A prospective study of red and processed meat intake in relation to cancer risk

Background

Red meat and processed meat have been associated with carcinogenesis at several anatomic sites, but no prospective study has examined meat intake in relation to a range of malignancies. We investigated whether red or processed meat intake increases cancer risk at a variety of sites.

Methods and Findings

The National Institutes of Health (NIH)-AARP (formerly the American Association for Retired Persons) Diet and Health Study is a cohort of approximately 500,000 people aged 50–71 y at baseline (1995–1996). Meat intake was estimated from a food frequency questionnaire administered at baseline. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals within quintiles of red and processed meat intake. During up to 8.2 y of follow-up, 53,396 incident cancers were ascertained. Statistically significant elevated risks (ranging from 20% to 60%) were evident for esophageal, colorectal, liver, and lung cancer, comparing individuals in the highest with those in the lowest quintile of red meat intake. Furthermore, individuals in the highest quintile of processed meat intake had a 20% elevated risk for colorectal and a 16% elevated risk for lung cancer.

Conclusions

Both red and processed meat intakes were positively associated with cancers of the colorectum and lung; furthermore, red meat intake was associated with an elevated risk for cancers of the esophagus and liver.     

Hyperuricemia and gout are associated with cancer incidence and mortality: A meta-analysis based on cohort studies

The association between hyperuricemia or gout and cancer risk has been investigated in various published studies, but their results are conflicting. We conducted a meta-analysis to investigate whether hyperuricemia or gout was associated with the cancer incidence and mortality. Linear and nonlinear trend analyses were conducted to explore the dose–response association between them. The pooled relative risk (RR) and 95% confidence interval (CI) were used to evaluate cancer risk. A total of 24 articles (33 independent studies) were eligible for inclusion. When compared participants with the highest SUA (hyperuricemia) levels and those with the lowest SUA levels, the pooled RR was 1.08 (95% CI, 1.04–1.12), it was significantly associated among males but not among females (males, RR = 1.07; 95% CI, 1.03–1.11; females, RR = 1.06; 95% CI, 0.96–1.17). Hyperuricemia increased total cancer mortality (RR = 1.15; 95% CI, 1.05–1.26), but a significant association was observed in females rather than in males (females: RR = 1.26; 95% CI, 1.09–1.45; males, RR = 1.02; 95% CI, 0.80–1.30). Linear relationships of SUA levels with overall cancer incidence (p for nonlinearity = 0.238) and overall cancer mortality (p for nonlinearity = 0.263) were identified. However, 1 mg/dL increment in SUA levels was weakly significant in overall cancer incidence (RR = 1.01; 95% CI, 1.01–1.01) but not associated with overall cancer mortality (RR = 1.01; 95% CI, 0.99–1.03). Gout was significantly associated with increased cancer incidence (RR = 1.19; 95% CI, 1.12–1.25). In conclusion, Hyperuricemia or gout was associated with higher cancer incidence and mortality. Though a potential linear relationship between them was found, we'd better treat this result with caution.     

Helicobacter pylori infection and colorectal cancer risk: a meta-analysis

BACKGROUND: Several studies suggested an association between Helicobacter pylori infection and colorectal carcinoma or adenoma risk. However, different authors reported quite varying estimates. We carried out a systematic review and meta-analysis of published studies investigating this association and paid special attention to the possibility of publication bias and sources of heterogeneity between studies. Materials and METHODS: An extensive literature search and cross-referencing were performed to identify all published studies. Summary estimates were obtained using random-effects models. The presence of possible publication bias was assessed using different statistical approaches. RESULTS: In a meta-analysis of the 11 identified human studies, published between 1991 and 2002, a summary odds ratio of 1.4 (95% CI, 1.1-1.8) was estimated for the association between H. pylori infection and colorectal cancer risk. The graphical funnel plot appeared asymmetrical, but the formal statistical evaluations did not provide strong evidence of publication bias. The proportion of variation of study results because of heterogeneity was small (36.5%). CONCLUSIONS: The results of our meta-analysis are consistent with a possible small increase in risk of colorectal cancer because of H. pylori infection. However, the possibility of some publication bias cannot be ruled out, although it could not be statistically confirmed. Larger, better designed and better controlled studies are needed to clarify the situation.     

Tea consumption reduces the incidence of gallbladder cancer based on a meta-analysis of epidemiologic studies

<正>Dear Editors,Gallbladder cancer comprises mostly of biliary tract malignancy which is the seventh most common digestive system cancers.The prognosis of gallbladder cancer is poor,whose five-year survival was reported 5%–10%.Many risk factors for gallbladder cancer have been identified in plenty of studies.There has been a definitive association between gall-     

Association of metformin use with cancer incidence and mortality: A meta-analysis

PurposeTo assess the effect of metformin intake on cancer incidence and mortality.MethodsOriginal articles in English published until June 15, 2012 were searched for in electronic databases (MEDLINE, ISI Web of Science and EMBASE databases) and relevant reviews were examined. Meta-analysis was applied to calculate the summary relative risk (SRR) and their 95% confidence intervals (95% CI). Sensitivity analysis was conducted to assess the robustness of the pooled estimator. The risk of publication bias was assessed by the Egger regression asymmetry test.ResultsAccording to the eligibility criteria, 37 studies comprising 1,535,636 participants, were selected in terms of intervention and data of cancer incidence or mortality. Among metformin users compared with non-users, the SRR for overall-cancer incidence was 0.73 (95% CI, 0.64–0.83) and that for mortality was 0.82 (95% CI, 0.76–0.89). The risk reductions for liver, pancreatic, colorectal and breast cancer incidence were 78%, 46%, 23% and 6%, respectively. Also, metformin can reduce the mortality of liver cancer (SRR, 0.23; 95% CI, 0.09–0.60) and breast cancer (SRR, 0.63; 95% CI, 0.40–0.99). No statistically significant association between metformin and prostate cancer incidence was found.ConclusionsMetformin can reduce the incidence of overall cancer, liver cancer, pancreatic cancer, colorectal cancer and breast cancer as well as the mortality of overall cancer, liver cancer and breast cancer. No beneficial effect on prostate cancer incidence was found for meformin intake in the meta-analysis.     

Matrix metalloproteinase 2 overexpression and prognosis in colorectal cancer: a meta-analysis

Many studies investigated the relationship between matrix metalloproteinase 2 (MMP-2) overexpression and survival in patients with colorectal cancer (CRC), but yielded inconsistent results. To derive a more precise estimate of the prognostic significance of MMP-2 overexpression, we reviewed published studies and carried out a meta-analysis. Eligible articles were identified for the period up to March 2012 in electronic databases. To evaluate the correlation between MMP-2 overexpression and the prognosis in CRC, pooled hazard ratio (HR) and its 95?% confidence interval (95?% CI) for poorer overall and progression-free survival were appropriately derived from fixed-effects or random-effects models using standard meta-analysis techniques. Thirteen studies with a total of 1,919 CRC patients stratifying overall survival (OS) and/or progression-free survival in CRC patients by MMP-2 expression status were eligible for analysis. Ten studies investigated the OS in a total of 1,612 cases with CRC, and five studies investigated the progression-free survival in a total of 508 patients CRC. The combined HR estimate for OS and progression-free survival was 1.74 (95?% CI, 1.34?C2.26) and 1.35 (95?% CI, 1.07?C1.80), respectively. Both subgroup analyses and sensitivity analysis further identified the prognostic role of MMP-2 overexpression in patients with CRC. There was no evidence for publication bias. In conclusion, MMP-2 overexpression is associated with poorer overall and progression-free survival in patients with CRC.     

Impact of the UK colorectal cancer screening pilot studies on incidence, stage distribution and mortality trends

Objective: To assess the impact of the UK colorectal cancer guaiac faecal occult blood test screening pilot studies on incidence trends, stage distribution and mortality trends. Design: Ecological study. Setting: Scotland and the West Midlands. Data: We extracted anonymised colorectal cancer (ICD-10 C18–C20) registration (1982–2006) and death records (1982–2007), along with corresponding mid-year population estimates. Intervention: Residents of the screening pilot areas, in the age group 50–69 years, were offered biennial guaiac faecal occult blood test screening from 2000 onwards. Screening was not offered routinely in non-pilot areas until the start of the roll-out of the national screening programmes in England and in Scotland in 2006 and 2007, respectively. Main outcome measures: We analysed trends in age-specific incidence and mortality rates, and Dukes’ stage distribution. Within each country/region, we compared the screening pilot areas to non-screening pilot (‘control’) areas using Chi square tests and Poisson regression modelling. Results: Following the start of the screening pilots, as expected in the prevalent round of a new screening programme, in the pilot areas there was a short-lived increase in incidence of colorectal cancer among 50–69 year olds except for females in the West Midlands. A trend towards earlier stage and less advanced disease was also observed, with males showing significant increases in Dukes’ A and corresponding decreases in Dukes’ C in the screening pilot areas (all P < 0.03). With the exception of females in the West Midlands, mortality rates for colorectal cancer decreased significantly and at a faster rate in the populations invited for screening. Conclusion: The existence of a natural control population not yet invited for screening provided a unique opportunity to assess whether the benefits of colorectal cancer screening, beyond the setting of a randomised controlled trial, could be detected using routinely collected statistics. Our analysis suggests that screening will fulfil its aim of reducing mortality from colorectal cancer.     

Vascular endothelial growth factor gene polymorphisms and colorectal cancer risk: a meta-analysis

Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen involved in a number of pathologic processes, including angiogenesis, tumor growth and metastasis. Polymorphisms of the VEGF gene have been associated with susceptibility to colorectal cancer (CRC). However, the specific association still remains controversial. We made a meta-analysis of the association between VEGF gene polymorphisms and CRC risk. Only eight case-control studies were retrieved, with a total of 2337 CRC patients and 2032 healthy controls. Six VEGF gene polymorphisms were addressed in all studies included, +936C>T (rs3025039), -2578C>A (rs699947), -1154G>A (rs1570360), -634G>C (rs2010963), -460C>T (rs833061), and +405C>G (rs2010963). There was a significant association between -2578C>A polymorphism and susceptibility to CRC in the comparison of C allele carriers (CC + CA) versus AA (odds ratio = 0.77, 95% confidence interval = 0.62-0.96, P = 0.02). No association was found between +936C>T, -1154G>A, -634G>C, -460C>T, and +405C>G with susceptibility to CRC. We conclude that the C allele carrier (CC + CA) of VEGF -2578C>A polymorphism appears to be a protective factor for CRC.     

Survival pattern of colorectal cancer in Sub-Saharan Africa: A systematic review and meta-analysis

Cancer incidence is relatively low in sub-Saharan Africa (SSA), however, prognosis is expected to be poor in comparison with high-income countries. Comprehensive evidence is limited on the survival pattern of colorectal cancer patients in the region. We conducted a systematic review and meta-analysis to investigate the pattern of colorectal cancer survival in the region and to identify variation across countries and over time. We searched international databases MEDLINE, Scopus, Embase, Web of Science, ProQuest, CINAHL, and Google Scholar to retrieve studies that estimated survival from colorectal cancer in SSA countries from inception to December 31, 2021 without language restriction. Due to between-study heterogeneity, we performed a random-effects meta-analysis to pool survival rates. To identify study-level sources of variation, we performed subgroup analysis and meta-regression. Results are reported in line with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) 2020 guideline and the protocol was registered in PROSPERO database (CRD42021246935). 23 studies involving 10,031 patients were included in the review, of which, 20 were included in the meta-analysis. The meta-analysis results showed that the pooled 1-, 2-, 3-, 4-, and 5-year survival rates in SSA were 0.74 (95% CI, 0.66–0.81), 0.50 (95% CI, 0.41–0.58), 0.36 (95% CI, 0.27–0.47), 0.31 (95% CI, 0.22–0.42), and 0.28 (95% CI, 0.19–0.38) respectively. Subgroup analyses indicated that the survival rate varied according to year of study, in which those conducted in recent decades showed relatively better survival. The 5-year survival was higher in middle-income SSA countries (0.31; 95%CI: 0.17–0.49) than low-income countries (0.20; 95%CI: 0.11–0.35), however, the difference was not statistically significant. In conclusion, survival from colorectal cancer is low in sub-Saharan Africa compared to other regions. Thus, intervention strategies to improve screening, early diagnosis and treatment of colorectal cancer should be developed and implemented to improve survival in the region.     

The association of polymorphisms on TGFBR1 and colorectal cancer risk: a meta-analysis

Epidemiological studies found inconsistent results on the association of two variants on TGFBR1 (TGFBR1*6A and Int7G24A) with colorectal cancer (CRC) risk. The present study was aimed to evaluate the association of these two variants with CRC susceptibility via the meta-analysis methods. For variant TGFBR1*6A, nine reports including 6,765 CRC patients and 8,496 unrelated controls were identified. The heterozygotes *6A/*9A showed a significant increased risk of CRC with the pooled OR was 1.12 (95% CI = 1.02–1.23), and the pooled OR for the homozygotes *6A/*6A was 1.13 (95% CI = 0.80–1.58) compared to the homozygotes *9A/*9A. However, under the dominant effect model, the TGFBR1*6A carriers showed a significantly increased CRC risk (pooled OR = 1.12, 95% CI = 1.03–1.23, *6A/*6A and *6A/*9A vs. *9A/*9A). For variant Int7G24A, three case–control studies with 1,074 cases and 1,945 controls were found. Although no significant association was found for heterozygosity Int7G24A carriers with CRC risk (pooled OR = 0.97, 95% CI = 0.67–1.42), the homozygosity A/A carriers showed a significant elevated risk of CRC (pooled OR = 1.68, 95% CI = 1.14–2.47) compared to G/G homozygotes. Under the recessive effect model, homozygotes A/A showed a 71% increase of CRC risk compared to the A/G and G/G genotype carriers (pooled OR = 1.71, 95% CI = 1.17–2.51). These data strongly suggested that the two polymorphisms of TGFBR1 may confer low-penetrance susceptibility of CRC risk.     

IL6 gene polymorphisms and susceptibility to colorectal cancer: a meta-analysis and review

A number of case-control studies were conducted to investigate the association of IL6 gene polymorphisms with colorectal cancer (CRC). However, the results were not always consistent. We performed a systematic review and meta-analysis to examine the association between the IL6 gene polymorphisms and CRC. Data were collected from the following electronic databases: PubMed, EMBASE, Web of Science, BIOSIS Previews, HuGENet, and Chinese Biomedical Literature Database, with the last report up to July 2011. A total of 17 studies involving 4 SNPs were included (16 for rs1800795, 2 for rs1800796, 2 for rs1800797, and 1 for rs13306435). Overall, no significant association of these polymorphisms with CRC was found in heterozygote comparisons as well as homozygote comparison, dominant genetic model and recessive model. In subgroup analysis, among studies using population-based controls, fulfilling Hardy-Weinberg equilibrium, or using Taqman genotyping method, we did not find any significant association. However, the rs1800795 C allele was significantly associated with reduced risk for CRC among persons who regularly or currently took NSAIDs (four studies, OR = 0.750; 95 % CI, 0.64-0.88; P = 0.474 for heterogeneity test), and with increased risk for CRC among persons who drank (one study, OR = 1.97; 95 % CI, 1.32-2.94). Individuals with the rs1800795 C allele in the IL6 gene have a significantly lower risk of CRC, but in the setting of NSAIDs use. Further studies are merited to assess the association between the IL6 gene polymorphisms and CRC risk among persons who take NSAIDs, drink or smoke, etc.     

Gamma-glutamyltransferase predicts increased risk of mortality: A systematic review and meta-analysis of prospective observational studies

Abstract

The aim of this study was to evaluate the association between gamma-glutamyltransferase (GGT) and mortality through a comprehensive analysis of existing evidence. PubMed, Embase, Chinese Biomedical Literature, and Science Citation Index databases were electronically searched. Studies were included if the study design was prospective and included reference and at-risk levels of GGT at baseline and mortality as a separate outcome. The quality of the studies included was assessed on the basis of Newcastle–Ottawa scale. Data from selected qualified studies were systematically reviewed, pooled, and analyzed according to the MOOSE guidelines and PRISMA statement. The results included the following: 1. 35 studies including 571 511 participants and 72 196 cases of mortality; 2. GGT, even at physiologic levels, was associated with increased all-cause mortality and cardiovascular mortality, and might also be associated with cancer-related mortality in the general population; and 3. GGT was very likely to be associated with all-cause mortality and cardiovascular mortality in patients with coronary artery disease and type 2 diabetes mellitus. Many of the studies included did not specifically exclude subjects with hepatic diseases or alcohol abuse, which may have obscured the results. Moderate heterogeneity was observed in the meta-analysis of GGT and all-cause mortality. Different compositions of cause-specific mortality might be the reason. However, subgroup analysis could only be performed on cardiovascular death because of insufficient information. GGT, even at physiologic high levels, predicted mortality, especially cardiovascular mortality and cancer mortality. The underlining mechanism and potential effects of GGT-targeted intervention on health warrant further investigation.     

Socioeconomic position and incidence of colorectal cancer in the Swedish population

BackgroundThe association between socioeconomic position and incidence of colorectal cancer is inconsistent and differs by global region. We aimed to clarify this association in the Swedish population.MethodsWe conducted a population-based open cohort study using data from Swedish national registers. We included all individuals, aged ≥30 years, residing in Sweden between 1993 and 2010. Socioeconomic position was indicated by (1) highest educational level (five groups), and (2) disposable income (quintiles). We used Poisson regression to estimate incidence rate ratios (IRR) and 95% confidence intervals (95% CI) of colon and rectal cancer, and colon and rectal dysplasia.ResultsIn total, 97,827,817 person-years were accumulated and 82,686 cases of colorectal cancer were diagnosed. Compared to men with ‘higher secondary’ education, the adjusted IRRs (95% CI) of rectal cancer in men with ‘primary or less’, ‘lower secondary’, ‘lower university’ or ‘higher university’ education were: 1.06 (1.00, 1.11), 1.05 (0.99, 1.10), 0.96 (0.89, 1.03), and 0.92 (0.86, 0.98), respectively. In women, the corresponding figures were: 1.04 (0.95, 1.14), 1.03 (0.94, 1.13), 0.92 (0.82, 1.02) and 0.92 (0.82, 1.02). Disposable income was not associated with rectal cancer incidence. Adjusted IRRs of colon cancer did not differ between levels of education or disposable income overall or for specific colon sub-sites. Neither education nor disposable income was consistently associated with incidence of colon or rectal dysplasia.ConclusionsPrevention strategies for colon cancer should be applicable to individuals regardless of their socioeconomic position. However, factors conferred by education, e.g., health awareness, may be important for approaches aiming to reduce inequalities in incidence of rectal cancer. Further evaluation of cancer prevention and health promotion strategies among less educated groups is warranted.     

Genome-wide association studies of pigmentation and skin cancer: a review and meta-analysis

Recent genome-wide association studies (GWAS) identified genetic loci associated with pigmentation, nevi, and skin cancer. We performed a review and meta-analysis of GWAS results, grouping them into four categories: (i) loci associated with pigmentation (hair, eye, and/or skin color), cutaneous UV-response (sun sensitivity and/or freckling), and skin cancer; (ii) loci associated with nevi and melanoma; (iii) loci associated with pigmentation and/or cutaneous UV-response but not skin cancer; and (iv) loci associated distinctly with skin cancer, mostly basal cell carcinoma, but not pigmentation or cutaneous UV-response. These findings suggest at least two pathways for melanoma development (via pigmentation and via nevi), and two pathways for basal cell carcinoma development (via pigmentation and independent of pigmentation). However, further work is necessary to separate the association with skin cancer from the association with pigmentation. As with any GWAS, the identified loci may not include the causal variants and may need confirmation by direct genome sequencing.     

Objectively measured physical activity and fat mass in children: a bias-adjusted meta-analysis of prospective studies

Background

Studies investigating the prevention of weight gain differ considerably in design and quality, which impedes pooling them in conventional meta-analyses, the basis for evidence-based policy making. This study is aimed at quantifying the prospective association between measured physical activity and fat mass in children, using a meta-analysis method that allows inclusion of heterogeneous studies by adjusting for differences through eliciting and incorporating expert opinion.

Methods

Studies on prevention of weight gain using objectively measured exposure and outcome were eligible; they were adopted from a recently published systematic review. Differences in study quality and design were considered as internal and external biases and captured in checklists. Study results were converted to correlation coefficients and biases were considered either additive or proportional on this scale. The extent and uncertainty of biases in each study were elicited in a formal process by six quantitatively-trained assessors and five subject-matter specialists. Biases for each study were combined across assessors using median pooling. Results were combined across studies by random-effects meta-analysis.

Results

The combined correlation of the unadjusted results from the six studies was −0.04 (95%CI: −0.22, 0.14) with considerable heterogeneity (I² = 78%), which makes it difficult to interpret the result. After bias-adjustment the pooled correlation was −0.01 (95%CI: −0.18, 0.16) with apparent study compatibility (I² = 0%).

Conclusion

By using this method the prospective association between physical activity and fat mass could be quantitatively synthesized; the result suggests no association. Objectively measured physical activity may not be the key determinant of unhealthy weight gain in children.