Dietary glycemic index, glycemic load, and cause-specific mortality: two population-based prospective cohort studies.

BACKGROUND: Epidemiological studies on the relationship between dietary glycemic index (GI), glycemic load (GL) and all-cause and cause-specific mortality yielded conflict results. We aimed to assess these associations in Chinese. METHODS: We conducted this study based on two prospective cohort studies in Shanghai. Dietary information was collected using validated cohort-specific food frequency questionnaires. We used Cox regression model to estimate the hazard ratios (HR) for mortality associated with GI and GL. RESULTS: After median follow-up periods of 12.8 years for 59,770 men and 18.2 years for 74,735 women, 8,711 deaths in men and 10,501 deaths in women were documented. After we controlled the potential confounders, dietary GI, GL, and carbohydrate intake were associated with a higher risk of cardiovascular disease (CVD) mortality (P values for trend = 0.025, 0.001, and 0.001). Dietary GI was associated with lower risk of total and cause-specific mortality in men in the second quartile (Q) (all-cause mortality: HR Q2 vs. Q1 = 0.89, 95%CI: 0.84, 0.95). Dietary GL was associated with lower risk of cancer mortality but higher risk of CVD mortality in men. In women, dietary GI was associated with mortality due to all-cause (HRMax Q4 vs. Q1 = 1.10, 95%CI: 1.04, 1.06), cancer (HRMax Q4 vs. Q1 = 1.12, 95%CI: 1.02, 1.23), and CVD (HRMax Q4 vs. Q1 = 1.10, 95%CI: 1.00, 1.22). CONCLUSIONS: The present study indicates that diet with higher GI and GL was associated with an increased risk of CVD mortality in Chinese adults. The association may vary for men and women, which need further investigating in other Asian populations.

Tea Drinking and Risk of Cancer Incidence: A Meta-Analysis of Prospective Cohort Studies and Evidence Evaluation.

Here we provide a comprehensive meta-analysis to summarize and appraise the quality of the current evidence on the associations of tea drinking in relation to cancer risk. PubMed, Embase, and the Cochrane Database of Systematic Reviews were searched up to June 2020. We reanalyzed the individual prospective studies focused on associations between tea drinking and cancer risk in humans. We conducted a meta-analysis of prospective studies and provided the highest- versus lowest-category analyses, dose-response analyses, and test of nonlinearity of each association by modeling restricted cubic spline regression for each type of tea. We graded the evidence based on the summary effect size, its 95% confidence interval, 95% prediction interval, the extent of heterogeneity, evidence of small-study effects, and excess significance bias. We identified 113 individual studies investigating the associations between tea drinking and 26 cancer sites including 153,598 cancer cases. We assessed 12 associations for the intake of black tea with cancer risk and 26 associations each for the intake of green tea and total tea with cancer risk. Except for an association between lymphoid neoplasms with green tea, we did not find consistent associations for the highest versus lowest categories and dose-response analyses for any cancer. When grading current evidence for each association (number of studies ≥2), weak evidence was detected for lymphoid neoplasm (green tea), glioma (total tea, per 1 cup), bladder cancer (total tea, per 1 cup), and gastric and esophageal cancer (tea, per 1 cup). This review of prospective studies provides little evidence to support the hypothesis that tea drinking is associated with cancer risk. More well-designed studies are still needed to identify associations between tea intake and rare cancers.

Diet and ovarian cancer risk: An umbrella review of systematic reviews and meta-analyses of cohort studies.

BACKGROUND & AIMS: Diet may play an important role in the etiology of ovarian cancer (OC). We aimed to evaluate the strength and credibility of evidence pertaining to dietary risk factors for OC. METHODS: We comprehensively searched PubMed, Web of Science, Cochrane, CINAHL, JBI Database of Systematic Reviews and Implementation Reports, PROSPERO and EMBASE databases to identify related systematic reviews and meta-analyses of prospective cohort studies. This study had been registered at PROSPERO. The registration number is CRD42020187651. For each association, we estimated the summary effect size using fixed and random effects models, the 95% confidence interval and the 95% prediction interval. We assessed heterogeneity, evidence of small-study effects, and excess significance bias. RESULTS: A total of 22 systematic reviews and meta-analyses were included in the present study. These previous reports evaluated 184 individual studies, which proposed a total of 36 associations between dietary factors and OC risk. Out of the 36 associations, there were no strong, highly suggestive and suggestive evidence, only four (black tea, skim/low-fat milk, lactose, and calcium) were determined to be supported by weak evidence. OC risk was inversely associated with intake of black tea or calcium, and positively associated with intake of skim/low-fat milk or lactose. CONCLUSIONS: Our studies revealed that four associations between OC risk and dietary factors (black tea, skim/low-fat milk, lactose, and calcium) were supported by weak evidence. The remaining 32 associations were not confirmed. Additional studies are needed to carefully evaluate the relationship between dietary factors and OC risk.

Coffee drinking and cancer risk: an umbrella review of meta-analyses of observational studies.

BACKGROUND: Epidemiological studies on the association between coffee intake and cancer risk have yielded inconsistent results. To summarize and appraise the quality of the current evidence, we conducted an umbrella review of existing findings from meta-analyses of observational studies. METHODS: We searched PubMed, Embase, Web of Science and the Cochrane database to obtain systematic reviews and meta-analyses of associations between coffee intake and cancer incidence. For each association, we estimated the summary effect size using the fixed- and random-effects model, the 95% confidence interval, and the 95% prediction interval. We also assessed heterogeneity, evidence of small-study effects, and excess significance bias. RESULTS: Twenty-eight individual meta-analyses including 36 summary associations for 26 cancer sites were retrieved for this umbrella review. A total of 17 meta-analyses were significant at P ≤ 0.05 in the random-effects model. For the highest versus lowest categories, 4 of 26 associations had a more stringent P value (P ≤ 10- 6). Associations for five cancers were significant in dose-response analyses. Most studies (69%) showed low heterogeneity (I2 ≤ 50%). Three and six associations had evidence of excessive significance bias and publication bias, respectively. Coffee intake was inversely related to the risk of liver cancer and endometrial cancer and was characterized by dose-response relationships. There were no substantial changes when we restricted analyses to meta-analysis of cohort studies. CONCLUSIONS: There is highly suggestive evidence for an inverse association between coffee intake and risk of liver and endometrial cancer. Further research is needed to provide more robust evidence for cancer at other sites.

Personal Characteristics Effects on Validation of Self-reported Type 2 Diabetes From a Cross-sectional Survey Among Chinese Adults.

BACKGROUND: The objective was to evaluate the effects of personal characteristics on the validation of self-reported type 2 diabetes among Chinese adults in urban Shanghai. METHODS: During 2015 through 2016, 4,322 participants were recruited in this validation study. We considered the criteria of diabetes verification to use the laboratory assays of fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), or self-reported use of diabetic medication. RESULTS: When taking diabetic medication or FPG ≥7.0 mmol/L was as identified diabetes, the measurements of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Kappa value of self-reported diabetes were 72.0%, 99.2%, 95.1%, 93.9%, and 0.78, respectively. If an additional HbA1c test was used for 708 subjects (aged <65 years), slightly lower values of sensitivity, NPV, and Kappa were observed. More potential diabetes cases were found compared to only using FPG. Subjects who were female, older, or had a family history of diabetes had sensitivity over 75% and excellent Kappa over 0.8, while the sensitivity and Kappa of opposite groups had poorer values. Specificity, PPV, and NPV were similar among groups with different demographic or disease characteristics. The prevalence of type 2 diabetes was 19.3% in the study (14.1% diagnosed diabetes, 5.2% undiagnosed diabetes). About 26.2% of subjects were pre-diabetic. Additional HbA1c test indicated an increased prevalence of undiagnosed diabetes and pre-diabetes. CONCLUSIONS: Findings support self-reported diabetes is sufficiently valid to be used in large-scale, population-based epidemiologic studies. Participants with different characteristics may have different indicators in terms of validation, such as age, gender, and family history of diabetes in first-degree relatives.

Dietary protein intake and risk of type 2 diabetes: a dose-response meta-analysis of prospective studies.

PURPOSE: The association between dietary protein intake and type 2 diabetes risk has been inconsistent in the previous epidemiological studies. We aimed to quantitatively assess whether dietary total, animal, and plant protein would be associated with type 2 diabetes risk. METHODS: A comprehensive literature review was conducted to identify related articles by searching PubMed, Embase, Web of Science, and Wiley Online Library through 20th March 2018. Generalized least squares for trend estimation and restricted cubic spline regression model were applied in the dose-response analysis. RESULTS: Eight publications with ten prospective cohorts of 34,221 type 2 diabetes cases were included. After adjustment of potential confounders, a 5% of energy increment from dietary total and animal protein intake was related to a 9% (1.04, 1.13; I2 = 42.0%) and 12% (95% CI 1.08, 1.17; I2 = 14.0%) higher risk of type 2 diabetes respectively. However, for plant protein, a significant U-shaped curve was observed with the most risk reduction at intake of about 6% of energy intake from plant protein intake (Pnonlinearity = 0.001). The results were robust in sensitivity analysis and no publication bias was detected. CONCLUSIONS: These findings indicate that the consumption of protein particularly animal protein may be associated with an increased risk of type 2 diabetes.

Prospective cohort studies of dietary vitamin B6 intake and risk of cause-specific mortality.

BACKGROUND & AIMS: Vitamin B6 has been postulated to play an important role in determining chronic diseases. However, few studies have evaluated associations between dietary vitamin B6 and cause-specific mortality comprehensively. METHODS: We investigated the associations between vitamin B6 from diet and risk of all-cause, and cause-specific mortality in 134,480 participants from the Shanghai Men's Health Study (2002-2014) and Shanghai Women's Health Study (1997-2014). The median follow-up periods for men and women were 10.3 and 16.2 years, respectively. We estimated hazard ratio (HR) and 95% confidence interval (CI) using Cox proportional hazards models. RESULTS: After adjustment for suspected confounders, the multivariable-adjusted HRs for the highest versus lowest quintiles for total, CVD, stroke and CHD mortality among men were 0.83 (95%CI = 0.76, 0.90), 0.73 (95%CI = 0.63, 0.85), 0.71 (95%CI = 0.58, 0.88), 0.66 (95%CI = 0.47, 0.91), accordingly. Women with the highest intake had significantly 17% (HR = 0.83; 95% CI = 0.77, 0.90), 20% (HR = 0.80; 95% CI = 0.70, 0.92), and 28% (HR = 0.72; 95% CI = 0.59, 0.86) lower risks of total, CVD and stroke mortality compared with those of women with lowest vitamin B6 intake. No significant association was observed between dietary vitamin B6 and cancer mortality both among men and women. CONCLUSIONS: In the current study with two prospective Chinese cohorts, high dietary vitamin B6 consumption was inversely associated with risk of all-cause and CVD mortality.

Association between breastfeeding and risk of endometrial cancer: a meta-analysis of epidemiological studies.

Epidemiological studies have yielded inconsistent findings on the relationship between breastfeeding and the risk of endometrial cancer. Pertinent studies were identified by searching PubMed, Embase, and Web of Knowledge through February 2015 and by reviewing the reference lists of retrieved articles. Study-specific estimates were pooled using a random-effects model. Dose-response analysis was carried out for every 6-month increase in the duration of breastfeeding in relation to the risk of endometrial cancer. Three prospective and 11 case-control studies were included in this meta-analysis. The pooled estimates for ever compared with never breastfeeding and the longest duration of breastfeeding compared with the shortest were 0.91 [95% confidence interval (CI): 0.75-1.09] and 0.76 (95% CI: 0.59-0.98). The risk of endometrial cancer decreased by 7% for every 6-month increase in the duration of breastfeeding (relative risk: 0.93; 95% CI: 0.88-0.97). This study provides evidence that ever breastfeeding, particularly a longer duration of breastfeeding, is associated with a lower risk of endometrial cancer.

The joint effects of major lifestyle factors on colorectal cancer risk among Chinese men: A prospective cohort study.

Previous studies have suggested individual healthy lifestyle factors are related to lower risk of colorectal cancer. Their joint effects, however, have rarely been investigated. We aimed to assess the combined lifestyle impact on colorectal cancer risk and to estimate the population attributable risks of these lifestyle factors. Using data from the Shanghai Men's Health Study (2002-2013), we constructed healthy lifestyle index composing the following lifestyle factors: smoking, alcohol consumption, diet, waist-hip ratio and exercise participation. Cox proportional hazards models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs). Over a median of 9.28 years' follow-up, 671 colorectal cancer cases occurred (400 colon cancer and 274 rectal cancer) among 59,503 men. Each increment of healthy lifestyle index was associated with a 17% lower risk of colorectal cancer (HR = 0.83, 95% CI: 0.78, 0.89), 10% of colon cancer (HR = 0.90, 95% CI: 0.83, 0.99) and 27% of rectal cancer (HR = 0.73, 95% CI: 0.66, 0.82). If all men in the cohort followed a lifestyle as defined by these five factors, 21% colorectal cancer cases would have been prevented (PAR = 21%, 95% CI: 4%, 36%). In conclusion, combined lifestyle factors are significantly related to lower risk of colorectal cancer and the effects are more pronounced on rectal cancer than on colon cancer.

Association between insulin therapy and risk of liver cancer among diabetics: a meta-analysis of epidemiological studies.

As the results of the association between insulin therapy and risk of liver cancer among diabetics have been inconsistent in epidemiological studies, we conducted a meta-analysis to quantify this issue. Data of relevant epidemiological studies were collected by searching articles in PubMed, Web of Science, and Embase till 29 June 2017. Random-effects models were employed to combine study-specific risks. Five cohort studies and nine case-control studies were included in our meta-analysis with 285 008 patients with diabetes mellitus and 4329 liver cancer cases. When we compared insulin-use group with noninsulin use group in patients with diabetes mellitus, we observed a statistically significant association between insulin therapy and liver cancer, with an overall relative risk of 1.90 (95% confidence interval: 1.44-2.50, I=76.1%). We did not find heterogeneity between subgroups stratified by study characteristics and adjusted confounders, except for subgroups related to 'follow-up years' of cohort studies. The combined estimate was robust across sensitivity analysis, and no publication bias was detected. Our results indicated that insulin therapy was associated with elevated incidence of liver cancer among diabetics. Given the high prevalence of diabetes, avoiding excess or unnecessary insulin use to control the blood glucose may offer a potential public health benefit in reducing liver cancer risk. Further studies are warranted to investigate the types, doses, and treatment duration of insulin use in large sample size or cohort of diabetic patients.

Combined Impact of Known Lifestyle Factors on Total and Cause-Specific Mortality among Chinese Men: A Prospective Cohort Study.

Impact of combined lifestyles on risk of mortality needs to be explored quantitatively. We aimed to evaluate the associations of combined lifestyle factors with total and cause-specific mortality in Chinese men. We used data from the Shanghai Men's Health Study (2002-2013), an on-going population-based prospective cohort study of men (aged 40 to 74 years). Four traditional unfavorable lifestyle factors were included: smoking, heavy alcohol use, unhealthy diet and physical inactivity. Cox proportional hazards models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs). Among about 61,480 men in the cohort, a total of 4,952 men died, of which 1,637 men died from cardiovascular diseases (CVD), 2,122 from cancer during a median of 9.29 years' follow-up. The HRs of men with four risk practices comparing to those with zero were 2.92 (95%CI: 2.53, 3.38) for all-cause mortality, 3.15 (95%CI: 2.44, 4.05) for CVD mortality, and 3.18 (95%CI: 2.55, 3.97) for cancer mortality. The population attributable risks (PARs) were 0.41, 0.40 and 0.38 for total, CVD and cancer mortality, accordingly. As combined unhealthy lifestyle behaviors had substantial impact on total and cause-specific mortality, promotion of healthy lifestyle should be a public health priority.

Dietary antioxidant vitamins intake and mortality: A report from two cohort studies of Chinese adults in Shanghai.

BACKGROUND: Few studies have evaluated dietary antioxidant vitamins intake in relation to risk of mortality in Asia. METHODS: We examined the associations between total carotene, vitamin C, and vitamin E from diet and risk of mortality from all causes, cancer, and cardiovascular disease in 134,358 participants (59,739 men and 74,619 women) from the Shanghai Men's Health Study and Shanghai Women's Health Study, two prospective cohort studies of middle-aged and elderly Chinese adults in urban Shanghai. Participants were followed up for a median period of 8.3 and 14.2 years for men and women, respectively. Hazard ratios (HRs) and 95% confidence interval (CIs) were estimated using Cox proportional hazards regression models. RESULTS: During the 495,332 and 1,029,198 person-years of follow-up for men and women, respectively, there were 10,079 deaths (4170 men and 5909 women). For men, compared with the lowest quintiles, the multivariable-adjusted risk reductions in the highest categories were 17% (HR 0.83; 95% CI, 0.76-0.92) for dietary total carotene and 17% (HR 0.83; 95% CI, 0.75-0.91) for dietary vitamin C. Associations were weaker in women than in men, though they were still statistically significant (highest versus lowest quintiles of dietary total carotene, HR 0.87; 95% CI, 0.80-0.95; dietary vitamin C: HR 0.83; 95% CI, 0.77-0.91). Significant inverse associations were observed between dietary total carotene, vitamin C, and risk of cardiovascular disease mortality but not cancer mortality. CONCLUSION: This study suggests that total carotene and vitamin C intake from diet were inversely associated with deaths from all causes and cardiovascular disease in middle-aged or elderly people in China.

Green tea consumption and cause-specific mortality: Results from two prospective cohort studies in China.

BACKGROUND: Green tea is one of the most widely consumed beverages in Asia. While a possible protective role of green tea against various chronic diseases has been suggested in experimental studies, evidence from human studies remains controversial. METHODS: We conducted this study using data from Shanghai Men's Health Study (SMHS) and Shanghai Women's Health Study (SWHS), two population-based prospective cohorts of middle-aged and elderly Chinese adults in urban Shanghai, China. Hazard ratios (HR) and 95% confidence intervals (CI) for risk of all-cause and cause-specific mortality associated with green tea intake were estimated using Cox proportional hazards regression models. RESULTS: During a median follow-up of 8.3 and 14.2 years for men and women, respectively, 6517 (2741 men and 3776 women) deaths were documented. We found that green tea consumption was inversely associated with risk of all-cause mortality (HR 0.95; 95% CI, 0.90-1.01), particularly among never-smokers (HR 0.89; 95% CI, 0.82-0.96). The inverse association with cardiovascular disease (CVD) mortality (HR 0.86; 95% CI, 0.77-0.97) was slightly stronger than that with all-cause mortality. No significant association was observed between green tea intake and cancer mortality (HR 1.01; 95% CI, 0.93-1.10). CONCLUSIONS: Green tea consumption may be inversely associated with risk of all-cause and CVD mortality in middle-aged and elderly Chinese adults, especially among never smokers.

Dietary, circulating beta-carotene and risk of all-cause mortality: a meta-analysis from prospective studies.

Observational studies evaluating the relation between dietary or circulating level of beta-carotene and risk of total mortality yielded inconsistent results. We conducted a comprehensive search on publications of PubMed and EMBASE up to 31 March 2016. Random effect models were used to combine the results. Potential publication bias was assessed using Egger's and Begg's test. Seven studies that evaluated dietary beta-carotene intake in relation to overall mortality, indicated that a higher intake of beta-carotene was related to a significant lower risk of all-cause mortality (RR for highest vs. lowest group = 0.83, 95%CI: 0.78-0.88) with no evidence of heterogeneity between studies (I(2) = 1.0%, P = 0.416). A random-effect analysis comprising seven studies showed high beta-carotene level in serum or plasma was associated with a significant lower risk of all-cause mortality (RR for highest vs. lowest group = 0.69, 95%CI: 0.59-0.80) with low heterogeneity (I(2) = 37.1%, P = 0.145). No evidence of publication bias was detected by Begg's and Egger's regression tests. In conclusion, dietary or circulating beta-carotene was inversely associated with risk of all-cause mortality. More studies should be conducted to clarify the dose-response relationship between beta-carotene and all-cause mortality.

Dietary selenium intake and mortality in two population-based cohort studies of 133 957 Chinese men and women.

OBJECTIVE: To investigate the potential influence of dietary Se intake on mortality among Chinese populations. DESIGN: We prospectively evaluated all-cause, CVD and cancer mortality risks associated with dietary Se intake in participants of the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health study (SMHS). Dietary Se intake was assessed by validated FFQ during in-person interviews. Cox proportional hazards models were used to calculate hazard ratios (HR) and 95 % CI. SETTING: Urban city in China. SUBJECTS: Chinese adults (n 133 957). RESULTS: During an average follow-up of 13·90 years in the SWHS and 8·37 years in the SMHS, 5749 women and 4217 men died. The mean estimated dietary Se intake was 45·48 µg/d for women and 51·34 µg/d for men, respectively. Dietary Se intake was inversely associated with all-cause mortality and CVD mortality in both women and men, with respective HR for the highest compared with the lowest quintile being 0·79 (95 % CI 0·71, 0·88; P trend<0·0001) and 0·80 (95 % CI 0·66, 0·98; P trend=0·0268) for women, and 0·79 (95 % CI 0·70, 0·89; P trend=0·0001) and 0·66 (95 % CI 0·54, 0·82; P trend=0·0002) for men. No significant associations were observed for cancer mortality in both women and men. Results were similar in subgroup and sensitivity analyses. CONCLUSIONS: Dietary Se intake was inversely associated with all-cause and cardiovascular mortality in both sexes, but not cancer mortality.

Quantitative evaluation of hepatitis B virus mutations and hepatocellular carcinoma risk: a meta-analysis of prospective studies.

BACKGROUND: The temporal relationship between hepatitis B virus (HBV) mutations and hepatocellular carcinoma (HCC) remains unclear. METHODS: We conducted a meta-analysis including cohort and nested case-control studies to prospectively examine the HCC risk associated with common variants of HBV in the PreS, Enhancer II, basal core promoter (BCP) and precore regions. Pertinent studies were identified by searching PubMed, Web of Science and the Chinese Biological Medicine databases through to November 2014. Study-specific risk estimates were combined using fixed or random effects models depending on whether significant heterogeneity was detected. RESULTS: Twenty prospective studies were identified, which included 8 cohort and 12 nested case-control studies. There was an increased risk of HCC associated with any PreS mutations with a pooled relative risk (RR) of 3.82 [95% confidence interval (CI): 2.59-5.61]. The pooled-RR for PreS deletion was 3.98 (95% CI: 2.28-6.95), which was higher than that of PreS2 start codon mutation (pooled-RR=2.63, 95% CI: 1.30-5.34). C1653T in Enhancer II was significantly associated with HCC risk (pooled-RR=1.83; 95% CI: 1.21-2.76). For mutations in BCP, statistically significant pooled-RRs of HCC were obtained for T1753V (pooled-RR=2.09; 95% CI: 1.49-2.94) and A1762T/G1764A double mutations (pooled-RR=3.11; 95% CI: 2.08-4.64). No statistically significant association with HCC risk was observed for G1896A in the precore region (pooled-RR=0.77; 95% CI: 0.47-1.26). CONCLUSIONS: This study demonstrated that PreS mutations, C1653T, T1753V, and A1762T/G1764A, were associated with an increased risk of HCC. Clinical practices concerning the HCC risk prediction and diagnosis may wish to focus on patients with these mutations.

Association Between Television Viewing Time and All-Cause Mortality: A Meta-Analysis of Cohort Studies.

Findings on the association between television (TV) viewing and all-cause mortality in epidemiologic studies have been inconsistent. Therefore, we conducted a meta-analysis of data from prospective cohort studies to quantify this association. Relevant articles were identified by searching MEDLINE (PubMed; National Library of Medicine, Bethesda, Maryland) and EMBASE (Elsevier B.V., Amsterdam, the Netherlands) from inception to March 1, 2015, and reviewing the reference lists of retrieved articles. Study-specific results were pooled using a random-effects model. Of 2,578 citations identified by the search strategy, 10 cohort studies (61,494 deaths among 647,475 individuals) met the inclusion criteria. The summary relative risk of all-cause mortality for the highest category of TV viewing time versus the lowest was 1.33 (95% confidence interval: 1.20, 1.47), with heterogeneity among studies (I(2) = 66.7%, P(heterogeneity) = 0.001). In dose-response meta-analysis, TV viewing time was statistically significantly associated with all-cause mortality risk in a J-shaped fashion (P(nonlinearity) = 0.001). These results indicate that prolonged TV viewing time might increase the risk of all-cause mortality. Given the high prevalence of excessive TV viewing, public health recommendations or interventions aimed at decreasing the amount of TV viewing time in modern societies are warranted.

Obesity and risk of bladder cancer: a dose-response meta-analysis of 15 cohort studies.

BACKGROUND: Epidemiological studies have reported inconsistent association between obesity and risk of bladder cancer, and the dose-response relationship between them has not been clearly defined. METHODS: We carried out a meta-analysis to summarize available evidence from epidemiological studies on this point. Relevant articles were identified by searching the PubMed and Web of Science databases through September 30, 2014. We pooled the relative risks from individual studies using random-effect model, and the dose-response relationship was estimated by using restricted cubic spline model. RESULTS: Fifteen cohort studies with 38,072 bladder cancer cases among 14,201,500 participants were included. Compared to normal weight, the pooled relative risks and corresponding 95% confidence intervals of bladder cancer were 1.07(1.01-1.14) and 1.10(1.06-1.14) for preobese and obesity, with moderate (I² = 37.6%, P = 0.029) and low (I² = 15.5%, P = 0.241) heterogeneities between studies, respectively. In a dose-response meta-analysis, body mass index (BMI) was associated with bladder cancer risk in a linear fashion (P(non-linearity) = 0.467) and the risk increased by 4.2% for each 5 kg/m2 increase. No significant publication bias was found (P = 0.912 for Begg's test, P = 0.712 for Egger's test). CONCLUSIONS: Findings from this dose-response meta-analysis suggest obesity is associated with linear-increased risk of bladder cancer.

Association between dietary fiber and lower risk of all-cause mortality: a meta-analysis of cohort studies.

Although in vitro and in vivo experiments have suggested that dietary fiber might have beneficial effects on health, results on the association between fiber intake and all-cause mortality in epidemiologic studies have been inconsistent. Therefore, we conducted a meta-analysis of prospective cohort studies to quantitatively assess this association. Pertinent studies were identified by searching articles in PubMed and Web of Knowledge through May 2014 and reviewing the reference lists of the retrieved articles. Study-specific risk estimates were combined using random-effects models. Seventeen prospective studies (1997-2014) that had a total of 67,260 deaths and 982,411 cohort members were included. When comparing persons with dietary fiber intakes in the top tertile with persons whose intakes were in the bottom tertile, we found a statistically significant inverse association between fiber intake and all-cause mortality, with an overall relative risk of 0.84 (95% confidence interval: 0.80, 0.87; I(2) = 41.2%). There was a 10% reduction in risk for per each 10-g/day increase in fiber intake (relative risk = 0.90; 95% confidence interval: 0.86, 0.94; I(2) = 77.2%). The combined estimate was robust across subgroup and sensitivity analyses. No publication bias was detected. A higher dietary fiber intake was associated with a reduced risk of death. These findings suggest that fiber intake may offer a potential public health benefit in reducing all-cause mortality.