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Dive into the research topics where Christopher D. Jensen is active.

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Featured researches published by Christopher D. Jensen.


Clinical Gastroenterology and Hepatology | 2013

Variation of adenoma prevalence by age, sex, race, and colon location in a large population: implications for screening and quality programs.

Douglas A. Corley; Christopher D. Jensen; Amy R. Marks; Wei K. Zhao; Jolanda de Boer; Theodore R. Levin; Chyke A. Doubeni; Bruce Fireman; Charles P. Quesenberry

BACKGROUND & AIMS Reliable community-based colorectal adenoma prevalence estimates are needed to inform colonoscopy quality standards and to estimate patient colorectal cancer risks; however, minimal data exist from populations with large numbers of diverse patients and examiners. METHODS We evaluated the prevalence of adenomas detected by sex, age, race/ethnicity, and colon location among 20,792 Kaiser Permanente Northern California members ≥50 years of age who received a screening colonoscopy examination (102 gastroenterologists, 2006-2008). RESULTS Prevalence of detected adenomas increased more rapidly with age in the proximal colon (adjusted odds ratio [OR], 2.39; 95% confidence interval [CI], 2.05-2.80; 70-74 vs 50-54 years) than in the distal colon (OR, 1.89; 95% CI, 1.63-2.19). Prevalence was higher among men vs women at all ages (OR, 1.77; 95% CI, 1.66-1.89), increasing in men from 25% to 39% at ≥70 years and in women from 15% at 50-54 years to 26% (P < .001). Proximal adenoma prevalence was higher among blacks than whites (OR, 1.26; 95% CI, 1.04-1.54), although total prevalence was similar, including persons <60 years old (OR, 1.17; 95% CI, 0.91-1.50). CONCLUSIONS Prevalence of detected adenomas increases substantially with age and is much higher in men; proximal adenomas are more common among blacks than whites, although the total prevalence and the prevalence for ages <60 years were similar by race. These demographic differences are such that current adenoma detection guidelines may not be valid, without adjustment, for comparing providers serving different populations. The variation in prevalence and location may also have implications for the effectiveness of screening methods in different demographic groups.


Nutrition Research Reviews | 2010

Dietary factors and the risks of oesophageal adenocarcinoma and Barrett's oesophagus.

Ai Kubo; Douglas A. Corley; Christopher D. Jensen; Rubinder Kaur

Incidence rates for oesophageal adenocarcinoma have increased by over 500% during the past few decades without clear reasons. Gastro-oesophageal reflux disease, obesity and smoking have been identified as risk factors, although the demographic distribution of these risk factors is not consistent with the demographic distribution of oesophageal adenocarcinoma, which is substantially more common among whites and males than any other demographic groups. Numerous epidemiological studies have suggested associations between dietary factors and the risks of oesophageal adenocarcinoma and its precursor, Barretts oesophagus, though a comprehensive review is lacking. The main aim of the present review is to consider the evidence linking dietary factors with the risks of oesophageal adenocarcinoma, Barretts oesophagus, and the progression from Barretts oesophagus to oesophageal adenocarcinoma. The existing epidemiological evidence is strongest for an inverse relationship between intake of vitamin C, β-carotene, fruits and vegetables, particularly raw fruits and vegetables and dark green, leafy and cruciferous vegetables, carbohydrates, fibre and Fe and the risk of oesophageal adenocarcinoma and Barretts oesophagus. Patients at higher risk for Barretts oesophagus and oesophageal adenocarcinoma may benefit from increasing their consumption of fruits and vegetables and reducing their intake of red meat and other processed food items. Further research is needed to evaluate the relationship between diet and the progression of Barretts oesophagus to oesophageal adenocarcinoma. Evidence from cohort studies will help determine whether randomised chemoprevention trials are warranted for the primary prevention of Barretts oesophagus or its progression to cancer.


Annals of Internal Medicine | 2016

Fecal Immunochemical Test Program Performance Over 4 Rounds of Annual Screening: A Retrospective Cohort Study

Christopher D. Jensen; Douglas A. Corley; Virginia P. Quinn; Chyke A. Doubeni; Ann G. Zauber; Jeffrey K. Lee; Wei K. Zhao; Amy R. Marks; Joanne E. Schottinger; Nirupa R. Ghai; Alexander Lee; Richard Contreras; Carrie N. Klabunde; Charles P. Quesenberry; Theodore R. Levin; Pauline A. Mysliwiec

Context The fecal immunochemical test is an effective way to screen for colorectal cancer, but we know more about how well it does the first time it is used and less about how well it does in later years with repeated testing. Contribution The researchers show that, after 4 years of repeated testing, patients continued to use the test and it continued to identify colorectal cancer. Caution This study did not measure whether identification of cancer changed outcomes. Implication The fecal immunochemical test is acceptable and effective for repeated testing. Colorectal cancer (CRC) is the second leading cause of cancer death in the United States (13), and screening with fecal occult blood tests (FOBTs) reduces CRC incidence and mortality (46). In randomized trials (711), annual or biennial guaiac-based FOBTs reduced CRC incidence by 17% to 20% and CRC mortality by 15% to 33%. Thus, the U.S. Preventive Services Task Force (4) and U.S. Multi-Society Task Force on Colorectal Cancer (12) recommend annual FOBT as an option for CRC screening for average-risk patients, defined as those aged 50 to 75 years with no history of CRC or adenoma, with no first-degree relatives with CRC, and who are not up to date with CRC screening according to other methods (that is, sigmoidoscopy within 5 years or colonoscopy within 10 years). Annual highly sensitive FOBTs are believed to be as effective as screening colonoscopy performed every 10 years if levels of adherence are high (13), although colonoscopy is recommended for those with a family history of CRC. Fecal blood tests are noninvasive and can be delivered by mail (14). In contrast to guaiac-based stool tests, fecal immunochemical test (FIT) screening can be done without dietary or medication restrictions, which allows it to achieve higher patient acceptance in organized CRC screening programs (15). This test also has higher detection rates for CRC and advanced adenomas than guaiac-based stool tests (1517). In a recent meta-analysis (18), the sensitivity of a single FIT application was 79% for CRC diagnosed within 2 years of testing; however, little is known about performance characteristics over several rounds of annual screening, particularly in community practice. The present study was conducted to evaluate FIT sensitivity for CRC and other performance characteristics over 4 rounds of annual testing in a U.S. community-based CRC screening program. Methods Study Population This retrospective longitudinal study was performed in a fixed cohort of Kaiser Permanente Northern California (KPNC) and Southern California (KPSC) health plan members. These integrated health care delivery organizations serve approximately 7 million persons in urban, suburban, and semirural regions throughout California. Kaiser Permanente health plan membership in California is diverse and similar in socioeconomic characteristics to the regions census demographics (1921). Study Oversight The study was approved by the institutional review boards of KPNC and KPSC, both of which waived the requirement for informed consent. The listed authors had sole responsibility for the study design, data collection, decision to submit the manuscript for publication, and drafting of the manuscript. This study was conducted within the National Cancer Institutefunded Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) consortium, which conducts multisite, coordinated, transdisciplinary research to evaluate and improve cancer-screening processes. Organized CRC Screening Program The KPNC and KPSC initiated similar organized FIT screening programs between 2006 and 2008; the KPNC program has been described previously (14). Briefly, each year, the programs mail a FIT kit to eligible health plan members aged 50 to 75 years without a record of a colonoscopy within 10 years, sigmoidoscopy within 5 years, or fecal blood test within the prior year. The kit includes the FIT (OC FIT-CHEK; Polymedco), a standardized letter from the patients primary care provider, directions for completing and mailing the test, and a preprinted laboratory requisition order form. Outreach includes in-person, mail, secure e-mail, and telephone reminders as needed. The kits are returned by mail to regional laboratories and analyzed on or shortly after the return date using an OC-Sensor Diana automated system (Polymedco) with a cutoff level of 20 g of hemoglobin/g of buffer for a positive result. Patients with a positive FIT result are referred for follow-up colonoscopy. Study Eligibility Criteria and Participant Tracking The study cohort included CRC screening program participants aged 50 to 70 years on the date an initial kit was mailed to them in 2007 or 2008. Patients were excluded if they had been enrolled in the health plan for less than 1 year before the round 1 FIT mail date (to allow for the recording of prior out-of-system endoscopy procedures). They were also excluded if they were mailed a kit but subsequently had sigmoidoscopy or colonoscopy, were diagnosed with CRC, died, or terminated membership in the health plan before returning the initial FIT or within 1 year after their round 1 mail date if no FIT was returned. A total of 670841 health plan members was mailed the initial kit in 2007 or 2008 and met the study eligibility criteria; 323349 (48.2%) returned a FIT within 1 year after the mail date (Figure). The analytic cohort comprised these round 1 participants who were tracked from their baseline mail date (cohort entry) through up to 4 rounds of testing for mail dates; result dates; results (positive or negative); whether follow-up colonoscopy was performed within 1 year after a positive FIT result; and diagnoses of adenoma, adenoma with advanced histology, and CRC. Cohort members were followed for CRC through the follow-up screening rounds, even if they subsequently became ineligible for screening because of sigmoidoscopy or colonoscopy. Patients were censored at the time of CRC diagnosis, death, or termination of membership in the health plan if they did not rejoin. Figure. Study flow diagram.* The figure includes 1192 patients with CRC who were screened by FIT the year before diagnosis. Further, there were 118 additional patients with CRC diagnosed more than 1 y beyond the FIT screening date and 101 additional patients diagnosed with CRC who either crossed over to endoscopy in subsequent rounds or terminated health plan membership but then rejoined. CRC = colorectal cancer; FIT = fecal immunochemical test. * Shading indicates where patients were censored or became ineligible for subsequent FIT screening. Patients were eligible for the initial FIT mailing if they were aged 50 to 70 y and had 1 y of membership. See Methods section for exclusions. Number censored because of CRC and includes patients with CRC diagnosed within 1 y after their FIT result. Defining Annual Screening Episodes For each patient, the initial kit mail date in 2007 or 2008 was the anchor date for round 1 and for each subsequent round of testing. However, because subsequent mailing dates varied each round, mail dates within 3 months before to 12 months after each subsequent rounds anchor date were counted as having been distributed during that specific round. For example, a patient with a round 1 mail date of 15 March 2007 had subsequent anchor dates of 15 March for rounds 2 through 4 (2008, 2009, and 2010, respectively). If their next FIT was mailed on 15 January 2008, the test was considered to be distributed in round 2 because the second mail date occurred within 3 months of the round 2 anchor date. The FIT results recorded within 1 year of each mail date, and colonoscopies performed and adenomas or CRC diagnosed within 1 year after FIT results, were considered part of a single screening episode for the round when the FIT was distributed. Among round 1 participants, FITs with no recorded mail dates returned in rounds 2 through 4 were assumed to be distributed through in-reach methods (such as a clinic visit) and were counted in the follow-up round returned. In general, the first result per patient was counted in any given round. The earliest possible date of cohort entry (first mail date) was 1 January 2007, and the last possible date of follow-up was 31 December 2013 (12 months after the last possible FIT result date of 31 December 2012). Data Sources The FIT-related dates and results were obtained from the CRC screening program and laboratory databases for each region, respectively. Endoscopy procedures were identified using Current Procedural Terminology codes (22). Adenoma diagnoses used Systematized Nomenclature of Medicine codes. Prior validation studies have confirmed high levels of sensitivity and accuracy for capture of colonoscopy examinations and assignment of adenoma status (23). Colorectal adenocarcinomas and disease stage were obtained from the KPNC and KPSC cancer registries, which report to the SEER (Surveillance, Epidemiology, and End Results) registry. Cancer databases capture more than 98% of cancer diagnoses within the KPNC and KPSC populations. Advanced-stage cancer was defined as stage III (regional disease with spread to regional lymph nodes only) or stage IV (distant metastasis) according to the American Joint Committee on Cancer staging system; for patients who did not have such staging, advanced-stage cancer was defined as code 3 (disease in the regional lymph nodes), code 4 (regional disease with direct extension and spread to regional lymph nodes), or code 7 (distant metastasis) according to the SEER Program Coding and Staging Manual 2013 (24). Data Analysis The following performance characteristics were calculated for each round of screening and overall: 1) participation (percentage of eligible patients who were distributed and completed a FIT within 1 year of their mailing date), 2) FIT positivity (percentage of participants who completed FITs and had positive results), 3) follow-up colonoscopy (per


International Journal of Food Sciences and Nutrition | 2011

Effects of vitamin D supplementation on 25-hydroxyvitamin D, high-density lipoprotein cholesterol, and other cardiovascular disease risk markers in subjects with elevated waist circumference

Kevin C. Maki; Martyn R. Rubin; Les G. Wong; Jamie F. McManus; Christopher D. Jensen; Andrea Lawless

The objective of the present trial was to assess the effects of vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D] and high-density lipoprotein cholesterol (HDL-C) in subjects with high waist circumference. Subjects were randomly assigned a daily multivitamin and mineral (MVM) supplement or a MVM supplement plus vitamin D 1,200 IU/day (MVM+D) for 8 weeks. There was a significant difference in mean change for 25(OH)D between the MVM and MVM+D treatment groups ( − 1.2 ± 2.5 nmol/l vs. 11.7 ± 3.0 nmol/l, respectively; P = 0.003). Vitamin D 1,200 IU/day did not increase 25(OH)D to a desirable level ( ≥ 75 nmol/l) in 61% of participants. There were no significant changes in cardiovascular disease risk markers. Thus, vitamin D supplementation with 1,200 IU/day was insufficient to achieve desirable serum 25(OH)D in most participants and did not affect cardiovascular disease risk markers.


JAMA | 2015

Variation in Adenoma Detection Rate and the Lifetime Benefits and Cost of Colorectal Cancer Screening: A Microsimulation Model.

Reinier G. Meester; Chyke A. Doubeni; Iris Lansdorp-Vogelaar; Christopher D. Jensen; Miriam P. van der Meulen; Theodore R. Levin; Virginia P. Quinn; Joanne E. Schottinger; Ann G. Zauber; Douglas A. Corley; Marjolein van Ballegooijen

IMPORTANCE Colonoscopy is the most commonly used colorectal cancer screening test in the United States. Its quality, as measured by adenoma detection rates (ADRs), varies widely among physicians, with unknown consequences for the cost and benefits of screening programs. OBJECTIVE To estimate the lifetime benefits, complications, and costs of an initial colonoscopy screening program at different levels of adenoma detection. DESIGN, SETTING, AND PARTICIPANTS Microsimulation modeling with data from a community-based health care system on ADR variation and cancer risk among 57,588 patients examined by 136 physicians from 1998 through 2010. EXPOSURES Using modeling, no screening was compared with screening initiation with colonoscopy according to ADR quintiles (averages 15.3%, quintile 1; 21.3%, quintile 2; 25.6%, quintile 3; 30.9%, quintile 4; and 38.7%, quintile 5) at ages 50, 60, and 70 years with appropriate surveillance of patients with adenoma. MAIN OUTCOMES AND MEASURES Estimated lifetime colorectal cancer incidence and mortality, number of colonoscopies, complications, and costs per 1000 patients, all discounted at 3% per year and including 95% confidence intervals from multiway probabilistic sensitivity analysis. RESULTS In simulation modeling, among unscreened patients the lifetime risk of colorectal cancer incidence was 34.2 per 1000 (95% CI, 25.9-43.6) and risk of mortality was 13.4 per 1000 (95% CI, 10.0-17.6). Among screened patients, simulated lifetime incidence decreased with lower to higher ADRs (26.6; 95% CI, 20.0-34.3 for quintile 1 vs 12.5; 95% CI, 9.3-16.5 for quintile 5) as did mortality (5.7; 95% CI, 4.2-7.7 for quintile 1 vs 2.3; 95% CI, 1.7-3.1 for quintile 5). Compared with quintile 1, simulated lifetime incidence was on average 11.4% (95% CI, 10.3%-11.9%) lower for every 5 percentage-point increase of ADRs and for mortality, 12.8% (95% CI, 11.1%-13.7%) lower. Complications increased from 6.0 (95% CI, 4.0-8.5) of 2777 colonoscopies (95% CI, 2626-2943) in quintile 1 to 8.9 (95% CI, 6.1-12.0) complications of 3376 (95% CI, 3081-3681) colonoscopies in quintile 5. Estimated net screening costs were lower from quintile 1 (US


Gut | 2018

Effectiveness of screening colonoscopy in reducing the risk of death from right and left colon cancer: a large community-based study

Chyke A. Doubeni; Douglas A. Corley; Virginia P. Quinn; Christopher D. Jensen; Ann G. Zauber; Michael Goodman; Jill Johnson; Shivan J. Mehta; Tracy A Becerra; Wei K. Zhao; Joanne Schottinger; V. Paul Doria-Rose; Theodore R. Levin; Noel S. Weiss; Robert H. Fletcher

2.1 million, 95% CI,


JAMA | 2017

Association Between Time to Colonoscopy After a Positive Fecal Test Result and Risk of Colorectal Cancer and Cancer Stage at Diagnosis

Douglas A. Corley; Christopher D. Jensen; Virginia P. Quinn; Chyke A. Doubeni; Ann G. Zauber; Jeffrey K. Lee; Joanne E. Schottinger; Amy R. Marks; Wei K. Zhao; Nirupa R. Ghai; Alexander T. Lee; Richard Contreras; Charles P. Quesenberry; Bruce Fireman; Theodore R. Levin

1.8-


Clinical Gastroenterology and Hepatology | 2016

Consequences of Increasing Time to Colonoscopy Examination After Positive Result From Fecal Colorectal Cancer Screening Test

Reinier G. Meester; Ann A. Zauber; Chyke A. C.A. Doubeni; Christopher D. Jensen; Virginia P. Quinn; Mark M. Helfand; Jason A. Dominitz; Theodore R. Levin; Douglas A. Corley; Iris Lansdorp-Vogelaar

2.4 million) to quintile 5 (US


Gastrointestinal Endoscopy | 2016

Factors influencing variation in physician adenoma detection rates: a theory-based approach for performance improvement.

Louise Atkins; Enid M. Hunkeler; Christopher D. Jensen; Susan Michie; Jeffrey K. Lee; Chyke A. Doubeni; Ann G. Zauber; Theodore R. Levin; Virginia P. Quinn; Douglas A. Corley

1.8 million, 95% CI,


Clinical Gastroenterology and Hepatology | 2015

Adjusting for Patient Demographics has Minimal Effects on Rates of Adenoma Detection in a Large, Community-Based Setting

Christopher D. Jensen; Chyke A. Doubeni; Virginia P. Quinn; Theodore R. Levin; Ann G. Zauber; Joanne E. Schottinger; Amy R. Marks; Wei K. Zhao; Jeffrey K. Lee; Nirupa R. Ghai; Jennifer L. Schneider; Bruce Fireman; Charles P. Quesenberry; Douglas A. Corley

1.3-

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Chyke A. Doubeni

University of Pennsylvania

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Ann G. Zauber

Memorial Sloan Kettering Cancer Center

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Jeffrey K. Lee

University of California

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