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Ronald K Ross

Publications and source records attributed to Ronald K Ross.

At least 19 recordsLinked to original sources
PubMed2007

Diet and risk of ovarian cancer in the California Teachers Study cohort.

Dietary phytochemical compounds, including isoflavones and isothiocyanates, may inhibit cancer development but have not yet been examined in prospective epidemiologic studies of ovarian cancer. The authors have investigated the association between consumption of these and other nutrients and ovarian cancer risk in a prospective cohort study. Among 97,275 eligible women in the California Teachers Study cohort who completed the baseline dietary assessment in 1995-1996, 280 women developed invasive or borderline ovarian cancer by December 31, 2003. Multivariable Cox proportional hazards regression, with age as the timescale, was used to estimate relative risks and 95% confidence intervals; all statistical tests were two sided. Intake of isoflavones was associated with lower risk of ovarian cancer. Compared with the risk for women who consumed less than 1 mg of total isoflavones per day, the relative risk of ovarian cancer associated with consumption of more than 3 mg/day was 0.56 (95% confidence interval: 0.33, 0.96). Intake of isothiocyanates or foods high in isothiocyanates was not associated with ovarian cancer risk, nor was intake of macronutrients, antioxidant vitamins, or other micronutrients. Although dietary consumption of isoflavones may be associated with decreased ovarian cancer risk, most dietary factors are unlikely to play a major role in ovarian cancer development.

Adult↗
PubMed2007

Wine and other alcohol consumption and risk of ovarian cancer in the California Teachers Study cohort.

OBJECTIVE: Whether alcohol consumption influences ovarian cancer risk is unclear. Therefore, we investigated the association between alcohol intake at various ages and risk of ovarian cancer. METHODS: Among 90,371 eligible members of the California Teachers Study cohort who completed a baseline alcohol assessment in 1995-1996, 253 women were diagnosed with epithelial ovarian cancer by the end of 2003. Multivariate Cox proportional hazards regression analysis was performed to estimate relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: Consumption of total alcohol, beer, or liquor in the year prior to baseline, at ages 30-35 years, or at ages 18-22 years was not associated with risk of ovarian cancer. Consumption of at least one glass per day of wine, compared to no wine, in the year before baseline was associated with increased risk of developing ovarian cancer: RR = 1.57 (95% CI 1.11-2.22), P (trend) = 0.01. The association with wine intake at baseline was particularly strong among peri-/post-menopausal women who used estrogen-only hormone therapy and women of high socioeconomic status. CONCLUSIONS: Alcohol intake does not appear to affect ovarian cancer risk. Constituents of wine other than alcohol or, more likely, unmeasured determinants of wine drinking were associated with increased risk of ovarian cancer.

Adolescent↗
PubMed2006

Prediagnostic level of serum retinol in relation to reduced risk of hepatocellular carcinoma.

BACKGROUND: Retinol and its derivatives (retinoids), which have antioxidant activity and promote cell differentiation, may protect against the development of hepatocellular carcinoma (HCC) by controlling hepatocellular differentiation and reducing inflammatory responses. METHODS: We examined prospectively the relationship between prediagnostic serum concentrations of retinol, alpha-carotene; beta-carotene; beta-cryptoxanthin; lutein; lycopene; zeaxanthin; alpha-, gamma-, and delta-tocopherols; and selenium and the risk of developing HCC among 213 patients with HCC and 1087 matched control subjects from a cohort of 18,244 men in Shanghai, China, who were monitored from 1986 through 2001. Odds ratios (ORs) and 95% confidence intervals (CIs) for men by quartile of serum concentrations of micronutrients were estimated by using logistic regression with adjustment for cigarette smoking status, alcohol intake, self-reported history of physician-diagnosed hepatitis or liver cirrhosis at recruitment, and seropositivity for hepatitis B surface antigen (HBsAg). All statistical tests were two-sided. RESULTS: Men with high prediagnostic serum retinol levels had a lower risk of HCC than men in the lowest quartile (Q2 versus Q1, OR = 0.37, 95% CI = 0.22 to 0.61; Q3 versus Q1, OR = 0.30, 95% CI = 0.17 to 0.50; and Q4 versus Q1, OR = 0.13, 95% CI = 0.06 to 0.26; Ptrend < .001). A statistically significant interaction was observed between retinol and HBsAg seropositivity on HCC risk; HBsAg-positive men in the lowest tertile of retinol had a greater than 70-fold higher risk (OR = 72.7, 95% CI = 31.6 to 167.4) of HCC than HBsAg-negative men in the highest tertile of retinol (Pinteraction = .018). No independent effect of serum levels of alpha-carotene; beta-carotene; beta-cryptoxanthin; lutein; lycopene; zeaxanthin; alpha-, gamma-, and delta-tocopherols; or selenium on HCC risk were observed. CONCLUSION: High prediagnostic serum level of retinol is associated with a decreased risk of HCC in this population.

Carcinoma, Hepatocellular↗
PubMed2006

Hormone-related risk factors for breast cancer in women under age 50 years by estrogen and progesterone receptor status: results from a case-control and a case-case comparison.

INTRODUCTION: It has been suggested that hormonal risk factors act predominantly on estrogen receptor and progesterone receptor (ER/PR)-positive breast cancers. However, the data have been inconsistent, especially in younger women. METHODS: We evaluated the impact of age at menarche, pregnancy history, duration of breastfeeding, body mass index, combined oral contraceptive use, and alcohol consumption on breast cancer risk by ER/PR status in 1,725 population-based case patients and 440 control subjects aged 20 to 49 years identified within neighborhoods of case patients. We used multivariable unconditional logistic regression methods to conduct case-control comparisons overall as well as by ER/PR status of the cases, and to compare ER+PR+ with ER-PR- case patients. RESULTS: The number of full-term pregnancies was inversely associated with the risk of ER+PR+ breast cancer (ptrend = 0.005), whereas recent average alcohol consumption was associated with an increased risk of ER+PR+ breast cancer (ptrend = 0.03). Neither of these two factors was associated with the risk of ER- PR- breast cancer. Late age at menarche and a longer duration of breastfeeding were both associated with decreased breast cancer risk, irrespective of receptor status (all ptrend< or = 0.03). CONCLUSION: Our results suggest that the number of full-term pregnancies and recent alcohol consumption affect breast cancer risk in younger women predominantly through estrogen and progesterone mediated by their respective receptors. Late age at menarche and breastfeeding may act through different hormonal mechanisms.

Adult↗
PubMed2005

Nonsteroidal anti-inflammatory drug use and breast cancer risk by stage and hormone receptor status.

BACKGROUND: Epidemiologic studies of the association between nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, and breast cancer risk have yielded inconsistent results. We investigated the association of NSAID use with risk of breast cancer in the California Teachers Study cohort, with special attention to risk of specific breast cancer subtypes and to type of NSAID used. METHODS: We analyzed data on 114 460 women in the California Teachers Study cohort who were aged 22 to 85 years and free of breast cancer at baseline in 1995 to 1996. Information on frequency and duration of NSAID use was collected through a self-administered questionnaire. A total of 2391 women were diagnosed with breast cancer during the follow-up period from 1995 to 2001. We used Cox proportional hazards regression to estimate relative risks (RR) and 95% confidence intervals (CI) of breast cancer subtypes with NSAID use. RESULTS: Neither regular use (more than once a week) of any NSAID (aspirin and ibuprofen combined) nor regular use of aspirin was associated with breast cancer risk (RR = 1.09, 95% CI = 0.97 to 1.21 for daily versus no regular use of NSAIDs and RR = 0.98, 95% CI = 0.86 to 1.13 for daily versus no regular use of aspirin). However, long-term (> or = 5 years) daily aspirin users had a non-statistically significant decreased risk of estrogen receptor and progesterone receptor (ER/PR)-positive breast cancer (RR = 0.80, 95% CI = 0.62 to 1.03). In contrast, we observed a statistically significantly increased risk of ER/PR-negative breast cancer with long-term daily use of aspirin (RR = 1.81, 95% CI = 1.12 to 2.92). In this population, 11 fewer ER/PR-positive breast cancer cases and seven excess ER/PR-negative breast cancer cases may be due to daily long-term aspirin use among 2391 breast cancer cases observed over 6 years if the association were proven to be causal. Long-term daily use of ibuprofen was also associated with an increased risk of breast cancer (RR = 1.51, 95% CI = 1.17 to 1.95), particularly of nonlocalized tumors (RR = 1.92, 95% CI = 1.24 to 2.97). If causality were subsequently proven, 16 of the observed 2391 breast cancer cases and 8 of the 713 non-localized breast cancer cases would be attributable to long-term daily use of ibuprofen. CONCLUSIONS: Long-term daily use of NSAIDs was not associated with breast cancer risk overall. Ibuprofen use was associated with an increased risk of breast cancer, and long-term daily aspirin use was associated with an increased risk of ER/PR-negative breast cancer. However, it is not clear if the observed association is causal.

Acetaminophen↗
PubMed2005

Prescription drug use and risk of acute myeloid leukemia by French-American-British subtype: results from a Los Angeles County case-control study.

Chemotherapy is a well-established risk factor for acute myeloid leukemia (AML) but little is known about other prescription drugs and AML risk. We report data from a population-based Los Angeles County study in which 299 matched case-control pairs had complete data on prescription drug use and 88% of cases were subtyped according to the French-American-British (FAB) criteria. Cases were diagnosed between 1987 and 1994. Prescription nonsteroidal anti-inflammatory drug (NSAID) use for at least 4 weeks in the 2 to 10 years before diagnosis was associated with decreased risk (odds ratio = 0.5, 95% confidence interval=0.3, 1.0; p=0.04) with dose-response most evident for FAB subtype M2 (OR = 0.6, CI: 0.1, 2.9 for duration < or =6 months; OR = 0.2, CI: 0.0, 1.6 for >6 months). For subtype M4, ORs increased with increasing duration of benzodiazepine use in the 2 to 10 years before diagnosis (OR = 1.5, CI: 0.3, 9.0 for < or =6 months vs. OR = 5.0, CI: 0.6, 42.8 for >6 months). These results suggest that prescription drugs other than chemotherapy may have FAB subtype-specific effects on AML risk.

Adult↗
PubMed2005

Residential mobility in the California Teachers Study: implications for geographic differences in disease rates.

BACKGROUND: Especially for cancers with long latency periods, such as breast cancer, the issue of residential mobility hinders ecologic analyses seeking to examine the role of environmental contaminants in chronic disease etiology. This study describes and evaluates characteristics associated with residential mobility in a sub-sample of the California Teachers Study (CTS) cohort. METHODS: In 2000, lifetime residential histories were collected for a sub-sample of 328 women enrolled in the CTS; women's degree of residential mobility and associated factors were analyzed. RESULTS: While most women moved many times during their lives (average = 8.9), the average number of years at their residence when they enrolled in the study was reasonably long (15.1 years). Age strongly predicted duration at current residence but was not related to the number of lifetime residences. After adjusting for age, California-born women and women living in high socioeconomic status (SES) neighborhoods were significantly more residentially stable. Agreement between self-reported urbanization of recent residences and that based on census data of the geocoded residences was very good (80% concordant). Among women currently living in urban areas, an average of 43.3 years, or 77%, of their lifetimes were spent in urban residences; among women currently living in a rural area, an average of 37.3 years, or 67% of their lifetimes were spent in rural residences. CONCLUSIONS: This suggests that analyses of incidence rates based on current residence, while not capturing a woman's full exposure history, may reasonably reflect some aspect of longer term chronic exposures, especially those related to urbanization, at least in professional women.

Adult↗
PubMed2004

Dietary soy and increased risk of bladder cancer: a prospective cohort study of men in Shanghai, China.

To verify our previous finding of a positive association between dietary soy and bladder cancer risk, we examined the association in a second, geographically distinct prospective cohort of Chinese subjects, the Shanghai Cohort Study. Briefly, 18,244 men aged 45-64 years were recruited between January 1986 and September 1989. As of December 31, 2002, 61 incident bladder cancer cases were identified. Information on soy consumption was obtained through in-person interviews at baseline using a food frequency questionnaire. Cox proportional hazard regression methods were used to estimate relative risks (RR) and their corresponding 95% confidence intervals (CI), with adjustment for age (years) at baseline interview, level of education and other potential confounders. Compared to men consuming soy less than once a week, the RR (95% CI) for those who consumed soy 1-<3 times per week, 3-<7 times a week and daily were 2.05 (0.80-5.29), 2.45 (0.89-6.76) and 4.61 (1.57-13.51), respectively (p for trend = 0.004), after adjustment for age, cigarette smoking and level of education. The soy-bladder cancer risk associations in smokers and non-smokers were comparable. The soy-bladder cancer relationship became stronger when the analysis was restricted to subjects with 2 or more years of follow-up.

China↗
PubMed2004

Alkylaniline-hemoglobin adducts and risk of non-smoking-related bladder cancer.

BACKGROUND: Some members of the arylamine family of compounds, specifically 4-aminobiphenyl (ABP), 2-naphthylamine, and benzidine, are established human bladder carcinogens. Cigarette smoking and use of permanent hair dye contribute substantially to current arylamine exposure. Low levels of 4-ABP exposure have been associated with non-smoking-related bladder cancer. Other arylamine compounds coming from as yet unidentified environmental sources may also be human bladder carcinogens. METHODS: We conducted a population-based case-control study in Los Angeles County, California, involving 298 case subjects with bladder cancer and 308 control subjects, who were matched on age, sex, race/ethnicity, and neighborhood of residence. In-person interviews provided information on tobacco smoking and other potential risk factors for bladder cancer. To assess arylamine exposure, levels of arylamine-hemoglobin adducts of nine selected alkylanilines (2,3-dimethylaniline [2,3-DMA], 2,4-DMA, 2,5-DMA, 2,6-DMA, 3,4-DMA, 3,5-DMA, 2-ethylaniline [2-EA], 3-EA, 4-EA) were measured in peripheral blood collected from study subjects. Analysis of covariance and conditional logistic regression methods were used to analyze the relationship between arylamine-hemoglobin adducts and bladder cancer risk. All statistical tests were two-sided. RESULTS: Levels of all arylamine-hemoglobin adducts, with the exception of 2,6-DMA, were higher in smokers than in nonsmokers, and levels of all arylamine-hemoglobin adducts were higher in case subjects than in control subjects. Arylamine-hemoglobin adducts of 2,6-DMA, 3,5-DMA, and 3-EA were all independently, statistically significantly (all P<.001) associated with bladder cancer risk after adjusting for cigarette smoking at the time of blood collection, lifetime smoking history, and other potential risk factors. These adducts were also independently associated with bladder cancer risk when only nonsmokers at time of blood draw were considered (highest quartile versus lowest quartile: 2,6-DMA, relative risk [RR] of bladder cancer = 8.1, 95% confidence interval [CI] = 3.6 to 18.0; 3,5-DMA, RR = 2.7, 95% CI = 1.2 to 6.0; 3-EA, RR = 4.3, 95% CI = 1.6 to 11.6). CONCLUSIONS: Diverse arylamine exposures are strongly associated with bladder cancer risk among nonsmokers. Because arylamines may account for a substantial proportion of bladder cancers among the general population, identification of environmental sources of these compounds is needed.

Aminobiphenyl Compounds↗
PubMed2004

Carotenoids/vitamin C and smoking-related bladder cancer.

Previous epidemiological studies of fruit and vegetable intake and bladder cancer risk have yielded inconsistent results, especially with respect to the role of cigarette smoking as a possible modifier of the diet-bladder cancer association. A population-based case-control study was conducted in nonAsians of Los Angeles, California, which included 1,592 bladder cancer patients and an equal number of neighborhood controls matched to the index cases by sex, date of birth (within 5 years) and race between January 1, 1987 and April 30, 1996. Information on smoking, medical and medication history, and intake frequencies of food groups rich in preformed nitrosamines, vitamins A and C and various carotenoids, were collected through in-person, structured interviews. Beginning in January 1992, all case patients and their matched control subjects were asked for a blood sample donation at the end of the in-person interviews for measurements of 3- and 4-aminobiphenyl (ABP) hemoglobin adducts, and glutathione S-transferases M1/T1/P1 (GSTM1/T1/P1) and N-acetyltransferase-1 (NAT1) genotypes. Seven hundred seventy-one (74%) case patients and 775 (79%) control subjects consented to the blood donation requests. In addition, all case patients and matched control subjects were asked to donate an overnight urine specimen following caffeine consumption for measurements of cytochrome P4501A2 (CYP1A2) and N-acetyltransferase-2 (NAT2) phenotypes. Urine specimens were collected from 724 (69%) case patients and 689 (70%) control subjects. After adjustment for nondietary risk factors including cigarette smoking, there were strong inverse associations between bladder cancer risk and intake of dark-green vegetables [p value for linear trend (p) = 0.01], yellow-orange vegetables (p = 0.01), citrus fruits/juices (p = 0.002) and tomato products (p = 0.03). In terms of nutrients, bladder cancer risk was inversely associated with intake of both total carotenoids (p = 0.004) and vitamin C (p = 0.02). There was a close correlation (r = 0.58, p = 0.0001) between intakes of total carotenoids and vitamin C in study subjects. When both nutrients were included in a multivariate logistic regression model, only total carotenoids exhibited a residual effect that was of borderline statistical significance (p = 0.07 and p = 0.40 for total carotenoids and vitamin C, respectively). Cigarette smoking was a strong modifier of the observed dietary effects; these protective effects were confined largely to ever smokers and were stronger in current than ex-smokers. Smokers showed a statistically significant or borderline statistically significant decrease in 3- and 4-aminobiphenyl (ABP)-hemoglobin adduct level with increasing intake of carotenoids (p = 0.04 and 0.05, respectively). The protective effect of carotenoids on bladder cancer seemed to be influenced by NAT1 genotype, NAT2 phenotype and CYP1A2 phenotype; the association was mainly confined to subjects possessing the putative NAT1-rapid, NAT2-rapid and CYP1A2-rapid genotype/phenotype. The carotenoid-bladder cancer association was not affected by the GSTM1, GSTT1 and GSTP1 genotypes.

Acyltransferases↗
PubMed2004

Active smoking, household passive smoking, and breast cancer: evidence from the California Teachers Study.

BACKGROUND: There is great interest in whether exposure to tobacco smoke, a substance containing human carcinogens, may contribute to a woman's risk of developing breast cancer. To date, literature addressing this question has been mixed, and the question has seldom been examined in large prospective study designs. METHODS: In a 1995 baseline survey, 116 544 members of the California Teachers Study (CTS) cohort, with no previous breast cancer diagnosis and living in the state at initial contact, reported their smoking status. From entry into the cohort through 2000, 2005 study participants were newly diagnosed with invasive breast cancer. We estimated hazard ratios (HRs) for breast cancer associated with several active smoking and household passive smoking variables using Cox proportional hazards models. RESULTS: Irrespective of whether we included passive smokers in the reference category, the incidence of breast cancer among current smokers was higher than that among never smokers (HR = 1.32, 95% confidence interval [CI] = 1.10 to 1.57 relative to all never smokers; HR = 1.25, 95% CI = 1.02 to 1.53 relative to only those never smokers who were unexposed to household passive smoking). Among active smokers, breast cancer risks were statistically significantly increased, compared with all never smokers, among women who started smoking at a younger age, who began smoking at least 5 years before their first full-term pregnancy, or who had longer duration or greater intensity of smoking. Current smoking was associated with increased breast cancer risk relative to all nonsmokers in women without a family history of breast cancer but not among women with such a family history. Breast cancer risks among never smokers reporting household passive smoking exposure were not greater than those among never smokers reporting no such exposure. CONCLUSION: Our study provides evidence that active smoking may play a role in breast cancer etiology and suggests that further research into the connection is warranted, especially with respect to genetic susceptibilities.

Adult↗
PubMed2004

Correlates of active and passive smoking in the California Teachers Study cohort.

OBJECTIVES: These analyses were designed to describe characteristics associated with active and passive smoking in a large cohort of women in order to identify possible confounders of the relationship between smoking exposures and breast cancer risk. METHODS: Analyses were based on 1995 data collected from the California Teachers Study (CTS) and were restricted to those with complete and usable tobacco data (n = 128,174). Age-adjusted and race-adjusted odds ratios (OR) were generated by unconditional logistic regression. RESULTS: Compared with never smokers, both current and former smokers experienced menarche at an earlier age. Current and former smokers also were more likely than their never smoking counterparts to be nulliparous. Among parous women, current, but not former smokers were less likely than never smokers to have had their first child at an older age. Similarly, among never smokers, those exposed to household passive smoking experienced menarche at an earlier age, were more likely to be nulliparous, and among parous women, were less likely to have had their first child at an older age than never smokers not exposed to passive smoking. Greater alcohol consumption was strongly associated with both active and passive smoking exposures. Compared with never smokers, current smokers were less likely to take antioxidant supplements, whereas former smokers were more likely to take antioxidant supplements. Among never smokers, antioxidant use did not differ depending on passive smoking exposure. A number of other dietary correlates of active and passive smoking were identified. CONCLUSIONS: We identified a number of reproductive and dietary correlates to smoking exposures that underscore the need to adjust for such factors in an analysis of smoking and breast cancer and potentially other disease entities. Furthermore, these findings may suggest potential mechanisms underlying an association between breast cancer and smoking.

Adult↗
PubMed2004

Regional variations in breast cancer among california teachers.

BACKGROUND: Observed regional differences in breast cancer incidence could provide valuable clues to the etiology of this disease. The pattern of historically higher breast cancer rates among residents of California's San Francisco Bay and Southern Coastal areas is evident in the disease experience among members of the California Teachers Study. This large cohort study has followed female professional school employees for cancer incidence since 1995 and has collected extensive information on breast cancer risk factors. METHODS: Between 1996 and 1999, invasive breast cancer was diagnosed in 1562 of the 115,611 cohort members who could be geocoded to a California address in 1995 and who had no previous breast cancer diagnosis. Adjusted hazard rate ratios (HRs) were estimated through multivariate Cox proportional hazards modeling. RESULTS: Rates were higher for cohort members in the San Francisco Bay area (HR = 1.22; 95% confidence interval = 1.06-1.40) and Southern Coastal area (1.16; 1.04-1.30) compared with those in the rest of California. The distributions of variables representing socioeconomic status, urbanization, and personal risk factors were consistent with higher risks for cohort members residing in the San Francisco Bay and Southern Coastal areas. Adjustment for these factors, however, did not explain regional differences in incidence, resulting in HRs that remained elevated for these 2 areas. CONCLUSION: Regional differences in breast cancer incidence in this large, well-defined cohort are not easily explained by known risk factors.

Adolescent↗
PubMed2004

Patterns of alcohol consumption and breast cancer risk in the California Teachers Study cohort.

Alcohol consumption of approximately two drinks or more per day has been associated with elevated breast cancer risk in the California Teachers Study cohort as well as in many other populations. The objective of this analysis is to examine effects of age at drinking and drinking patterns and to identify effect modifiers. Of the 103,460 at-risk cohort members, age <85, who resided in California and completed the baseline alcohol assessment, 1,742 were diagnosed with invasive breast cancer after joining the cohort and before January 2001. Incident breast cancers were identified through the California Cancer Registry and follow-up for death and confirmation of continued California residence used various sources. Multivariate Cox proportional hazards regression models were used to estimate relative risks (RRs). Elevated breast cancer risk was most evident for recent drinking [RR = 1.28, 95% confidence interval (CI): 1.06-1.54 for >/=20 g/day versus nondrinkers], with no clear pattern for consumption during earlier periods of life. This elevation in risk was 32% among postmenopausal women (95% CI: 1.06-1.63) and 21% among pre/perimenopausal women (95% CI: 0.76-1.92). Highest risks associated with heavy alcohol consumption were observed among postmenopausal women with a history of biopsy-diagnosed benign breast disease (RR = 1.97, 95% CI: 1.39-2.79 compared to nondrinkers without benign breast disease) or who had used combination hormone replacement therapy (HRT) (RR = 2.24, 95% CI: 1.59-3.14 compared to nondrinkers who never used HRT). Recent alcohol consumption equivalent to two or more drinks per day increases the risk of invasive breast cancer, with the greatest RRs observed among heavy drinkers who are also postmenopausal and have a history of benign breast disease or who use HRT.

Adolescent↗
PubMed2004

Prediagnostic levels of serum micronutrients in relation to risk of gastric cancer in Shanghai, China.

Data on blood levels of specific carotenoids and vitamins in relation to gastric cancer are scarce. Little is known about the relationship between prediagnostic serum levels of carotenoids other than beta-carotene and risk of gastric cancer especially in non-Western populations. Prediagnostic serum concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein/zeaxanthin, retinol, alpha-tocopherol, gamma-tocopherol, and vitamin C were determined on 191 cases and 570 matched controls within a cohort of 18,244 middle-aged or older men in Shanghai, China, with a follow-up of 12 years. High serum levels of alpha-carotene, beta-carotene, and lycopene were significantly associated with reduced risk of developing gastric cancer (all Ps for trend </= 0.05); the odds ratios (95% confidence intervals) for the highest versus the lowest quartile of alpha-carotene, beta-carotene, and lycopene were 0.38 (0.13-1.11), 0.54 (0.32-0.89), and 0.55 (0.30-1.00), respectively. Increased serum level of vitamin C was significantly associated with reduced risk of gastric cancer among men who neither smoked cigarettes over lifetime nor consumed >/=3 drinks of alcohol per day; the odds ratios (95% confidence intervals) for the second, third, and fourth quartile categories were 0.69 (0.28-1.70), 0.36 (0.14-0.94), and 0.39 (0.15-0.98), respectively, compared with the lowest quartile of vitamin C (P for trend = 0.02). There were no statistically significant relationships of serum levels of beta-cryptoxanthin, lutein/zeaxanthin, retinol, alpha-tocopherol, and gamma-tocopherol with gastric cancer risk. The present study implicates that dietary carotenes, lycopene, and vitamin C are potential chemopreventive agents for gastric cancer in humans.

Alcohol Drinking↗
PubMed2003

Validating California teachers study self-reports of recent hospitalization: comparison with California hospital discharge data.

Determining an accurate method of obtaining complete morbidity data is a long-standing challenge for epidemiologists. The authors compared the accuracy and completeness of existing California hospital discharge data with self-reports of recent hospitalizations and surgeries from participants in the California Teachers Study. Self-reports were collected by questionnaire in 1997 from 91433 female teachers and administrators residing in California. Of the 13430 hospital discharge diagnoses identified for these women, cohort members reported 58%. Self-reporting was highest for neoplasms and musculoskeletal and connective tissue diseases and was most accurate for scheduled admissions, more recent admissions, longer lengths of stay, and less severe disorders. Hospitalizations for mental health and infectious disease were not as well reported. Among the 26383 self-reports-including outpatient surgeries, which are not captured by the hospital discharge database-confirmation was lower, as expected, especially for disorders of the nervous system and sense organs and skin and subcutaneous tissue. Confirmation was highest for childbirth admissions. The hospital discharge database was more specific, but the self-reports were more comprehensive, since many conditions are now treated in outpatient settings. The combination of self-reports and secondary medical records provides more accurate and complete morbidity data than does use of either source alone.

Aged↗
PubMed2003

Effect of family history, obesity and exercise on breast cancer risk among postmenopausal women.

We examined effects of obesity and lifetime exercise patterns on postmenopausal breast cancer risk according to family history in a large population-based case control study conducted in Los Angeles County, California, because we hypothesized that both factors would affect risk through similar mechanistic pathways, and that their effects would be stronger among women with a family history. We studied 1883 postmenopausal breast cancer case subjects and 1628 postmenopausal control subjects ranging in age from 55-72 years. Cases were diagnosed with incident breast cancer in the late 1980s and 1990s. Controls were individually matched to case subjects on age, ethnic origin and neighborhood. In-person interviews determined known breast cancer risk factors including: height, weight, lifetime exercise, and family history of breast and other cancers. Breast cancer risk was raised among women who had at least 1 first-degree relative with breast cancer (odds ratio [OR] = 1.68; 95% confidence interval [CI] = 1.36-2.08). Risk increased with increasing levels of body-mass index (wt-kg/ht-m(2)) (p-trend = 0.005). Breast cancer risk was reduced among women who maintained, on average, 17.6 metabolic equivalent of energy expenditure (MET)-hr of activity/week from menarche onward (OR = 0.66; 95% CI = 0.48-0.90). Body-mass index, adjusted for lifetime exercise, was strongly associated with breast cancer risk among women with a positive family history of breast cancer (p-trend < 0.0001), but only weakly associated among women with no family history (p-trend = 0.08; homogeneity of trends p = 0.0005). In contrast, the risk reduction associated with exercise activity, adjusting for body-mass index, was limited to women without a family history of breast cancer (p-trend = 0.001; homogeneity of trends p = 0.005). Body-mass index and exercise activity, both modifiable risk factors for breast cancer, seem to have differential effects depending on a woman's family history of breast cancer, and may impact risk through different biological mechanisms.

Aged↗