Cigarette smoking, gastric acidity and peptic ulceration. What are the relationships?

Use of proton pump inhibitors and subsequent risk of celiac disease

BACKGROUND

The prevalence of celiac disease and the use of medications that inhibit acid secretion have both increased in recent decades.

AIM

To explore the association between antisecretory medication exposure and subsequent development of celiac disease.

METHODS

In this population-based case control study, we identified patients with celiac disease diagnosed at all pathology departments in Sweden from July 2005 through February 2008. Patients were matched by age and gender with up to 5 controls. We identified prior prescriptions for proton pump inhibitors and histamine-2 receptor antagonists in all subjects. We used conditional logistic regression to measure the association between these prescriptions and the subsequent diagnosis of celiac disease.

RESULTS

Prior proton pump inhibitor prescription was strongly associated with celiac disease (OR 4.79; 95% CI 4.17-5.51). Patients prescribed both proton pump inhibitors and histamine-2 receptor antagonists had a higher risk of celiac disease (OR 5.96; 95% CI 3.58-9.91) than those prescribed proton pump inhibitors alone (OR 4.91; 95% CI 4.26-5.66) or histamine-2 receptor antagonists alone (OR 4.16; 95% CI 2.89-5.99).

CONCLUSIONS

Exposure to antisecretory medications is associated with a subsequent diagnosis of celiac disease. The persistence of this association after excluding prescriptions in the year preceding the celiac disease diagnosis suggests a causal relationship.

Gastric histology, serological markers and age as predictors of gastric acid secretion in patients infected with Helicobacter pylori

BACKGROUND

Acid secretion is intimately associated with most upper gastrointestinal diseases. Helicobacter pylori infection is a major environmental factor modifying acid secretion.

AIM

To study the association between the pattern of H pylori gastritis and gastric secretory function in a large number of subjects without specific upper gastrointestinal disease.

METHODS AND MATERIALS

Maximal acid output (MAO) was measured in 255 patients with dyspepsia showing normal endoscopy. Activity and severity of gastritis, atrophy and H pylori infection were assessed in body and antral biopsies. The correlations of histological parameters as well as age, sex, height, weight, smoking, serum gastrin, pepsinogen I and II, and their ratio with MAO were determined. Multiple linear regression was used to show the best possible predictors of MAO.

RESULTS

Negative relationships: Body atrophy and body-combined (active and chronic) inflammatory scores showed a potent inverse correlation with MAO (correlation coefficients (CC) 0.59 and 0.50, respectively). Body:antral chronic gastritis ratio and body:antral combined inflammation ratio (both with CC = 0.49) and age (CC = 0.44) were also inversely correlated with MAO. Intestinal metaplasia at both antral and body sites had negative relationships with acid output with CC = 0.23 and 0.20, respectively. Positive relationships: Serum pepsinogen I, body H pylori density:combined inflammation ratio and pepsinogen I:II ratio with CC of 0.38, 0.38 and 0.30, respectively, correlated with MAO. The H pylori density: combined inflammation of both antrum and body positively correlated with MAO (CC = 0.29 and 0.38, respectively). Male sex and patient height also positively correlated with acid output. Modelling showed that body combined inflammatory score, body atrophy, age and serum pepsinogen I are independent predictors of acid output (R(2) = 0.62).

CONCLUSION

Combination of body gastritis, body atrophy, age and serum pepsinogen I can be used as predictors of acid-secretory state in populations infected with H pylori.

Smoking and systemic disease

Cigarette smoking is associated with a number of adverse health effects, including well-established links to cardiopulmonary disease and several cancers. Some of the other important systemic diseases associated with smoking are the subjects of this article, such as diabetes mellitus and insulin resistance and thyroid diseases. Also reviewed here is the negative impact of smoking on male and female infertility, on selected dermatologic conditions, and on gastrointestinal diseases including peptic ulcer and inflammatory bowel diseases.

Meta-analysis of risk factors for peptic ulcer. Nonsteroidal antiinflammatory drugs, Helicobacter pylori, and smoking

Attributable risk models describe the role of three risk factors for peptic ulcer and related serious upper gastrointestinal (GI) events. The factors-nonsteroidal antiinflammatory drugs (NSAIDs), Helicobacter pylori, and cigarette smoking-have been identified as major risk factors for peptic ulcer in numerous clinical and epidemiologic studies. Overall risk ratios for each risk factor were based on meta-analyses of English-language studies of risk for peptic ulcer-related GI events. Exposure estimates for factors used data from North American populations. Summary risk and exposure values were computed for the general population, males and females separately, and the elderly. Hypothetical models of multiple factor attributable risks were developed using population attributable risk percent calculated from these summary values. General population attributable risk percent were as follows: 24%, NSAIDs; 48%, H. pylori; and 23%, cigarette smoking. Based on these numbers, the "no interaction" attributable risk model estimates that 95% of total peptic ulcer related risk is attributable to these factors in the general population. The "interaction" model attributes 89% of cases to these risk factors: 24%, NSAIDs alone; 31%, H. pylori alone; 34%, H. pylori/smoking combined. Between 89% and 95% of peptic ulcer-related serious upper GI events may be attributed to NSAID use, H. pylori infection, and cigarette smoking.

Problems with the interpretation of gastric pH measurement

The present study examines some of the assumptions underlying the use of intragastric pH-metry for assessing the degree of therapeutic gastric inhibition. Three separate studies were performed to determine the relationship between pH and titratable hydrogen ion concentration in gastric juice and to assess the relationship between the concentration of acid and the rate of gastric secretion. The concentration of acid derived from pH measurements tended to be lower than the titrated hydrogen ion concentration. The difference between the two readings--the "buffered" hydrogen ion concentration--was increased by the presence of food and was reduced during gastric secretory inhibition with ranitidine. The titrated hydrogen ion concentration reflected more accurately the amount of hydrochloric acid added to a container in vitro than pH measurement. However, in vivo even the measurement of titratable acidity was poorly correlated with the volume of secreted gastric juice so that measurement of gastric acid concentration does not permit inferences about the rate of gastric secretion. The results of the present study indicate that measurement of intragastric pH is unsatisfactory for assessing gastric secretion, particularly in response to a food stimulus, so that measurement of gastric acidity alone does not reflect the rate, or changes in the rate, of gastric acid secretion.

Circadian acidity pattern in prepyloric ulcers: a comparison with normal subjects and duodenal ulcer patients

We used continuous 24-h pH monitoring to compare the circadian intragastric acidity of 36 patients with prepyloric ulcers (PPU) with that of 101 normal subjects (NS) and that of 206 patients with duodenal ulcer (DU). The ulcer crater was endoscopically ascertained in all cases, and PPU were located within an area up to 2 cm proximal to the pylorus. The pH curve pertaining to DU patients ran below that of NS during most of the circadian period, whereas the pH profile of PPU patients was higher than that of NS, and this was particularly true during the evening and the night. The acidity of PPU patients was significantly lower (p < 0.01) than that of NS during the night only, whereas it was lower (p < 0.05-0.001) than that of DU patients during each time interval analysed (24 h, nighttime, and daytime). Our findings show that the gastric acidity of PPU patients differs greatly from that of DU patients, since it is lower throughout the whole 24-h period, and particularly during the night. Thus these two entities are pathophysiologically different with regard to the acidity pattern and should be considered two distinct subgroups of peptic ulcer disease instead of being incorporated, as usually happens, in the clinical group 'duodenal ulcer disease'.

Acute effects of smoking during modified sham feeding in duodenal ulcer patients. An analysis of nicotine, acid secretion, gastrin, catecholamines, epidermal growth factor, prostaglandin E2, and bile acids

Smoking is associated with an increased incidence of duodenal ulcer with a high relapse rate, and smokers tend to be slow healers. The etiology responsible for this remains unknown, and there is general disagreement as to whether smoking affects gastric secretion. The aim of the present study was to investigate both aggressive and protective factors in response to vagal stimulation induced by modified sham feeding (MSF) in duodenal ulcer patients when smoking versus not smoking. On smoking days, nicotine concentrations in plasma averaged about 15 ng/ml and were extremely high in saliva and gastric juice (> 1300 and > 800 ng/ml, respectively). MSF induced a significant decrease in intragastric pH during non-smoking (p = 0.01) but not during smoking. Acid output 1 h after MSF was lower on smoking than on non-smoking days (p = 0.02), as was volume secretion (p = 0.02). Plasma gastrin concentrations were significantly increased during MSF on non-smoking days (p = 0.04) but not on smoking days, the concentrations during the whole day being lower on smoking days (p = 0.002). Plasma catecholamine levels were unaffected by MSF, whether smoking or not. However, plasma concentrations of noradrenaline decreased during the smoking of a single cigarette (p = 0.03), whereas those of adrenaline were increased on smoking days (p = 0.02). Epidermal growth factor concentrations were decreased in gastric juice after MSF during non-smoking (p = 0.01) but not during smoking. Although prostaglandin E2 (PGE2) concentrations in gastric juice were unaffected by MSF, PGE2 output increased after MSF whether smoking or not, the increment being non-significantly less during smoking (p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Cigarette smoking and Helicobacter pylori infection

The direct urease test was used in 462 patients with normal upper digestive tracts, 108 with duodenal ulcers and 43 with gastric ulcers who attended for upper digestive endoscopy in a prospective study. There was a strong association between Helicobacter pylori infection and current cigarette smoking in patients with normal endoscopy (49.6% vs 35.5%, P < 0.01). The associations of peptic ulcer both with H. pylori infection and cigarette smoking were also confirmed. The excess of peptic ulcer disease in cigarette smokers may be explained by their increased susceptibility to H. pylori infection.

Effect of nicotine on the enterochromaffin like cells of the oxyntic mucosa of the rat

Smoking has an unfavourable effect on peptic ulcer disease. The pathophysiological mechanisms underlying this effect are not known. The enterochromaffin like (ECL) cell is the cellular source of histamine participating in the regulation of acid secretion. The ECL cell is under functional and trophic control of gastrin and the vagus nerves. Nicotine may affect acid secretion through vagal pathways. Furthermore, nicotine may also stimulate neuroendocrine cells. The present study examined if chronic nicotine administration could stimulate the function and growth of the ECL cell. Rats inhaled nicotine vapour at a concentration of approximately 6.2 mumol/m3, 20 hours/day, 5 days/week for 11 weeks. Steady state plasma nicotine concentration was 461.8 (137.5 (SD)) nmol/l. The ECL cell density, histamine content and histidine decarboxylase activity of the oxynitic mucosa were similar to the controls. We also examined the effect of acute nicotine stimulation on the acid output and histamine release from the totally isolated vascularly perfused rat stomach. Nicotine did not stimulate acid secretion or histamine release. Thus no evidence could be provided to support the hypothesis that nicotine exerts its negative effects on peptic ulcer disease by stimulating the ECL cell.

Clinical aspects of gastroduodenal ulcer recurrence: an overview

Duodenal ulcer is a disease characterized by very high rates of recurrence: up to 80% at 1 year, 95% at 2 years. Maintenance therapy will reduce relapse rates. However, when therapy directed against gastric acid is stopped, the slope of the recurrence curve is identical whether therapy is stopped after 6 weeks, 8 weeks, 3 months, 6 months, 1 year, or 2 years. This suggests that therapy directed against acid does nothing to change the natural history of ulcer disease. Cytoprotective therapy is equally successful as H2-blockers at healing ulcer or reducing relapse rates, but the time to recurrence is significantly prolonged after either acute or maintenance cytoprotective therapy is stopped. This suggests that cytoprotective therapy has a beneficial effect that does improve the natural history of ulcer disease. The mechanism by which maintenance therapy reduces ulcer relapse could be masking symptoms (analgesic), accelerated healing, or true prevention of ulcer recurrence. By using frequent endoscopic assessment combined with complex statistical evaluation (calculating traditional ulcer prevalence, point prevalence, and maximal ulcer prevalence), we showed that sucralfate cytoprotection genuinely prevents ulcer recurrence. The incidence of asymptomatic ulcer recurrence after sucralfate is 10% but is up to 40% after H2-blocker therapy.

Influence of smoking on basal and on vagally and maximally stimulated gastric acid and pepsin secretion

Published data show that smokers have greater basal or peak acid and pepsin outputs, but the mechanisms underlying these effects are unknown. To confirm this and to determine whether these findings extend to, and implicate, any vagal overactivity, gastric secretions collected for 1 h basally, 1 h after 15 min of modified sham feeding (MSF), and 1 h after pentagastrin (6 micrograms/kg subcutaneously) were analyzed for acid and pepsin content in 204 subjects, 104 with duodenal ulcer (66 smokers) and 101 without (57 smokers). Maximal acid outputs (MAO, mu eq/kg/h, means +/- SEM) were higher in smokers than in non-smokers in both duodenal ulcer (DU) (623 +/- 35 versus 491 +/- 35, p less than 0.005) and non-DU (502 +/- 32 versus 376 +/- 20, p less than 0.005). Basal and MSF secretions were generally increased in smokers but, when expressed as a percentage of MAO, were not different in smokers and non-smokers (18% versus 17% and 43% versus 39%, respectively, in DU, and 13% versus 16% and 40% versus 36% in non-DU). Maximal pepsin outputs (units x 10(-2)/kg/h) were also higher in smokers than in non-smokers (DU, 129 +/- 7.9 versus 105 +/- 9.5, p = 0.05, and non-DU, 101 +/- 7.5 versus 77 +/- 10, p = 0.05). Basal and MSF secretions as a percentage of maximal pepsin output were not different in smokers versus non-smokers. Multivariate logistic regression shows that smoking was most strongly associated with MAO and sham feeding outputs, but the duration-intensity (pack-years) of smoking was associated only with elevated MAO.(ABSTRACT TRUNCATED AT 250 WORDS)