Tag Archives: epidemiology

Tipping Point for Obesity?

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A bit of encouraging news from California where investigators showed a small drop in the prevalence of childhood obesity from 2008 to 2013 (C Koebnick et al. J Pediatr 2015; 167: 1264-71).  Using a population-based cohort of ~1.3 million patients, the authors found the following:

  • Obesity prevalence decreased from 19.1% (2008) to 17.5% (2013).  This was observed across all ages, sexes, races, and socioeconomic groups but with variability.
  • Younger children had a greater decline in obesity prevalence compared with adolescents: ages 2-5 years:  -15.4% decline, ages 6-11 years: -11,8% decline and in 12-19 years: -4.5%.

My take: This is a good indication that increased awareness of the obesity epidemic may be leading to some improvement.

Related blog posts:

Lights at Life University

Lights at Life University

Hepatitis C Prevalence Underestimated

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A recent study (BR Edlin et al. Hepatology 2015; 62: 1353-63) provides data suggesting that Hepatitis C virus (HCV) infection has been underestimated.

The number most commonly used is derived from the 2003-2010 National Health and Nutrition Examination Survey (NHANES) which showed 3.6 million in the U.S. with antibodies to HCV and 2.7 million currently infected.

The authors performed a systemic review and note that ~1 million people were excluded from this survey including a large number at high risk for HCV: ~500,000 incarcerated people, and 220,000 homeless people.

Based on their analysis, they conclude that “the number of US residents who have been infected with hepatitis C is unknown but is probably at least 4.6 million…and of these, at least 3.5 million… are currently infected.”

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The Story Behind a 30 Year Esophagitis Study

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A recent retrospective study ( SS Baker et al. JPGN 2015; 61: 538-40) reported on changes in esophagitis over a 30 year period at one center.  While the authors focus on the fluctuating percentage of esophagitis noted during three periods, in my opinion, they miss the opportunity to discuss more relevant findings.

Specifically, the authors note the following:

  • From 1980-88 (n=186 over 8 years) that 26.9% had esophagitis and 4.8% had >15 eos/hpf.  Normal pathology in the esophagus was noted in 73.1%.
  • From 2000-2002 (n=321 over 2 years), 41.2% had esophagitis and 8.5% had >15 eos/hpf.  Normal pathology in the esophagus was noted in 58.8%.
  • In the most recent period, 2011, (n=675 over 1 year), 31%* had esophagitis and 12.7% had >15 eos/hpf.  Normal pathology in the esophagus was noted in 69%.     *erroneously reported as 33%

What is baffling to me are the following:

  • Why the authors assert that there has been a fluctuating prevalence.  In absolute terms, the increase in cases is marked, though one can argue that in earlier periods there may have been many undiagnosed cases.
  • Why the authors do not comment on the tremendous increase in the use of endoscopy in their discussion.  In the first period, they were averaging ~23/year, the second period ~95/year and in the most recent period, they performed 675 in one year.

My take: This study shows that esophageal eosinophilia has been present for a long time and that identification of cases has increased considerably over 32 years.  In addition, the use of endoscopy has increased markedly, yet the yield of abnormal findings remains similar.

Briefly noted: C Menard-Katcher et al. JPGN 2015; 61: 541-46.  This retrospective study of 22 children showed that 55% had esophageal strictures identified by esophagram but not endoscopy.

Related blog posts:

Bamboo

Increasing Inflammatory Bowel Disease Among U.S. Patients From India

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An interesting epidemiology study (Malhotra R, et al. Clin Gastroenterol Hepatol 2015; 13: 683-89) shows a high prevalence of inflammatory bowel disease among U.S. residents with Indian Ancestry.

Using a national pathology database on 1,027,977 subjects who had ileocolonic biopsies from 2008-2013, the authors identified 30,812 patients who were diagnosed with inflammatory bowel disease (IBD): 20,308 with ulcerative colitis (UC), 7706 with Crohn’s disease (CD), and 2798 with indeterminate colitis (IC).

Key findings:

  • Among patients with Indian ancestry, the overall prevalence of IBD was 9.1% (n=197 compared with 1960 controls) compared with 4.3% for those of Jewish ethnicity, 2.4% for hispanic ethnicity, and 1.4% for East Asian ethnicity.  The adjusted odds ratio for patients with Indian ancestry was 2.5.
  • In addition, UC was predominant, accounting for 153 of the 197 cases; 26 were diagnosed with CD and 18 were IC.  IBD and UC were highest in subjects with roots in Gujarat.

Take-home point (from authors): “Considering the reported relatively low prevalence of IBD in India, these findings suggest that genetic factors may interact with new environmental conditions to trigger the expression of disease.”

Related blog post: Emigration -One Way to Acquire IBD

Briefly Noted:

Rungoe C, et al. “Inflammatory Bowel Disease and Cervical Neoplasia: A Population-Based Nationwide Cohort Study” Clin Gastroenterol Hepatol 2015; 13: 693-700. Using a Dutch national cohort with more than 27,000 patients, the authors showed a “2-way association between IBD, notably CD, and neoplastic lesions of the uterine cervix.” Overall the risk was mildly increased; for CD, the incidence rate ratio of cervical cancer was 1.53 (CI 1.04-2.27).

Reinisch W, et al. “Factors Associated with Poor Outcomes in Adults with Newly Diagnosed Ulcerative Colitis” Clin Gastroenterol Hepatol 2015; 13: 635-42. The tables in this article summarize clinical characteristics, biologic markers, and treatment factors associated with poor outcomes.  For clinical factors, younger age at diagnosis and age >65 years increase the risk for more severe disease. For biomarkers, increased CRP, ESR, and cal protection were associated with higher risk of progressing to colectomy. For treatment factors, not surprisingly, failing to respond to therapy and absence of mucosal healing were associated with higher risk of progressing to colectomy.

Chattahoochee River National Recreation Area

Chattahoochee River National Recreation Area

Emigration -One Way to Acquire Inflammatory Bowel Disease

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A recent study (Shitrit AB, et al. Inflamm Bowel Ds 2015; 21: 631-35) highlights the phenomenon of acquiring inflammatory bowel disease (IBD) by moving from a non-developed country to a developed country; the implication is that the changes in environment and diet predispose towards the development of IBD.

This study examined Ethiopian Jews who migrated to Israel.  Using a case-control study, the authors compared 32 Ethiopian immigrants to 33 Ashkenazi patients with IBD.

Key findings:

  • No Ethiopian immigrants had a positive family history compared with 42% of Ashkenazi group.
  • Crohn’s disease was more prevalent in the Ethiopian immigrants: 94% versus 73%.
  • The Ethiopian immigrants lived in Israel for at least 8 years before developing IBD an da median duration of 13 years.

The study discusses the difficulty of diagnosing IBD in rural Africa but speculates that rather than an underdiagnosis of IBD, it is likely to have a true low prevalence of IBD.

Take-home message: It takes many years for the environment exposures to allow for the development of IBD.  Additional work is needed to establish the clinical, genetic, and microbial factors that influence the acquisition of IBD in immigrants to developing countries.  Understanding the susceptibility of immigrants would have widespread application.

Related blog posts:

IBD Incidence Increasing: 30 Years of Data from Manitoba

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A recent study (JPGN 2014; 59: 763-66) shows a steady trend of increased incidence of IBD in Manitoba. This figure is available online:

 

Increasing IBD Incidence in Children

Increasing IBD Incidence in Children from JPGNonline

Abstract:

Objectives: The aim of this study was to describe the incidence and prevalence of inflammatory bowel disease (IBD) in children <17 years of age in 30 years from 1978 to 2007.

Methods: From January 1, 1978, to December 31, 2007, the sex- and age-adjusted annual incidence and prevalence of pediatric IBD per 100,000 population were calculated based on the pediatric IBD database of the only pediatric tertiary center in the province. The annual health statistics records for the Province of Manitoba were used to calculate population estimates for the participants. To ensure validity of data, the University of Manitoba IBD Epidemiology Database was analyzed for patients <17 years of age from 1989 to 2000.

Results: The sex- and age-adjusted incidence of pediatric Crohn disease has increased from 1.2/100,000 in 1978 to 4.68/100,000 in 2007 (P < 0.001). For ulcerative colitis, the incidence has increased from 0.47/100,000 in 1978 to 1.64/100,000 in 2007 (P < 0.001). During the same time period, the prevalence of Crohn disease has increased from 3.1 to 18.9/100,000 (P < 0.001) and from 0.7 to 12.7/100,000 for ulcerative colitis (P < 0.001). During the last 5 years of the study the average annual incidence of IBD in urban patients was 8.69/100,000 as compared with 4.75/100,000 for rural patients (P < 0.001).

Conclusions: The incidence and prevalence of pediatric IBD are increasing. The majority of patients were residents of urban Manitoba, confirming the important role of environmental factors in the etiopathogenesis of IBD.

Unrelated: As a bonus for those who made it to the bottom of this post : there’s a new Bristol Stool App for iPhones.  Here’s the link: http://www.bristol-stool-scale.com (from John Pohl’s twitter feed)

 

Unknown unknowns for Hepatitis C

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“ [T]here are known knowns; there are things we know that we know.
There are known unknowns; that is to say there are things that, we now know we don’t know.
But there are also unknown unknowns – there are things we do not know, we don’t know.		 ”
—United States Secretary of Defense, Donald Rumsfeld February 2002

Reading a recent epidemiology article reminded me of the preceding referenced quote  (Hepatology 2012; 55: 1652-61).  This study took a close look at knowledge of being infected with hepatitis C virus (HCV) and what HCV infection may indicate.

The study identified 30,140 participants through the National Health and Nutrition Examination Survey (NHANES) conducted from 2001-2008.  The Centers for Disease Control (CDC) obtains nationally representative data on the health and nutritional status of noninstitutionalized civilians across the U.S.  NHANES uses a ‘complex, stratified, and mulitstage probability sampling design and collects information from approximately 5,000 persons per year using standardized household interviews, physical examinations, and testing of biologic samples.’

Participants 6 years of age or older who tested positive for anti-HCV antibodies were sent a report.  Out of the 30,140 participants, 393 (1.4%) had evidence of past or current HCV infection; 170 were available for the study investigators.  Only 49.7% were aware of HCV status prior to receiving NHANES letter.  Furthermore, only 3.7% were first tested for HCV because they or their doctor thought they were at risk for infection; most were tested as part of a routine exam (perhaps detected after elevated ALT values) (46.7%), due to symptoms (15.9%), or blood donation (9.7%).

Another aspect of the study was determining the participants’ understanding of HCV infection.  Correct responses to the HCV survey were more likely in individuals between 40-59 years of age, white non-Hispanics, and patients who had seen a doctor about their HCV infection.  Specific questions often answered incorrectly included the following:

  • whether HCV could be contacted by kissing –only 68% knew this was false
  • whether HCV could be transmitted sexually –only 64% knew this was true
  • whether HCV could be acquired during birth if mother had HCV –only 57% knew this was true

Take home points:

  • Risk-based screening for HCV will continue to fail.  Physicians may not elicit adequate information and patients may deny risky behaviors even if asked.
  • Approximately half of patients in this cohort were unaware of HCV infection.
  • Many misconceptions about HCV persist even among those who had received counseling.

Related blog posts:

Pediatric HCV Guidelines

HCV now more deadly than HIV

The cost of progress in treating Hepatitis C

Additional resource:

http://www.cdc.gov/hepatitis/RiskAssessment/  This website allows individuals to assess their risk for hepatitis.