Obesity is a risk factor for cardiovascular disease (CVD) mortality, but the association between obesity and specific causes of CVD mortality are still under investigation.
We prospectively examined body-mass index (BMI) in relation to CVD-specific causes of death in approximately 86,000 US men and women in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, followed for up to 13 years. BMI was calculated from self-reported weight and height at baseline. Hazard ratios (HRs) were calculated overall and stratified by sex, smoking status, and educational level.
Overweight non-obese participants (BMI: 25.0–29.9) were not at excess risk for CVD mortality (HR and CIs are 1.02 [0.92–1.13], compared to participants of normal BMI (18.5–24.9). Excess CVD mortality was observed for participants of BMI 30.0–34.9 (HR and CIs: 1.29 [1.13–1.48], BMI 35.0–39.9 (HR and CIs: 1.87 [1.51–2.32]) and BMI 40.0+ (HR and CIs: 2.21 [1.57–3.21]) (p<0.001 for trend). BMI was unrelated to mortality due to stroke. The observed association of BMI with CVD was independent of gender, smoking status and educational level.
Obesity is associated with increased mortality due to CVD.
Obesity has consistently been linked to an increased risk of colorectal cancer, particularly among men. Whether body mass index (BMI) differentially influences the risk across the stages of colorectal cancer development remains unclear. We evaluated the associations of BMI with colorectal adenoma incidence, adenoma recurrence, and cancer in the context of a large screening trial, in which cases and controls had an equal chance for disease detection.
We prospectively evaluated the association between baseline BMI and the risk of incident distal adenoma (1,213 cases), recurrent adenoma (752 cases), and incident colorectal cancer (966 cases) among men and women, ages 55 to 74 years, randomly assigned to receive flexible sigmoidoscopy screening as part of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. We calculated odds ratios (ORs) and 95% CIs for adenoma incidence and recurrence, and hazard ratios (HRs) and 95% CIs for colorectal cancer incidence, using multivariable-adjusted models.
Compared with normal-weight men (18.5 to 24.9 kg/m2), obese men (≥ 30 kg/m2) had significantly higher risk of incident adenoma (OR, 1.32; 95% CI, 1.06 to 1.65) and colorectal cancer (HR, 1.48; 95% CI, 1.16 to 1.89) and a borderline increased risk of recurrent adenoma (OR, 1.50; 95% CI, 0.98 to 2.30). No associations were observed for either adenoma or cancer in women.
Data from this large prospective study suggest that obesity is important throughout the natural history of colorectal cancer, at least in men, and colorectal cancer prevention efforts should encourage the achievement and maintenance of a healthy body weight in addition to regular screenings.
Effective means are needed to efficiently collect fecal samples for microbiome analysis in large-scale epidemiological studies. Using twenty-four fecal aliquots prepared from three healthy individuals, we compared the following four fecal sample collection methods for assessment of human gut microbiome: 1) fecal occult blood test cards, held at room temperature for three days, 2) Eppendorf tubes, at room temperature for three days, 3) Eppendorf tubes with RNAlater, at room temperature, and 4) as controls, samples immediately frozen at −80°C. The 24 samples were assayed by 16S rRNA gene sequencing to compare overall microbiome structure and taxon distributions according to collection method.
Storing fecal occult blood test card samples at room temperature for three days did not affect total DNA purity and relative 16S rRNA bacterial gene contents, compared with fresh frozen collection. Overall microbiome structure, based on phylogenetic UniFrac index, differed significantly by subject (p = 0.001), but microbiome structure (p = 0.497) and relative abundance of major microbial taxa (phyla) (p > 0.05) did not differ significantly by collection method.
Our findings suggest that low-cost fecal occult blood test card collection may be a feasible means of sample collection for fecal microbiome assessment in large-scale population-based studies.
Comparison; Methods; Fecal; Microbiome; Collection
A growing body of evidence implicates human oral bacteria in the etiology of oral and gastrointestinal cancers. Epidemiological studies consistently report increased risks of these cancers in men and women with periodontal disease or tooth loss, conditions caused by oral bacteria. More than 700 bacterial species inhabit the oral cavity, including at least 11 bacterial phyla and 70 genera. Oral bacteria may activate alcohol and smoking-related carcinogens locally or act systemically, through chronic inflammation. High-throughput genetic-based assays now make it possible to comprehensively survey the human oral microbiome, the totality of bacteria in the oral cavity. Establishing the association of the oral microbiome with cancer risk may lead to significant advances in understanding of cancer etiology, potentially opening a new research paradigm for cancer prevention.
Human microbiome; Oral and gastrointestinal cancer; Assay; Epidemiology
We tested the hypothesis that an altered community of gut microbes is associated with risk of colorectal cancer (CRC) in a study of 47 CRC case subjects and 94 control subjects. 16S rRNA genes in fecal bacterial DNA were amplified by universal primers, sequenced by 454 FLX technology, and aligned for taxonomic classification to microbial genomes using the QIIME pipeline. Taxonomic differences were confirmed with quantitative polymerase chain reaction and adjusted for false discovery rate. All statistical tests were two-sided. From 794217 16S rRNA gene sequences, we found that CRC case subjects had decreased overall microbial community diversity (P = .02). In taxonomy-based analyses, lower relative abundance of Clostridia (68.6% vs 77.8%) and increased carriage of Fusobacterium (multivariable odds ratio [OR] = 4.11; 95% confidence interval [CI] = 1.62 to 10.47) and Porphyromonas (OR = 5.17; 95% CI = 1.75 to 15.25) were found in case subjects compared with control subjects. Because of the potentially modifiable nature of the gut bacteria, our findings may have implications for CRC prevention.
Inherited variation in genes that regulate innate immunity and inflammation may contribute to colorectal neoplasia risk. To evaluate this association, we conducted a nested case–control study of 451 colorectal cancer cases, 694 colorectal advanced adenoma cases and 696 controls of European descent within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. A total of 935 tag single-nucleotide polymorphisms (SNPs) in 98 genes were evaluated. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association with colorectal neoplasia. Sixteen SNPs were associated with colorectal neoplasia risk at P < 0.01, but after adjustment for multiple testing, only rs2838732 (ITGB2) remained suggestively associated with colorectal neoplasia (ORper T allele = 0.68, 95% CI: 0.57–0.83, P = 7.7 × 10–5, adjusted P = 0.07). ITGB2 codes for the CD18 protein in the integrin beta chain family. The ITGB2 association was stronger for colorectal cancer (ORper T allele = 0.41, 95% CI: 0.30–0.55, P = 2.4 × 10−
9) than for adenoma (ORper T allele = 0.84, 95%CI: 0.69–1.03, P = 0.08), but it did not replicate in the validation study. The ITGB2 rs2838732 association was significantly modified by smoking status (P value for interaction = 0.003). Among never and former smokers, it was inversely associated with colorectal neoplasia (ORper T allele = 0.5, 95% CI: 0.37–0.69 and ORper T allele = 0.72, 95% CI: 0.54–0.95, respectively), but no association was seen among current smokers. Other notable findings were observed for SNPs in BPI/LBP and MYD88. Although the results need to be replicated, our findings suggest that genetic variation in inflammation-related genes may be related to the risk of colorectal neoplasia.
Genetic loci for body mass index (BMI) in adolescence and young adulthood, a period of high risk for weight gain, are understudied, yet may yield important insight into the etiology of obesity and early intervention. To identify novel genetic loci and examine the influence of known loci on BMI during this critical time period in late adolescence and early adulthood, we performed a two-stage meta-analysis using 14 genome-wide association studies in populations of European ancestry with data on BMI between ages 16 and 25 in up to 29 880 individuals. We identified seven independent loci (P < 5.0 × 10−8) near FTO (P = 3.72 × 10−23), TMEM18 (P = 3.24 × 10−17), MC4R (P = 4.41 × 10−17), TNNI3K (P = 4.32 × 10−11), SEC16B (P = 6.24 × 10−9), GNPDA2 (P = 1.11 × 10−8) and POMC (P = 4.94 × 10−8) as well as a potential secondary signal at the POMC locus (rs2118404, P = 2.4 × 10−5 after conditioning on the established single-nucleotide polymorphism at this locus) in adolescents and young adults. To evaluate the impact of the established genetic loci on BMI at these young ages, we examined differences between the effect sizes of 32 published BMI loci in European adult populations (aged 18–90) and those observed in our adolescent and young adult meta-analysis. Four loci (near PRKD1, TNNI3K, SEC16B and CADM2) had larger effects and one locus (near SH2B1) had a smaller effect on BMI during adolescence and young adulthood compared with older adults (P < 0.05). These results suggest that genetic loci for BMI can vary in their effects across the life course, underlying the importance of evaluating BMI at different ages.
Cigar and pipe smoking are considered risk factors for head and neck cancers, but the magnitude of effect estimates for these products has been imprecisely estimated. By using pooled data from the International Head and Neck Cancer Epidemiology (INHANCE) Consortium (comprising 13,935 cases and 18,691 controls in 19 studies from 1981 to 2007), we applied hierarchical logistic regression to more precisely estimate odds ratios and 95% confidence intervals for cigarette, cigar, and pipe smoking separately, compared with reference groups of those who had never smoked each single product. Odds ratios for cigar and pipe smoking were stratified by ever cigarette smoking. We also considered effect estimates of smoking a single product exclusively versus never having smoked any product (reference group). Among never cigarette smokers, the odds ratio for ever cigar smoking was 2.54 (95% confidence interval (CI): 1.93, 3.34), and the odds ratio for ever pipe smoking was 2.08 (95% CI: 1.55, 2.81). These odds ratios increased with increasing frequency and duration of smoking (Ptrend ≤ 0.0001). Odds ratios for cigar and pipe smoking were not elevated among ever cigarette smokers. Head and neck cancer risk was elevated for those who reported exclusive cigar smoking (odds ratio = 3.49, 95% CI: 2.58, 4.73) or exclusive pipe smoking (odds ratio = 3.71, 95% CI: 2.59, 5.33). These results suggest that cigar and pipe smoking are independently associated with increased risk of head and neck cancers.
head and neck neoplasms; smoking
Several epidemiological studies have shown a positive association between adult height and cancer incidence. The only study conducted among women on mouth and pharynx cancer risk, however, reported an inverse association. This study aims to investigate the association between height and the risk of head and neck cancer (HNC) within a large international consortium of HNC.
We analyzed pooled individual-level data from 24 case-control studies participating in the International Head and Neck Cancer Epidemiology Consortium. Odds Ratios (ORs) and 95% Confidence Intervals (CIs) were estimated separately for men and women for associations between height and HNC risk. Educational level, tobacco smoking, and alcohol consumption were included in all regression models. Stratified analyses by HNC subsites were performed.
This project included 17,666 cases and 28,198 controls. We found an inverse association between height and HNC (adjusted OR per 10 cm height =0.91, 95% CI 0.86–0.95 for men; adjusted OR=0.86, 95% CI 0.79–0.93 for women). In men, the estimated OR did vary by educational level, smoking status, geographic area, and control source. No differences by subsites were detected.
Adult height is inversely associated with HNC risk. As height can be considered a marker of childhood illness and low energy intake, the inverse association is consistent with prior studies showing that HNC occur more frequently among deprived individuals. Further studies designed to elucidate the mechanism of such association would be warranted.
It has been hypothesized that a high intake of dairy protein may increase prostate cancer risk by increasing the production of insulin-like growth factor 1 (IGF-1). Several single nucleotide polymorphisms (SNPs) have been weakly associated with circulating concentrations of IGF-1 and IGF binding protein 3 (IGFBP-3), but none of these SNPs was associated with risk of prostate cancer. We examined whether an association between 16 SNPs associated with circulating IGF-1 or IGFBP-3 concentrations and prostate cancer exists within subgroups defined by dietary protein intake in 5,253 cases and 4,963 controls of European ancestry within the NCI Breast and Prostate Cancer Cohort Consortium (BPC3). The BPC3 includes nested case-control studies within large North-American and European cohorts. Per allele odds ratios for prostate cancer for the SNPs were compared across tertiles of protein intake, which was expressed as the percentage of energy derived from total, animal, dairy or plant protein sources, using conditional logistic regression models. Total, animal, dairy and plant protein intakes were significantly positively associated with blood IGF-1 (P<0.01), but not with IGFBP-3 concentrations (P>0.10) or with risk of prostate cancer (P>0.20). After adjusting for multiple testing, the SNP-prostate cancer associations did not differ by intakes of protein, although two interactions by intake of plant protein were of marginal statistical significance (SSTR5 (somatostatin receptor 5) -rs197056 [uncorrected P for interaction, 0.001]; SSTR5-rs197057 [uncorrected P for interaction, 0.002]). We found no strong evidence that the associations between 16 IGF pathway SNPs and prostate cancer differed by intakes of dietary protein.
gene*environment interaction; genetic epidemiology; insulin-like growth factor; diet; prostate cancer
Circulating adipokine levels may be associated with endometrial cancer risk, yet few studies have evaluated these markers prospectively.
We conducted a nested case-control study of postmenopausal women in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (n=78,216), including 167 incident endometrial cancer cases and 327 controls that were matched on age, study center, race, study year of diagnosis, year of blood draw, time of day of blood draw and menopausal hormone therapy (MHT) use. Adipokine and estradiol levels were categorized into tertiles (T). Odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of adiponectin, leptin and visfatin with endometrial cancer risk were estimated by conditional logistic regression, adjusting for known endometrial cancer risk factors, including body mass index (BMI) and circulating estradiol levels.
Adiponectin levels were inversely associated with risk of endometrial cancer [OR T3vsT1=0.48 (95%CI: 0.29-0.80); p-trend<0.01], whereas elevated leptin levels showed a positive association [2.77 (1.60-4.79); p-trend<0.01]. These results remained significant after adjustment for estradiol, but not after further adjustment for BMI. When analyses were restricted to non-MHT users, associations of adiponectin and leptin were stronger and remained significant after adjustment for estradiol and BMI [0.27 (0.09-0.80); p-trend=0.01 and 4.29 (1.07-17.15); p-trend=0.02, respectively]. Non-significant positive associations were observed for visfatin.
Adipokines may influence endometrial cancer risk through pathways other than estrogen-mediated cell growth in postmenopausal women not currently on MHT.
Understanding how adipokines influence endometrial cancer risk may help to elucidate biological mechanisms important for the observed obesity-endometrial cancer association.
endometrial cancer risk; adiponectin; leptin; visfatin; obesity
Dietary factors, including meat, fruits, vegetables and fiber, are associated with colorectal cancer; however, there is limited information as to whether these dietary factors interact with genetic variants to modify risk of colorectal cancer. We tested interactions between these dietary factors and approximately 2.7 million genetic variants for colorectal cancer risk among 9,287 cases and 9,117 controls from ten studies. We used logistic regression to investigate multiplicative gene-diet interactions, as well as our recently developed Cocktail method that involves a screening step based on marginal associations and gene-diet correlations and a testing step for multiplicative interactions, while correcting for multiple testing using weighted hypothesis testing. Per quartile increment in the intake of red and processed meat were associated with statistically significant increased risks of colorectal cancer and vegetable, fruit and fiber intake with lower risks. From the case-control analysis, we detected a significant interaction between rs4143094 (10p14/near GATA3) and processed meat consumption (OR = 1.17; p = 8.7E-09), which was consistently observed across studies (p heterogeneity = 0.78). The risk of colorectal cancer associated with processed meat was increased among individuals with the rs4143094-TG and -TT genotypes (OR = 1.20 and OR = 1.39, respectively) and null among those with the GG genotype (OR = 1.03). Our results identify a novel gene-diet interaction with processed meat for colorectal cancer, highlighting that diet may modify the effect of genetic variants on disease risk, which may have important implications for prevention.
High intake of red and processed meat and low intake of fruits, vegetables and fiber are associated with a higher risk of colorectal cancer. We investigate if the effect of these dietary factors on colorectal cancer risk is modified by common genetic variants across the genome (total of about 2.7 million genetic variants), also known as gene-diet interactions. We included over 9,000 colorectal cancer cases and 9,000 controls that were not diagnosed with colorectal cancer. Our results provide strong evidence for a gene-diet interaction and colorectal cancer risk between a genetic variant (rs4143094) on chromosome 10p14 near the gene GATA3 and processed meat consumption (p = 8.7E-09). This genetic locus may have interesting biological significance given its location in the genome. Our results suggest that genetic variants may interact with diet and in combination affect colorectal cancer risk, which may have important implications for personalized cancer care and provide novel insights into prevention strategies.
BACKGROUND & AIMS
Heritable factors contribute to the development of colorectal cancer. Identifying the genetic loci associated with colorectal tumor formation could elucidate the mechanisms of pathogenesis.
We conducted a genome-wide association study that included 14 studies, 12,696 cases of colorectal tumors (11,870 cancer, 826 adenoma), and 15,113 controls of European descent. The 10 most statistically significant, previously unreported findings were followed up in 6 studies; these included 3056 colorectal tumor cases (2098 cancer, 958 adenoma) and 6658 controls of European and Asian descent.
Based on the combined analysis, we identified a locus that reached the conventional genome-wide significance level at less than 5.0 × 10−8: an intergenic region on chromosome 2q32.3, close to nucleic acid binding protein 1 (most significant single nucleotide polymorphism: rs11903757; odds ratio [OR], 1.15 per risk allele; P = 3.7 × 10−8). We also found evidence for 3 additional loci with P values less than 5.0 × 10−7: a locus within the laminin gamma 1 gene on chromosome 1q25.3 (rs10911251; OR, 1.10 per risk allele; P = 9.5 × 10−8), a locus within the cyclin D2 gene on chromosome 12p13.32 (rs3217810 per risk allele; OR, 0.84; P = 5.9 × 10−8), and a locus in the T-box 3 gene on chromosome 12q24.21 (rs59336; OR, 0.91 per risk allele; P = 3.7 × 10−7).
In a large genome-wide association study, we associated polymorphisms close to nucleic acid binding protein 1 (which encodes a DNA-binding protein involved in DNA repair) with colorectal tumor risk. We also provided evidence for an association between colorectal tumor risk and polymorphisms in laminin gamma 1 (this is the second gene in the laminin family to be associated with colorectal cancers), cyclin D2 (which encodes for cyclin D2), and T-box 3 (which encodes a T-box transcription factor and is a target of Wnt signaling to β-catenin). The roles of these genes and their products in cancer pathogenesis warrant further investigation.
Colon Cancer; Genetics; Risk Factors; SNP
The HOXB13 gene has been implicated in prostate cancer (PrCa) susceptibility. We performed a high resolution fine-mapping analysis to comprehensively evaluate the association between common genetic variation across the HOXB genetic locus at 17q21 and PrCa risk. This involved genotyping 700 SNPs using a custom Illumina iSelect array (iCOGS) followed by imputation of 3195 SNPs in 20,440 PrCa cases and 21,469 controls in The PRACTICAL consortium. We identified a cluster of highly correlated common variants situated within or closely upstream of HOXB13 that were significantly associated with PrCa risk, described by rs117576373 (OR 1.30, P = 2.62×10−14). Additional genotyping, conditional regression and haplotype analyses indicated that the newly identified common variants tag a rare, partially correlated coding variant in the HOXB13 gene (G84E, rs138213197), which has been identified recently as a moderate penetrance PrCa susceptibility allele. The potential for GWAS associations detected through common SNPs to be driven by rare causal variants with higher relative risks has long been proposed; however, to our knowledge this is the first experimental evidence for this phenomenon of synthetic association contributing to cancer susceptibility.
Genome-wide association studies (GWAS) have identified numerous low penetrance disease susceptibility variants, yet few causal alleles have been unambiguously identified. The underlying causal variants are expected to be predominantly common; however synthetic associations with rare, higher penetrance variants have been hypothesised though not yet observed. Here, we report detection of a novel common, low penetrance prostate cancer association at the HOXB locus at ch17q and show that this signal can actually be attributed to a previously identified rare, moderate penetrance coding variant (G84E) in HOXB13. This study therefore provides the first experimental evidence for the existence of synthetic associations in cancer and shows that where GWAS signals arise through this phenomenon, risk predictions derived using the tag SNP would substantially underestimate the relative risk conferred and overestimate the number of carriers of the causal variant. Synthetic associations at GWAS signals could therefore account for a proportion of the missing heritability of complex diseases.
Twin studies suggest a heritable component to circulating sex steroid hormones and sex hormone-binding globulin (SHBG). In the NCI-Breast and Prostate Cancer Cohort Consortium, 874 SNPs in 37 candidate genes in the sex steroid hormone pathway were examined in relation to circulating levels of SHBG (N = 4720), testosterone (N = 4678), 3α-androstanediol-glucuronide (N = 4767) and 17β-estradiol (N = 2014) in Caucasian men. rs1799941 in SHBG is highly significantly associated with circulating levels of SHBG (P = 4.52 × 10−21), consistent with previous studies, and testosterone (P = 7.54 × 10−15), with mean difference of 26.9 and 14.3%, respectively, comparing wild-type to homozygous variant carriers. Further noteworthy novel findings were observed between SNPs in ESR1 with testosterone levels (rs722208, mean difference = 8.8%, P = 7.37 × 10−6) and SRD5A2 with 3α-androstanediol-glucuronide (rs2208532, mean difference = 11.8%, P = 1.82 × 10−6). Genetic variation in genes in the sex steroid hormone pathway is associated with differences in circulating SHBG and sex steroid hormones.
Genome-wide association studies (GWAS) have identified multiple common genetic variants associated with an increased risk of prostate cancer (PrCa), but these explain less than one-third of the heritability. To identify further susceptibility alleles, we conducted a meta-analysis of four GWAS including 5953 cases of aggressive PrCa and 11 463 controls (men without PrCa). We computed association tests for approximately 2.6 million SNPs and followed up the most significant SNPs by genotyping 49 121 samples in 29 studies through the international PRACTICAL and BPC3 consortia. We not only confirmed the association of a PrCa susceptibility locus, rs11672691 on chromosome 19, but also showed an association with aggressive PrCa [odds ratio = 1.12 (95% confidence interval 1.03–1.21), P = 1.4 × 10−8]. This report describes a genetic variant which is associated with aggressive PrCa, which is a type of PrCa associated with a poorer prognosis.
Prostate cancer is the most frequently diagnosed cancer in males in developed countries. To identify common prostate cancer susceptibility alleles, we genotyped 211,155 SNPs on a custom Illumina array (iCOGS) in blood DNA from 25,074 prostate cancer cases and 24,272 controls from the international PRACTICAL Consortium. Twenty-three new prostate cancer susceptibility loci were identified at genome-wide significance (P < 5 × 10−8). More than 70 prostate cancer susceptibility loci, explaining ~30% of the familial risk for this disease, have now been identified. On the basis of combined risks conferred by the new and previously known risk loci, the top 1% of the risk distribution has a 4.7-fold higher risk than the average of the population being profiled. These results will facilitate population risk stratification for clinical studies.
Insulin and glucose may influence cancer mortality via their proliferative and anti-apoptotic properties. Using longitudinal data from the nationally representative Third National Health and Nutrition Examination Survey (NHANES III;1988–1994), with an average follow-up of 8.5y to mortality, we evaluated markers of glucose and insulin concentrations, with cancer mortality, ascertained using death certificates using the National Death Index. Plasma glucose, insulin, C-peptide, and lipid concentrations were measured. Anthropometrics, lifestyle, medical and demographic information was obtained during in-person interviews. After adjusting for age, race, sex, smoking status, physical activity and body mass index, for every increase in 50 mg/dl of plasma glucose, there was a 22% increased risk of overall cancer mortality. Insulin resistance was associated with a 41% (95% confidence interval (CI)(1.07–1.87;p=0.01) increased risk of overall cancer mortality. These associations were stronger after excluding lung cancer deaths for insulin resistant individuals (HR:1.67; 95% CI:1.15–2.42;p=0.01), specifically among those with lower levels of physical activity (HR:2.06; 95% CI:1.4–3.0;p=0.0001). Similar associations were observed for other blood markers of glucose and insulin, albeit not statistically significant. In conclusions, hyperglycemia and insulin resistance may be ‘high-risk’ conditions for cancer mortality. Managing these conditions may be effective cancer control tools.
cancer mortality; insulin; glucose control; epidemiology; longitudinal study
Systematic genome-wide reductions of methylated cytosine (5-mC) levels have been observed in colorectal cancer tissue and are suspected to play a role in carcinogenesis, possibly as a consequence of inadequate folate intake. Reduced 5-mC levels in peripheral blood leukocytes have been associated with increased risk of colorectal cancer and adenoma in cross-sectional studies.
To minimize disease- and/or treatment-related effects, we studied leukocyte 5-mC levels in prospectively collected blood specimens of 370 cases and 493 controls who were cancer-free at blood collection from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial., Leukocyte 5-mC level was determined by an HPLC/Tandem Mass Spectrometry method and expressed as the relative amount of methyl- to total cytosine residues, or %5-mC. We estimated the association between colorectal cancer risk and %5-mC categories by computing odds ratios (ORs) and 95% confidence intervals (CIs) through logistic regression modeling.
We observed no dose-dependent association between colorectal cancer and %5-mC categories (lowest tertile vs. highest: OR=1.14, 95% CI=0.80–1.63; P trend=0.51). However, among subjects whose 5-mC levels were at the highest tertile, we observed an inverse association between natural folate intake and colorectal cancer (highest tertile of natural folate vs. lowest: OR=0.35, 95% CI=0.17–0.71; P trend=0.003; P interaction=0.003).
This prospective investigation show no clear association between leukocyte 5-mC level and subsequent colorectal cancer risk, but a suggestive risk modification between 5-mC level and natural folate intake.
Adequate folate status may protect against colorectal carcinogenesis through mechanisms involving adequate DNA methylation in the genome.
5-mC; PLCO; folate; colorectal
To investigate the potential role of vitamin or mineral supplementation on the risk of head and neck cancer (HNC), we analyzed individual-level pooled data from 12 case-control studies (7,002 HNC cases and 8,383 controls) participating in the International Head and Neck Cancer Epidemiology consortium. There were a total of 2,028 oral cavity cancer, 2,465 pharyngeal cancer, and 874 unspecified oral/pharynx cancer, 1,329 laryngeal cancer and 306 overlapping HNC cases. Odds ratios (OR) and 95% confidence intervals (CIs) for self reported ever use of any vitamins, multivitamins, vitamin A, vitamin C, vitamin E, and calcium, beta-carotene, iron, selenium, and zinc supplements were assessed. We further examined frequency, duration and cumulative exposure of each vitamin or mineral when possible and stratified by smoking and drinking status. All ORs were adjusted for age, sex, race/ethnicity, study center, education level, and pack-years of smoking, frequency of alcohol drinking and fruit/vegetable intake. A decreased risk of HNC was observed with ever use of vitamin C (OR=0.76, 95% CI=0.59-0.96) and with ever use of calcium supplement (OR=0.64, 95% CI=0.42-0.97). The inverse association with HNC risk was also observed for 10 or more years of vitamin C use (OR=0.72, 95% CI=0.54-0.97) and more than 365 tablets of cumulative calcium intake (OR=0.36, 95% CI=0.16-0.83), but linear trends were not observed for the frequency or duration of any supplement intake. We did not observe any strong associations between vitamin or mineral supplement intake and the risk of head and neck cancer.
vitamin supplement; mineral supplement; head and neck cancer
To investigate the relationship between non-steroidal anti-inflammatory drug (NSAID) use and the incidence of benign prostatic hyperplasia (BPH)-related outcomes and nocturia, a lower urinary tract symptom (LUTS) of BPH, in light of accumulating evidence suggesting a role for inflammation in BPH/LUTS development.
Patients and methods
At baseline, participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial completed questions on recent, regular aspirin and ibuprofen use, BPH surgery, diagnosis of an enlarged prostate/BPH, and nocturia. Participants in the intervention arm also underwent a digital rectal examination (DRE), from which prostate dimensions were estimated, as well as a prostate-specific antigen (PSA) test. Only participants in the intervention arm without BPH/LUTS at baseline were included in the analysis (n = 4771).
During follow-up, participants underwent annual DREs and PSA tests, provided annual information on finasteride use, and completed a supplemental questionnaire in 2006–2008 that included additional questions on diagnosis of an enlarged prostate/BPH and nocturia.
Information collected was used to investigate regular aspirin or ibuprofen use in relation to the incidence of six BPH/LUTS definitions: diagnosis of an enlarged prostate/BPH, nocturia (waking two or more times per night to urinate), finasteride use, any self-reported BPH/LUTS, prostate enlargement (estimated prostate volume ≥ 30 mL on any follow-up DRE) and elevation in PSA level (> 1.4 ng/mL on any follow-up PSA test).
Generally, null results were observed for any recent, regular aspirin or ibuprofen use (risk ratio = 0.92–1.21, P = 0.043–0.91) and frequency of use (risk ratio for one category increase in NSAID use = 0.98–1.11, P-trends = 0.10–0.99) with incident BPH/LUTS.
The findings obtained in the present study do not support a protective role for recent NSAID use in BPH/LUTS development.
aspirin; benign prostatic hyperplasia; ibuprofen; lower urinary tract symptoms; non-steroidal anti-inflammatory drugs
The insulin-like growth factor (IGF) signaling pathway is involved in cell proliferation and differentiation. Elevated serum IGF1 levels have been associated with increased colorectal cancer risk; however, studies of this association with colorectal adenoma are inconclusive. We examined serum IGF1, IGF2, and IGFBP3 levels in relation to risk of advanced colorectal adenoma in a case-control study within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A total of 764 advanced, left-sided colorectal adenoma cases and 775 controls frequency-matched on gender and ethnicity, without evidence of a left-sided polyp on sigmoidoscopy were included in the current study. Serum levels of IGF1, IGF2, and IGFBP3 were measured using an enzyme linked immunosorbent assay in serum samples collected at baseline. Logistic regression was used to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations adjusting for age, race, sex, year of blood draw, body mass index, smoking, and education. Higher IGF1 levels were associated with increased adenoma risk: ORs = 1.58 (95% CI=1.16–2.16), 1.42 (95% CI=1.04–1.93), and 1.80 (95% CI=1.30–2.47) for the second, third, and fourth quartiles, respectively (Ptrend=0.002). Elevated IGF2 levels were also associated with increased adenoma risk (OR=1.43, 95% CI=1.05–1.96 for the fourth vs. first quartile, Ptrend=0.02), but the association was no longer significant after adjustment for IGF1 (Ptrend=0.28). IGFBP3 levels were not associated with adenoma risk. Our analysis showed a significant positive association between circulating IGF1 levels and risk of advanced colorectal adenoma, suggesting that IGF1 is associated with the pivotal precursor to colorectal cancer.
colorectal adenoma; insulin-like growth factor
Alcohol and tobacco consumption are well recognized risk factors for head and neck cancer (HNC). Evidence suggests that genetic predisposition may also play a role. Only a few epidemiologic studies, however, have considered the relation between HNC risk and family history of HNC and other cancers. We pooled individual- level data across 12 case-control studies including 8,967 HNC cases and 13,627 controls. We obtained pooled odds ratios (OR) using fixed and random effect models, and adjusting for potential confounding factors. All statistical tests were two-sided. A family history of HNC in first-degree relatives increased the risk of HNC (OR=1.7, 95% confidence interval, CI, 1.2-2.3). The risk was higher when the affected relative was a sibling (OR=2.2, 95% CI 1.6-3.1) rather than a parent (OR=1.5, 95% CI 1.1-1.8), and for more distal HNC anatomic sites (hypopharynx and larynx). The risk was also higher, or limited to, subjects exposed to tobacco. The OR rose to 7.2 (95% CI 5.5-9.5) among subjects with family history, who were alcohol and tobacco users. A weak but significant association (OR=1.1, 95% CI 1.0-1.2) emerged for family history of other tobacco-related neoplasms, particularly with laryngeal cancer (OR=1.3, 95% CI 1.1-1.5). No association was observed for family history of non-tobacco related neoplasms and the risk of HNC (OR=1.0, 95% CI 0.9-1.1). Familial factors play a role in the etiology of HNC. In both subjects with and without family history of HNC, avoidance of tobacco and alcohol exposure may be the best way to avoid HNC.
Head and neck cancer; family history; pooled analysis; tobacco; alcohol