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Most epidemiological studies evaluating the association of fruit and vegetable intakes on lung cancer risk were conducted in North American and European countries. We investigated the association of intakes of fruits, vegetables, dietary vitamins A and C, and folate with lung cancer risk among 61,491 adult Chinese men who were recruited into the Shanghai Men's Health Study, a population-based, prospective cohort study. Baseline dietary intake was assessed through a validated food frequency questionnaire during in-home visits. Multivariate Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of lung cancer risk associated with dietary intakes. During a median follow-up of 5.5 yr, 359 incident lung cancer cases accrued after the first year of follow-up and 68.8% of them were current smokers. Intakes of green leafy vegetables, β-carotene-rich vegetables, watermelon, vitamin A, and carotenoids were inversely associated with lung cancer risk; the corresponding HR (95% CI) comparing the highest with the lowest quartiles were 0.72 (0.53-0.98), 0.69 (0.51-0.94), 0.65 (0.47-0.90), 0.63 (0.44-0.88), and 0.64 (0.46-0.88). Intake of all fruits and vegetables combined was marginally associated with lower risk. Our study suggests that the consumption of carotenoid-rich vegetables is inversely associated with lung cancer risk.
Few food frequency questionnaires (FFQs) have been developed specifically for use among African Americans, and reports of FFQ performance among African Americans or low-income groups assessed using biochemical indicators are scarce. The authors conducted a validation study within the Southern Community Cohort Study to evaluate FFQ-estimated intakes of alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, lycopene, folate, and alpha-tocopherol in relation to blood levels of these nutrients. Included were 255 nonsmoking participants (125 African Americans, 130 non-Hispanic whites) who provided a blood sample at the time of study enrollment and FFQ administration in 2002-2004. Levels of biochemical indicators of each micronutrient (alpha-tocopherol among women only) significantly increased with increasing FFQ-estimated intake (adjusted correlation coefficients: alpha-carotene, 0.35; beta-carotene, 0.28; beta-cryptoxanthin, 0.35; lutein/zeaxanthin, 0.28; lycopene, 0.15; folate, 0.26; alpha-tocopherol, 0.26 among women; all P's < 0.05). Subjects in the top decile of FFQ intake had blood levels that were 27% (lycopene) to 178% (beta-cryptoxanthin) higher than those of subjects in the lowest decile. Satisfactory FFQ performance was noted even for participants with less than a high school education. Some variation was noted in the FFQ's ability to predict blood levels for subgroups defined by race, sex, and other characteristics, but overall the Southern Community Cohort Study FFQ appears to generate useful dietary exposure rankings in the cohort.
INTRODUCTION - Assessments by the handful of prospective studies of the association of serum antioxidants and breast cancer risk have yielded inconsistent results. This multiethnic nested case-control study sought to examine the association of plasma carotenoids, retinol, and tocopherols with postmenopausal breast cancer risk.
METHODS - From the biospecimen subcohort of the Multiethnic Cohort Study, 286 incident postmenopausal breast cancer cases were matched to 535 controls on age, sex, ethnicity, study location (Hawaii or California), smoking status, date/time of collection and hours of fasting. We measured prediagnostic circulating levels of individual carotenoids, retinol, and tocopherols. Conditional logistic regression was used to compute odds ratios and 95% confidence intervals.
RESULTS - Women with breast cancer tended to have lower levels of plasma carotenoids and tocopherols than matched controls, but the differences were not large or statistically significant and the trends were not monotonic. No association was seen with retinol. A sensitivity analysis excluding cases diagnosed within 1 year after blood draw did not alter the findings.
CONCLUSIONS - The lack of significant associations in this multiethnic population is consistent with previously observed results from less racially-diverse cohorts and serves as further evidence against a causal link between plasma micronutrient concentrations and postmenopausal breast cancer risk.
Although smoking is the primary risk factor for lung cancer, there is evidence to suggest that fruit and vegetable intake are important cofactors. The present case-control study, nested within the Multiethnic Cohort Study, examined the associations of biomarkers of fruit and vegetable intake (individual plasma micronutrient levels), serum selenium, and a urinary biomarker for total lipid peroxidation with lung cancer risk. Two hundred seven incident cases were matched to 414 controls on age, sex, ethnicity, study location (Hawaii or California), smoking status, date/time of collection, and hours of fasting. We measured prediagnositic circulating levels of individual tocopherols and carotenoids, retinol, and serum selenium, and urinary 15-isoprostane F(2t). Conditional logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI). For men, strong reductions in risk were seen with increasing tertiles of each plasma carotenoid, with the ORs for the third tertile, compared with the first tertile, ranging from 0.24 to 0.45 (P(trends), 0.002-0.04). No associations were found among women for carotenoids or among either sex for tocopherols, selenium, and retinol. A doubling in risk was seen for men in the second and third tertiles, compared with the first tertile of urinary 15-isoprostane F(2t) (OR, 2.31; 95% CI, 1.02-5.25; and OR, 2.16; 95% CI, 0.98-4.78). This study supports the previously observed association between circulating carotenoids and lung cancer risk in men, and adds to the limited literature regarding urinary 15-isoprostane F(2t) as a marker of cancer risk. Future research examining the possible relationship between isoprostanes and lung cancer is warranted.
Evidence from some previous studies suggests that lipophilic antioxidants, particularly carotenoids, may reduce the risk of breast cancer. We prospectively investigated the associations of plasma levels of tocopherols, retinol, carotenoids with the risk of developing breast cancer among Chinese women. We conducted a study of 365 incident breast cancer cases and 726 individually matched controls nested within a large cohort study of women aged 40-70 years at baseline. We observed no associations between breast cancer risk and any of the tocopherols, retinol, and most carotenoids. However, high levels of plasma lycopene other than trans, 5- and 7-cis or trans alpha-cryptoxanthin were inversely associated with the risk of developing breast cancer. Our results do not support an overall protective effect of lipophilic antioxidants on breast cancer risk. The few inverse associations observed for subtype of carotenoids may need to be confirmed in future studies.
We evaluated the validity and reproducibility of the FFQ used in the Shanghai Men's Health Study (SMHS). The study included 195 randomly selected participants of the SMHS who completed one FFQ at baseline, twelve 24-hour dietary recalls (24-HDR) (once a month for twelve consecutive months) and a second FFQ at the end of the study. The FFQ accounted for 88.78% of the foods recorded in the 24-HDR surveys. The validity of the FFQ was evaluated by comparing nutrient and food group intake levels from the second FFQ and the multiple 24-HDR. Correlation coefficients ranged from 0.38 to 0.64 for macronutrients, 0.33 to 0.58 for micronutrients and 0.35 to 0.72 for food groups. Misclassification to opposite quartiles for nutrients and food groups was rare, ranging from 1.5 to 7.7%, while exact agreement rates were between 31.8 and 53.3%. The reliability of the FFQ was assessed by comparing the intake levels from the two FFQ. Correlation coefficients were 0.39 to 0.53 for macronutrients, 0.38 to 0.52 for micronutrients and 0.39 to 0.64 for food groups. Exact agreement rates for quartile distribution were between 31.8 and 49.2%, while misclassification to opposite quartiles was between 1.5 and 6.2%. These data indicate that the SMHS FFQ can reasonably categorise usual intake of nutrients and food groups among men living in urban Shanghai.
We evaluated the associations of dietary intake of calcium, fiber and vitamins with colorectal cancer risk in a population-based prospective cohort study conducted among Chinese women in Shanghai. Subjects were recruited in urban Shanghai from March 1997 to May 2000. All subjects were interviewed in-person to obtain information on demographic and lifestyle factors and anthropometric measurement was conducted. Usual dietary intake, using a validated food frequency questionnaire was assessed at the baseline survey. After following a total of 73,314 women for a median of 5.74 years, 283 incident colorectal cancer cases were recorded. Excluding the first 2 years of follow-up, a high intake of calcium was associated with a decreased risk of colorectal cancer. Comparing the highest quintile of nutrients intake to the lowest, the adjusted relative risk for colorectal cancer was 0.6 (p value for trend = 0.023) for calcium. No apparent associations were found for fiber, total vitamin A, carotene, vitamins B1, B2, B3, C and E with colorectal cancer risk. Our results suggest that calcium may be protective against colorectal cancer development even at a lower consumption level compared to Western populations.
Copyright 2006 Wiley-Liss, Inc.
OBJECTIVES - To report a prospective trial of lycopene supplementation in biochemically relapsed prostate cancer.
METHODS - A total of 36 men with biochemically relapsed prostate cancer were enrolled in a dose-escalating, Phase I-II trial of lycopene supplementation. Six consecutive cohorts of 6 patients each received daily supplementation with 15, 30, 45, 60, 90, and 120 mg/day for 1 year. The serum levels of prostate-specific antigen (PSA) and plasma levels of lycopene were measured at baseline and every 3 months. The primary endpoints were PSA response (defined as a 50% decrease in serum PSA from baseline), pharmacokinetics, and the toxicity/tolerability of this regimen.
RESULTS - A total of 36 patients were enrolled. The median age was 74 years (range 56 to 83), with a median serum PSA at entry of 4.4 ng/mL (range 0.8 to 24.9). No serum PSA responses were observed, and 37% of patients had PSA progression. The median time to progression was not reached. Toxicity was mild, with 1 patient discontinuing therapy because of diarrhea. Significant elevations of plasma lycopene were noted at 3 months and then appeared to plateau for all six dose levels. The plasma levels for doses between 15 and 90 mg/day were similar, with additional elevation only at 120 mg/day.
CONCLUSIONS - Lycopene supplementation in men with biochemically relapsed prostate cancer is safe and well tolerated. The plasma levels of lycopene were similar for a wide dose range (15 to 90 mg/day) and plateaued by 3 months. Lycopene supplementation at the doses used in this study did not result in any discernible response in serum PSA.
Complimentary and alternative medicines (CAM) have increased drastically in popularity in the past decade. These are largely in the form of nutritional supplements. Despite a wealth of information sources on the subject, the fundamental problem with CAM therapies is a dearth of evidence-based medicine. Advanced prostate cancer has significant long-term morbidity, and there is a growing interest in alternative and complimentary forms of therapy that will improve the outcomes of patients who have recurrent or advanced prostate cancer while obviating the need for more toxic forms of therapy. In this article we summarize the use of some of the more common CAM nutritional supplements and review the scientific data that are available to support their use.
Antioxidants, particularly carotenoids and tocopherols, may protect against cardiovascular disease. The objective of this study was to determine whether dietary and adipose tissue carotenoids and tocopherols are associated with the risk of myocardial infarction (MI). Cases (n = 1456) of a first acute MI were identified and matched by age, sex, and residence to randomly selected population controls (n = 1456) living in Costa Rica. Carotenoids and tocopherols were measured in adipose tissue using HPLC. Dietary intake was assessed using a validated FFQ. Anthropometrical and lifestyle data were collected using an interviewer-administered questionnaire. Subjects were distributed into quintiles of intake or adipose tissue concentration of carotenoids or tocopherols. The lowest quintile was used as the referent in conditional logistic regression analyses. Adipose tissue beta-carotene showed a significant inverse relation with MI risk; the odds ratio (OR) comparing the highest to the lowest quintile was 0.70 (95% CI: 0.51-0.96, P for trend = 0.02). Intake of fruits and vegetables that are rich in beta-carotene was also inversely associated with the risk of MI (OR = 0.74; CI: 0.54-1.01, P for trend = 0.09). In contrast, lutein + zeaxanthin in adipose tissue (OR = 1.46; CI: 1.05-2.05, P for trend = 0.02) and diet (OR = 1.18; CI: 0.88-1.57, P for trend = 0.02) was positively associated with MI risk. MI risk was not associated with any of the other carotenoids or tocopherols in the diet or adipose tissue. Thus, the inverse association between beta-carotene and MI risk suggests that beta-carotene protects against MI or it is a marker of some protective factor in foods containing beta-carotene. The mechanism underlying the positive association between lutein + zeaxanthin and the risk of MI warrants investigation.