Statins Are Associated With a Decreased Risk of Severe Liver Disease in Individuals With Noncirrhotic Chronic Liver Disease

BACKGROUND & AIMS

Little is known about the potential impact of statins on the progression of noncirrhotic chronic liver diseases (CLDs) to severe liver disease.

METHODS

Using liver histopathology data in a nationwide Swedish cohort, we identified 3862 noncirrhotic individuals with CLD and statin exposure, defined as a statin prescription filled for 30 or more cumulative defined daily doses. Statin users were matched to 3862 (statin) nonusers with CLD through direct 1:1 matching followed by propensity score matching. Cox regression was used to estimate hazard ratios (HRs) for the primary outcome of incident severe liver disease (a composite of cirrhosis, hepatocellular carcinoma, and liver transplantation/liver-related mortality).

RESULTS

A total of 45.3% of CLD patients had nonalcoholic fatty liver disease, 21.9% had alcohol-related liver disease, 17.7% had viral hepatitis, and 15.1% had autoimmune hepatitis. During follow-up evaluation, 234 (6.1%) statin users vs 276 (7.1%) nonusers developed severe liver disease. Statin use was associated with a decreased risk of developing severe liver disease (HR, 0.60; 95% CI, 0.48-0.74). Statistically significantly lower rates of severe liver disease were seen in alcohol-related liver disease (HR, 0.30; 95% CI, 0.19-0.49) and in nonalcoholic fatty liver disease (HR, 0.68; 95% CI, 0.45-1.00), but not in viral hepatitis (HR, 0.76; 95% CI, 0.51-1.14) or autoimmune hepatitis (HR, 0.88; 95% CI, 0.48-1.58). Statin use had a protective association in both prefibrosis and fibrosis stages at diagnosis. Statin use was associated with lower rates of progression to cirrhosis (HR, 0.62; 95% CI, 0.49-0.78), hepatocellular carcinoma (HR, 0.44; 95% CI, 0.27-0.71), and liver-related mortality (HR, 0.55; 95% CI, 0.36-0.82).

CONCLUSIONS

Among individuals with noncirrhotic CLD, incident statin use was linked to lower rates of severe liver disease, suggesting a potential disease-modifying role.

Statin use and risk of colorectal cancer in patients with inflammatory bowel disease

Background

Statin use has been linked to a reduced risk of advanced colorectal adenomas, but its association with colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD) - a high risk population for CRC - remains inconclusive.

Methods

From a nationwide IBD cohort in Sweden, we identified 5273 statin users and 5273 non-statin users (1:1 propensity score matching) from July 2006 to December 2018. Statin use was defined as the first filled prescription for ≥30 cumulative defined daily doses and followed until December 2019. Primary outcome was incident CRC. Secondary outcomes were CRC-related mortality and all-cause mortality. Cox regression estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

Findings

During a median follow-up of 5.6 years, 70 statin users (incidence rate (IR): 21.2 per 10,000 person-years) versus 90 non-statin users (IR: 29.2) were diagnosed with incident CRC (rate difference (RD), -8.0 (95% CIs: -15.8 to -0.2 per 10,000 person-years); aHR = 0.76 (95% CIs: 0.61 to 0.96)). The benefit for incident CRC was duration-dependent in a nested case-control design: as compared to short-term use (30 days to <1 year), the adjusted odd ratios were 0.59 (0.25 to 1.43) for 1 to <2 years of use, 0.46 (0.21 to 0.98) for 2 to <5 years of use, and 0.38 (0.16 to 0.86) for ≥5 years of use (Pfor tread = 0.016). Compared with non-statin users, statin users also had a decreased risk for CRC-related mortality (IR: 6.0 vs. 11.9; RD, -5.9 (-10.5 to -1.2); aHR, 0.56 (0.37 to 0.83)) and all-cause mortality (IR: 156.4 vs. 231.4; RD, -75.0 (-96.6 to -53.4); aHR, 0.63 (0.57 to 0.69)).

Interpretation

Statin use was associated with a lower risk of incident CRC, CRC-related mortality, and all-cause mortality. The benefit for incident CRC was duration-dependent, with a significantly lower risk after ≥2 years of statin use.

Funding

This research was supported by Forte (i.e., the Swedish Research Council for Health, Working Life and Welfare).

Lifestyle factors for the prevention of inflammatory bowel disease

OBJECTIVE

To estimate the proportion of cases of Crohn's disease (CD) and ulcerative colitis (UC) that could be prevented by modifiable lifestyle factors.

DESIGN

In a prospective cohort study of US adults from the Nurses' Health Study (NHS; n=72 290), NHSII (n=93 909) and Health Professionals Follow-up Study (HPFS; n=41 871), we created modifiable risk scores (MRS; 0-6) for CD and UC based on established lifestyle risk factors, and healthy lifestyle scores (HLS; 0-9) derived from American healthy lifestyle recommendations. We calculated the population attributable risk by comparing the incidence of CD and UC between low-risk (CD-MRS≤1, UC-MRS≤2, HLS≥7) and high-risk groups. We externally validated our findings in three European cohorts: the Swedish Mammography Cohort (n=37 275), Cohort of Swedish Men (n=40 810) and European Prospective Investigation into Cancer and Nutrition (n=404 144).

RESULTS

Over 5 117 021 person-years of follow-up (NHS, HPFS: 1986-2016; NHSII: 1991-2017), we documented 346 CD and 456 UC cases. Adherence to a low MRS could have prevented 42.9% (95% CI 12.2% to 66.1%) of CD and 44.4% (95% CI 9.0% to 69.8%) of UC cases. Similarly, adherence to a healthy lifestyle could have prevented 61.1% (95% CI 16.8% to 84.9%) of CD and 42.2% (95% CI 1.7% to 70.9%) of UC cases. In our validation cohorts, adherence to a low MRS and healthy lifestyle could have, respectively, prevented 43.9%-51.2% and 48.8%-60.4% of CD cases and 20.6%-27.8% and 46.8%-56.3% of UC cases.

CONCLUSIONS

Across six US and European cohorts, a substantial burden of inflammatory bowel diseases risk may be preventable through lifestyle modification.

Risk Factors for Incident Inflammatory Bowel Disease According to Disease Phenotype

BACKGROUND & AIMS

We examined whether relationships between known risk factors for Crohn's disease (CD) and ulcerative colitis (UC) differ according to disease phenotype, defined by Montreal classification, at the time of diagnosis.

METHODS

We performed a prospective cohort study of 208,070 adults from the Nurses' Health Study (NHS), NHSII, and Health Professionals Follow-Up Study (HPFS). Dietary, lifestyle, and medical data were obtained at baseline and every 2-4 years. We confirmed cases of inflammatory bowel disease (IBD) and their phenotypes via medical record review. We tested for heterogeneity across CD subtypes using the likelihood ratio test and for linear heterogeneity across UC subtypes using the meta-regression method.

RESULTS

We ascertained 346 cases of CD and 456 cases of UC over 5,117,021 person-years of follow-up (1986-2016 for NHS and HPFS; 1991-2017 for NHSII). Fiber intake was associated with decreased risk for ileocolonic but not ileal or colonic CD (Pheterogeneity = .04). Physical activity was associated with decreased risk of nonstricturing and nonpenetrating CD but not of penetrating CD (Pheterogeneity = .02). Higher body mass index and current smoking were associated with decreased risk of proctitis and left-sided UC but not of pan-UC (Plinear heterogeneity= .004 and .02, respectively). The associations between other risk factors examined and risk of CD and UC did not differ by disease phenotype (all Pheterogeneity > .06).

CONCLUSIONS

In 3 large prospective cohorts, we observed that dietary and lifestyle risk factors for IBD may differ according to disease phenotype. These findings highlight the need for disease stratification in future epidemiologic studies.

Association of Proton Pump Inhibitor Use With All-Cause and Cause-Specific Mortality

BACKGROUND & AIMS

The use of proton pump inhibitors (PPIs) has increased rapidly in the past 2 decades. Concerns about the regular use of PPIs contributing to mortality have been raised.

METHODS

We conducted a prospective cohort study using data collected from the Nurses' Health Study (2004-2018) and the Health Professionals Follow-up Study (2004-2018). Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% CIs for mortality according to PPI use. We used a modified lag-time approach to minimize reverse causation (ie, protopathic bias).

RESULTS

Among 50,156 women and 21,731 men followed for 831,407 person-years and a median of 13.8 years, we documented 22,125 deaths, including 4592 deaths from cancer, 5404 from cardiovascular diseases, and 12,129 deaths from other causes. Compared with nonusers of PPIs, PPI users had significantly higher risks of all-cause mortality (HR, 1.19; 95% CI, 1.13-1.24) and mortality due to cancer (HR, 1.30; 95% CI, 1.17-1.44), cardiovascular diseases (HR, 1.13; 95% CI, 1.02-1.26), respiratory diseases (HR, 1.32; 95% CI, 1.12-1.56), and digestive diseases (HR, 1.50; 95% CI, 1.10-2.05). Upon applying lag times of up to 6 years, the associations were attenuated and no longer statistically significant (all-cause: HR, 1.04; 95% CI, 0.97-1.11; cancer: HR, 1.07; 95% CI, 0.89-1.28; cardiovascular diseases: HR, 0.94; 95% CI, 0.81-1.10; respiratory diseases: HR, 1.20; 95% CI, 0.95-1.50; digestive diseases: HR, 1.38; 95% CI, 0.88-2.18). Longer duration of PPI use did not confer higher risks for all-cause and cause-specific mortality.

CONCLUSIONS

After accounting for protopathic bias, PPI use was not associated with higher risks of all-cause mortality and mortality due to major causes.

Ultra-processed Foods and Risk of Crohn's Disease and Ulcerative Colitis: A Prospective Cohort Study

BACKGROUND & AIMS

The rising incidence of inflammatory bowel disease in regions undergoing Westernization has coincided with the increase in ultra-processed food (UPF) consumption over the past few decades. We aimed to examine the association between consumption of UPFs and the risk of Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We performed a prospective cohort study of 3 nationwide cohorts of health professionals in the United States-the Nurses' Health Study (1986-2014), the Nurses' Health Study II (1991-2017), and the Health Professionals Follow-up Study (1986-2012). We employed Cox proportional hazards models with adjustment for confounders to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for CD and UC according to self-reported consumption of UPFs.

RESULTS

The study included 245,112 participants. Over 5,468,444 person-years of follow-up, we documented 369 incident cases of CD and 488 incident cases of UC. The median age at diagnosis was 56 years (range, 29-85 years). Compared with participants in the lowest quartile of simple updated UPF consumption, those in the highest quartile had a significantly increased risk of CD (HR, 1.70; 95% CI, 1.23-2.35; P_trend = .0008). Among different UPF subgroups, ultra-processed breads and breakfast foods; frozen or shelf-stable ready-to-eat/heat meals; and sauces, cheeses, spreads, and gravies showed the strongest positive associations with CD risk (HR per 1 standard deviation increase in intake, 1.18 [95% CI, 1.07-1.29], 1.11 [95% CI, 1.01-1.22], and 1.14 [95% CI, 1.02-1.27], respectively). There was no consistent association between UPF intake and UC risk.

CONCLUSIONS

Higher UPF intake was associated with an increased risk of incident CD. Further studies are needed to identify specific contributory dietary components.

Obesity is Associated With Increased Risk of Crohn's disease, but not Ulcerative Colitis: A Pooled Analysis of Five Prospective Cohort Studies

BACKGROUND AND AIMS

It is unclear whether obesity is associated with the development of inflammatory bowel disease despite compelling data from basic science studies. We therefore examined the association between obesity and risk of Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We conducted pooled analyses of 5 prospective cohorts with validated anthropometric measurements for body mass index (BMI) and waist-hip ratio and other lifestyle factors. Diagnoses of CD and UC were confirmed through medical records or ascertained using validated definitions. We used Cox proportional hazards modeling to calculate pooled multivariable-adjusted HRs (aHRs) and 95% confidence intervals (CIs).

RESULTS

Among 601,009 participants (age range, 18-98 years) with 10,110,018 person-years of follow-up, we confirmed 563 incident cases of CD and 1047 incident cases of UC. Obesity (baseline BMI ≥30 kg/m2) was associated with an increased risk of CD (pooled aHR, 1.34; 95% CI, 1.05-1.71, I2 = 0%) compared with normal BMI (18.5 to <25 kg/m2). Each 5 kg/m2 increment in baseline BMI was associated with a 16% increase in risk of CD (pooled aHR, 1.16; 95% CI, 1.05-1.22; I2 = 0%). Similarly, with each 5 kg/m2 increment in early adulthood BMI (age, 18-20 years), there was a 22% increase in risk of CD (pooled aHR, 1.22; 95% CI, 1.05-1.40; I2 = 13.6%). An increase in waist-hip ratio was associated with an increased risk of CD that did not reach statistical significance (pooled aHR across quartiles, 1.08; 95% CI, 0.97-1.19; I2 = 0%). No associations were observed between measures of obesity and risk of UC.

CONCLUSIONS

In an adult population, obesity as measured by BMI was associated with an increased risk of older-onset CD but not UC.

Plasma concentrations of perfluoroalkyl substances and risk of inflammatory bowel diseases in women: A nested case control analysis in the Nurses' Health Study cohorts

BACKGROUND

Perfluoroalkyl substances (PFASs) are synthetic compounds used in a wide variety of industrial and consumer applications. An association between PFAS exposure and risk of ulcerative colitis (UC) has been reported in a highly exposed population. However, data are limited on risk of inflammatory bowel diseases (IBD) among individuals with background population levels of PFAS exposure.

OBJECTIVES

We set out to examine the association between plasma PFAS concentrations and risk of IBD among women in two population-based, prospective cohort studies in which pre-diagnostic blood specimens were available.

METHODS

We conducted a nested case-control study in the Nurses' Health Study and Nurses' Health Study II cohorts. We identified 73 participants with incident Crohn's disease (CD) and 80 participants with incident UC who had provided blood samples before diagnosis. Cases were matched 1:2 to IBD-free controls. Plasma concentrations of five major PFASs were measured by liquid chromatography and tandem mass spectrometry. We used conditional logistic models to estimated odds ratios for risk of IBD according to log10-transformed PFAS concentrations, adjusting for potential confounders.

RESULTS

In multivariable models, we observed inverse associations between plasma concentrations of three PFASs and risk of CD (all P ≤ 0.012 for a standard deviation increase in log10PFAS). The inverse association with CD was strongest for perfluorodecanoate, where, compared to the lowest tertile, the odds ratio (OR) for the highest tertile was 0.39 (95% confidence interval, 0.17-0.92). No associations were observed between PFAS concentrations and UC risk.

DISCUSSION

Our results do not support the hypothesis that elevated PFAS exposure is associated with higher risk of UC. Contrary to expectation, our data suggest that circulating concentrations of some PFASs may be inversely associated with CD development.

Association of midlife antibiotic use with subsequent cognitive function in women

The gut microbiome is increasingly recognized to play a role in cognition and dementia. Antibiotic use impacts the gut microbiome and has been linked with chronic disease. Despite these data, there is no evidence supporting an association between long-term antibiotic use in adults and cognitive function. We conducted a prospective population-based cohort study among 14,542 participants in the Nurses’ Health Study II who completed a self-administered computerized neuropsychological test battery between 2014–2018. Multivariate linear regression models were used to assess if chronic antibiotic use in midlife was associated with cognitive impairment assessed later in life. Women who reported at least 2 months of antibiotic exposure in midlife (mean age 54.7, SD 4.6) had lower mean cognitive scores seven years later, after adjustment for age and educational attainment of the spouse and parent, with a mean difference of -0.11 standard units for the global composite score (P_trend <0.0001), -0.13 for a composite score of psychomotor speed and attention (P_trend <0.0001), and -0.10 for a composite score of learning and working memory (P_trend <0.0001) compared with non-antibiotic users. These differences were not materially changed after multivariate adjustment for additional risk factors, including comorbid conditions. As a benchmark, the mean difference in score associated with each additional year of age was (-0.03) for global cognition, (-0.04) for psychomotor speed and attention, and (-0.03) for learning and working memory; thus the relation of antibiotic use to cognition was roughly equivalent to that found for three to four years of aging. Long-term antibiotic use in midlife is associated with small decreases in cognition assessed seven years later. These data underscore the importance of antibiotic stewardship, especially among aging populations.

Smoking Behaviour Changes After Diagnosis of Inflammatory Bowel Disease and Risk of All-cause Mortality

BACKGROUND AND AIMS

We examined smoking behaviour changes after diagnoses of Crohn's disease [CD] and ulcerative colitis [UC] and evaluated their impact on mortality.

METHODS

Study population included incident CD or UC cases from three cohorts of the Nurses' Health Study [NHS], NHSII, and Health Professionals Follow-up Study. Smoking and other risk factors were prospectively assessed. Smoking behaviour changes were categorised as never, former [i.e., quit smoking before diagnosis], quitters [i.e., quit smoking after diagnosis], and current [i.e., continue smoking after diagnosis]. Follow-up for date and cause of death was completed through linkage to the National Death Index. Cox proportional hazard regression was used to estimate hazard ratios [HRs] and 95% confidence intervals [CIs].

RESULTS

Among 909 eligible CD and UC cases, 45% were never smokers, 38% were past smokers, and 16% were active smokers at the time of diagnosis. Among active smokers, 70% of patients with CD and 44% of patients with UC continued to smoke after diagnosis. In patients with CD, compared with current smokers, the multivariable-adjusted HRs [95% CI] of death were 0.19 [0.10 to 0.38] for never smokers, 0.31 [0.16 to 0.57] for former smokers, and 0.41 [0.18 to 0.93] for quitters. Similarly for UC, compared with current smokers, we observed a reduced risk of mortality for never smokers [HR = 0.23, 95% CI 0.10 to 0.51], former smokers [HR = 0.23, 95% CI 0.11 to 0.48], and quitters [HR = 0.28, 95% CI 0.11 to 0.72].

CONCLUSIONS

In three cohorts of health professionals, a substantial proportion of patients with new diagnosis of CD and UC and history of smoking continued to smoke after diagnosis. Smoking cessation around the time of diagnosis was associated with a significant reduction in mortality.

Dietary Gluten Intake Is Not Associated With Risk of Inflammatory Bowel Disease in US Adults Without Celiac Disease

BACKGROUND & AIMS

Diet is thought to play a role in the development of inflammatory bowel disease (IBD), though it is unknown whether gluten intake confers risk of IBD. The aim of this study was to determine the relationship between gluten intake and risk of incident Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We performed a prospective cohort study of 208,280 US participants from the Nurses' Health Study (1986-2016), Nurses' Health Study II (1991-2017), and the Health Professionals Follow-up Study (1986-2016) who did not have IBD at baseline or celiac disease, and who completed semiquantitative food frequency questionnaires. We used Cox proportional hazards modeling to estimate the risk of IBD according to quintiles of cumulative average energy-adjusted dietary gluten intake over the follow-up period.

RESULTS

We documented 337 CD cases and 447 UC cases over 5,115,265 person-years of follow-up evaluation. Dietary gluten intake was not associated with risk of IBD. Compared with participants in the lowest quintile of gluten intake, the adjusted hazard ratios and 95% CIs for participants in the highest quintile of gluten intake were 1.16 (95% CI, 0.82-1.64; P_trend = .41) for CD and 1.04 (95% CI, 0.75-1.44; P_trend = .64) for UC. Adjusting for primary sources of gluten intake did not materially change our estimates.

CONCLUSIONS

In 3 large adult US prospective cohorts, gluten intake was not associated with risk of CD or UC. Our findings are reassuring at a time when consumption of gluten has been increasingly perceived as a trigger for chronic gastrointestinal diseases.

Alcohol consumption and risk of inflammatory bowel disease among three prospective US cohorts

BACKGROUND AND AIMS

There are limited data on alcohol dose and types and risk of Crohn's Disease (CD) and Ulcerative Colitis (UC). We therefore sought to comprehensively examine the association between alcohol consumption and risk of CD and UC.

METHODS

We conducted a prospective cohort study of 237,835 participants from the Nurses' Health Study, Nurses' Health Study II, and Health Professional Follow-Up Study. Alcohol consumption was obtained through questionnaires submitted every four years; additional covariates were obtained at two or four-year intervals. Cases were confirmed independently by two physicians through medical record review. We used Cox proportional hazards regression to estimate age and multivariable-adjusted hazards ratios and 95% confidence intervals.

RESULTS

Across 5,170,474 person-years of follow-up, 370 cases of CD and 486 cases of UC were documented. Increased consumption of alcohol intake was not associated with CD (Ptrend = 0.455) or UC (Ptrend = 0.745). Compared to non-users, the MV-adjusted HRs for 15.0 + g/day of alcohol intake group were 0.84 (95% CI 0.56, 1.24) for CD and 1.08 (95% CI 0.77, 1.51) for UC. In analyses of alcohol subtypes, we observed that only moderate consumption of beer (>1-4 servings/week) was marginally associated with reduced risk of CD, while consumption of >4 servings/week of liquor was associated with an increased risk of UC.

CONCLUSION

This prospective study did not identify a relationship between overall alcohol consumption and risk of CD or UC. Our suggestive associations between alcohol types and risk of CD and UC deserve additional investigation.

Alcohol Consumption is Associated With An Increased Risk of Microscopic Colitis: Results From 2 Prospective US Cohort Studies

BACKGROUND

No dietary factors have yet been shown to conclusively impact the incidence of microscopic colitis (MC). Here, we sought to examine the relationship between alcohol intake and the risk of MC.

METHODS

We conducted a prospective cohort study of 209,902 participants (age range, 28.5-66.7 years) enrolled in the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII). Validated data on alcohol consumption were collected at baseline in 1986 in the NHS and 1991 in the NHSII and updated every 4 years. Diagnoses of MC were confirmed via review of histopathology data. We used Cox proportional hazards modeling to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

RESULTS

Through 2016 in the NHS and 2017 in the NHSII, we confirmed 352 incident cases of MC over 4,994,324 person-years. Higher alcohol consumption was associated with an increased risk of MC (Ptrend < .001). Compared to non-users, the aHRs of MC were 1.20 (95% CI, 0.86-1.67) for consumers of 0.1-4.9 g/day of alcohol, 1.90 (95% CI, 1.34-2.71) for consumers of 5-14.9 g/day, and 2.31 (95% CI, 1.54-3.46) for consumers of ≥15 g/day. The associations were consistent across the histologic subtypes of collagenous and lymphocytic colitis (Pheterogeneity = .523). When stratified by alcohol type, the risk according to every 2 servings/week appeared to be strongest with consumption of wine (aHR, 1.08; 95% CI, 1.04-1.12) as compared to beer (aHR, 1.01; 95% CI, 0.91-1.12) or liquor (aHR, 1.00; 95% CI, 0.92-1.09).

CONCLUSIONS

Alcohol consumption was associated with an increased risk of MC. Further studies are needed to determine the mechanism underlying these associations, as well as the impact of reducing alcohol intake in patients with MC.

Histological differences between lumbar and tail intervertebral discs in mice

Both the lumbar and tail intervertebral discs (IVD) of mice serve as models for the pathogenesis and histologic progression of degenerative disc disease. Recent studies in mature mice, however, demonstrate that the mechanics and physical attributes of lumbar and tail IVD‐endplate (EP)‐interfaces are strikingly different. We hypothesized that these structural disparities are associated with differences in the composition and organization of soft tissue elements that influence the biomechanical properties of the spine. Lumbar and tail vertebral segments and discs were collected from the same C57BL/6N and C57BL/6JRj mice, respectively for histological comparison of coronal sections at the ages of 4 weeks (weaned, both strains, C57BL/6N: n = 7; C57BL/6JRj: n = 4), three (mature, C57BL/6N: n = 7; C57BL/6JRj: n = 4), twelve (middle aged, C57BL/6JRj only: n = 3) and eighteen (old, C57BL/6JRj only: n = 3) months old. The histology of lumbar and tail IVD‐EP‐interfaces of mature mice differed markedly. The lumbar IVD‐EP‐interphase was characterized by a broad cartilaginous EP, while the tail IVD‐EP‐interphase comprised a thin layer of cartilage cells adjacent to a broad bony layer abutting the vertebral growth plate. Furthermore, the composition of the nuclei pulposi (NP) of lumbar and tail IVD in mature mice differed greatly. Lumbar NP consisted of a compact cluster of mainly large, uni‐vacuolated cells centered in an amorphous matrix, while tail NP were composed of a loose aggregate of vacuolated and non‐vacuolated cells. The anuli fibrosi also differed, with more abundant and sharply defined lamellae in tail compared to lumbar discs. The observed histological differences in the EP were even most prominent in weaned mice but were still discernible in middle‐aged and old mice. An appreciation of the histological differences between lumbar and tail IVD components in mice, including nucleus pulposus, annulus fibrosus, and endplates, is essential to our understanding of spinal biomechanics in these animals and should inform the design and interpretation of future IVD‐studies.

Long-term Intake of Gluten and Cognitive Function Among US Women

IMPORTANCE

Gluten avoidance has been suggested as having a benefit to cognitive health among the general population, given the link between gluten and cognitive impairment in patients with celiac disease. However, data are lacking in individuals without celiac disease.

OBJECTIVE

To examine whether gluten intake is associated with cognitive function in women without celiac disease.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included US women who participated in the longitudinal, population-based Nurses' Health Study II and had not previously or subsequently been diagnosed with celiac disease. Dietary data were collected from 1991 to 2015, and data on cognitive function were collected from 2014 to 2019. Data analysis was conducted from October 2020 to April 2021.

EXPOSURES

Energy-adjusted gluten intake, cumulatively averaged across questionnaire cycles prior to cognitive assessment.

MAIN OUTCOMES AND MEASURES

Three standardized cognitive scores assessed by the validated Cogstate Brief Battery: (1) psychomotor speed and attention score, (2) learning and working memory score, and (3) global cognition score. Higher scores indicated better performance.

RESULTS

The cohort included 13 494 women (mean [SD] age, 60.6 [4.6] years). The mean (SD) gluten intake was 6.3 (1.6) g/d. After controlling for demographic and lifestyle risk factors in linear regression, no significant differences in standardized cognitive scores (mean [SD], 0 [1]) by quintile of gluten intake were found across highest and lowest quintiles of gluten intake (psychomotor speed and attention: -0.02; 95% CI, -0.07 to 0.03; P for trend = .22; learning and working memory: 0.02; 95% CI, -0.03 to 0.07; P for trend = .30; global cognition: -0.002; 95% CI, -0.05 to 0.05; P for trend = .78). The null associations persisted after additional adjustment for major sources of dietary gluten (ie, refined grains or whole grains), comparing decile categories of gluten intake, using gluten intake updated at each previous questionnaire cycle, or modeling changes in gluten intake. Similarly, these associations were not materially altered in sensitivity analyses that excluded women who had reported cancer or dementia diagnosis or had not completed all dietary assessments.

CONCLUSIONS AND RELEVANCE

In this study, long-term gluten intake was not associated with cognitive scores in middle-aged women without celiac disease. Our results do not support recommendations to restrict dietary gluten to maintain cognitive function in the absence of celiac disease or established gluten sensitivity.

Inflammatory bowel disease and risk of severe COVID-19: A nationwide population-based cohort study in Sweden

BACKGROUND

There are concerns that individuals with chronic immune-mediated diseases are at increased risk of COVID-19 and related severe adverse outcome, including intensive care admission or death. We aimed to explore the absolute and relative risk of severe COVID-19 in inflammatory bowel disease (IBD).

METHODS

This population-based cohort study used nationwide registers in Sweden, with 67,292 individuals with a diagnosis of IBD 1969-2017 (Crohn's disease, n = 21,599; ulcerative colitis: n = 43,622; IBD-unclassified: n = 2071) and alive on 1 February 2020. Patients with IBD were matched to up to five controls from the general population (n = 297,910). Cox regression estimated hazard ratios (HRs) for (i) hospital admission with laboratory-confirmed COVID-19 as the primary diagnosis, and (ii) severe COVID-19 (composite outcome consisting of (a) COVID-19 intensive care admission, or (b) death from COVID-19 or (c) death within 30 days of COVID-19 hospital admission), were calculated. Analyses were conditioned on age, sex, calendar period, and county and adjusted for other comorbidities.

RESULTS

Between 1 February and 31 July 2020, 179 (0.27%) IBD patients and 500 (0.17%) general population controls were admitted to hospital with COVID-19 (adjusted HR [aHR] = 1.43; 95% CI = 1.19-1.72). The corresponding numbers for severe COVID-19 was 65 (0.10%) and 183 (0.06%; aHR = 1.11; 95% CI = 0.81-1.52). Adjusted HRs were similar in Crohn's disease and ulcerative colitis. In a propensity score-matched model taking comorbidity into account until 2016, the increased risk for COVID-19 hospital admission remained (aHR = 1.32; 1.12-1.56), but there was no increased risk of severe COVID-19 (aHR = 1.12; 0.85-1.47).

CONCLUSIONS

While individuals with IBD were more likely to be admitted to hospital for COVID-19 than the general population, the risk of severe COVID-19 was not higher.

Immune-mediated diseases and risk of Crohn's disease or ulcerative colitis: a prospective cohort study

BACKGROUND

Although immune-mediated diseases (IMDs) including inflammatory bowel diseases (IBDs) are known to cluster, to what extent this is due to common environmental influences is unknown.

AIM

To examine the incidence of IBD in individuals with another IMD.

METHODS

We used data from the prospective Nurses' Health Study II cohort (1995-2017) to examine the effect of diagnoses of several common IMDs on subsequent risk of Crohn's disease (CD) or ulcerative colitis (UC) using Cox proportional hazards models, adjusting for detailed diet and lifestyle confounders.

RESULTS

We documented 132 cases of CD and 186 cases of UC over 2 016 163 person-years of follow-up (median age at IBD diagnosis 50 years). Compared to participants with no history of IMD, the HRs of CD for those with 1 and ≥ 2 IMDs were 2.57 (95% CI 1.77-3.74) and 2.74 (95% CI 1.36 to 5.49), respectively (P_trend  < 0.0001). This association was only modestly attenuated by adjustment for environmental risk factors (HR 2.35 and 2.46, respectively). The risk of UC was not increased, with multivariable-adjusted HRs of 1.22 (95% CI 0.85-1.76) and 1.33 (95% CI 0.67-2.65) for those with 1 and ≥ 2 IMDs, respectively, compared to those with none (P_trend 0.16) (P_{heterogeneity} comparing CD and UC 0.037). Asthma, atopic dermatitis, psoriasis and rosacea were individually associated with higher risk of CD (HR ranging from 2.15 to 3.39) but not UC.

CONCLUSIONS

Individuals with one or more IMDs are at an increased risk for CD but not UC.

Healthy Lifestyle Is Associated With Reduced Mortality in Patients With Inflammatory Bowel Diseases

BACKGROUND & AIMS

It is not clear whether a healthy lifestyle affects mortality of patients with inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We collected data form the Nurses' Health Study (1986-2014), Nurses' Health Study II (1991-2015), and Health Professionals Follow-up Study (1986-2014), which assess lifestyles with serial questionnaires. We estimated joint and individual associations between 5 healthy lifestyle factors after IBD diagnosis (never smoking, body mass index 18.5-24.9 kg/m², vigorous physical activity in the highest 50% with non-zero value, alternate Mediterranean diet score ≥4, and light drinking [0.1-5.0 g/d]) and mortality using Cox proportional hazards models.

RESULTS

We documented 83 deaths in 363 patients with CD during 4741 person-years and 80 deaths in 465 patients with UC during 6061 person-years. The median age of IBD diagnosis was 55 y. Compared to patients with IBD with no healthy lifestyle factors, patients with IBD with 3-5 healthy lifestyle factors had a significant reduction in all-cause mortality (hazard ratio [HR], 0.29; 95% CI, 0.16-0.52; P_trend < .0001). This reduction was significant in patients with CD (P_trend = .003) as well as in patients with UC (P_trend = .0003). Individual associations were more than 25 pack-years (HR, 1.92; 95% CI, 1.24-2.97; P_trend < .0001), physical activity (HR according to quintiles, 0.55-0.31; P_trend = .001), Mediterranean diet (HR, 0.69; 95% CI, 0.49-0.98), and alcohol consumption (HR_{0.1-5 g/d} 0.61; 95% CI, 0.39-0.95 vs HR_{>15 g/d} 1.84; 95% CI, 1.02-3.32). The findings did not change when we adjusted for family history of IBD, immunomodulator use, and IBD-related surgery.

CONCLUSIONS

In an analysis of data from 3 large cohort studies, we associated adherence to a healthy lifestyle with reduced mortality in patients with CD or UC.

Association Between Statin Use and Inflammatory Bowel Diseases: Results from a Swedish, Nationwide, Population-based Case-control Study

BACKGROUND

In addition to their potent lipid-lowering action, statins may modulate inflammation. However, data on statin use and the risk of inflammatory bowel diseases [IBD] have been inconsistent.

METHODS

We searched the Nationwide Swedish Patient Register [inpatient and non-primary outpatient care] to identify adults diagnosed with Crohn's disease [CD, n = 7637] or ulcerative colitis [UC, n = 15 652] from 2006 to 2014. Each case was matched to 10 general population controls [n = 232 890]. Data on dispensed statin prescriptions were extracted from the Prescribed Drug Register. Conditional logistic regression models estimated odds ratios [ORs] for risk of IBD according to statin exposure while controlling for potential confounders, including indications for statin therapy.

RESULTS

In multivariable adjusted models, compared with no statin use, any statin use was associated with a lower risk of CD (OR = 0.71; 95% confidence interval [CI], 0.63-0.79), but not UC [OR = 1.03; 95% CI, 0.96-1.11]. The lowest OR for CD was seen for current statin use [OR = 0.67; 95% CI, 0.60-0.75]. For CD, the lowest category of cumulative statin dose [31-325 defined daily dose, DDD] was associated with an OR of 0.73 [95% CI, 0.61-0.88] and the highest category [>1500 DDD] with an OR of 0.66 [95% CI, 0.55-0.80], ptrend = 0.10. For UC, the lowest and highest dose categories yielded ORs of 1.12 [95% CI, 1.00-1.25] and 0.99 [95% CI, 0.88-1.13], respectively, ptrend = 0.13.

CONCLUSIONS

Statin use was associated with a lower risk of CD, but not of UC. The association with CD risk appeared strongest for current statin use. Our findings suggest that statin use may influence the development of CD.

Immunosuppressive Therapy and Risk of COVID-19 Infection in Patients With Inflammatory Bowel Diseases

BACKGROUND

The effect of immunosuppressive treatment for immune-mediated diseases on risk of the novel coronavirus disease 2019 (COVID-19) has not been established. We aimed to define the effect of targeted biologic and immunomodulator therapy on risk of COVID-19 in a multi-institutional cohort of patients with inflammatory bowel disease (IBD).

METHODS

We identified patients 18 years and older who received care for IBD at Partners Healthcare between January 2019 and April 2020. The primary outcome was development of COVID-19 defined as a positive polymerase chain reaction test for severe acute respiratory syndrome coronavirus 2. Multivariable regression models were used to examine the effect of immunosuppression on risk of COVID-19 and its outcomes.

RESULTS

In a cohort of 5302 IBD patients, 39 (0.7%) developed COVID-19. There was no difference in age, sex, or race between IBD patients with and without COVID-19. The rate of COVID-19 was similar between patients treated with immunosuppression (0.8%) compared with those who were not (0.64%; P = 0.55). After adjusting for age, sex, race, and comorbidities, use of immunosuppressive therapy was not associated with an increased risk of COVID-19 (odds ratio, 1.73; 95% confidence interval, 0.82-3.63). The presence of obesity was associated with a higher risk of COVID-19 (odds ratio, 8.29; 95% confidence interval, 3.72-18.47). There were 7 hospitalizations, 3 intensive care unit stays, and 1 death. Older age and obesity but not immunosuppressive treatment were associated with severe COVID-19 infection.

CONCLUSIONS

The use of systemic immunosuppression was not associated with an increased risk of COVID-19 in a multi-institutional cohort of patients with IBD.

Adherence to a Mediterranean diet is associated with a lower risk of later-onset Crohn's disease: results from two large prospective cohort studies

OBJECTIVE

To examine the relationship between Mediterranean diet and risk of later-onset Crohn's disease (CD) or ulcerative colitis (UC).

DESIGN

We conducted a prospective cohort study of 83 147 participants (age range: 45-79 years) enrolled in the Cohort of Swedish Men and Swedish Mammography Cohort. A validated food frequency questionnaire was used to calculate an adherence score to a modified Mediterranean diet (mMED) at baseline in 1997. Incident diagnoses of CD and UC were ascertained from the Swedish Patient Register. We used Cox proportional hazards modelling to calculate HRs and 95% CI.

RESULTS

Through December of 2017, we confirmed 164 incident cases of CD and 395 incident cases of UC with an average follow-up of 17 years. Higher mMED score was associated with a lower risk of CD (P_trend=0.03) but not UC (P_trend=0.61). Compared with participants in the lowest category of mMED score (0-2), there was a statistically significant lower risk of CD (HR=0.42, 95% CI 0.22 to 0.80) but not UC (HR=1.08, 95% CI 0.74 to 1.58). These associations were not modified by age, sex, education level, body mass index or smoking (all P_interaction >0.30). The prevalence of poor adherence to a Mediterranean diet (mMED score=0-2) was 27% in our cohorts, conferring a population attributable risk of 12% for later-onset CD.

CONCLUSION

In two prospective studies, greater adherence to a Mediterranean diet was associated with a significantly lower risk of later-onset CD.

Dietary Inflammatory Potential and Risk of Crohn's Disease and Ulcerative Colitis

BACKGROUND & AIMS

Inflammation is a potential mechanism through which diet modulates the onset of inflammatory bowel disease. We analyzed data from 3 large prospective cohorts to determine the effects of dietary inflammatory potential on the risk of developing Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We collected data from 166,903 women and 41,931 men in the Nurses' Health Study (1984-2014), Nurses' Health Study II (1991-2015), and Health Professionals Follow-up Study (1986-2012). Empirical dietary inflammatory pattern (EDIP) scores were calculated based on the weighted sums of 18 food groups obtained via food frequency questionnaires. Self-reported CD and UC were confirmed by medical record review. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

We documented 328 cases of CD and 428 cases of UC over 4,949,938 person-years of follow-up. The median age at IBD diagnosis was 55 years (range 29-85 years). Compared with participants in the lowest quartile of cumulative average EDIP score, those in the highest quartile (highest dietary inflammatory potential) had a 51% higher risk of CD (HR 1.51; 95% CI 1.10-2.07; P_trend = .01). Compared with participants with persistently low EDIP scores (at 2 time points, separated by 8 years), those with a shift from a low to high inflammatory potential of diet or persistently consumed a proinflammatory diet had greater risk of CD (HR 2.05; 95% CI 1.10-3.79 and HR 1.77; 95% CI 1.10-2.84). In contrast, dietary inflammatory potential was not associated with the risk of developing UC (P_trend = .62).

CONCLUSIONS

In an analysis of 3 large prospective cohorts, we found dietary patterns with high inflammatory potential to be associated with increased risk of CD but not UC.

Acid-suppressive medications and risk of colorectal cancer: results from three large prospective cohort studies

BACKGROUND

Despite several plausible biological mechanisms linking proton pump inhibitors (PPIs) and H2 receptor antagonists (H2RAs) with colorectal tumorigenesis, their association with risk of colorectal cancer (CRC) has not been adequately assessed in prospective epidemiological studies.

METHODS

We evaluated the association of acid-suppressive medication use with CRC risk among 175,871 (PPI) and 208,831 (H2RA) participants from three large prospective cohort studies. Medication use was assessed at baseline and updated biennially. The association was evaluated using multivariate Cox proportional hazards regression models.

RESULTS

There was no significant association between baseline PPI use (hazard ratio (HR) = 0.89, 95% confidence interval (CI), 0.71-1.12) or PPI use after a lag of 8-10 years (HR = 1.12, 95% CI, 0.78-1.59) with CRC risk. We observed no significant association between H2RA use after a lag of 8-10 years and CRC risk (HR = 1.02, 95% CI, 0.81-1.28), while risk was lower for participants with baseline H2RA use (HR = 0.76, 95% CI, 0.60-0.95). Duration of PPI use or H2RA use was not associated with CRC risk (P-trend = 0.21 and 0.95, respectively).

CONCLUSIONS

Among participants from three large prospective cohorts, use of PPI or H2RA was not associated with higher risk of colorectal cancer.

Obesity and Weight Gain Since Early Adulthood Are Associated With a Lower Risk of Microscopic Colitis

BACKGROUND & AIMS

Obesity promotes intestinal inflammation and might contribute to the pathogenesis of inflammatory bowel disease. We examined the association between obesity and risk of microscopic colitis in a prospective cohort study.

METHODS

We collected data from 192,101 women enrolled in the Nurses' Health Study (NHS) (from 1986 through 2014) or the NHSII (from 1991 through 2015). Anthropomorphic and lifestyle information were self-reported biennially. Obesity was defined using body mass index (BMI). Microscopic colitis was confirmed by review of medical records. We used Cox proportional hazard models to estimate adjusted hazard ratios (aHRs) and 95% CIs.

RESULTS

Among the participants in the NHS and NHSII, we confirmed 244 cases of microscopic colitis during 4,223,868 person-years of follow-up evaluation. Higher BMI was associated inversely with risk of microscopic colitis (Ptrend < .001). Compared with women with BMIs ranging from 18.5 to 20.9 kg/m², the aHRs were 0.61 (95% CI, 0.41-0.91) for overweight women (BMI, 25-29.9 kg/m²) and 0.50 (95% CI, 0.32-0.79) for obese women (BMI ≥ 30 kg/m²). The aHR for each 5-kg/m² increase in BMI was 0.79 (95% CI, 0.69-0.90). Weight gain since early adulthood (age, 18 y) also was associated inversely with risk of microscopic colitis (Ptrend = .001). The aHR for each 10-kg weight gain since early adulthood was 0.85 (95% CI, 0.77-0.94). The associations were not modified by age, cohort, physical activity, or smoking status (all Pinteraction ≥ .26).

CONCLUSIONS

Unlike many other immune- and metabolic-related disorders, obesity and weight gain since early adulthood were associated with a lower risk of microscopic colitis, based on an analysis of participants in the NHS and NHSII.

Integrative Genome-Scale DNA Methylation Analysis of a Large and Unselected Cohort Reveals 5 Distinct Subtypes of Colorectal Adenocarcinomas

BACKGROUND & AIMS

Colorectal cancer is an epigenetically heterogeneous disease, however, the extent and spectrum of the CpG island methylator phenotype (CIMP) is not clear.

METHODS

Genome-scale methylation and transcript expression were measured by DNA Methylation and RNA expression microarray in 216 unselected colorectal cancers, and findings were validated using The Cancer Genome Atlas 450K and RNA sequencing data. Mutations in epigenetic regulators were assessed using CIMP-subtyped Cancer Genome Atlas exomes.

RESULTS

CIMP-high cancers dichotomized into CIMP-H1 and CIMP-H2 based on methylation profile. KRAS mutation was associated significantly with CIMP-H2 cancers, but not CIMP-H1 cancers. Congruent with increasing methylation, there was a stepwise increase in patient age from 62 years in the CIMP-negative subgroup to 75 years in the CIMP-H1 subgroup (P < .0001). CIMP-H1 predominantly comprised consensus molecular subtype 1 cancers (70%) whereas consensus molecular subtype 3 was over-represented in the CIMP-H2 subgroup (55%). Polycomb Repressive Complex-2 (PRC2)-marked loci were subjected to significant gene body methylation in CIMP cancers (P < 1.6 × 10^-78). We identified oncogenes susceptible to gene body methylation and Wnt pathway antagonists resistant to gene body methylation. CIMP cluster-specific mutations were observed in chromatin remodeling genes, such as in the SWItch/Sucrose Non-Fermentable and Chromodomain Helicase DNA-Binding gene families.

CONCLUSIONS

There are 5 clinically and molecularly distinct subgroups of colorectal cancer. We show a striking association between CIMP and age, sex, and tumor location, and identify a role for gene body methylation in the progression of serrated neoplasia. These data support our recent findings that CIMP is uncommon in young patients and that BRAF mutant polyps in young patients may have limited potential for malignant progression.

Dietary Gluten Intake and Risk of Microscopic Colitis Among US Women without Celiac Disease: A Prospective Cohort Study

OBJECTIVE

Microscopic colitis is a common cause of chronic watery diarrhea among the elderly. Although the prevalence of celiac disease appears to be higher in patients with microscopic colitis, the relationship between dietary gluten intake and risk of microscopic colitis among individuals without celiac disease has not been explored.

METHODS

We conducted a prospective study of 160,744 US women without celiac disease enrolled in the Nurses' Health Study (NHS) and the NHSII. Dietary gluten intake was estimated using validated food frequency questionnaires every 4 years. Microscopic colitis was confirmed through medical records review. We used Cox proportional hazard modeling to estimate the multivariable-adjusted hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

We documented 219 incident cases of microscopic colitis over more than 20 years of follow-up encompassing 3,716,718 person-years (crude incidence rate: 5.9/100,000 person-years) in NHS and NHSII. Dietary gluten intake was not associated with risk of microscopic colitis (Ptrend = 0.88). Compared to individuals in the lowest quintile of energy-adjusted gluten intake, the adjusted HR of microscopic colitis was 1.18 (95% CI: 0.77-1.78) for the middle quintile and 1.03 (95% CI: 0.67-1.58) for the highest quintile. Additional adjustment for primary dietary sources of gluten including refined and whole grains did not materially alter the effect estimates (All Ptrend ≥ 0.69). The null association did not differ according to lymphocytic or collagenous subtypes (Pheterogeneity = 0.72) and was not modified by age, smoking status, or body mass index (All Pinteraction ≥ 0.17).

CONCLUSIONS

Dietary gluten intake during adulthood was not associated with risk of microscopic colitis among women without celiac disease.

Identification of Menopausal and Reproductive Risk Factors for Microscopic Colitis-Results From the Nurses' Health Study

BACKGROUND & AIMS

Microscopic colitis is a chronic inflammatory disorder of the colon primarily affecting postmenopausal women. However, the relation between hormonal determinants, including reproductive and menopausal factors, and risk of microscopic colitis has yet to be characterized.

METHODS

We collected data from 227,766 women who participated in the Nurses' Health Study (NHS) and the NHSII without a baseline history of microscopic colitis. Reproductive and menopausal factors were assessed in 1988 in the NHS and 1989 in the NHSII and updated biennially. Cases of microscopic colitis were confirmed through review of pathology records. We used Cox proportional hazards modeling to estimate hazard ratios and 95% confidence intervals.

RESULTS

Through 2014 in the NHS and 2015 in the NHSII, we confirmed 275 incident cases of microscopic colitis over 5,147,282 person-years. Compared with never use, current use of menopausal hormone therapy was associated with increased risk of microscopic colitis (multivariable-adjusted hazard ratio 2.64; 95% confidence interval 1.78-3.90). The risk increased with longer duration of use (P for trend < .0001) and decreased after discontinuation (P for trend = .002). The association did not differ according to disease subtype (P for heterogeneity = .34). Similarly, ever use of oral contraceptives was associated with increased risk of microscopic colitis (multivariable-adjusted hazard ratio 1.57; 95% confidence interval 1.16-2.13). There were no associations between age at menarche, parity, age at first birth, age at menopause, or menopause type and incident microscopic colitis.

CONCLUSIONS

In 2 large prospective cohort studies, we observed an association between exogenous hormone use and incident microscopic colitis. Further studies are needed to determine the mechanisms underlying these associations.

IRGM Gene Variants Modify the Relationship Between Visceral Adipose Tissue and NAFLD in Patients With Crohn's Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized comorbidity in Crohn's disease (CD), but the mechanisms are poorly understood. Autophagy is a highly conserved process regulating innate immunity that contributes to CD susceptibility. Emerging data suggest that variants in the autophagy-governing IRGM gene may contribute to the accumulation of visceral adipose tissue (VAT) and hepatic fat. Our objective was to characterize the relationship between VAT, IRGM gene variants, and NAFLD risk in patients with CD.

METHODS

We included all CD patients in the Prospective Registry in Inflammatory Bowel Disease Study at Massachusetts General Hospital (PRISM) without history of alcohol abuse or liver disease. Hepatic fat was quantified by liver attenuation (LA) on computed tomography, with NAFLD defined by the validated liver:spleen (L:S) ratio. NAFLD severity was estimated by the FIB-4 Index and alanine aminotransferase (ALT). Using logistic regression modeling, we examined the relationship between VAT, autophagy gene variants, and NAFLD risk.

RESULTS

Among 462 patients, 52% had NAFLD. Increasing VAT quartile was associated with reduced LA (mean change, -7.43; 95% confidence interval [CI], -10.05 to -4.81; Ptrend < 0.0001). In the fully adjusted model, patients in the highest VAT quartile had a 2.2-fold increased NAFLD risk (95% CI, 1.21 to 4.14; Ptrend = 0.032) and a 4.2-fold increased risk of ALT>upper limit of normal (ULN) (95% CI, 1.19 to 14.76; Ptrend = 0.017). The relationship between VAT and NAFLD was modified by IRGM variants rs4958847 and rs13361189 (Pinteraction = 0.005 and Pinteraction < 0.001, respectively).

CONCLUSIONS

In a large CD cohort, VAT was directly associated with prevalent NAFLD, and this relationship was augmented by functionally annotated IRGM variants associated with impaired autophagy.

The role of diet in the aetiopathogenesis of inflammatory bowel disease

Crohn's disease and ulcerative colitis, collectively known as IBD, are chronic inflammatory disorders of the gastrointestinal tract. Although the aetiopathogenesis of IBD is largely unknown, it is widely thought that diet has a crucial role in the development and progression of IBD. Indeed, epidemiological and genetic association studies have identified a number of promising dietary and genetic risk factors for IBD. These preliminary studies have led to major interest in investigating the complex interaction between diet, host genetics, the gut microbiota and immune function in the pathogenesis of IBD. In this Review, we discuss the recent epidemiological, gene-environment interaction, microbiome and animal studies that have explored the relationship between diet and the risk of IBD. In addition, we highlight the limitations of these prior studies, in part by explaining their contradictory findings, and review future directions.

Systematic review with meta-analysis: association between acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) and risk of Crohn's disease and ulcerative colitis exacerbation

BACKGROUND

Unlike acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs) have generally been thought to be associated with increased risk of IBD exacerbation.

AIM

To carry out a systematic review and meta-analysis of previous studies examining the association between acetaminophen and NSAIDs including cyclooxygenase (COX-2) inhibitors use, and risk of Crohn's disease (CD) and ulcerative colitis (UC) exacerbation.

METHODS

We identified published manuscripts and abstracts through 1 March 2017 by systematic search of Medline, Embase, Cochrane and other trial registries. Quality assessment was done using Newcastle-Ottawa scale and random-effect meta-analysis using pooled relative risks (RRs) and 95% CIs were calculated.

RESULTS

Eighteen publications between years 1983 and 2016 were identified. For the meta-analysis, pooled RRs of disease exacerbation with NSAIDs use were (1.42, 95% CI, 0.65-3.09), I2  = 60.3% for CD, and (1.52, 95% CI, 0.87-2.63), I2  = 56.1% for UC. The corresponding values for acetaminophen use were (1.40, 95% CI, 0.96-2.04), I2  = 45.6% for UC, and (1.56, 95% CI, 1.22-1.99), I2  = 0.0% for IBD. Sensitivity analyses limited to studies with low risk of bias showed a significantly increased risk of CD exacerbation (1.53, 95% CI, 1.08-2.16) but not UC (0.94, 95% CI, 0.36-2.42) with NSAIDs use.

CONCLUSIONS

Contrary to generally accepted belief, we did not find a consistent association between NSAIDs use and risk of CD and UC exacerbation. There was also no consistent evidence for association with acetaminophen although further studies are needed.

Smoking is Associated with an Increased Risk of Microscopic Colitis: Results From Two Large Prospective Cohort Studies of US Women

BACKGROUND

Long-term data on the influence of smoking on risk of microscopic colitis are limited. We therefore sought to examine and characterize the association between smoking and risk of incident microscopic colitis in two large prospective cohorts of women.

METHODS

We conducted a prospective study of 231015 women enrolled in the Nurses' Health Study [NHS] and NHSII. Information regarding smoking, other lifestyle factors and medications were collected biennially from 1976 to 2012 in NHS and from 1989 to 2013 in NHSII. Incident cases of microscopic colitis were confirmed through physician medical record review. We used Cox proportional hazards modelling to examine the association between smoking and risk of microscopic colitis.

RESULTS

We documented 166 incident cases of microscopic colitis over 6122779 person-years of follow up. Compared to non-smokers, the multivariable-adjusted hazard ratio [HR] for microscopic colitis was 2.52 (95% confidence interval [CI] 1.59-4.00) amongst current smokers and 1.54 [95% CI 1.09-2.17] amongst past smokers. The risk increased with higher pack-years of smoking [p trend = 0.001] and diminished following smoking cessation [p trend = 0.017]. Current smoking appeared to be more strongly associated with risk of collagenous colitis [HR 3.68; 95% CI 1.94-6.97] than lymphocytic colitis [HR 1.71; 95% CI 0.83-3.53].

CONCLUSION

In two large prospective cohort studies, we observed an association between current smoking and risk of microscopic colitis. Risk of microscopic colitis appeared to increase with higher pack-years and diminish following smoking cessation. Future studies focused on characterizing the biological mechanisms underlying these associations are warranted.

No Significant Association Between Proton Pump Inhibitor Use and Risk of Stroke After Adjustment for Lifestyle Factors and Indication

BACKGROUND & AIMS

Proton pump inhibitors (PPI) are among the top 10 most prescribed medications worldwide. We investigated the association between PPI use and ischemic stroke.

METHODS

We collected data on 68,514 women (mean age, 65 ± 7 years) enrolled in the Nurses' Health Study since 2000 and 28,989 men (mean age, 69 ± 8 years) in the Health Professionals Follow-up Study since 2004, without a history of stroke. We used Cox proportional hazards models to examine the association between risk of incident stroke and PPI use among participants. The primary end point was first incident stroke.

RESULTS

In the 2 cohorts, we documented 2599 incident strokes (2037 in women and 562 in men) over a 12-year period, encompassing 949,330 person-years. After adjustment for established risk factors for stroke, PPI use was associated with a significant increase in risk of ischemic stroke (hazard ratio, 1.18; 95% confidence interval, 1.02-1.37). The association was reduced after we adjusted for potential indications for PPI use, including history of peptic ulcer disease, gastroesophageal reflux disease, or gastrointestinal bleeding, and prior use of histamine-2 receptor antagonist therapy (hazard ratio, 1.08; 95% confidence interval, 0.91-1.27). Regular PPI use was not associated with increased risk of stroke overall or hemorrhagic stroke.

CONCLUSIONS

In an analysis of data from the Nurses' Health Study and the Health Professionals Follow-up Study, we did not find a significant association between PPI use and ischemic stroke, after accounting for indications for PPI use. Prior reports of an increased risk of stroke may be due to residual confounding related to chronic conditions associated with PPI use.

Long-term use of antibiotics and risk of colorectal adenoma

OBJECTIVE

Recent evidence suggests that antibiotic use, which alters the gut microbiome, is associated with an increased risk of colorectal cancer. However, the association between antibiotic use and risk of colorectal adenoma, the precursor for the majority of colorectal cancers, has not been investigated.

DESIGN

We prospectively evaluated the association between antibiotic use at age 20-39 and 40-59 (assessed in 2004) and recent antibiotic use (assessed in 2008) with risk of subsequent colorectal adenoma among 16 642 women aged ≥60 enrolled in the Nurses' Health Study who underwent at least one colonoscopy through 2010. We used multivariate logistic regression to calculate ORs and 95% CIs.

RESULTS

We documented 1195 cases of adenoma. Increasing duration of antibiotic use at age 20-39 (ptrend=0.002) and 40-59 (ptrend=0.001) was significantly associated with an increased risk of colorectal adenoma. Compared with non-users, women who used antibiotics for ≥2 months between age 20 and 39 had a multivariable OR of 1.36 (95% CI 1.03 to 1.79). Women who used ≥2 months of antibiotics between age 40 and 59 had a multivariable OR of 1.69 (95% CI 1.24 to 2.31). The associations were similar for low-risk versus high-risk adenomas (size ≥1 cm, or with tubulovillous/villous histology, or ≥3 detected lesions), but appeared modestly stronger for proximal compared with distal adenomas. In contrast, recent antibiotic use within the past four years was not associated with risk of adenoma (ptrend=0.44).

CONCLUSIONS

Long-term antibiotic use in early-to-middle adulthood was associated with increased risk of colorectal adenoma.

Stability of the human faecal microbiome in a cohort of adult men

Characterizing the stability of the gut microbiome is important to exploit it as a therapeutic target and diagnostic biomarker. We metagenomically and metatranscriptomically sequenced the faecal microbiomes of 308 participants in the Health Professionals Follow-Up Study. Participants provided four stool samples-one pair collected 24-72 h apart and a second pair ~6 months later. Within-person taxonomic and functional variation was consistently lower than between-person variation over time. In contrast, metatranscriptomic profiles were comparably variable within and between subjects due to higher within-subject longitudinal variation. Metagenomic instability accounted for ~74% of corresponding metatranscriptomic instability. The rest was probably attributable to sources such as regulation. Among the pathways that were differentially regulated, most were consistently over- or under-transcribed at each time point. Together, these results suggest that a single measurement of the faecal microbiome can provide long-term information regarding organismal composition and functional potential, but repeated or short-term measures may be necessary for dynamic features identified by metatranscriptomics.

Molecular Predictors of Gastric Neoplastic Progression

In this issue of Cancer Cell, Huang et al. describe comprehensive genetic and epigenetic profiling of gastric intestinal metaplasia lesions from a longitudinal cohort in which outcome data allowed for identification of potential markers of gastric neoplastic progression.

Association Between Inflammatory Diet Pattern and Risk of Colorectal Carcinoma Subtypes Classified by Immune Responses to Tumor

BACKGROUND & AIMS

Dietary patterns affect systemic and local intestinal inflammation, which have been linked to colorectal carcinogenesis. Chronic inflammation can interfere with the adaptive immune response. We investigated whether the association of a diet that promotes intestinal inflammation with risk of colorectal carcinoma was stronger for tumors with lower lymphocytic reactions than tumors with higher lymphocytic reactions.

METHODS

We collected data from the molecular pathological epidemiology databases of 2 prospective cohort studies: the Nurses' Health Study (since 1976) and the Health Professionals Follow-Up Study (since 1986). We used duplication-method time-varying Cox proportional cause-specific hazards regression to assess the association of empirical dietary inflammatory pattern (EDIP) score (derived from food frequency questionnaire data) with colorectal carcinoma subtype. Foods that contribute to high EDIP scores include red and processed meats, refined grains, carbonated beverages, and some vegetables; foods that contribute to low EDIP scores include beer, wine, coffee, tea, yellow and leafy vegetables, and fruit juice. Colorectal tissue samples were analyzed histologically for patterns of lymphocytic reactions (Crohn's-like lymphoid reaction, peritumoral lymphocytic reaction, intratumoral periglandular reaction, and tumor-infiltrating lymphocytes).

RESULTS

During follow-up of 124,433 participants, we documented 1311 incident colon and rectal cancer cases with available tissue data. The association between the EDIP and colorectal cancer risk was significant (P_trend = .02), and varied with degree of peritumoral lymphocytic reaction (P_{heterogeneity} < .001). Higher EDIP scores were associated with increased risk of colorectal cancer with an absent or low peritumoral lymphocytic reaction (highest vs lowest EDIP score quintile hazard ratio, 2.60; 95% confidence interval, 1.60-4.23; P_trend < .001), but not risk of tumors with intermediate or high peritumoral lymphocytic reaction (P_trend > .80).

CONCLUSIONS

In 2 prospective cohort studies, we associated inflammatory diets with a higher risk of colorectal cancer subtype that contains little or no peritumoral lymphocytic reaction. These findings suggest that diet-related inflammation might contribute to development of colorectal cancer, by suppressing the adaptive anti-tumor immune response.

Genetic Polymorphisms in Fatty Acid Metabolism Modify the Association Between Dietary n3: n6 Intake and Risk of Ulcerative Colitis: A Prospective Cohort Study

INTRODUCTION

High intake of dietary n-3 polyunsaturated fatty acids (PUFA) is associated with a decreased risk of ulcerative colitis (UC) and Crohn's disease (CD). However, results have been heterogeneous suggesting that genetic variations in PUFA metabolism may modify this risk.

METHODS

We conducted a case-control study nested within 2 prospective cohorts, the Nurses' Health Study (NHS) and NHS II. Among women providing blood (n = 62,437) or buccal cells (n = 59,543) for genotyping, we confirmed new diagnoses of CD or UC. Dietary intake was assessed 4 years before diagnosis. Confirmed cases were matched 1:2 to controls. Subjects were genotyped for single nucleotide polymorphisms at CYP4F3, FADS1, and FADS2 loci. Conditional logistic regression models examined the interaction between genotype, n3:n6 PUFA intake and risk of CD and UC.

RESULTS

Our study included 101 CD and 139 UC patients matched to 495 controls. On multivariable analysis, high intake of n3:n6 PUFA (above median) demonstrated a trend toward reduced risk of UC (Odds ratio [OR] 0.71, 95% confidence interval [CI], 0.47-1.09, P = 0.11). High n3:n6 PUFA intake was associated with a reduced risk of UC in individuals with the GG/AG genotype at a single nucleotide polymorphism in CYP4F3 (OR 0.57, 95% CI, 0.32-0.99) but not those with the AA genotype (OR 0.95, 95% CI, 0.47-1.93) (P-interaction = 0.049). No gene-diet interactions were noted for CD.

CONCLUSIONS

The association between dietary n3:n6 PUFA intake and risk of UC may be modified variants at CYP4F3. Further gene-environment studies of the association between diet and IBD risk are warranted.

Clinical Predictors and Natural History of Disease Extension in Patients with Ulcerative Proctitis

BACKGROUND

A proportion of patients with initial presentation of ulcerative proctitis (UP) progress to more extensive colitis. We sought to characterize the natural history and identify clinical predictors of extension in UP.

METHODS

We performed a retrospective cohort study of participants with a new diagnosis of UP from January 2000 to December 2015. We used Cox proportional hazard modeling to identify predictors of disease extension.

RESULTS

We identified 169 new cases of UP with a median age of diagnosis of 40 years (range: 16-91 yr) and a median follow-up of 4.3 years (range: 3.3-15.1 yr). Fifty-three (31%) patients developed extension over the follow-up time. Compared with nonextenders, the need for immunosuppressive or biologic therapy was significantly higher among extenders (34% versus 2.6%, P < 0.001). In multivariable analyses, compared with UP cases with body mass index <25, the adjusted hazard ratios of extension were 1.75 (95% confidence interval [CI], 0.95-3.23) and 2.77 (95% CI, 1.07-7.14) among overweight and obese patients, respectively (Ptrend = 0.03). Similarly, patients with a history of appendectomy or endoscopic finding of moderate to severe disease had a higher risk of extension (adjusted hazard ratio = 2.74, 95% CI, 1.07-7.01 and 1.96, 95% CI, 1.05-3.67, respectively).

CONCLUSIONS

In a retrospective cohort study, we show that appendectomy, body mass index, and endoscopic activity at the time of diagnosis of proctitis are associated with an increased risk of extension. In addition, our data suggest that extenders are more likely to require immunosuppressive or biologic therapy.

Systematic review with meta-analysis: breastfeeding and the risk of Crohn's disease and ulcerative colitis

BACKGROUND

Breastfeeding is a modifiable factor that may influence development of inflammatory bowel diseases. However, literature on this has been inconsistent and not accounted for heterogeneity in populations and exposure.

AIM

To conduct a meta-analysis to examine the association between breastfeeding in infancy and risk of Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

A systematic search of Medline/PubMed and Embase was performed for full text, English-language literature through November 2016. Studies were included if they described breastfeeding in infancy in patients with CD or UC, and healthy controls. Data were pooled using a random effects model for analysis.

RESULTS

A total of 35 studies were included in the final analysis, comprising 7536 individuals with CD, 7353 with UC and 330 222 controls. Ever being breastfed was associated with a lower risk of CD (OR 0.71, 95% CI 0.59-0.85) and UC (OR 0.78, 95% CI 0.67-0.91). While this inverse association was observed in all ethnicity groups, the magnitude of protection was significantly greater among Asians (OR 0.31, 95% CI 0.20-0.48) compared to Caucasians (OR 0.78, 95% CI 0.66-0.93; P = .0001) in CD. Breastfeeding duration showed a dose-dependent association, with strongest decrease in risk when breastfed for at least 12 months for CD (OR 0.20, 95% CI 0.08-0.50) and UC (OR 0.21, 95% CI 0.10-0.43) as compared to 3 or 6 months.

CONCLUSION

Breastfeeding in infancy protects against the development of CD and ulcerative colitis.

Association Between Proton Pump Inhibitor Use and Cognitive Function in Women

BACKGROUND & AIMS

Studies have reported associations between proton pump inhibitor (PPI) use and dementia. However, data are lacking on long-term PPI use and cognitive function. We therefore examined associations between PPI use and performance in tests of cognitive function. Because of shared clinical indications, we examined associations for H2 receptor antagonists (H2RAs) as a secondary aim.

METHODS

We used prospectively collected data on medication use and other potential risk factors from 13,864 participants in the Nurses' Health Study II who had completed a self-administered computerized neuropsychological test battery. Multivariable linear regression models were used to examine associations between medication use and composite scores of psychomotor speed and attention, learning and working memory, and overall cognition.

RESULTS

We observed a modest association between duration of PPI use and scores for psychomotor speed and attention (mean score difference for PPI use of 9-14 years vs never users, -0.06; 95% confidence interval, -0.11 to 0.00; P_trend = .03). After controlling for H2RA use, the magnitude of this score difference was attenuated. Among individuals who did not use PPIs regularly, duration of H2RA use was associated with poorer cognitive scores, with the strongest association apparent for learning and working memory (mean score difference for H2RA users of 9-14 years vs never users, -0.20; 95% confidence interval, -0.32 to -0.08; P_trend < .001).

CONCLUSIONS

In an analysis of data from the Nurses' Health Study II, we did not observe a convincing association between PPI use and cognitive function. Our data do not support the suggestion that PPI use increases dementia risk. Because our primary hypothesis related to PPI use, our findings for H2RAs should be interpreted with caution.

Dietary Iron and Heme Iron Consumption, Genetic Susceptibility, and Risk of Crohn's Disease and Ulcerative Colitis

BACKGROUND

Dietary iron and heme, likely through their effect on gut commensal bacteria and colonic barrier function, have been shown to modulate colonic inflammation in animal models of colitis. Nonetheless, the link between dietary total and heme iron and risk of Crohn's disease (CD) and ulcerative colitis (UC) has not been previously explored.

METHODS

We conducted a prospective cohort study of 165,331 U.S. women enrolled in the Nurses' Health Study and Nurses' Health Study II. Dietary information was collected using a validated food frequency questionnaire at baseline (1984) and updated every 2 to 4 years. Self-reported CD and UC diagnoses were confirmed through medical records review. We used Cox proportional hazard models to calculate hazard ratios and 95% confidence intervals while adjusting for potential confounders. In a case-control study nested within these cohorts, we evaluated the interaction between single-nucleotide polymorphisms associated with genome-wide susceptibility to CD and UC and dietary total and heme iron intake on risk of CD and UC using logistic regression modeling.

RESULTS

Through 2011, over 3,038,049 person-years of follow-up, we documented 261 incident cases of CD and 321 incident cases of UC. Dietary heme iron was nonsignificantly associated with increased risk of UC (Ptrend = 0.12). This association seemed to be modified by the UC susceptibility locus, rs1801274, a coding variant in the FcγRIIA gene (Pinteraction = 7.00E-05). In contrast, there was no association between dietary heme iron and risk of CD (Ptrend = 0.67). We also did not observe an association between total dietary intake of iron and risk of CD or UC (All Ptrend > 0.35).

CONCLUSION

In 2 large prospective cohort studies, dietary total and heme iron were not associated with risk of CD or UC. Our suggestive finding that the association between dietary heme iron intake and risk of UC may be modified by a coding variant in FcγRIIA gene warrants additional investigation.

Long-term use of antibiotics and risk of colorectal adenoma

OBJECTIVE

Recent evidence suggests that antibiotic use, which alters the gut microbiome, is associated with an increased risk of colorectal cancer. However, the association between antibiotic use and risk of colorectal adenoma, the precursor for the majority of colorectal cancers, has not been investigated.

DESIGN

We prospectively evaluated the association between antibiotic use at age 20-39 and 40-59 (assessed in 2004) and recent antibiotic use (assessed in 2008) with risk of subsequent colorectal adenoma among 16 642 women aged ≥60 enrolled in the Nurses' Health Study who underwent at least one colonoscopy through 2010. We used multivariate logistic regression to calculate ORs and 95% CIs.

RESULTS

We documented 1195 cases of adenoma. Increasing duration of antibiotic use at age 20-39 (p_trend=0.002) and 40-59 (p_trend=0.001) was significantly associated with an increased risk of colorectal adenoma. Compared with non-users, women who used antibiotics for ≥2 months between age 20 and 39 had a multivariable OR of 1.36 (95% CI 1.03 to 1.79). Women who used ≥2 months of antibiotics between age 40 and 59 had a multivariable OR of 1.69 (95% CI 1.24 to 2.31). The associations were similar for low-risk versus high-risk adenomas (size ≥1 cm, or with tubulovillous/villous histology, or ≥3 detected lesions), but appeared modestly stronger for proximal compared with distal adenomas. In contrast, recent antibiotic use within the past four years was not associated with risk of adenoma (p_trend=0.44).

CONCLUSIONS

Long-term antibiotic use in early-to-middle adulthood was associated with increased risk of colorectal adenoma.

Abstract A24: Lifetime use of antibiotics and risk of colorectal adenoma

Background: Antibiotics shift the gut microbiota to temporally quasi-stable or alternative stable states, marked by a loss of diversity, alternations in the abundance of specific taxa, shifts in metabolic capacity, and by reduced resistance to colonization against invading pathogens. Recent evidence suggests that antibiotic use may be associated with an increased risk of colorectal cancer. However, these prior studies may be confounded by symptoms associated with colorectal cancer or differential exposure to medical care. To address these potential concerns, we examined the association of chronic antibiotic exposure and recent antibiotic use with risk of colorectal adenomas, which are largely asymptomatic and the precursor of majority of colorectal cancers.

Methods: We prospectively evaluated the association between chronic lifetime antibiotic use at age 20-39 and age 40-59 (assessed in 2004), and recent antibiotic use (assessed in 2008) and risk of subsequent colorectal adenoma among women aged ≥60 in the Nurses' Health Study who underwent at least one lower endoscopy through 2010. Antibiotic use was categorized according to the total time using antibiotics (excluding skin creams, mouthwash or Isoniazid) during a specific time period (age 20-39, or age 40-59, or past 4 years). We also investigated the association between antibiotic exposure during each time period and risk of high-risk (adenoma ≥1cm, or with villous histology, or ≥3 adenomas) vs. low-risk adenoma, as well as risk of adenoma according to anatomic location. We used multivariate logistic regression adjusting for known and putative risk factors for adenoma to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results: Among 17,002 women aged ≥60 who reported their antibiotic exposure and then subsequently underwent at least one lower endoscopy, we documented 1,213 cases of adenoma over 6 years of follow-up. An increasing duration of antibiotic use at age 20-39 (Ptrend=0.002) and 40-59 (Ptrend=0.001) was significantly associated with an increased risk of colorectal adenoma. Compared to non-users, women who used antibiotics for ≥2 months between age 20-39 had a multivariable OR for adenoma of 1.37 (95% CI: 1.04-1.81). Women who used ≥2 months of antibiotics between age 40-59 had a multivariable OR of 1.71 (95% CI: 1.25-2.33). The associations were similar for high-risk compared to low-risk adenomas, but appeared somewhat stronger for adenomas of the proximal compared with distal colon. In contrast, recent antibiotic use within the past 4 years was not associated with risk of adenoma (Ptrend=0.44).

Conclusion: In this prospective study, exposure to antibiotics earlier in life (age 20-39 and 40-59) was significantly associated with an increased risk for colorectal adenoma. This increased risk was evident even after adjustment for known colorectal cancer risk factors. In contrast, more recent antibiotic use (within 4 years) was not associated with risk. To the best of our knowledge, this study is the first to link midlife antibiotic use, in a dose-dependent fashion, to colorectal adenoma. These data provide additional support for the association of the gut microbiome with colorectal neoplasia.

Citation Format: Yin Cao, Kana Wu, Raaj Mehta, David Drew, Mingyang Song, Paul Lochhead, Jacques Izard, Charles Fuchs, Wendy Garrett, Curtis Huttenhower, Shuji Ogino, Edward Giovannucci, Andrew Chan. Lifetime use of antibiotics and risk of colorectal adenoma. [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer: From Initiation to Outcomes; 2016 Sep 17-20; Tampa, FL. Philadelphia (PA): AACR; Cancer Res 2017;77(3 Suppl):Abstract nr A24.

Regular Aspirin Use Associates With Lower Risk of Colorectal Cancers With Low Numbers of Tumor-Infiltrating Lymphocytes

BACKGROUND & AIMS

Aspirin use reduces colorectal cancer risk. Aspirin, a nonsteroidal anti-inflammatory drug, inhibits prostaglandin-endoperoxide synthase 2 (PTGS2 or cyclooxygenase-2); PTGS2 promotes inflammation and suppresses T-cell-mediated adaptive immunity. We investigated whether the inverse association of aspirin use with colorectal carcinoma risk was stronger for tumors with lower degrees of lymphocytic infiltrates than for tumors with higher degrees of lymphocytic infiltrates.

METHODS

We collected aspirin use data biennially from participants in the Nurses' Health Study and Health Professionals Follow-up Study. Participants were asked whether they took aspirin in most weeks, the number of tablets taken per week, and years of aspirin use. We collected available tumor specimens (n = 1458) from pathology laboratories in the United States. A pathologist confirmed the diagnosis of colorectal adenocarcinoma (excluding anal squamous cell carcinoma), and evaluated histopathology features, including patterns and degrees of lymphocytic infiltrates within and around tumor areas. Person-years of follow-up evaluation were accrued from the date of return of questionnaires until dates of colorectal cancer diagnosis, death, or the end of follow-up evaluation (June 2010). Duplication-method Cox proportional hazards regression was used to assess the association of aspirin with the incidence of colorectal carcinoma subgroups according to the degree of tumor-infiltrating lymphocytes (TILs), intratumoral periglandular reaction, peritumoral reaction, or Crohn's-like reaction.

RESULTS

We documented 1458 rectal and colon cancers. The inverse association between regular aspirin use and colorectal cancer risk significantly differed by concentrations of TILs (P_{heterogeneity} = .007). Compared with nonregular use, regular aspirin use was associated with a lower risk of tumors that had low levels of TILs (relative risk, 0.72; 95% confidence interval, 0.63-0.81), and strength of the association depended on aspirin dose and duration (both P_trend < .001). In contrast, aspirin use was not associated with a risk of tumors having intermediate or high levels of TILs. This differential association was consistent regardless of the status of tumor microsatellite instability, mutations in BRAF, or expression of PTGS2. Regular aspirin use was associated with a lower risk of tumors that contained low levels of CD3⁺ T cells, CD8⁺ T cells, or CD45RO (PTPRC)⁺ T cells (measured by immunohistochemistry and computer-assisted image analysis).

CONCLUSIONS

Based on data from the prospective cohort studies, regular use of aspirin is associated with a lower risk of colorectal carcinomas with low concentrations of TILs. These findings indicate that the immune response in the tumor microenvironment could be involved in the chemopreventive effects of aspirin.

Abstract 4348: A prospective study of smoking habit and risk of synchronous colorectal cancers

Background: Synchronous colorectal cancers (CRC) (2 or more distinct primary carcinomas simultaneously identified in one patient) may arise as a result of a “field effect” or shared etiologic factors. Synchronous CRC has been associated with somatic epigenetic changes; cigarette smoking has been associated with DNA methylation in CRC. Thus, we examined the association between cigarette smoking and risk of synchronous CRC.

Methods: Among men and women enrolled in the Health Professionals Follow-up Study and Nurses’ Health Study over 24 and 32 years, respectively, we examined the association of smoking with CRC. We examined the differential risk of developing synchronous CRC compared with solitary CRC, classified based on review of pathology reports, through duplication-method Cox proportional hazards regression.

Results: During 3,477,211 person-years of follow-up of 45,691 men and 88,614 women, we documented 1,960 individuals with solitary CRC and 45 individuals with synchronous CRC. The association of smoking with CRC differed significantly according to the presence of synchronous compared with solitary tumors (Pheterogeneity = 0.0008). Compared with never smokers, current smokers experienced a higher risk of synchronous CRC (multivariable HR = 5.26; 95% CI, 2.08-13.32). In contrast, current smokers did not experience an elevated risk of solitary cancer (multivariable HR = 0.97; 95% CI, 0.83-1.13). Similar differences in the association of cumulative pack-years smoked with CRC according to tumor synchronicity status were also observed (Pheterogeneity = 0.006). Smoking cessation for ≥10 years was significantly associated with reduced risk of synchronous tumors (multivariable HR = 0.44; 95% CI, 0.20-1.00), but not solitary tumors (multivariable HR = 1.07; 95% CI, 0.91-1.25) (Pheterogeneity = 0.003).

Conclusion: Current cigarette smoking is associated with an increased risk of synchronous but not solitary CRC. These data support a model in which smoking contributes to an etiologic field effect predisposing individuals to the development of synchronous CRC.

Citation Format: David A. Drew, Reiko Nishihara, Paul Lochhead, Aya Kuchiba, Zhi Rong Qian, Kosuke Mima, Katsuhiko Nosho, Kana Wu, Molin Wang, Donna Spiegelman, Edward L. Giovannucci, Charles S. Fuchs, Shuji Ogino, Andrew T. Chan. A prospective study of smoking habit and risk of synchronous colorectal cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4348.

Association Between Circulating Levels of C-Reactive Protein and Interleukin-6 and Risk of Inflammatory Bowel Disease

BACKGROUND & AIMS

There is evidence that immune dysfunction precedes symptoms of inflammatory bowel disease (IBD) by several years. Characterization of preclinical systemic inflammation could contribute to the understanding of the biology of IBD and, ultimately, facilitate development of strategies for early disease detection and intervention. We evaluated associations between circulating levels of interleukin-6 (IL6) and high-sensitivity C-reactive protein (hsCRP) and diagnosis of incident Crohn's disease (CD) or ulcerative colitis (UC).

METHODS

We conducted a nested case-control study of participants enrolled in 2 population-based, nationwide, prospective cohort studies (the Nurses' Health Study and the Nurses' Health Study II). We analyzed blood specimens, collected before diagnosis, from 83 persons with CD, 90 persons with UC, and 344 matched individuals without IBD (control subjects). Plasma levels of hsCRP and IL6 were measured. We investigated associations between each inflammatory marker and IBD risk using multivariable logistic regression models to adjust for potential confounding exposures.

RESULTS

Compared with the lowest quintile of IL6 level, the highest quintile was associated with an odds ratio (OR) of 4.68 (95% confidence interval, 1.91-11.46) for CD (Ptrend < .001) and an OR of 3.43 (95% confidence interval, 1.44-8.15) for UC (Ptrend = .004). The highest quintile of hsCRP level, compared with the lowest quintile, was associated with an OR of 2.82 (95% confidence interval, 1.15-6.87) for CD (Ptrend = .019) and an OR of 1.79 (95% confidence interval, 0.80-3.99) for UC (Ptrend = .015).

CONCLUSIONS

Plasma levels of IL6 and hsCRP before diagnosis are associated with risk of incident CD and UC. Subclinical levels of systemic inflammation may be a feature of an early disease state that precedes the development of symptomatic IBD.

Statistical methods for studying disease subtype heterogeneity

A fundamental goal of epidemiologic research is to investigate the relationship between exposures and disease risk. Cases of the disease are often considered a single outcome and assumed to share a common etiology. However, evidence indicates that many human diseases arise and evolve through a range of heterogeneous molecular pathologic processes, influenced by diverse exposures. Pathogenic heterogeneity has been considered in various neoplasms such as colorectal, lung, prostate, and breast cancers, leukemia and lymphoma, and non-neoplastic diseases, including obesity, type II diabetes, glaucoma, stroke, cardiovascular disease, autism, and autoimmune disease. In this article, we discuss analytic options for studying disease subtype heterogeneity, emphasizing methods for evaluating whether the association of a potential risk factor with disease varies by disease subtype. Methods are described for scenarios where disease subtypes are categorical and ordinal and for cohort studies, matched and unmatched case-control studies, and case-case study designs. For illustration, we apply the methods to a molecular pathological epidemiology study of alcohol intake and colon cancer risk by tumor LINE-1 methylation subtypes. User-friendly software to implement the methods is publicly available.

Prediagnosis Plasma Adiponectin in Relation to Colorectal Cancer Risk According to KRAS Mutation Status

BACKGROUND

Low levels of adiponectin (ADIPOQ; HGNC ID; HGNC:13633), an adipokine, are associated with obesity, adiposity, excess energy balance, and increased risk of colorectal neoplasia. Given the reported association of increased body mass index (BMI) and low-level physical activity with KRAS-mutated colorectal tumor, we hypothesized that low-level plasma adiponectin might be associated with increased risk of KRAS-mutant colorectal carcinoma but not with risk of KRAS wild-type carcinoma.

METHODS

We conducted molecular pathological epidemiology research using a nested case-control study design (307 incident rectal and colon cancer case patients and 593 matched control individuals) within prospective cohort studies, the Nurses' Health Study (152 case patients and 297 control individuals, with blood collection in 1989-1990) and the Health Professionals Follow-up Study (155 case patients and 296 control individuals, with blood collection in 1993-1995). Multivariable conditional logistic regression models and two-sided likelihood ratio tests were used to assess etiologic heterogeneity of the associations.

RESULTS

The association of low-level plasma adiponectin with colorectal cancer risk statistically significantly differed by KRAS mutation status (P heterogeneity = .004). Low levels of plasma adiponectin were associated with KRAS-mutant colorectal cancer (for the lowest vs highest tertile: multivariable odds ratio [OR] = 2.83, 95% confidence interval [CI] = 1.50 to 5.34, P trend = .002) but not with KRAS wild-type cancer (for the lowest vs highest tertile: multivariable OR = 0.83, 95% CI = 0.49 to 1.43, P trend = .48). In secondary analyses, the association between plasma adiponectin and colorectal cancer did not appreciably differ by BRAF or PIK3CA oncogene mutation status.

CONCLUSIONS

Low-level plasma adiponectin is associated with KRAS-mutant colorectal cancer risk but not with KRAS wild-type cancer risk.