More bad news for smokers

Add two more cancer risks for tobacco smoke (Gastroenterology 2012: 142: 233-40, 242-47).  There is now evidence linking tobacco smoke to 18 different cancers and tobacco smoke is probably the most preventable cause of death in the world.

In the first study, the investigators examined 3167 patients with Barrett’s esophagus.  This retrospective study followed patients for 7.5 years.  Patients who were current smokers (any form of tobacco) had double the risk of developing high-grade dysplasia or cancer compared to those who had never smoked.  Former cigarette smokers had a hazard ratio of 1.53.

In the second study, 386 patients with Lynch syndrome were analyzed during a 10 month period.  The hazard ratio for developing colorectal adenomas was 6.13 for current smokers and 3.03 for former smokers compared with patients who never smoked.  In addition, the authors identified a trend for developing adenomas based on pack-years.

Two more reasons to quit smoking.  On a side note, my grandmother said quitting smoking was the easiest thing that she ever did.  So easy, she did it a thousand times.

Additional references:

  • -Gastroenterolgy 2005; 129: 1825-31.  1.6% incidence of BE in adult Swedish population. Alcohol & smoking increase risk.
  • -NEJM 2011; 365: 1222. Treating smokers -useful review.
  • -NEJM 2011; 365: 1193. Cytisine -inexpensive- helps with smoking cessation (8.4% success vs 2.4%in placebo)
  • -NEJM 2008 358; 2249. Smoking and role of social networks.
  • -Gastroenterology 2011; 141: 2000. Lower risk of Barrett’s in pts taking NSAIDs & statins. n=570.
  • -Gastroenterology 2011; 141: 1179. Lower risk of Barrett’s in pts with low-grade dysplasia than previously noted -similar to non-dysplastic Barrett’s.
  • -NEJM 2011; 365: 1375. Large Danish study, n=11028. Lower incidence of Barrett’s than previous estimates. Relative risk of 11.3 compared to general population for adenoca of Esophagus with absolute annual risk of 0.12%. Barrett’s patients have the same life expectancy as general population (ed. pg 1437). Detecting cancer only ~1 in 1460 scopes with screening whereas Barrett’s detected in 10% of pts.
  • -Gastroenterology 2011; 140: 1084. AGA statement on Barrett’s . Recs screening only in those with multiple risk factors (age 50, male, chronic GERD, white, incr BMI)
  • -NEJM 2005; 352: 1851. Cases of Lynch can be missed when following screening guidelines.
  • -Gastroenterology 2010; 138: 207-2177 (entire issue) Colon cancer, Lynch syndrome
  • -Gastroenterology 2008; 135: 380.  Review of colon cancer screening and prevention -2008 up-to-date- literature review
  • -Gastroenterology 1967; 53: 517-27.  Seminal article.  Lynch HT showed gene-related cancer in family cancer syndrome -different than polyposis syndromes.

Holes in the fiber theory

Since the 1970s, it has been accepted that diverticular disease is related to low fiber intake and the Western diet.  Problem is that this might not be right (Gastroenterology 2012; 142: 205-10).  In this observational cross-sectional study (n=2104), low dietary fiber was not associated with diverticulosis; just the opposite.  High fiber intake, after adjusting for other factors, had an adjusted prevalence ratio of 1.3.  Due to the nature of the study, there may be potential bias that would not be present with a prospective study, especially with regard to dietary recall.  An editorial in the same issue (pg 205-07) lists three other studies; two of these also could not demonstrate a protective effect of fiber.  In addition to these findings, this study did not find an association between fat, red meat, physical activity and diverticulosis.

Although these data throw a big question mark regarding the pathogenesis of diverticular disease, this does not mean you should throw away your fiber bars quite yet.  Although low fiber may not cause diverticular disease, several large prospective studies have been completed which convincing show an association with lower complications/hospitalizations among individuals with higher fiber intake.  In addition, increased fiber in the diet has been shown to lower cardiovascular complications.

Additional references:

  • -Br Med J 1971; 2: 450-54.  Seminal article on diverticular disease and association with Western countries with low fiber intake.
  • -Am J Clin Nutr 1994; 60: 757-64.  Prospective study showing benefits of fiber in preventing diverticular complications (n=47,888); RR=0.58 for developing symptomatic diverticulitis.
  • -BMJ 2011; 343: d4131.  EPIC study, n=47,033, showing benefit of fiber in reducing hospitalizations due to diverticular dz over 12yrs (0.59 RR)
  • -NEJM 1999; 340: 169. fiber does not decrease Colon Ca risk.
  • -NEJM 2000; 342: 1149 & 1159. fiber does not decrease risk of recurrent adenomas.
  • -Am J Clin Nutr 2000; 70: 1433-1438. Fiber lowers cholesterol & can decrease risk of heart attack by 15%.