Emerging tobacco-related cancer risks in China: A nationwide, prospective study of 0.5 million adults.

BACKGROUND: In China, cigarette consumption has increased substantially since the 1980s, almost exclusively in men. This study was aimed at assessing the emerging cancer risks. METHODS: A nationwide, prospective study recruited 210,259 men and 302,632 women aged 30 to 79 years from 10 areas of China from 2004 to 2008; approximately 18,000 incident cancers were recorded during 7 years of follow-up. Cox regression yielded adjusted risk ratios (RRs) comparing smokers (including those who had stopped because of illness but not those who had stopped by choice) with never-smokers. RESULTS: Among men, 68% were smokers; their overall cancer risk was significantly increased (RR, 1.44; 95% confidence interval [CI], 1.37-1.53), and it was greater in urban (RR, 1.55; 95% CI, 1.41-1.70) than in rural areas (RR, 1.39; 95% CI, 1.30-1.49). This excess accounted for 23% of all cancers between the ages of 40 and 79 years, with significantly elevated risks of lung cancer (RR, 2.51; 95% CI, 2.18-2.90), liver cancer (RR, 1.32; 95% CI, 1.12-1.54), stomach cancer (RR, 1.34; 95% CI, 1.16-1.55), esophageal cancer (RR, 1.47; 95% CI, 1.24-1.73), and an aggregate of 5 other minor sites (RR, 1.52; 95% CI, 1.25-1.86). For lung cancer, the RRs were much greater for nonadenocarcinoma (RR, 5.83; 95% CI, 5.02-6.77) than for adenocarcinoma (RR, 1.78; 95% CI, 1.36-2.34). Among exsmokers (6.7%) who had stopped by choice, there was little excess cancer risk approximately 15 years after quitting. Among the few female smokers (3%), the overall cancer risk was also significantly increased (RR, 1.42; 95% CI, 1.28-1.57). Smoking was estimated to cause approximately 435,000 new cancers per year in China (approximately 360,000 in men and approximately 75,000 in women). CONCLUSIONS: In China, smoking now causes a quarter of all adult male cancers. High male uptake rates before the age of 20 years and nearly universal use of cigarettes foreshadow substantial tobacco-attributed risks in China unless there is widespread cessation.

Effect of NaFeEDTA-Fortified Soy Sauce on Anemia Prevalence in China: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

OBJECTIVE: To assess the effect of sodium iron ethylenediaminetetraacetate (NaFeEDTA)-fortified soy sauce on anemia prevalence in the Chinese population. METHODS: A systematic review was performed to identify potential studies by searching the electronic databases of PubMed, Cochrane Library, WHO Library, HighWire, CNKI, and other sources. The selection criteria included randomized controlled trials that compared the efficacy of NaFeEDTA-fortified soy sauce with that of non-fortified soy sauce. Anemia rates and hemoglobin levels were the outcomes of interest. Inclusion decisions, quality assessment, and data extraction were performed by two reviewers independently. A total of 16 studies met the inclusion criteria for anemia rate analysis, of which 12 studies met the inclusion criteria for hemoglobin analysis. All included studies assessed the effect of NaFeEDTA-fortified soy sauce on anemia rates and hemoglobin concentrations. RESULTS: After the intervention, the hemoglobin concentration increased and anemia rates decreased significantly as compared with the non-fortified soy sauce groups. For anemia rates, data from 16 studies could be pooled, and the pooled estimate odds ratio was 0.25 (95% CI 0.19-0.35). For hemoglobin concentrations, data from 12 studies could be pooled, and the pooled weighted mean difference was 8.81 g/L (95% CI 5.96-11.67). CONCLUSION: NaFeEDTA-fortified soy sauce has a positive effect on anemia control and prevention in the at-risk population.

Efficacy of different iron fortificants in wheat flour in controlling iron deficiency.

OBJECTIVE: To observe the different impacts of electrolytic iron, FeSO4, and NaFeEDTA on body iron store of anemic school students. METHODS: Four hundreds anemic students at the age of 11-18 years were divided into four groups. Of which, three consumed different iron fortificants from wheat flour as food vehicle for six months and one consumed non-fortified flour (control). The fortification level of electrolytic iron, FeSO4, and NaFeEDTA was 60 mg Fe/kg, 30 mg Fe/kg, and 20 mg Fe/kg, respectively. Blood samples were collected at 0, 2, 4, and 6 months and hemoglobin (Hb), serum ferritin (SF), and transferrin receptor (TfR) were measured. RESULTS: The hemoglobin levels in three intervention groups increased, the increments of Hb in the NaFeEDTA group were significantly higher than that in the other groups. SF and TfR levels increased in the tested groups and body iron store in the NaFeEDTA group was higher than that in the other groups. These parameters did not show any significant changes in the control group. CONCLUSION: NaFeEDTA and FeSO4 fortified wheat flour has positive impacts on iron status in anemic students and NaFeEDTA is more effective than FeSO4, while electrolytic iron is less effective in improving iron store in anemic students.

NaFeEDTA fortified soy sauce showed higher iron absorption rate in Chinese females.

OBJECTIVE: NaFeEDTA was considered as a promising iron fortificant for controlling iron deficiency anemia. Soy sauce is a suitable food carrier for iron fortification and is a popular condiment in China. Iron absorption rates of NaFeEDTA and FeSO4 were observed and compared in adult female subjects. METHODS: The stable isotope tracer method was used in Chinese females consuming a typical Chinese diet. Ten healthy young Chinese women were selected as subjects in the 15-day study. A plant-based diet was used based on the dietary pattern of adult women in the 1992 National Nutrition Survey. Six milligram of 54Fe in 54FeSO4 soy sauce and 3 mg 58Fe in Na58FeEDTA soy sauce were given to the same subjects in two days. Food samples and fecal samples were collected and analyzed. RESULTS: Iron absorption rates of NaFeEDTA and FeSO4 were 10.51% +/- 2.83 and 4.73% +/- 2.15 respectively. The 58Fe (NaFeEDTA) absorption was significantly higher than that of 54Fe (FeSO4) (P < 0.01). The iron absorption rate from NaFeEDTA was 1.2 times higher than that from FeSO4 in Chinese adult women consuming a typical Chinese diet. CONCLUSION: The higher absorption rate of NaFeEDTA suggested that NaFeEDTA would be a better iron fortificant used in soy sauce for the controlling of iron deficiency anemia in China.

[Relationship between smoking and risk of esophageal cancer in 103 areas in China: a large-scale case-control study incorporated into a nationwide survey of mortality].

OBJECTIVE: To examine the relationship between smoking and risk of esophageal cancer (EC), and present a theoretical framework of control selection in population-based case-control study which was incorporated into a nationwide retrospective survey of mortality in China. METHODS: A large-scale population-based case-control study was incorporated into the nationwide retrospective survey of mortality conducted 1989 - 1991 in 24 urban cities selected by non-random sampling and 79 rural counties selected from 3000 counties included in the 1973 - 1975 cancer distribution survey by random sampling during. A questionnaire survey was conducted by home visit to investigate the death causes and smoking history of 19 734 deceased male adults who died of esophageal cancer during 1986 - 1988 at the age >or= 35. Two control groups were set up to undergo questionnaire survey by home visit to investigate the smoking history of the deceased persons and the informants. Control group I included the surviving spouses or other informants of 31 989 male adults who died of non-malignant digestive diseases during 1986 - 1988 at the age >or= 35, and control group II included 104 846 male spouses of the deceased female adults who died of different causes during 1986 - 1989 at the age >or= 35. The relative risks and population smoking attributable risks for EC were calculated using non-conditional logistic model, and the results were compared for consistency between the analyses using two different control groups. RESULTS: The EC absolute death rates were higher in the smokers than in the non-smokers in all urban and rural area groups. The total EC absolute death rate per 1000 among the non-smokers vs. smokers was 0.37:0.65 in the urban areas, 0.99:1.29 in the inland rural areas, and 1.09:1.62 in the coastal rural areas in the control group I, and there was a similar trend in the control group II. There was a significant dose-response relation between the period of smoking and the death risk of EC and between the daily cigarette consumption and the death risk of EC. The risk ratios, for example, for cigarette per day < 10, 10-, and 20- in the urban men were 1.42, 1.82, 2.22 in the control group I (trend test P < 0.01), and 1.57, 1.95, and 3.18 in the control group II (trend test P < 0.01). CONCLUSION: Smoking is an important risk factor for mortality from EC in China. Investigating the surviving spouses of the deceased patients is a creative, effective, and feasible trial, with the prerequisite of whole population-based survey, in study of the main types of death and the relevant risk factors.

[Chinese total diet study in 2000--the dietary mercuric intakes].

OBJECTIVE: To assess the safety of dietary mercuric intakes in different areas in China. METHODS: Using the Chinese total dietary study method, the analytical samples were obtained in different areas by food consumption survey, food aggregation, food sampling and preparation. The levels of dietary total mercury were determined by cold vapor atomic absorption spectrometry. The dietary total mercuric intakes in different areas were obtained by timing the food consumption data and the mercuric content in different dietary samples. The safety of dietary mercury was evaluated in Chinese four regions and average adults by using the dietary mercuric PTWI recommended by WHO. RESULTS: The results indicate that the dietary mercuric intakes are safe in different regions. Only a few samples in some areas exceed tolerance limits of China national standard. Dietary total mercuric intakes (of PTWI) in four different regions adults and mean were 8.86 microg (19.7%), 4.69 microg (10.4%), 7.01 microg (15.6%), 6.88 microg (15.3%), 6.86 microg (15.2%), respectively. Mainly sources of dietary mercuric intake were cereals, vegetables and sea foods. CONCLUSION: The result shows that the total mercuric intakes in Chinese people are safe.

[2000 Chinese total dietary study--the dietary arsenic intakes].

OBJECTIVE: To assess the safety of dietary arsenic intakes in different areas in China. METHODS: Using the total dietary study method, the analytical samples were obtained in different areas by food consumption survey, food aggregation, food sampling and preparation. The levels of dietary total and inorganic arsenic were determined by the hydride generation atomic absorption spectrometry and atomic fluorospectrophotometry. The dietary total and inorganic arsenic intakes in different areas were obtained by timing the food consumption data and the arsenic content in different dietary samples. The safety of dietary arsenic was evaluated in Chinese four regions and average adults by using the dietary inorganic arsenic PTWI recommended by WHO. RESULTS: The results indicate that the dietary arsenic intake is safety in different regions. Only a few samples in some areas exceed tolerance limits of China national standard. Dietary total and inorganic arsenic (of PTWI) intakes in four different regions (north1, north2, south1, south2 and average adults) were 0.220 mg and 0.094 mg (69.3%), 0.254 mg and 0.098 mg (72.2%), 0.296 mg and 0.048 mg (35.6%), 0.335 mg and 0.077 mg (57.3%), 0.276 mg and 0.079 mg (58.6%) respectively. Mainly sources of dietary arsenic intake were cereals, vegetables and beverage and water. CONCLUSION: It is the first time that the dietary total arsenic and inorganic arsenic intakes of the adult were investigated in Chinese total diet study. The result shows that the total and inorganic arsenic intakes in Chinese people are safe.

Tea pigments induce cell-cycle arrest and apoptosis in HepG2 cells.

AIM: To investigate the molecular mechanisms by which tea pigments exert preventive effects on liver carcinogenesis. METHODS: HepG2 cells were seeded at a density of 5X10(5)/well in six-well culture dishes and incubated overnight. The cells then were treated with various concentrations of tea pigments over 3 d, harvested by trypsinization, and counted using a hemocytometer. Flow cytometric analysis was performed by a flow cytometer after propidium iodide labeling. Bcl-2 and p21(WAF1) proteins were determined by Western blotting. In addition, DNA laddering assay was performed on treated and untreated cultured HepG2 cells. RESULTS: Tea pigments inhibited the growth of HepG2 cells in a dose-dependent manner. Flow-cytometric analysis showed that tea pigments arrested cell cycle progression at G1 phase. DNA laddering was used to investigate apoptotic cell death, and the result showed that 100 mg/L of tea pigments caused typical DNA laddering. Our study also showed that tea pigments induced upregulation of p21(WAF1) protein and downregulation of Bcl-2 protein. CONCLUSION: Tea pigments induce cell-cycle arrest and apoptosis. Tea pigments may be used as an ideal chemopreventive agent.

[Effects of tea polyphenols and tea pigments on apoptosis in HepG2 cell line].

OBJECTIVE: To investigate the effect of tea polyphenols and tea pigments on apoptosis in HepG2 cells. METHODS: HepG2 cells were seeded at a density of 5 x 10(5)/well in six-well culture dishes. The cells were then treated with 50 or 100 mg/L tea pigments and harvested at 48h by trypsinization. Agrose electrophoresis was applied to investigate DNA-LADDER, Bcl-2 and Bax protein expression were detected by Western blot. RESULTS: Tea polyphenols and tea pigments induced the appearance of DNA-LADDER; Western blot analysis demonstrated that Bcl-2 expression was significantly inhibited and the expression of Bax was significantly induced by tea polyphenols and tea pigments. CONCLUSION: Induction of apoptosis may be an important mechanism of cancer chemoprevention by tea.

Direct reduction of N-acetoxy-PhIP by tea polyphenols: a possible mechanism for chemoprevention against PhIP-DNA adduct formation.

The chemopreventive effect of tea against 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-DNA adduct formation and its mechanism were studied. Rats were exposed to freshly prepared aqueous extracts of green tea (3% (w/v)) as the sole source of drinking water for 10 days prior to administration with a single dose of PhIP (10 mg/kg body weight) by oral gavage. PhIP-DNA adducts in the liver, colon, heart, and lung were measured using the 32P-postlabelling technique. Rats pre-treated with tea and given PhIP 20 h before sacrifice had significantly reduced levels of PhIP-DNA adducts as compared with controls given PhIP alone. The possible mechanism of protective effect of tea on PhIP-DNA adduct formation was then examined in vitro. It was found that an aqueous extract of green and black tea, mixtures of green and black tea polyphenols, as well as purified polyphenols could strongly inhibit the DNA binding of N-acetoxy-PhIP, a putative ultimate carcinogen of PhIP formed in vivo via metabolic activation. Among these, epigallocatechin gallate was exceptionally potent. HPLC analyses of these incubation mixtures containing N-acetoxy-PhIP and the tea polyphenols each revealed the production of the parent amine, PhIP, indicating the involvement of a redox mechanism. In view of the presence of relatively high levels of tea polyphenols in rat and human plasma after ingestion of tea, this study suggests that direct reduction of the ultimate carcinogen N-acetoxy-PhIP by tea polyphenols is likely to be involved in the mechanism of chemoprotection of tea against this carcinogen.

Helicobacter pylori eradication to prevent gastric cancer in a high-risk region of China: a randomized controlled trial.

CONTEXT: Although chronic Helicobacter pylori infection is associated with gastric cancer, the effect of H pylori treatment on prevention of gastric cancer development in chronic carriers is unknown. OBJECTIVE: To determine whether treatment of H pylori infection reduces the incidence of gastric cancer. DESIGN, SETTING, AND PARTICIPANTS: Prospective, randomized, placebo-controlled, population-based primary prevention study of 1630 healthy carriers of H pylori infection from Fujian Province, China, recruited in July 1994 and followed up until January 2002. A total of 988 participants did not have precancerous lesions (gastric atrophy, intestinal metaplasia, or gastric dysplasia) on study entry. INTERVENTION: Patients were randomly assigned to receive H pylori eradication treatment: a 2-week course of omeprazole, 20 mg, a combination product of amoxicillin and clavulanate potassium, 750 mg, and metronidazole, 400 mg, all twice daily (n = 817); or placebo (n = 813). MAIN OUTCOME MEASURES: The primary outcome measure was incidence of gastric cancer during follow-up, compared between H pylori eradication and placebo groups. The secondary outcome measure was incidence of gastric cancer in patients with or without precancerous lesions, compared between the 2 groups. RESULTS: Among the 18 new cases of gastric cancers that developed, no overall reduction was observed in participants who received H pylori eradication treatment (n = 7) compared with those who did not (n = 11) (P =.33). In a subgroup of patients with no precancerous lesions on presentation, no patient developed gastric cancer during a follow-up of 7.5 years after H pylori eradication treatment compared with those who received placebo (0 vs 6; P =.02). Smoking (hazard ratio [HR], 6.2; 95% confidence interval [CI], 2.3-16.5; P<.001) and older age (HR, 1.10; 95% CI, 1.05-1.15; P<.001) were independent risk factors for the development of gastric cancer in this cohort. CONCLUSIONS: We found that the incidence of gastric cancer development at the population level was similar between participants receiving H pylori eradication treatment and those receiving placebo during a period of 7.5 years in a high-risk region of China. In the subgroup of H pylori carriers without precancerous lesions, eradication of H pylori significantly decreased the development of gastric cancer. Further studies to investigate the role of H pylori eradication in participants with precancerous lesions are warranted.

[Effects of tea polyphenols and tea pigments on telomerase activity of HepG2 cells].

OBJECTIVE: This study is to investigate the effect of tea polyphenols and tea pigments on telomerase activity of human liver cancer cell line, HepG2 cells. METHODS: TRAP-PCR-ELISA was applied to investigate the telomerase activity. RESULTS: Telomerase was positive in tea polyphenols treated groups, tea pigments treated groups and blank control group. Telomerase activities (A(450 approximately 690) values) were 1.56 and 1.46 in 50 mg/L and 100 mg/L tea polyphenols-treated groups, 1.55 and 1.49 in 50 mg/L and 100 mg/L tea pigments-treated groups, respectively. The results showed that telomerase activity was significantly inhibited by tea polyphenols and tea pigments treatment as compared with the blank control group (A(450 approximately 690) = 2.11). CONCLUSIONS: Tea polyphenols and tea pigments could significantly inhibit telomerase activity of HepG2 cells, and telomerase activity may be a useful biomarker for cancer chemoprevention.

[The China Kadoorie Biobank: related methodology and baseline characteristics of the participants].

OBJECTIVE: To study the separate and combined effects of environment, lifestyle, physical characteristics, blood biomarkers and genetic factors on aetiology of major chronic diseases in adult Chinese. METHODS: China Kadoorie Biobank (CKB) is a large blood-based prospective cohort study. The baseline survey took place in 5 urban and 5 rural areas across China during 2004-2008, with collection of data through questionnaire, physical examination and blood samples. Following the baseline survey, 5% of the randomly selected participants were surveyed in 2008, and repeated every 4-5 years. All participants would be followed for cause-specific mortality and morbidity through registries and for any hospital admission through linkages with health insurance databases. RESULTS: Overall, 512 891 adults aged 30-79 years (mean 51.5) were recruited, including 41.0% men and 55.9% from rural areas. Blood collection was successfully done in 99.98% of the participants. The prevalence of current regular smoking was 61.3% in men and 2.4% in women. The prevalence of regular alcohol consumption (i.e., weekly) was 33.4% in men and 2.1% in women. At the baseline, 41.8% of men and 45.3% of women were overweight or obese (i.e., BMI≥24.0 kg/m2) and 32.2% of men and 30.2% of women were hypertensive (i.e., SBP≥140 mm Hg or DBP≥90 mm Hg). For each of the main baseline variables, there were large variations on age, sex and areas of study. CONCLUSION: CKB seemed to be a powerful and rich resource in studying the environmental and genetic determinants of major chronic diseases in the Chinese population.