause of cancer deaths and exposure to dietary aflatoxins is widespread, were enrolled and followed in a Phase II chemoprevention trial. The goals of the study were to define a dose and schedule of oltipraz for reducing levels of validated aflatoxin biomarkers and to characterize dose-limiting toxicities. Healthy eligible individuals, including those infected with hepatitis B virus, were randomized to receive either 125 mg of oltipraz daily, 500 mg of oltipraz weekly, or placebo. Blood and urine specimens were collected to monitor toxicities and evaluate biomarkers over the 8-week intervention period and subsequent 8-week follow-up period. Unique trial aspects included a synchronous follow-up schedule, daily observed administration of all medications, timely international data transference, and use of biomarkers as outcomes. One hundred thirty-two participants took their medications without interruptions, approximately 77% contributed all nine urine samples, and 78% contributed all seven blood samples. Fifty-one participants (21.8%) reported clinical adverse events. An extremity syndrome, developing soon after the start of treatment, was the only event that occurred more frequently (P = 0.002) among the active groups (18.4 and 14.1% of the daily 125 and weekly 500 mg arms, respectively) compared with placebo (2.5%). The oltipraz arms did not differ in symptom type or severity, and there were no indications of exacerbated drug intolerance among the few participants infected with hepatitis B virus. The good compliance with an intense follow-up schedule shows that chemoprevention trials with biomarker end points may be conducted in such populations.
- Published
- 1997
16. Serological precursors of cancer: malignant melanoma, basal and squamous cell skin cancer, and prediagnostic levels of retinol, beta- carotene, lycopene, alpha-tocopherol, and selenium.
- Author
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Breslow RA, Alberg AJ, Helzlsouer KJ, Bush TL, Norkus EP, Morris JS, Spate VE, and Comstock GW
- Subjects
- Adult, Aged, Antioxidants analysis, Carcinoma, Basal Cell blood, Carcinoma, Basal Cell epidemiology, Carcinoma, Squamous Cell blood, Carcinoma, Squamous Cell epidemiology, Carotenoids blood, Case-Control Studies, Female, Humans, Lycopene, Male, Maryland epidemiology, Melanoma blood, Melanoma epidemiology, Middle Aged, Risk Factors, Selenium blood, Sensitivity and Specificity, Skin Neoplasms blood, Skin Neoplasms epidemiology, Vitamin A blood, Vitamin E blood, Carcinoma, Basal Cell etiology, Carcinoma, Squamous Cell etiology, Melanoma etiology, Micronutrients analysis, Skin Neoplasms etiology
- Abstract
To determine the association between prediagnostic serum levels of retinol, beta-carotene, lycopene, alpha-tocopherol, and selenium and the subsequent risk of malignant melanoma, and basal and squamous cell skin cancer, a nested case-control study among residents of Washington County, MD, was performed. Cases with melanoma (n = 30), basal cell (n = 32), and squamous cell (n = 37) skin cancer who were admitted to hospital for treatment or biopsy of metastatic lesions were each matched by age, sex, and race with two controls. There were no significant associations between serum micronutrient levels and the risk of subsequent skin cancer.
- Published
- 1995
17. Stability of ascorbic acid, carotenoids, retinol, and tocopherols in plasma stored at -70 degrees C for 4 years.
- Author
-
Comstock GW, Norkus EP, Hoffman SC, Xu MW, and Helzlsouer KJ
- Subjects
- Adult, Aged, Drug Stability, Female, Humans, Male, Middle Aged, Retrospective Studies, Time Factors, Ascorbic Acid blood, Blood Preservation, Carotenoids blood, Cryopreservation, Plasma chemistry, Vitamin A blood, Vitamin E blood
- Abstract
Aliquots from 40 plasma pools preserved with metaphosphoric acid were assayed for their ascorbic acid values after 12, 24, and 42 months of storage at -70 degrees C. Similarly, aliquots from 16 plasma pools were assayed for values of retinol, several carotenoids, and two tocopherols at 15.5, 27.5, and 51.5 months of storage at -70 degrees C. There were no indications of important losses of these antioxidant micronutrients during storage from the first to the last assay.
- Published
- 1995
18. Summary of the round table discussion on strategies for cancer prevention: diet, food, additives, supplements, and drugs.
- Author
-
Helzlsouer KJ, Block G, Blumberg J, Diplock AT, Levine M, Marnett LJ, Schulplein RJ, Spence JT, and Simic MG
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Ascorbic Acid adverse effects, Aspirin therapeutic use, Colonic Neoplasms prevention & control, Food, Fortified, Humans, Nutritional Physiological Phenomena, Vitamin E adverse effects, Anticarcinogenic Agents therapeutic use, Ascorbic Acid therapeutic use, Diet, Food, Neoplasms epidemiology, Neoplasms prevention & control, Vitamin E therapeutic use
- Abstract
A Round Table Discussion was held at the Fourth International Conference on Anticarcinogenesis and Radiation Protection. Scientists from government and academia were brought together to discuss the evidence for the preventive effect of foods, specific nutrients and drugs against cancer, and the most appropriate methods of initiating nutritional cancer prevention activities to improve the health of the public. The panel reviewed the epidemiological evidence of the role of diet and specific micronutrients for the prevention of cancer, the doses of specific micronutrients required for preventive effects and their safety, the evidence for aspirin as a chemopreventive agent, the issue of foods versus specific micronutrients in the prevention of cancer, food safety, and approaches to prevention such as food fortification or dietary supplements. The remarks of the panel members are summarized.
- Published
- 1994
19. Serological markers of cancer and their applications in clinical trials.
- Author
-
Helzlsouer KJ
- Subjects
- Female, Humans, Incidence, Male, Monitoring, Physiologic methods, Neoplasms diagnosis, Neoplasms mortality, Risk Factors, Biomarkers, Tumor blood, Clinical Trials as Topic methods, Neoplasms epidemiology, Neoplasms prevention & control
- Abstract
Strategies for the prevention of cancer include those aimed at reducing the incidence of cancer (primary prevention) and cancer mortality through early detection of tumors (secondary prevention). The efficacy of prevention interventions is evaluated by clinical trials. The conduct of clinical trials is aided by the use of serological indicators of the carcinogenic process measured using plasma or red or white blood cells. The accessibility and acceptability of obtaining blood samples for the measurement of serological markers of carcinogenesis permit widespread applications in the conduct of clinical trials. Serological markers must be shown to be valid and reliable before their use. Serological markers identify a variety of stages in the process of carcinogenesis such as inherited or acquired susceptibility to cancer, environmental exposures to carcinogens, biological effects of exposures, and the presence of preinvasive or invasive cancer. Serological markers may be used in clinical trials to select high risk but disease-free individuals for participation in clinical trials based on susceptibility factors or carcinogenic exposures. Other uses of serological markers include monitoring adherence to interventions and establishing trial outcomes of intermediate cancer end points or incident invasive disease. Examples of these applications are discussed. Serological markers of carcinogenesis have widespread applications in clinical research and potentially for clinical practice. Currently, the only limitation to their widespread use is the availability of validated serological markers. Because of the ease and acceptability of their use, research into the development of serological markers should continue. Methods for quickly validating serological markers should be developed in order to aid the transition to clinical applications.
- Published
- 1994
20. Serum levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate and the risk of developing gastric cancer.
- Author
-
Gordon GB, Helzlsouer KJ, Alberg AJ, and Comstock GW
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Case-Control Studies, Child, Dehydroepiandrosterone Sulfate, Humans, Middle Aged, Prospective Studies, Risk Factors, Smoking adverse effects, Biomarkers, Tumor blood, Dehydroepiandrosterone analogs & derivatives, Dehydroepiandrosterone blood, Stomach Neoplasms blood, Stomach Neoplasms etiology
- Abstract
Although the incidence of gastric cancer varies widely between countries it is nonetheless a leading cause of cancer deaths worldwide. Migration studies indicate that dietary choices are an important exogenous factor. The United States has a very low incidence of gastric cancer, suggesting that exogenous etiological agents are at a minimum and providing a favorable setting for detecting important endogenous etiological factors. Dehydroepiandrosterone and dehydroepiandrosterone sulfate are endogenous steroids produced in the adrenal gland. Epidemiological studies show that the risk of developing specific cancers is related to the serum or urinary levels of these steroids. In addition, dehydroepiandrosterone prevents a variety of spontaneous and chemically induced tumors when administered to laboratory animals. To examine the association between circulating levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate and the development of gastric cancer, we measured the serum levels of these steroids in 13 individuals who donated serum to the Washington County Maryland serum bank in 1974 and who subsequently developed gastric cancer and in 52 matched controls. Prediagnostic serum levels of dehydroepiandrosterone were 38% lower in cases as compared to controls (P = 0.09). The risk of developing gastric cancer increased with decreasing levels of both steroids. Adjustment for confounding factors such as smoking or the interval between blood donation and time to diagnosis did not alter the findings. These results suggest that there may be a role for this steroid in the prevention of gastric cancer.
- Published
- 1993
21. Prostate-specific antigen levels and subsequent prostate cancer: potential for screening.
- Author
-
Helzlsouer KJ, Newby J, and Comstock GW
- Subjects
- Adult, Aged, Case-Control Studies, Humans, Male, Mass Screening, Middle Aged, Pilot Projects, Prostatic Neoplasms diagnosis, Prostatic Neoplasms epidemiology, Prostatic Neoplasms prevention & control, Sensitivity and Specificity, Time Factors, Prostate-Specific Antigen blood, Prostatic Neoplasms blood
- Abstract
Prostate-specific antigen levels are increased in men with prostatic disease, including prostate cancer, and have been used clinically to monitor the response of prostate cancer to therapy. More recently, prostate-specific antigen levels, usually in combination with digital rectal examination or transrectal prostatic ultrasonography, have been suggested to be useful for the detection of prostate cancer. To evaluate the association between a single serum prostate-specific antigen level and the subsequent development of prostate cancer, we measured serum levels in 35 men who donated blood to a community-based serum bank in 1974 and who subsequently developed prostate cancer and in 35 matched controls from the same group of volunteers. Levels of prostate-specific antigen were significantly higher in men who went on to develop prostate cancer, up to 6 years prior to the time of diagnosis in the cases. The level of prostate-specific antigen decreased with increasing time to diagnosis. The mean level for prostate cancer cases diagnosed within the first 3 years of follow-up was 16.2 micrograms/liter compared to 2.4 micrograms/liter for controls (P = 0.002). The mean level for cancer cases diagnosed in years 4 through 6 following blood sampling was 9.6 micrograms/liter compared to 1.3 micrograms/liter for controls (P = 0.0002). The sensitivity and specificity of a prostate-specific antigen level > or = 4 micrograms/liter up to 3 years prior to the time of clinical diagnosis were both 75% and up to 6 years were 67% and 85%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1992
22. Relationship of prediagnostic serum levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate to the risk of developing premenopausal breast cancer.
- Author
-
Helzlsouer KJ, Gordon GB, Alberg AJ, Bush TL, and Comstock GW
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Breast Neoplasms blood, Case-Control Studies, Child, Dehydroepiandrosterone analogs & derivatives, Dehydroepiandrosterone Sulfate, Female, Humans, Middle Aged, Parity, Risk Factors, Smoking blood, Breast Neoplasms etiology, Dehydroepiandrosterone blood
- Abstract
Dehydroepiandrosterone and dehydroepiandrosterone sulfate are steroids which may be associated with the development of breast cancer. To examine the association between serum levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate and the risk of developing premenopausal breast cancer, we measured hormone levels in 15 women who donated blood to a community-based serum bank in 1974 and who subsequently developed premenopausal breast cancer and in 29 matched controls from the same group of volunteers. The mean serum level of dehydroepiandrosterone among cases was 10% lower than among controls. The risk of developing breast cancer for women in the highest tertile compared with the lowest tertile of serum dehydroepiandrosterone was 0.40 with a suggestion of a dose-response trend with increasing levels. No consistent association between dehydroepiandrosterone sulfate and the risk of premenopausal breast cancer was evident. In contrast to postmenopausal breast cancer, a protective effect of dehydroepiandrosterone against premenopausal breast cancer is suggested, but because of the small sample size, the results of this study need to be replicated by others.
- Published
- 1992
23. Serum levels of dehydroepiandrosterone and its sulfate and the risk of developing bladder cancer.
- Author
-
Gordon GB, Helzlsouer KJ, and Comstock GW
- Subjects
- Aged, Dehydroepiandrosterone Sulfate, Female, Humans, Male, Middle Aged, Risk, Smoking adverse effects, Smoking blood, Urinary Bladder Neoplasms blood, Urinary Bladder Neoplasms prevention & control, Dehydroepiandrosterone analogs & derivatives, Dehydroepiandrosterone blood, Urinary Bladder Neoplasms etiology
- Abstract
Dehydroepiandrosterone and dehydroepiandrosterone sulfate are endogenous steroids largely produced in the adrenal cortex and excreted in the urine. Many studies have demonstrated that administration of dehydroepiandrosterone to animals protects against a variety of chemical carcinogens. Epidemiological studies suggest that the circulating levels of these steroids in humans are related to the risk of developing some cancers and of dying from atherosclerotic cardiovascular disease. We measured serum levels of both of these steroids in 35 individuals who donated serum to a community-based serum bank in 1974 and who subsequently developed bladder cancer and in 69 matched controls from the same cohort of volunteers. Prediagnostic serum levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate were significantly lower among cases compared with controls. The risk of developing bladder cancer increased monotonically with decreasing serum levels of both steroids. The observed associations were not affected by adjustment for smoking or the time interval between serum collection and diagnosis. These results support a role for dehydroepiandrosterone and/or dehydroepiandrosterone sulfate in the prevention of bladder cancer.
- Published
- 1991
24. Relationship of serum levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate to the risk of developing postmenopausal breast cancer.
- Author
-
Gordon GB, Bush TL, Helzlsouer KJ, Miller SR, and Comstock GW
- Subjects
- Aged, Aged, 80 and over, Blood Donors, Dehydroepiandrosterone analogs & derivatives, Dehydroepiandrosterone Sulfate, Female, Humans, Middle Aged, Odds Ratio, Predictive Value of Tests, Risk Factors, Smoking blood, Breast Neoplasms etiology, Dehydroepiandrosterone blood, Menopause blood
- Abstract
Dehydroepiandrosterone and dehydroepiandrosterone sulfate are endogenous steroids that are produced in the adrenal cortex. A number of studies have suggested that circulating levels of these hormones are related in some way to the risk of developing breast cancer. We measured serum levels of these steroids in 30 postmenopausal women who donated blood in 1974 for a community-based serum bank and who subsequently, at least 9 years later, developed breast cancer and in 59 matched controls from the same group of volunteers. Significantly elevated serum levels of dehydroepiandrosterone were found among cases prior to diagnosis compared to controls; serum levels of dehydroepiandrosterone sulfate were slightly increased among cases. In controls, current cigarette use was associated with increased serum levels of these steroids, and levels of both steroids decreased with age.
- Published
- 1990
25. Selenium, lycopene, alpha-tocopherol, beta-carotene, retinol, and subsequent bladder cancer.
- Author
-
Helzlsouer KJ, Comstock GW, and Morris JS
- Subjects
- Adult, Age Factors, Aged, Biomarkers, Tumor blood, Case-Control Studies, Female, Humans, Lycopene, Male, Middle Aged, Retinol-Binding Proteins analysis, Sex Factors, Smoking blood, Surveys and Questionnaires, Urinary Bladder Neoplasms blood, beta Carotene, Carotenoids blood, Selenium blood, Urinary Bladder Neoplasms etiology, Vitamin A blood, Vitamin E blood
- Abstract
To examine the association between serum nutrients and the development of bladder cancer we measured selenium, alpha-tocopherol, lycopene, beta-carotene, retinol, and retinol-binding protein in serum collected from 25,802 persons in Washington County, MD, in 1974. Serum samples were kept frozen at -70 degrees C. In the subsequent 12-year period, 35 cases of bladder cancer developed among participants. Comparisons of serum levels in 1974 among cases and two matched controls for each case showed that selenium was significantly lower among cases than controls (P = 0.03), lycopene was lower among cases at a borderline level of significance (P = 0.07), and alpha-tocopherol was nonsignificantly lower (P = 0.13). For selenium there was a nearly linear increase in risk with decreasing serum levels (P = 0.03). When examined by tertiles, the odds ratio associated with the lowest tertile of selenium compared to the highest tertile was 2.06. Serum levels of retinol, retinol-binding protein, and beta-carotene were similar among cases and controls. These results support a role for selenium in the prevention of bladder cancer.
- Published
- 1989
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