Plasma micronutrient antioxidant in cancer patients.

The distribution of breast, colon, gastric, thyroid, oral, rectal, pancreatic and renal cancers were determined in 71 Kuwaitis, 45 other Arabs, and 26 Indians. Plasma levels of micronutrient antioxidants, retinol, alpha-tocopherol, lycopene, and beta-carotene were measured in the groups and in 90 matched controls for comparison. Cholesterol was measured to determine its association with the micronutrient antioxidants. Pancreatic cancer occurred exclusively in Kuwaitis, while breast and colon cancers were disproportionately higher in Kuwaitis than in the other groups. Micronutrient antioxidant levels were similar in the groups, except for higher lycopene levels in Kuwaitis. In most instances, the micronutrient antioxidants, except beta-carotene, decreased significantly in levels in patients than in controls. Low levels of retinol, lycopene, and beta-carotene were strongly associated with pancreatic cancer. Compared to controls, significantly increased levels of beta-carotene occurred in breast, colon, thyroid, and renal cancers; increased lycopene occurred in oral cancer, and increased alpha-tocopherol occurred in pancreatic cancer. Alpha-tocopherol strongly correlated with cholesterol. Generally, changes in alpha-tocopherol/ cholesterol ratios mimicked those of alpha-tocopherol levels. Micronutrient antioxidant levels were significantly lower in male patients than female patients. Age showed a negative but statistically insignificant relationship with micronutrient antioxidants. Lycopene strongly correlated with alpha-carotene and alpha-tocopherol with retinol. Among the patients, all micronutrient antioxidants except retinol decreased significantly in levels in smokers than nonsmokers, suggesting susceptibility to cigarette smoke oxidative stress. We conclude that micronutrient antioxidant depletions and altered associations may imply tumor utilization or antioxidant burden in oxidative stress or both. Furthermore, the incidence of pancreatic, colon and breast cancers among Kuwaitis warrants further study.     

Prospective study of carotenoids, tocopherols, and retinoid concentrations and the risk of breast cancer.

Previous prospective studies have raised the possibility that the antioxidantproperties of carotenoids and vitamin E (alpha-tocopherol) and the role of vitamin A (retinol) in cellular differentiation may be associated with a reduced risk of subsequent breast cancer. To investigate the association between serum and plasma concentrations of retinol, retinyl palmitate, alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene, total-carotenoids, alpha-tocopherol, and gamma-tocopherol with subsequent development of breast cancer, a nested case control study was conducted among female residents of Washington County, Maryland, who had donated blood for a serum bank in 1974 or 1989. Cases (n = 295) and controls (n = 295) were matched on age, race, menopausal status, and date of blood donation, and the analyses were stratified by cohort participation. Median concentrations of beta-carotene, lycopene, and total carotene were significantly lower in cases compared with controls in the 1974 cohort (13.1, 12.5, and 7.9% difference; P = 0.01, 0.04, and 0.04, respectively) and for lutein in the 1989 cohort (6.7% difference; P = 0.02). The risk of developing breast cancer in the highest fifth was approximately half of that of women in the lowest fifth for beta-carotene [odds ratio (OR) = 0.41; 95% confidence interval (CI) 0.22-0.79; P trend = 0.007], lycopene (OR = 0.55; 95% CI 0.29-1.06; P trend = 0.04), and total carotene (OR = 0.55; 95% CI 0.29-1.03; P trend = 0.02) in the 1974 cohort. There was generally a protective association for other micronutrients in both cohorts, although none reached statistical significance. The results suggest that carotenoids may protect against the development of breast cancer.     

Selenium, lycopene, alpha-tocopherol, beta-carotene, retinol, and subsequent bladder cancer

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.     

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Both the tumour growth and progression and the systemic inflammatory response have the potential to increase oxidative stress. We therefore examined the relationship between lipid-soluble antioxidant vitamins, lipid peroxidation, the systemic inflammatory response and survival in patients with primary operable (n = 53) and advanced inoperable (n = 53) colorectal cancer. Compared with those patients with primary operable colorectal cancer, patients with unresectable liver disease had significantly lower median concentrations of alpha-tocopherol (p < 0.001), lutein (p < 0.001), lycopene (p < 0.001), alpha-carotene (p < 0.01) and beta-carotene (p < 0.001) and higher malondialdehyde concentrations. An elevated systemic inflammatory response (Glasgow prognostic score, mGPS) was associated with a greater proportion of females (p < 0.05) and more advanced tumour stage (p < 0.05), lower circulating levels of retinol (p < 0.01), lutein (p < 0.01), lycopene (p < 0.01) and alpha- (p < 0.01) and beta-carotene but not MDA (p = 0.633). In the liver metastases group 41 patients died of their cancer and a further 1 patient died of intercurrent disease on follow-up. On univariate survival analysis, mGPS (p < 0.01), retinol (p < 0.001), alpha-tocopherol (p < 0.05) and alpha-carotene (p < 0.05) were associated significantly with cancer-specific survival. On multivariate survival analysis of these significant variables, only mGPS (p < 0.01) and retinol (p < 0.001) were independently associated with cancer-specific survival. The results of the present study showed that the systemic inflammatory response was associated with a reduction of lipid-soluble antioxidant vitamins, whereas advanced tumour stage was associated with increased lipid peroxidation in patients with colorectal cancer. Of the antioxidant vitamins measured, only retinol was independently associated with cancer-specific survival.     

Serum carotenoids and vitamins and risk of cervical dysplasia from a case-control study in Japan

The relationships between risk of cervical dysplasia and dietary and serum carotenoids and vitamins were investigated in a case-control study. Cases were 156 women who attended Papanicolaou test screening in nine institutes affiliated with Japan Study Group of Human Papillomavirus (HPV) and Cervical Cancer and had cervical dysplasia newly histologically confirmed. Age-matched controls were selected from women with normal cervical cytology attending the same clinic. Blood sample and cervical exfoliated cells were obtained for measuring serum retinol, alpha-carotene, beta-carotene, zeaxanthin/lutein, cryptoxanthin, lycopene and alpha-tocopherol and for HPV detection. Higher serum level of alpha-carotene was significantly associated with decreased risk of cervical dysplasia after controlling for HPV infection and smoking status (odds ratio (OR) = 0.16, 95% confidence interval (CI) 0.04-0.62 for the highest as compared with the lowest tertile). Decreased risk for the highest tertile of serum lycopene (OR = 0.28) was marginally significant. Decreased risks observed for the highest tertiles of beta-carotene (OR = 0.65) and zeaxanthin/lutein (OR = 0.53), were not statistically significant.     

Differential Effects of Cigarette Smoking and Alcohol Consumption on the Plasma Levels of Carotenoids in Middle-aged Japanese Men

Although several studies have reported that cigarette smoking and alcohol consumption are inversely associated with the plasma level of beta-carotene even after adjustment for dietary carotene intake, their effects on other carotenoids have not been examined extensively. The authors examined the associations of smoking and alcohol with plasma levels of the five principal carotenoids (beta-carotene, alpha-carotene, lutein, lycopene, and zeaxanthin). The subjects were 634 apparently healthy men aged 40–49 years who were sampled randomly from five areas in Japan with varying rates of mortality from gastric cancer. Multiple linear regression analysis controlling for age, serum total cholesterol, serum triglycerides, body mass index, and consumption frequencies of green vegetables, yellow vegetables and fruit, showed that both smoking and alcohol had a significant inverse association with the plasma levels of beta-carotene and alpha-carotene; only smoking reduced the level of lutein, and neither smoking nor alcohol significantly affected the level of lycopene or zeaxanthin. With regard to the reduction of beta-carotene and alpha-carotene, the effect of smoking was smaller in drinkers than in nondrinkers, and the effect of alcohol was smaller in smokers than in nonsmokers, and significant interactions between smoking and alcohol were observed (P=0.034 for beta-carotene and 0.026 for alpha-carotene). The results indicate that the differential effects of smoking and alcohol should be considered when the health effects of plasma carotenoids are examined.     

Serum antioxidant micronutrients and the risk of oral leukoplakia among Japanese

A population-based case-control study was designed for the investigation of any association between serum micronutrient levels and oral leukoplakia. Out of a total of 9536 subjects over the age of 40 years who participated in the oral mucosal screening programme in Tokoname city, 48 cases detected with oral leukoplakia (38 male:10 female) were recruited. For each case, four controls matched by age and sex were selected from the same cohort. We examined the fasting serum levels of retinol, alpha-tocopherol, zeaxanthin and lutein, cryptoxanthin, lycopene and carotenoids (alpha-carotene and beta-carotene) by high-performance liquid chromatography. Among males with leukoplakia mean serum lycopene and beta-carotene levels (0.175+/-0.202, 0.357+/-0.295 micromol/l) were significantly lower than those of controls (0.257+/-0.252, 0.555+/-0.408 micromol/l) (P<0.05, P<0.005). Logistic regression analysis with leukoplakia as the dependent variable showed that high serum levels of beta-carotene were related to low risk of oral leukoplakia (odds ratio 0.160, 95% C.I.: 0.029-0.866, P<0.05). There were no significant differences in any of the serum nutrients estimated in female subjects. Our results suggest for the first time that high serum levels of beta-carotene may provide protection against oral precancer for the Japanese male.     

Plasma levels of carotenoids, retinol and tocopherol and the risk of gastric cancer in Japan: a nested case-control study

Fruits and vegetables have been suggested to confer protection against diseases such as cancer through the effects of antioxidants, often represented by carotenoids. We investigated the impact of carotenoids, retinol and tocopherol on gastric cancer development in a large nested case-control study among Japanese with known Helicobacter pylori infection status. A total of 36 745 subjects aged 40-69 in the Japan Public Health Center-based Prospective Study who responded to the baseline questionnaire and provided blood samples in 1990-1995 were followed until 2004. Plasma levels of carotenoids in 511 gastric cancer cases and 511 matched controls were measured by high-performance liquid chromatography. Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated using conditional logistic regression models. Plasma level of beta-carotene was inversely associated with the risk of gastric cancer (compared with the lowest quartile: OR = 0.63, 95% CI = 0.31-0.75; OR = 0.48, 95% CI = 0.31-0.75 and OR = 0.46, 95% CI = 0.28-0.75, for quartile 2, 3 and 4, respectively, P(trend) < 0.01). Inverse associations were evident in men for alpha-carotene (P(trend) = 0.04) and beta-carotene (P(trend) < 0.01), but not in women, who had relatively higher plasma levels compared with men. We found no statistically significant association between plasma levels of lutein/zeaxanthin, lycopene, retinol, alpha- or gamma-tocopherol and gastric cancer risk. Our findings suggest that those who have very low plasma levels of alpha-carotene and beta-carotene are at a higher risk of gastric cancer.     

Exposure to environmental tobacco smoke is associated with lower plasma beta-carotene levels among nonsmoking women married to a smoker.

We evaluated the association between exposure to environmental tobacco smoke (ETS) from husbands who smoke and plasma levels of antioxidant vitamins among nonsmoking women. A total of 1249 women from four areas in Italy answered a self-administered questionnaire, reported their diets on a food frequency questionnaire, had a medical examination, and gave their blood for alpha and beta-carotene, retinol, L-ascorbic acid, alpha-tocopherol, and lycopene determinations. Urinary cotinine was used to evaluate the level of recent exposure to ETS. After adjusting for study center, age and education, we found no association between ETS exposure and daily nutrient intake of beta-carotene, retinol, L-ascorbic acid, and alpha-tocopherol. However, we found an inverse dose-response relationship between intensity of current husband's smoke and concentrations of plasma beta-carotene and L-ascorbic acid. The associations remained even after controlling for daily beta-carotene and vitamin C intake and for other potential confounders (vitamin supplementation, alcohol consumption, and body mass index). Moreover, when urinary cotinine was considered as the exposure variable, a significant inverse association with plasma beta-carotene was found. The findings may be of interest to explain the biological mechanism that link ETS exposure with lung cancer and ischemic heart diseases.     

Lower prostate cancer risk in men with elevated plasma lycopene levels: results of a prospective analysis

Dietary consumption of the carotenoid lycopene (mostly from tomato products) has been associated with a lower risk of prostate cancer. Evidence relating other carotenoids, tocopherols, and retinol to prostate cancer risk has been equivocal. This prospective study was designed to examine the relationship between plasma concentrations of several major antioxidants and risk of prostate cancer. We conducted a nested case-control study using plasma samples obtained in 1982 from healthy men enrolled in the Physicians' Health Study, a randomized, placebo-controlled trial of aspirin and beta-carotene. Subjects included 578 men who developed prostate cancer within 13 years of follow-up and 1294 age- and smoking status-matched controls. We quantified the five major plasma carotenoid peaks (alpha- and beta-carotene, beta-cryptoxanthin, lutein, and lycopene) plus alpha- and gamma-tocopherol and retinol using high-performance liquid chromatography. Results for plasma beta-carotene are reported separately. Odds ratios (ORs), 95% confidence intervals (Cls), and Ps for trend were calculated for each quintile of plasma antioxidant using logistic regression models that allowed for adjustment of potential confounders and estimation of effect modification by assignment to either active beta-carotene or placebo in the trial. Lycopene was the only antioxidant found at significantly lower mean levels in cases than in matched controls (P = 0.04 for all cases). The ORs for all prostate cancers declined slightly with increasing quintile of plasma lycopene (5th quintile OR = 0.75, 95% CI = 0.54-1.06; P, trend = 0.12); there was a stronger inverse association for aggressive prostate cancers (5th quintile OR = 0.56, 95% CI = 0.34-0.91; P, trend = 0.05). In the placebo group, plasma lycopene was very strongly related to lower prostate cancer risk (5th quintile OR = 0.40; P, trend = 0.006 for aggressive cancer), whereas there was no evidence for a trend among those assigned to beta-carotene supplements. However, in the beta-carotene group, prostate cancer risk was reduced in each lycopene quintile relative to men with low lycopene and placebo. The only other notable association was a reduced risk of aggressive cancer with higher alpha-tocopherol levels that was not statistically significant. None of the associations for lycopene were confounded by age, smoking, body mass index, exercise, alcohol, multivitamin use, or plasma total cholesterol level. These results concur with a recent prospective dietary analysis, which identified lycopene as the carotenoid with the clearest inverse relation to the development of prostate cancer. The inverse association was particularly apparent for aggressive cancer and for men not consuming beta-carotene supplements. For men with low lycopene, beta-carotene supplements were associated with risk reductions comparable to those observed with high lycopene. These data provide further evidence that increased consumption of tomato products and other lycopene-containing foods might reduce the occurrence or progression of prostate cancer.     

Serum micronutrient and antioxidant levels at baseline and the natural history of men with localised prostate cancer on active surveillance

The aim of this study was to determine whether serum concentrations of micronutrients, antioxidants and vitamins predict rate of disease progression in untreated, localised prostate cancer. Patients with localised prostatic adenocarcinoma on a prospective study of active surveillance underwent monitoring with serial PSA levels and repeat prostate biopsies. Disease progression was defined as either adverse histology on repeat biopsy (primary Gleason grade ≥4 or >50% positive cores of total) or radical treatment for PSA velocity >1 ng ml⁻¹ year⁻¹. Time to disease progression was analysed with respect to baseline levels of alpha-tocopherol, gamma-tocopherol, alpha-carotene and beta-carotene, lycopene, retinol and selenium. One hundred four patients were evaluable, with a median follow-up of 2.5 years. Thirty-eight patients experienced disease progression, 13 biochemical and 25 histologic progression. Median time to disease progression was 2.62 years. No significant association was seen between time to disease progression and baseline serum levels of alpha-tocopherol (p = 0.86), gamma-tocopherol (p = 0.84), alpha-carotenoid (p = 0.66), beta-carotene (p = 0.65), lycopene (p = 0.0.15), retinol (p = 0.76) or selenium (p = 0.76). No significant association was seen between serum levels of the micronutrients, antioxidants or vitamins and either adverse histology on repeat biopsy or PSA velocity. Our data do not support the hypothesis that high serum concentrations of micronutrients, antioxidants and vitamins prevent disease progression in men with localised prostate cancer.     

Plasma retinol, beta-carotene and vitamin E levels in relation to the future risk of breast cancer.

In a prospective study of 5,004 women in Guernsey, plasma samples were collected and stored. Retinol, beta-carotene and vitamin E levels were later measured in the samples from 39 women who subsequently developed breast cancer and from 78 controls who did not develop cancer. Plasma retinol levels were not related to the risk of breast cancer, mean levels among cases and controls being 485 micrograms l-1 and 479 micrograms l-1 respectively. Plasma vitamin E levels showed a clear association, low levels being associated with a significantly higher risk of cancer. The mean vitamin E levels among cases and controls were 4.7 mg l-1 and 6.0 mg l-1 respectively (P less than 0.025), and the risk of breast cancer in women with vitamin E levels in the lowest quintile was about 5-times higher than the risk for women with levels in the highest quintile (P less than 0.01). beta-carotene levels showed a tendency to be lower in women who developed cancer than in controls (36 micrograms l-1 among cases compared with 50 micrograms l-1 among controls) but the difference was not statistically significant.     

Plasma carotenoid, alpha-tocopherol and retinol concentrations and risk of colorectal adenomas: A case-control study in Japan

To investigate associations between plasma carotenoids, alpha-tocopherol and retinol with colorectal adenomas risk, we measured concentrations in 224 asymptomatic colorectal adenoma cases and 230 population-based controls matched for age and sex. After adjustment for age, history of colorectal adenomas and cancers, BMI, smoking, drinking status, multivitamin consumption and plasma total cholesterol, the risk of colorectal adenomas in the highest quartile was approximately half of that of men in the lowest quartile for alpha-carotene (OR=0.38; 95% CI: 0.18-0.84; P(trend)=0.01), beta-carotene (OR=0.51; 95% CI: 0.24-1.07; P(trend)=0.03) and total carotenoids (OR=0.48; 95% CI: 0.22-1.03; P(trend)=0.04). In addition, a protective association for alpha-carotene in women was also indicated, but which did not reach statistical significance (OR=0.53; 95% CI: 0.19-1.52; P(trend)=0.35). Our findings suggest a protective effect of carotenoids against the development of colorectal adenomas.     

Serologic precursors of cancer. Retinol, carotenoids, and tocopherol and risk of prostate cancer

We investigated the associations of serum retinol, the carotenoids beta-carotene and lycopene, and tocopherol (vitamin E) with the risk of prostate cancer in a nested case-control study. For the study, serum obtained in 1974 from 25,802 persons in Washington County, MD, was used. Serum levels of the nutrients in 103 men who developed prostate cancer during the subsequent 13 years were compared with levels in 103 control subjects matched for age and race. Although no significant associations were observed with beta-carotene, lycopene, or tocopherol, the data suggested an inverse relationship between serum retinol and risk of prostate cancer. We analyzed data on the distribution of serum retinol by quartiles, using the lowest quartile as the reference value. Odds ratios were 0.67, 0.39, and 0.40 for the second, third, and highest quartiles, respectively.     

Significance of plasma retinol binding protein levels in recurrence of breast tumors in women

Plasma retinol-binding protein (RBP), prealbumin, vitamin A (total) and beta-carotene levels were studied in premenopausal women with node-positive breast carcinoma receiving adjuvant chemotherapy. Plasma levels were measured prior to chemotherapy and at monthly intervals during the chemotherapy course. The results showed that significantly lower RBP levels during the course of the study were associated with early tumor recurrence. Patients who maintained a disease-free status for 24 months or longer had significantly higher plasma RBP levels than those who had tumor metastasis at distant sites within 24 months after beginning chemotherapy. RBP levels were not associated with adjuvant chemotherapy (CMF)-induced hormonal changes (amenorrhea vs. no amenorrhea), or family history of breast cancer. In contrast, breast cancer patients with a prior history of benign breast disease had significantly lower RBP levels than did healthy, premenopausal women. Reduced RBP levels in these patients are due to neither an inadequate dietary intake of beta-carotene, nor to severe protein malnutrition.     

Modification effects of GSTM1, GSTT1 and CYP2E1 polymorphisms on associations between raw salted food and incomplete intestinal metaplasia in a high-risk area of stomach cancer

Incomplete intestinal metaplasia (IM) is a precursor of stomach cancer. To identify risk factors of incomplete IM, a 2-stage survey was carried out in 1995 among 1,485 residents in Matzu, an area with highest mortality from stomach cancer in Taiwan. There were 312 study subjects including 174 men and 138 women sampled for the gastroendoscopic examination of IM. Information on personal and familial history of stomach cancer, cigarette smoking, alcohol consumption and intake frequency of various salted food items were obtained by personal interview based on a structured questionnaire. Blood samples were collected from each participant. Four biopsies per subject were taken from all subjects at gastroendoscopic examination to diagnose the status of IM pathologically. The Helicobacter pylori in biopsies was detected by the histomorphological or immunochemistry method, and antibodies against H. pylori in serum by the enzyme-linked immunosorbent assay. Plasma level of selenium was determined by atomic absorption spectrometry, plasma level of retinol, alpha-tocopherol, alpha-carotene, and beta-carotene by high performance liquid chromatography, genotypes of glutathione S-transferase (GST) M1 and T1 and cytochrome P450 (CYP) 2E1 by polymerase chain reaction. The significant association between history of stomach cancer among first-degree relatives and incomplete IM was found (odds ratio [OR] = 2.50; 95% confidence interval [CI] = 1.15-5.43). There was no association between H. pylori infection and incomplete IM. Alcohol drinkers for >20 years had an elevated risk compared to non-drinkers (OR = 3.34; 95% CI = 1.19-9.39). No associations between incomplete IM and plasma levels of selenium, retinol, alpha-tocopherol, alpha-carotene and beta-carotene were found. Salted food including salted meat, dehydrated salted vegetables and raw salted seafood consumed at ages of 相似文献   

Retinol, carotenoids and the risk of prostate cancer: a case-control study from Italy

Several studies have evaluated the possible association between intakes of retinoids and carotenoids and the risk of prostate cancer, but the evidence is still inconsistent. Further, only a few studies have investigated the role of specific carotenoids other than beta-carotene. We have thus considered the association between retinol and various carotenoids using data from a multicentric case-control study conducted in Italy between 1991 and 2002. This included 1,294 incident, histologically confirmed prostate cancer cases below age 75 years admitted to major teaching and general hospitals in the areas under study, and 1,451 controls below age 75 years selected among patients admitted to the same hospitals as cases for a wide spectrum of acute nonneoplastic conditions not related to long-term modifications of diet. Subjects' usual diet was investigated by means of a validated food-frequency questionnaire. Multivariate odds ratios and the corresponding 95% confidence intervals were estimated using unconditional logistic regression models. The risk of prostate cancer tended to decrease with increasing intake of retinol (OR=0.79 for the highest versus the lowest quintile of intake), carotene (OR=0.70), alpha-carotene (OR=0.85) and beta-carotene (OR=0.72), although the estimates were significant for carotene and beta-carotene only. No meaningful associations emerged for nonprovitamin A carotenoids, such as lycopene (OR=0.94) and lutein/zeaxanthin (OR=0.91). No systematic heterogeneity was observed across strata of age, education and body mass index. Thus, our study supports the hypothesis of a weak protective effect of carotene, particularly beta-carotene, on the risk of prostate cancer, while it indicates that other carotenoids, including lycopene, and retinol are not appreciably related to the risk of this neoplasm.     

Prediagnostic levels of serum beta-cryptoxanthin and retinol predict smoking-related lung cancer risk in Shanghai, China.

Higher blood levels of beta-carotene have been found to be associated with reduced risk of lung cancer, but large intervention trials have failed to demonstrate reduced lung cancer incidence after prolonged high-dose beta-carotene supplementation. Data on blood levels of specific carotenoids other than beta-carotene in relation to lung cancer are scarce. Little is known about the relationship between prediagnostic serum levels of carotenoids, retinol, and tocopherols, and risk of lung cancer especially in non-Western populations. Between January 1986 and September 1989, 18,244 men ages 45-64 years participated in a prospective study of diet and cancer in Shanghai, China. Information on tobacco smoking and other lifestyle factors was obtained through in-person interviews. A serum sample was collected from each study participant at baseline. During the first 12 years of follow-up, 209 lung cancer cases, excluding those diagnosed within 2 years of enrollment, were identified. For each cancer case, three cancer-free control subjects were randomly selected from the cohort and matched to the index case by age (within 2 years), month and year of blood sample collection, and neighborhood of residence. Serum concentrations of retinol, alpha- and gamma-tocopherols, and specific carotenoids including alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin were determined on the 209 cases and 622 matched controls by high-performance liquid chromatography methods. A high prediagnostic serum level of beta-cryptoxanthin was significantly associated with reduced risk of lung cancer; relative to the lowest quartile, the smoking-adjusted relative risks (95% confidence intervals) for the 2nd, 3rd, and 4th quartile categories were 0.72 (0.41-1.26), 0.42 (0.21-0.84), and 0.45 (0.22-0.92), respectively (P for trend = 0.02). Increased serum levels of other specific carotenoids including alpha-carotene, beta-carotene, lycopene, and lutein/zeaxanthin were related to reduced risk of lung cancer although the inverse associations were no longer statistically significant after adjustment for smoking. A statistically significant 37% reduction in risk of lung cancer was noted in smokers with above versus below median level of total carotenoids. Serum retinol levels showed a threshold effect on lung cancer risk. Compared with the lowest quartile (<40 microg/dl), the smoking-adjusted relative risk (95% confidence interval) was 0.60 (0.39-0.92) for men in the 2nd-4th quartiles of retinol values combined; no additional decrease in risk was observed between individuals from the 2nd to 4th quartiles. There were no associations between prediagnostic serum levels of alpha- and gamma-tocopherols and lung cancer (all Ps for trend > or =0.4). The present data indicate that higher prediagnostic serum levels of total carotenoids and beta-cryptoxanthin were associated with lower smoking-related lung cancer risk in middle-aged and older men in Shanghai, China. Low level of serum retinol (with a threshold effect) is associated with increased lung cancer risk in this oriental population.     

The role of diet and nutrition in cervical carcinogenesis: a review of recent evidence

Our objective was to provide an update on recent epidemiologic evidence about the role of diet and nutrition on the risk of human papillomavirus (HPV) persistence and cervical neoplasia, taking HPV into account. We conducted a systematic review and qualitative classification of all observational studies controlling for HPV infection published between March 1995 and November 2003 and of all randomized clinical trials published between January 1991 and November 2003. Scientific evidence was classified as convincing, probable, possible or insufficient, as used in a previous study on diet and cancer. Thirty-three studies were eligible for this review (10 clinical trials, 8 observational prospective studies and 15 case-control studies). The few studies on HPV persistence showed a possible protective effect of fruits, vegetables, vitamins C and E, beta- and alpha-carotene, lycopene, luterin/zeaxanthin and cryptoxanthin. Evidence for a protective effect of cervical neoplasia was probable for folate, retinol and vitamin E and possible for vegetables, vitamins C and B12, alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin and cryptoxanthin. Evidence for an increased risk of cervical neoplasia associated with high blood homocysteine was probable. Results did not differ between studies looking at preneoplastic and invasive lesions or between retrospective and prospective studies. The available evidence for an association between diet and nutritional status and cervical carcinogenesis taking HPV infection into account is not yet convincing. Large cohort studies are needed to adequately assess the role of foods and nutrients in cervical HPV carcinogenesis.     

Plasma and dietary carotenoids are associated with reduced oxidative stress in women previously treated for breast cancer.

Dietary carotenoids show numerous biological activities, including antioxidant activity, induction of apoptosis, and inhibition of mammary cell proliferation. Studies examining the role of carotenoid consumption in relation to breast cancer recurrence are limited and report mixed results. We tested the hypothesis that breast cancer survivors with high dietary and plasma carotenoids would show significantly lower levels of oxidative stress than breast cancer survivors with low dietary and plasma carotenoid levels. Two hundred seven postmenopausal breast cancer survivors from the Women's Healthy Eating and Living Study volunteered for this ancillary study. Dietary data were analyzed by the Arizona Food Frequency Questionnaire and plasma carotenoids alpha-carotene, beta-carotene, lutein plus zeaxanthin, lycopene, and beta-cryptoxanthin and quantified with high-performance liquid chromatography, and immunoaffinity chromatography-monoclonal antibody-based ELISAs were used to analyze the urine samples for 8-hydroxy-2'-deoxyguanosine (8-OhdG) and 8-iso-prostaglandin-F2alpha (8-iso-PGF2alpha). The correlations between dietary and plasma carotenoids were 0.34 for beta-carotene, 0.46 for alpha-carotene, 0.39 for beta-cryptoxanthin, 0.27 for lycopene, 0.30 for lutein plus zeaxanthin, and 0.30 for total carotenoids. The 8-OHdG oxidative stress biomarker was significantly reduced at the highest quartile of total plasma carotenoid concentrations (P = 0.001) and 8-iso-PGF2alpha was moderately reduced (P = 0.088). Dietary carotenoid levels were not significantly associated with oxidative, stress indicators, although dietary lycopene and lutein/zeaxanthin were modestly associated with 8-OHdG levels (P = 0.054 and 0.088, respectively). Key findings include a significant inverse association between total plasma carotenoid concentrations and oxidative stress as measured by urinary 8-OHdG and a moderately significant inverse association with 8-iso-PGF2alpha, a protective association that was not shown for dietary carotenoid intake.