[Using chengqi prescription to prevent hepatic ischemia/reperfusion injury after liver transplantation in rats]

OBJECTIVE

To study the effect of Chengqi prescription in preventing hepatic ischemia/reperfusion injury after liver transplantation in rats.

METHODS

Rat in situ liver transplantation model was used, donor liver was preserved in Ringer's solution for 4 hrs under 4 degrees C, then divided randomly into Chinese medicine group (Chengqi prescription), polymyxin B group, mannitol group, normal saline group and sham operation control group, each group further subdivided into two subgroups: 1 hr group and 4 hrs group after transplantation. The serum ALT and liver injury index was determined.

RESULTS

In preventing hepatic ischemia/reperfusion injury after liver transplantation, the Chengqi prescription was polymyxin B showed more effective than that of mannitol and normal saline, and the effect of Chengqi prescription was higher than that of polymyxin B (P < 0.05).

CONCLUSION

Chengqi prescription was effective in preventing hepatic ischemia/reperfusion injury after liver transplantation in rat.

Association of body size and fat distribution with risk of breast cancer among Chinese women

Most previous studies addressing the association of body size, weight change and body fat distribution with the risk of breast cancer were conducted in Western societies with a high proportion of overweight people. It remains unclear whether the dose-response relation observed in earlier studies can be extended to women with "normal" weight based on prevailing Western standards. To address this issue, we analyzed data from a population-based case-control study of breast cancer recently completed among Chinese women in urban Shanghai. In-person interviews and anthropometric measurements were completed for 1,459 women newly diagnosed with breast cancer from 25 to 64 years of age and 1,556 controls frequency-matched to cases on age. Unconditional logistic regression was employed to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CI) related to anthropometric variables and self-reported body weight. Currently measured weight, body mass index [BMI: weight (kg)/height(m)(2)] or height was each found to be positively related to risk of postmenopausal breast cancer in a dose-response manner, with ORs (95% CI) being 2.0 (1.4-3.0), 2.0 (1.2-3.2) or 1.7 (1.2-2.5), respectively, for the highest category of weight, BMI or height compared to the lowest category of these variables. These variables were unrelated to premenopausal breast cancer risk. Reported weight at ages >40 years and weight gain after age 20 were more predictive for postmenopausal breast cancer than weight at an earlier age. After adjustment for BMI, waist-to-hip ratio was related to an increased risk of premenopausal [OR = 1.7 (1.3-2.3) for the highest category compared to the lowest category] but not postmenopausal breast cancer. This study suggests that, even in a relatively thin Chinese population, weight gain and height are related to an increased risk of postmenopausal breast cancer, while central fat distribution was associated with premenopausal breast cancer. General weight control may be an effective measurement for breast cancer prevention.

Fish and shellfish consumption in relation to death from myocardial infarction among men in Shanghai, China

Between 1986 and 1989, 18,244 men aged 45-64 years in Shanghai, China, participated in a prospective study of diet and cancer. All participants completed an in-person, structured interview and provided blood and urine samples. As of September 1, 1998, 113 deaths from acute myocardial infarction were identified. After analyses were adjusted for age, total energy intake, and known cardiovascular disease risk factors, men who consumed >or=200 g of fish/shellfish per week had a relative risk of 0.41 (95% confidence interval: 0.22, 0.78) for fatal acute myocardial infarction compared with men consuming <50 g per week. Similarly, dietary intake of n-3 fatty acids derived from seafood also was significantly associated with reduced mortality from myocardial infarction. Neither dietary seafood nor n-3 fatty acid intake was associated with a reduced risk of death from stroke or ischemic heart disease other than acute myocardial infarction. However, approximately a 20% reduction in total mortality associated with weekly fish/shellfish intake was observed in the study population (relative risk = 0.79, 95% confidence interval: 0.69, 0.91). These prospective data suggest that eating fish and shellfish weekly reduces the risk of fatal myocardial infarction in middle-aged and older men in Shanghai, China.

IGF-1, IGF-2 and IGFBP-3 in prediagnostic serum: association with colorectal cancer in a cohort of Chinese men in Shanghai

This is the first study to investigate the associations of IGF-1, IGF-2 and IGFBP-3 concentrations with the risk of colorectal cancer in prospectively collected blood samples from an Oriental population. Between 1986 and 1989 serum samples were collected at baseline from 18 244 men, aged 45-65 years, without a history of cancer and living in Shanghai, China. IGF-1, IGF-2 and IGFBP-3 were measured in the serum of 135 men who developed colorectal cancer over 12 years of follow-up and 661 control subjects drawn from the cohort, who were matched to the index cases by neighbourhood of residence, age, and year and month of sample collection. Serum IGF-1 was not associated with risk of colorectal cancer. IGF-2 and IGFBP-3, on the other hand, exhibited statistically significant, positive associations with colorectal cancer risk when cases were confined to those diagnosed within a relatively short time period after enrollment (within 8 years). After adjustment for body mass index, cigarette smoking and alcohol intake, men in the highest versus the lowest quintile of IGF-2 and IGFBP-3 showed odds ratios of 2.74 (95% Cl = 1.67-4.50; 2-sided P for trend = 0.0008) and 2.85 (95% Cl = 1.69-4.81; 2-sided P for trend = 0.01), respectively. Our data thus suggest that circulating IGF-2 and IGFBP-3 can serve as early indicators of impending colorectal cancer.

A population-based case-control study of lung cancer and green tea consumption among women living in Shanghai, China

Epidemiologic evidence regarding the association between the consumption of green tea and lung cancer is limited and inconclusive, although experimental studies have shown consistently that tea preparations and tea polyphenols may inhibit the induction of a variety of cancers, including lung cancer. In this population-based case-control study, we examined the association between past consumption of green tea and the risk of lung cancer. We identified 649 incident cases of primary lung cancer among women diagnosed from February 1992 through January 1994 using the population-based Shanghai Cancer Registry. We randomly selected a control group of 675 women from the Shanghai Residential Registry, frequency-matched to the expected age distribution of the cases. Green tea consumption was ascertained through face-to-face interviews. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) using unconditional logistic regression. Among nonsmoking women, consumption of green tea was associated with a reduced risk of lung cancer (OR = 0.65; 95% CI = 0.45-0.93), and the risks decreased with increasing consumption. We found little association, however, among women who smoked (OR = 0.94; 95% CI = 0.40-2.22). The inconsistency in the association between drinking tea and the risk of lung cancer reported in previous studies may in part be due to inadequate control of confounding of active smoking.

Polymorphic markers in the SRD5A2 gene and prostate cancer risk: a population-based case-control study

It has been suggested that the activity of the steroid 5alpha-reductase type II enzyme (encoded by the SRD5A2 gene) may be associated with prostate cancer risk and that population differences in this enzyme's activity may account for part of the substantial racial/ethnic disparity in prostate cancer risk. To provide etiological clues, we evaluated the relationships of four polymorphic markers in the SRD5A2 gene, specifically, A49T (a substitution of threonine for alanine at codon 49), V89L (a substitution of leucine for valine at codon 89), R227Q (a substitution of glutamine for arginine at codon 227), and a (TA)n dinucleotide repeat, with prostate cancer risk in a population-based case-control study in China, a population with the lowest reported prostate cancer incidence rate in the world. Genotypes of these four markers were determined from genomic DNA of 191 incident cases of prostate cancer and 304 healthy controls using PCR-based assays, and serum androgen levels were measured in relation to these genotypes. All study subjects had the wild-type AA genotype of the A49T marker, and 99% had the RR genotype of the R227Q marker. For the V89L marker, prevalences of the LL, VV, and VL genotypes among controls were 35%, 21%, and 45%, respectively. Compared with men with the VV genotype, those with the LL genotype had a statistically nonsignificant 12% reduced risk (odds ratio = 0.88, 95% confidence interval, 0.53-1.47). In addition, men with the LL genotype had significantly higher serum levels of testosterone and significantly lower serum levels of 5alpha-androstane-3alpha,17beta-diol glucuronide than men with other genotypes. Men heterozygous for the (TA)0 allele of the (TA)n marker had a modest, statistically nonsignificant risk reduction (odds ratio = 0.67; 95% confidence interval, 0.39-1.12) compared with men homozygous for the (TA)0 allele, along with significantly higher serum dihydrotestosterone levels. The observed V89L genotype prevalences and the association between V89L genotypes and serum androgen levels support the hypothesis that genotypes associated with lower levels of 5alpha-reductase activity are more common in low-risk populations. Although we found no statistically significant associations of these SRD5A2 polymorphisms with prostate cancer risk, a small effect of these markers cannot be ruled out because of the rarity of certain marker genotypes. Larger studies are needed to further clarify the role of these markers and to elucidate whether genetic diversity of the SRD5A2 gene, alone or in combination with other susceptibility genes, can help explain the large racial/ethnic differences in prostate cancer risk.

Dietary folate intake and breast cancer risk: results from the Shanghai Breast Cancer Study

Folate is involved in DNA synthesis, repair, and methylation. It has been hypothesized that high intake of folate may reduce the risk of human cancers, including cancer of the breast. Using data from a population-based case-control study of breast cancer conducted in urban Shanghai during 1996-1998, we evaluated the association of dietary folate intake and breast cancer risk among 1321 cases and 1382 controls, 25-64 years of age, who never drank alcohol regularly or used vitamin supplements. Usual dietary habits were assessed with an in-person, interviewer-administered food frequency questionnaire developed and tested for use in this population. Unconditional logistic regression models were used to calculate odds ratios (ORs) and their 95% confidence intervals (95% CIs) after adjusting for potential confounding factors. Dietary folate intake was inversely associated with breast cancer risk (P for trend, 0.05) with an adjusted OR of 0.71 (95% CI, 0.56-0.92) observed among women who were in the highest quintile of intake. The inverse association was stronger after further adjusting for total fruit and vegetable and animal food intakes (OR, 0.62; 95% CI, 0.46-0.82; P for trend, 0.01). A more pronounced inverse association between folate intake and breast cancer risk (OR, 0.47; 95% CI, 0.25-0.88; P for trend, 0.01) was observed among women who consumed high levels of folate cofactors (methionine, vitamin B(12), and vitamin B(6)) than those whose intake levels of these nutrients were low. Dietary intake of methionine, vitamin B(12), and vitamin B(6) were not independently related to risk of breast cancer after adjusting for confounding factors. Thus, our study adds additional support to the protective role of dietary folate in breast carcinogenesis and suggests further that the effect of folate may be modified by dietary intake of methionine, vitamin B(12), and vitamin B(6).

Population-based case-control study of soyfood intake and breast cancer risk in Shanghai

We evaluated the association of soyfood intake and breast cancer risk in a population-based case-control study among Chinese women in Shanghai. Included in the study were 1459 cases and 1556 age-matched controls, with respective response rates of 91.1% and 90.3%. Usual soyfood intake was assessed using a food frequency questionnaire (FFQ). Separate analyses were performed for all subjects and for the subset who reported no recent change in soyfood intake. The intake levels of soyfoods among women in Shanghai are high, with 96.6% women reporting soyfood consumption at least once a week. A statistically non-significant reduced risk (odds ratio (OR) = 0.78 95% CI = 0.52-1.16) of breast cancer was observed among those who reported eating soyfood at least once a week. Compared to those in the lowest decile intake group, women in the highest decile intake group had a 30% reduced risk of breast cancer (OR = 0.66, 95% CI = 0.46-0.95), but no monotonic dose-response relation was observed (P for trend, 0.28). Stratified analyses showed that the inverse association was restricted primarily among women who had a high body mass index (BMI), with an adjusted OR of 0.30 (95% CI = 0.10-0.94) observed for the highest intake group. The reduction in risk was stronger for breast cancer positive for both oestrogen receptor (ER) and progesterone receptor (PR) (OR = 0.44, 95% CI = 0.25-0.78) than those with other ER/PR status. More pronounced inverse associations were observed in analyses among those who reported no recent change in soyfood intake than those conducted in all subjects. A dose-response relation between soyfood intake and breast cancer risk was observed in this subset of women (P for trend, 0.02), with an OR of 0.46 (95%CI = 0.28-0.75) for those in the highest decile intake group. No clear monotonic dose-response relation was found between soyfood intake and breast cancer risk among regular soy eaters, but nevertheless the results suggest that regular soyfood consumption may reduce the risk of breast cancer, particularly for those positive for ER and PR; the effect may be modified by body mass index.

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.

Abortion history and breast cancer risk: results from the Shanghai Breast Cancer Study

Studies of the association between induced abortion and breast cancer risk have been inconsistent, perhaps due to underreporting of abortions. Induced abortion is a well-accepted family planning procedure in China, and women who have several induced abortions do not feel stigmatized. The authors used data from a population-based case-control study of breast cancer among women age 25-64 conducted between 1996 and 1998 in urban Shanghai to assess whether a history of and the number of induced abortions were related to breast cancer risk. In-person interviews were completed with 1,459 incident breast cancer cases ascertained through a population-based cancer registry, and 1,556 controls randomly selected from the general population in Shanghai (with respective response rates of 91% and 90%). After adjusting for confounding, there was no relation between ever having had an induced abortion and breast cancer (odds ratio [OR] = 0.9, 95% confidence interval [CI] 0.7-1.2). Women who had 3 or more induced abortions were not at increased risk of premenopausal breast cancer (OR = 0.9, 95% CI 0.6-1.4) or postmenopausal breast cancer (OR = 1.3, 95% CI 0.8-2.3). These results suggest that a history of several induced abortions has little influence on breast cancer risk in Chinese women.

Prostate cancer risk and serum levels of insulin and leptin: a population-based study

BACKGROUND

In a previous study of Chinese men, we found that men with a higher waist-to-hip ratio (WHR) have a higher prostate cancer risk. Because leptin and insulin are related to body fat distribution, we examined whether leptin and insulin were associated with prostate cancer risk.

METHODS

Blood samples were collected from 128 case patients with incident prostate cancer and from 306 healthy control subjects randomly selected from residents of Shanghai, CHINA: Epidemiologic information and anthropometric measurements were collected in personal interviews. Serum leptin, insulin, and sex hormone levels were measured by radioimmunoassay, and insulin-like growth factor-I (IGF-I) was measured by enzyme-linked immunosorbent assay. Multiple logistic regression analyses were used to estimate odds ratios for prostate cancer in relation to serum insulin and leptin levels. All statistical tests were two-sided.

RESULTS

After adjustment for body mass index, WHR, IGF-I, and sex hormone levels, higher serum insulin levels were associated with a statistically significantly elevated risk of prostate cancer (P<.001). Men in the highest tertile of insulin levels had a 2.56-fold (95% confidence interval [CI] = 1.38 to 4.75) risk of prostate cancer compared with men in the lowest tertile. Regardless of the tertile level of WHR, higher serum insulin levels were associated with an increased risk of prostate cancer: Men in the highest tertiles of WHR (>0.900) and insulin (>8.83 microU/mL) had 8.55 times (95% CI = 2.80 to 26.10) the prostate cancer risk of men in the lowest tertiles of both, and those in the lowest tertile of WHR (<0.873) and highest tertile of insulin had 4.30 times (95% CI = 1.17 to 15.70) the risk. By contrast, the association between leptin levels and prostate cancer risk was not statistically significant.

CONCLUSION

Our results suggest that serum insulin levels may influence the risk of prostate cancer in Chinese men. Further research, especially prospective studies, is needed to confirm these findings in high-risk populations and to clarify the underlying mechanisms involved.

Vitamin D receptor gene polymorphisms, insulin-like growth factors, and prostate cancer risk: a population-based case-control study in China

Operating through the vitamin D receptor (VDR), vitamin D inhibits prostate cancer growth and increases insulin-like growth factor binding protein (IGFBP) expression, suggesting that the vitamin D and insulin-like growth factor (IGF) regulatory systems may operate together to affect prostate cancer. Among 191 newly diagnosed prostate cancer cases and 304 randomly selected population controls in Shanghai, China, we found no significant association between the BsmI or FokI VDR gene polymorphisms and prostate cancer risk. However, we found that among men with the ff FokI genotype, those in the highest tertile of plasma IGFBP-3 had a decreased risk versus those in the lowest tertile (odds ratio, 0.14; 95% confidence interval, 0.04-0.56; P(trend) < 0.01), whereas among men with the FF and Ff genotypes, IGFBP-3 was not associated with risk. Similarly, IGFBP-1 was inversely associated with prostate cancer risk only among men with the ff FokI genotype (odds ratio, 0.25; 95% confidence interval, 0.07-0.85; P(trend) = 0.02). No such FokI genotype-specific effects were observed for IGF-I or IGF-II. Our findings in a low-risk population suggest that the IGF and vitamin D regulatory systems may interact to affect prostate cancer risk. Larger studies are needed to confirm these findings and clarify the underlying mechanisms.

Insulin-like growth factors and prostate cancer: a population-based case-control study in China

Insulin-like growth factors (IGFs) have potent mitogenic and antiapoptotic effects on prostate epithelial cells. Through modulation of IGF bioactivity and other mechanisms, IGF-binding proteins (IGFBPs) also have growth-regulatory effects on prostate cells. Recently, IGF-I and IGFBP-3 have been implicated in prostate cancer risk among Western populations. To assess whether IGF-I, IGF-II, IGFBP-1, or IGFBP-3 are also associated with prostate cancer in a low-risk population, we measured plasma levels of these factors among 128 newly diagnosed prostate cancer cases and 306 randomly selected population controls in Shanghai, China. Relative to the lowest quartile of IGF-I levels, men in the highest quartile had a 2.6-fold higher prostate cancer risk, with a significant trend [odds ratio (OR) = 2.63; 95% confidence interval (95% CI) = 1.19-5.79; P(trend) = 0.01]. In contrast, men in the highest quartile of IGFBP-3 levels had a 46% decreased risk relative to the lowest quartile (OR = 0.54; 95% CI = 0.26-1.15; P(trend) = 0.08). A similar but less distinct result was observed for IGFBP-1 (OR = 0.60; 95% CI = 0.31-1.17; P(trend) = 0.25). Men in the highest quartile for the IGF-I:IGFBP-3 molar ratio (an indirect measure of free IGF-I) had a 2.5-fold higher risk compared with the lowest quartile (OR = 2.51; 95% CI = 1.32-4.75, P(trend) < 0.001). These associations were more pronounced after adjustment for serum 5alpha-androstane-3alpha,17beta-diol glucuronide and sex hormone-binding globulin levels. There was no significant association with IGF-II levels. Our findings in a low-risk population provide evidence that IGF-I, IGFBP-3, and IGFBP-1 are determinants of prostate cancer and indicate that additional studies are needed to evaluate their effects on ethnic and geographic incidence differentials and to elucidate carcinogenic mechanisms.

Soyfood intake during adolescence and subsequent risk of breast cancer among Chinese women

Many experimental but few epidemiological studies have suggested that soyfoods and their constituents have cancer-inhibitory effects on breast cancer. No epidemiological study has evaluated the association of adolescent soyfood intake with the risk of breast cancer. To evaluate the effect of soyfood intake during adolescence, one of the periods that breast tissue is most sensitive to environmental stimuli, on subsequent risk of breast cancer, we analyzed data from a population-based case-control of 1459 breast cancer cases and 1556 age-matched controls (respective response rates were 91.1% and 90.3%). Information on dietary intake from ages 13-15 years was obtained by interview from all study participants and, in addition, from mothers of subjects less than 45 years of age (296 cases and 359 controls). Odds ratios (ORs) and 95% confidence intervals (CIs) derived from unconditional logistic models were used to measure soyfood intake and breast cancer risk. After adjustment for a variety of other risk factors, adolescent soyfood intake was inversely associated with risk, with ORs of 1.0 (reference), 0.75 (95% CI, 0.60-0.93), 0.69 (95% CI, 0.55-0.87), 0.69 (95% CI, 0.55-0.86), and 0.51 (95% CI, 0.40-0.65), respectively, for the lowest to highest quintiles of total soyfood intake (trend test, P < 0.001). The inverse association was observed for each of the soyfoods examined and existed for both pre- and postmenopausal women. Adolescent soyfood intakes reported by participants' mothers were also inversely associated with breast cancer risk (P for trend < 0.001), with an OR of 0.35 (95% CI, 0.21-0.60) for women in the highest soyfood intake group. Adjustment for rice and wheat products, the major energy source in the study population, and usual adult soyfood intake did not change the soyfood associations. Our study suggests that high soy intake during adolescence may reduce the risk of breast cancer in later life.

Beta-catenin mutations in biliary tract cancers: a population-based study in China

beta-Catenin is an ubiquitously expressed cytoplasmic protein that has a crucial role in both cadherin-mediated cell-cell adhesion and as a downstream signaling molecule in the wingless/Wnt pathway. Activating mutations in exon 3 of the beta-catenin gene, at the phosphorylation sites for ubiquitination and degradation of beta-catenin, are present in a variety of cancers. Because alterations of the adenomatous polyposis coli (APC) gene are present in biliary tract cancers and the APC protein modulates levels of beta-catenin, we evaluated the role of beta-catenin in biliary tract cancer by sequencing the third exon of the beta-catenin gene among 107 biliary tract cancers and 7 gallbladder adenomas from a population-based study in CHINA: Point mutations of serine or threonine phosphorylation sites in exon 3 of beta-catenin were present in 8 of 107 (7.5%) biliary tract cancers and 4 of 7 (57.1%) gallbladder adenomas. Mutations of beta-catenin were more frequent in ampullary and gallbladder carcinomas than in bile duct carcinomas (P = 0.04) and in papillary adenocarcinomas than other histological types of carcinomas (P = 0.02). These results suggest that the molecular pathways of biliary tract neoplasms vary by anatomical subsite and histological subtype.

Prostate cancer, benign prostatic hyperplasia and physical activity in Shanghai, China

BACKGROUND

Studies suggest that increased levels of physical activity might decrease the risk of prostate cancer. We ascertained lifetime measures of activity in a population-based case-control study of prostate cancer in Shanghai, China to investigate physical activity in a population where the incidence of prostate cancer is low but rising.

METHODS

In all, 238 men with prostate cancer, diagnosed 1993-1995, were identified through a rapid reporting system. A second group of 206 men with benign prostatic hyperplasia (BPH) was matched to prostate cancer cases, and 471 age-matched and population-based controls were identified from urban Shanghai. Through personal interviews, we ascertained all daily, occupational, and recreational activities at ages 20-29, ages 40-49, and in 1988 to generate hours spent sleeping, sitting, in moderate activity, and in vigorous activity. Time spent per week in different activities was converted to metabolic equivalents (MET-h) and energy expended.

RESULTS

Time spent in, MET-h of, and energy expended in physical activities were not consistently related to either prostate cancer or BPH when compared to controls. Few men reported regular vigorous activity. Occupational activity, based on an energy expenditure index using job titles, was suggestively associated with a decreased risk of BPH, but not associated with prostate cancer. Associations did not vary according to age or stage of prostate cancer at diagnosis.

CONCLUSIONS

Our results, based on regular physical activity, occupational activity, hours in activities, MET-h, and energy expended, did not support a protective role of physical activity in prostate cancer or BPH for men in a low-risk population.

Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study

Overall physical activity in adolescence and adulthood, and changes in activity over the lifespan were analysed by in-person interviews among 1459 women newly diagnosed with breast cancer and 1556 age-matched controls in urban Shanghai. Physical activity from exercise and sports, household, and transportation (walking and cycling) was assessed in adolescence (13-19 y) and adulthood (last 10 y), as was lifetime occupational activity. Logistic regression was used to estimate odds ratios (OR) and 95% confidence limits (OR (95% CL)) while controlling for confounders. Risk was reduced for exercise only in adolescence (OR = 0.84 (0.70-1.00)); exercise only in adulthood (OR = 0.68 (0.53-0.88)), and was further reduced for exercise in both adolescence and adulthood (OR = 0.47 (0.36-0.62)). Graded reductions in risk were noted with increasing years of exercise participation (OR(1-5 yrs)= 0.81 (0.67-0.94); OR(6-10 yrs)= 0.74 (0.59-0.93); OR(11-15 yrs)= 0.55 (0.38-0.79); OR(16 + yrs)= 0.40 (0.27-0.60);P(trend,)< 0.01). Lifetime occupational activity also was inversely related to risk (P(trend)< 0.01). These findings demonstrate that consistently high activity levels throughout life reduce breast cancer risk. Furthermore, they suggest that women may reduce their risk by increasing their activity levels in adulthood.

Epidemiological study of urinary 6beta-hydroxycortisol to cortisol ratios and breast cancer risk

The ratio of urinary 6beta-hydroxycortisol:cortisol is a measure of the activity of cytochrome p450 3A4 (CYP3A4). CYP3A4 catalyzes the formation of the genotoxic estrogen, 16alpha-hydroxyestrone. It is also involved in the activation of many other mammary carcinogens, such as the polycyclic aromatic hydrocarbons and heterocyclic amines. We evaluated the association between urinary cortisol ratios and breast cancer risk in a subgroup of women who participated in a population-based case-control study in Shanghai. Overnight urine samples from 246 case-control pairs were assayed for 6beta-hydroxycortisol (6beta-OHC) to cortisol. The urine samples from all of the breast cancer patients were collected before any chemotherapy or radiotherapy. In-person interviews were conducted to obtain comprehensive information on dietary habits, reproductive history, and other lifestyle factors. The median levels of 6beta-OHC:cortisol ratios were 2.61 in cases and 2.16 in controls, a 20.8% difference (P < 0.001). The case-control difference was larger in women over 45 years of age (31.3% difference; P < 0.001) than younger women (6.0%; P = 0.45). After adjusting for confounding variables, the risks of breast cancer were increased from 1.0 (reference) to 1.6 [95% confidence interval (CI), 0.9-3.1], 2.2 (95% CI, 1.1-4.2), and 3.7 (95% CI, 1.9-7.4; P for trend, <0.001) with increasing levels of 6beta-OHC:cortisol ratios. The positive association was more pronounced among older women (>45 years) than among younger women (< or = 45 years). The adjusted odds ratios associated with the highest cortisol ratio were 6.0 (95%CI, 2.2-16.1) among older women and 2.2 (95%CI, 0.8-6.1) among younger women. The association of the 6beta-OHC:cortisol ratio was stronger among older women who had a high body mass index, late age at menopause, and early age at menarche (factors related to high endogenous estrogen exposure) than those who did not have these factors. These findings are consistent with the role of CYP3A4 in estrogen and carcinogen metabolism and suggest that high CYP3A4 activity may be a risk factor for breast cancer risk.

Body size and prostate cancer: a population-based case-control study in China

We conducted a population-based case-control study in China to investigate whether body size plays a role in prostate cancer etiology and whether it can explain the rapid increase in prostate cancer incidence rates in China. A total of 238 cases newly diagnosed with primary prostate cancer in Shanghai, China, during 1993-1995 were included in the study. Four hundred and seventy-one healthy control subjects were randomly selected from among residents of Shanghai and frequency-matched to cases on the basis of age. In-person interviews were conducted to elicit information on height, weight history, and other lifestyle factors. Waist and hip circumferences were measured at interview. Odds ratios (ORs) were used to measure the association between prostate cancer and anthropometric variables including height, weight, body mass index (BMI), waist, hip, and right upper arm circumferences, and waist-to-hip ratio (WHR; an indicator of abdominal adiposity). High levels of WHR were related to an excess risk, with men in the highest quartile (WHR > 0.92) having an almost 3-fold risk (OR, 2.71; 95% CI = 1.66-4.41; Ptrend = 0.0001) compared with men in the lowest quartile (WHR < 0.86). In contrast, men in the highest quartile of hip circumference (>97.4 cm) had a reduced risk (OR, 0.46; 95% CI = 0.29-0.74; Ptrend = 0.0002) relative to men in the lowest quartile (<86 cm). No association was found for height, usual adult weight, or preadult and usual adult BMI. Our results suggest that even in a very lean population (average BMI = 21.9), abdominal adiposity may be associated with an increased risk of clinical prostate cancer, pointing to a role of hormones in prostate cancer etiology. Additional research is needed to confirm these findings in prospective studies, especially in Western populations where abdominal obesity is much more common, and to clarify the underlying hormonal mechanisms involved.

Prospective evaluation of infection with hepatitis G virus in relation to hepatocellular carcinoma in Shanghai, China

The health consequences of hepatitis G virus (HGV) infection in humans remain to be determined. Inconsistent results of HGV and the risk of hepatocellular carcinoma (HCC) have been found in retrospective case-control studies. No prospective studies have addressed this issue. A prospective study including 18,244 men in Shanghai, China, was conducted to assess the role of HGV infection in HCC development. Serum HGV RNA and hepatitis B surface antigen (HBsAg) were assessed in 127 HCC case patients and 660 matched control subjects drawn from the cohort. Four patients with HCC (3.1%) and 21 control subjects (3.2%) were positive for serum HGV RNA. The presence of HGV RNA in prediagnostic serum was not associated with the risk of HCC (odds ratio, 1.0; 95% confidence interval, 0.3-2.9). No association between HGV RNA positivity and HCC risk was observed in either HBsAg-positive carriers or noncarriers. It is concluded that HGV infection plays no role in HCC development in this high-risk population.

Polymorphic CAG and GGN repeat lengths in the androgen receptor gene and prostate cancer risk: a population-based case-control study in China

The length of the polymorphic CAG trinucleotide repeat in the polyglutamine region of the androgen receptor (AR) gene is inversely correlated with the transactivation function of the AR. Because increased androgenic activity has been linked to prostate cancer and because an ethnic variation exists in the CAG repeat length, this polymorphism has been suggested to explain part of the substantial racial difference in prostate cancer risk. We conducted a population-based case-control study in China to investigate whether CAG and other polymorphisms of the AR gene are associated with clinically significant prostate cancer in this low-risk population. Genomic DNA from 190 prostate cancer patients and 304 healthy controls was used for direct sequencing to evaluate the relationship of CAG and GGN (polyglycine) repeat length in the AR gene. Relative to western men, our study subjects had a longer CAG repeat length, with a median of 23 and only 10% of the subjects having a CAG repeat length shorter than 20. Men with a CAG repeat length shorter than 23 (median length) had a 65% increased risk of prostate cancer (odds ratio, 1.65; 95% confidence interval, 1.14-2.39), compared with men with a CAG repeat length of 23 or longer. For the GGN tract (GGT3GGG1GGT2GGCn), based on the sequencing results from 481 samples, we are the first to show that although GGC regions in the polyglycine tract are highly variable, there are no mutations or polymorphisms in the GGT and GGG regions. More than 72% of the subjects had a GGN repeat length of 23, and those with a GGN repeat length shorter than 23 had a 12% increased risk of prostate cancer (95% confidence interval, 0.71-1.78), compared with those with > or = 23 GGN repeats. Our study not only confirms that Chinese men do have a longer CAG repeat length than western men but also represents the first population-based study to show that even in a very low-risk population, a shorter CAG repeat length confers a higher risk of clinically significant prostate cancer. These results imply that CAG repeat length can potentially serve as a useful marker to identify a subset of individuals at higher risk of developing clinically significant prostate cancer. Larger studies are needed to evaluate the combined effect of CAG and GGN repeats. Because of the significance of AR in prostate cancer, investigation of factors that interact with the polyglutamine region of the AR gene to alter AR function and modulate prostate cancer risk is an important area for future research.

CYP1A1 I462V genetic polymorphism and lung cancer risk in a cohort of men in Shanghai, China

Cytochrome P450 (CYP) CYP1A1 activates tobacco-related carcinogens. A point mutation at codon 462 in exon 7 of CYP1A1 results in a substitution of isoleucine by valine near the heme binding site. This mutation is rare in Caucasians but common in Japanese populations, in which association with increased risk of lung cancer has been reported. There are few data in other Asian populations. We investigated this I462V polymorphism using DNA from 214 incident cases of lung cancer and 669 controls in a prospective cohort study of 18,244 middle-aged and older men in Shanghai, China. The valine allele frequency was 0.138 among the control population. The I462V genotype was not appreciably associated with lung cancer risk overall. There was some suggestion that having at least one valine allele might be related to increased risk of lung cancer among smokers of <20 cigarettes/day (odds ratio, 1.72; 95% confidence interval, 0.82-3.62), particularly among those with homozygous deletion of GSTM1 (odds ratio, 2.80; 95% confidence interval, 1.07-7.33), which is involved in the detoxification of activated tobacco carcinogens. In this Chinese cohort, with CYP1A1 valine allele frequency intermediate between Japanese and Caucasian populations, the I462V polymorphism is not related to lung cancer overall, but it might play a role at lower levels of cigarette smoking among subjects with impaired carcinogen detoxification as assessed by the GSTM1-null genotype.

Isothiocyanates, glutathione S-transferase M1 and T1 polymorphisms, and lung-cancer risk: a prospective study of men in Shanghai, China

BACKGROUND

Dietary isothiocyanates inhibit lung carcinogenesis in laboratory animals but human data are limited. Glutathione S-transferases M1 and T1 (GSTM1 and GSTT1) conjugate isothiocyanates leading to more rapid elimination. Common deletion polymorphisms of GSTM1 and GSTT1 abolish enzyme activity. We hypothesised that chemopreventive effects of isothiocyanates might be heightened when enzymes that enhance their elimination are lacking.

METHODS

We examined the relation between total isothiocyanate concentrations in urine, collected before diagnosis, and the subsequent risk of lung cancer among 232 incident cases of lung cancer and 710 matched controls from a cohort of 18,244 men in Shanghai, China, followed from 1986 to 1997. Homozygous deletion of the GSTM1 and GSTT1 genes were determined by PCR.

FINDINGS

Individuals with detectable isothiocyanates in the urine were at decreased risk of lung cancer (smoking-adjusted relative risk for lung cancer=0.65 [95% CI 0.43-0.97]). This protective effect of isothiocyanates was seen primarily among individuals with homozygous deletion of GSTM1 (0.36 [0.20-0.63]) and particularly with deletion of both GSTM1 and GSTT1 (0.28 [0.13-0.57]).

INTERPRETATION

Isothiocyanates appeared to reduce lung-cancer risk in this cohort of Chinese men. Reduction in risk was strongest among persons genetically deficient in enzymes that rapidly eliminate these chemopreventive compounds.