A meta-analysis of the role of smoking in inflammatory bowel disease

Transdermal nicotine as maintenance therapy for ulcerative colitis

BACKGROUND

Ulcerative colitis is largely a disease of nonsmokers. Having found previously that treatment with transdermal nicotine patches and mesalamine (5-aminosalicylic acid) has a beneficial effect on active colitis, we examined the value of transdermal nicotine for the maintenance of remission.

METHODS

We treated 80 patients with ulcerative colitis in remission with either transdermal nicotine or placebo patches for six months in a randomized, double-blind study. Incremental doses of nicotine were given for the first three weeks to achieve a maintenance dose; most patients tolerated 15 mg for 16 hours daily. All patients were taking mesalamine preparations as maintenance treatment at entry into the study; this treatment was stopped once the maintenance dose of nicotine was achieved. Clinical, sigmoidoscopic, and histologic assessments were made at the beginning and the end of the study, or at relapse. Side effects and serum nicotine and cotinine concentrations were monitored throughout the study.

RESULTS

There was no significant difference in the number of relapses between the groups. Twenty-two patients in the nicotine group were prematurely withdrawn from the study, 14 because of relapse and 8 for other reasons, including side effects and protocol violations. In the placebo group, 20 patients were withdrawn prematurely, 17 because of relapse and 3 for other reasons. Among patients using 15-mg nicotine patches, serum nicotine and cotinine concentrations were lower than expected and may reflect poor compliance. Side effects were reported by 35 patients--21 in the nicotine group and 14 in the placebo group--the most common of which were nausea, lightheadedness, and itching.

CONCLUSIONS

Transdermal nicotine alone was no better than placebo in the maintenance of remission of ulcerative colitis, and premature withdrawal due to side effects was more common in the nicotine group.

Inherited disorders of coagulation appear to protect against inflammatory bowel disease

BACKGROUND/AIMS

Crohn's disease and ulcerative colitis seem to be rarely associated with inherited diseases of coagulation. Histological and hematologic studies suggest that thrombotic mesenteric microvascular occlusion is involved in the pathogenesis of inflammatory bowel disease. The aim of this study was to perform a national survey to determine the prevalence of inflammatory bowel disease among patients with inherited disorders of coagulation.

METHODS

Using a postal and telephone questionnaire survey sent to directors of all 129 hemophilia centers in the United Kingdom, the number of patients with inflammatory bowel disease and either hemophilia or von Willebrand's disease was determined. The expected number of cases of inflammatory bowel disease in this population was estimated using published data.

RESULTS

Of 6433 patients with hemophilia and 3129 patients with von Willebrand's disease, 4 cases of Crohn's disease were reported compared with expected 11.97-16.58 cases (standardized morbidity ratio, 0.33-0.24; 95% confidence interval, 0.90-0.01; P < 0.05). Ulcerative colitis also occurred significantly less frequently than expected: 9 observed cases in comparison with expected 19.43-31.35 cases (standardized morbidity ratio, 0.46-0.29; 95% confidence interval, 0.91-0.01; P < 0.025).

CONCLUSIONS

This epidemiological study provides further evidence that thrombosis and vascular occlusion may be important in the pathogenesis of inflammatory bowel disease.

Risk factors for colorectal cancer in patients with ulcerative colitis: a case-control study

BACKGROUND/AIMS

The risk of colorectal cancer increases in patients with ulcerative colitis, most markedly among young patients and/or those with extensive disease at onset. However, it is unknown whether individual risk can be predicted more precisely and whether cancer risk can be reduced by long-term treatment with sulfasalazine.

METHODS

In a population-based cohort of 3112 patients with ulcerative colitis, we compared 102 cases of colorectal cancer and 196 matched controls without cancer. Hospital records were used to abstract information on pharmacological therapy, disease activity, and extraintestinal manifestations. The relative risk (RR) of cancer was estimated by conditional logistic regression.

RESULTS

Pharmacological therapy, especially sulfasalazine, lasting at least 3 months was associated with a significant protective effect (RR, 0.38; 95% confidence interval [CI], 0.20-0.69) independent of disease activity. There was also a tendency to an independent protective effect for cigarette smoking (RR, 0.15; 95% CI, 0.02-1.25) and higher disease activity (RR, 0.80; 95% CI, 0.49-1.33).

CONCLUSIONS

The risk of colorectal cancer among patients with ulcerative colitis can be reduced through pharmacological therapy. This finding is consistent with the reports of a protective effect of aspirin among individuals in the general population.

Cigarette smoking and ulcerative colitis: a case-control study

OBJECTIVE

To determine whether the previously reported decreased risk of ulcerative colitis in current smokers and increased risk in former smokers are explained by age, sex, race, ethnicity, or socioeconomic status.

DESIGN

We conducted a case-control study at a university hospital gastroenterology clinic.

MATERIAL AND METHODS

One hundred patients with ulcerative colitis and 100 age- and sex-matched community control subjects were randomly selected for a telephone interview to collect information on smoking habits, race, religion, income, education, and occupation. Smoking habits at the onset of symptoms were analyzed with use of conditional logistic regression for matched data to obtain adjusted odds ratios and 95% confidence intervals for current or former smokers.

RESULTS

In comparison with those who had never smoked, current smokers were less likely to have ulcerative colitis: odds ratio = 0.13; 95% confidence interval = 0.05 to 0.38. Former smokers had no increased risk for ulcerative colitis: odds ratio = 1.24; 95% confidence interval = 0.52 to 2.95. No dose-response effect was noted on the basis of pack-years of cigarette smoking, and among former smokers, the interval since quitting smoking was not significantly associated with the relative risk of ulcerative colitis. No confounding effect was detected from race, religion, income, education, or occupation.

CONCLUSION

An association seems to exist between ulcerative colitis and nonsmoking; perhaps patients with ulcerative colitis who smoke are less likely to experience symptoms than are nonsmokers because of the effects of nicotine.

Pouchitis after ileal pouch-anal anastomosis: a Pouchitis Disease Activity Index

OBJECTIVE

To develop a "Pouchitis Disease Activity Index" (PDAI) and to compare it with other diagnostic scoring systems for pouchitis.

DESIGN

We compared patients who had an optimal outcome with those who had a poor result attributable to recurrent pouchitis after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis at the Mayo Clinic.

MATERIAL AND METHODS

We evaluated the applicability of a PDAI that quantitated clinical findings and the endoscopic and histologic features of acute inflammation in four groups of patients: (1) 10 who underwent IPAA for ulcerative colitis and had symptoms compatible with a clinical diagnosis of pouchitis, (2) 5 who underwent IPAA for ulcerative colitis and did not have pouchitis, (3) 5 who underwent IPAA for familial adenomatous polyposis and had no symptoms of pouchitis, and (4) 5 who had a Brooke ileostomy for ulcerative colitis (control group).

RESULTS

The PDAI was significantly greater in patients with the clinical features of pouchitis than it was for patients in the other three groups. All 10 patients with pouchitis fulfilled the PDAI criteria for a diagnosis of pouchitis; in contrast, only 1 of these 10 patients met the diagnostic criteria for pouchitis by application of previously established scoring systems. No asymptomatic patient qualified for a diagnosis of pouchitis by the PDAI criteria.

CONCLUSION

The PDAI provides simple, objective, and quantitative criteria for pouch inflammation after IPAA and is more sensitive than prior scoring systems.

Medical management of chronic inflammatory bowel disease

In the absence of a definitive cure for Crohn's disease and ulcerative colitis, the aim of therapy must be to induce and maintain clinical remission at acceptable cost to the patient in terms of adverse effects. Despite the differences in their pathogenesis, the first-line treatments for Crohn's disease and ulcerative colitis are still based upon combinations of amino-salicylic acid derivatives and corticosteroids, although the use of enteral nutrition regimes is becoming increasingly widespread in Crohn's disease. In this chapter we attempt to provide reasonably didactic guidance for the management of most cases of chronic inflammatory bowel disease. However, we have tried to go beyond this brief, motivated by the recent explosion in knowledge of inflammatory mechanisms, to suggest a rational approach to the choice of newer and less well tested therapeutic approaches in the affected child who is not responding effectively. The relative failure of cyclosporine therapy in Crohn's disease has been particularly disappointing in view of its ideal theoretical suitability. However, the encouraging early reports of treatment with anti-CD4 and anti-TNF alpha monoclonals suggest that the shift from broad spectrum immunomodulation to the targeting of critical components of the inflammatory cascade may yet field important dividends.

Aetiology and pathogenesis of chronic inflammatory bowel disease

While Crohn's disease and ulcerative colitis are both conditions characterized by intestinal inflammation, with some overlap in their clinical and histological features, they are essentially different in pathogenesis. Crohn's disease appears to be primarily a condition of chronic T-lymphocyte activation, with tissue damage induced by secondary macrophage activation. What activates the T-cells is unknown. In this chapter we look at the evidence for and against cell-wall deficient mycobacteria species, viral infection of vascular endothelium and luminal contents as potential mechanisms of chronic activation. In ulcerative colitis, by contrast, there is no strong evidence for T-cell activation, and humoral mechanisms predominate. While the finding of atypical anti-neutrophil cytoplasmic antibodies (P-ANCAs) may be useful in screening, the only novel pathogenetic discovery is the co-localization of a 40 kD colonic autoantibody with immunoglobulins and complement on the apical enterocyte surface. Despite the fundamental differences in initiating mechanisms, the two conditions have many 'downstream' inflammatory processes in common. We discuss the evidence for local production of cytokines, arachidonic acid metabolites and reactive oxygen and nitrogen radicals, highlighting the potential adverse consequences for intestinal vascular integrity.

Smoking habits and recurrence in Crohn's disease

BACKGROUND/AIMS

Smoking may be a risk factor for surgical recurrence of Crohn's disease. However, other variables associated with recurrence could be confounding factors for smoking. The aim of this study was to evaluate the role of smoking as an independent predictor of clinical, surgical, and endoscopic recurrence.

METHODS

In a series of 182 patients who underwent surgery for Crohn's disease, a multivariate analysis was performed that included all of the significant variables associated with recurrence: sex, age at diagnosis, time between onset of symptoms and surgery, site of disease, indication for surgery, extent of disease, extraintestinal manifestation, and smoking habit.

RESULTS

Independent predictors of clinical recurrence by the Cox proportional hazard model were smoking (hazard ratio, 1.46; 95% confidence interval [CI], 1.1-1.8), extraintestinal manifestations (hazard ratio, 1.61; 95% CI, 1.0-2.5), and extent of disease (hazard ratio, 1.57; 95% CI, 1.0-2.4). Smoking was the only significant predictor of surgical recurrence (hazard ratio, 2.0; 95% CI, 1.2-2.3). For endoscopic recurrence, logistic regression showed that smoking (odds ratio, 2.2; 95% CI, 1.2-3.8) and extent of disease (odds ratio, 2.6; 95% CI, 1.0-6.7) were predictive factors of recurrence.

CONCLUSIONS

Smoking is an independent risk factor for clinical, surgical, and endoscopic recurrence in Crohn's disease.

Breast-feeding and maternal smoking in the etiology of Crohn's disease and ulcerative colitis in childhood

Medical records concerning pediatric or adolescent patients first diagnosed with Crohn's disease or ulcerative colitis in two New York hospitals during a 5-year period (1986 to 1990) were abstracted, and information concerning sex, age, race, birthplace, sibship size, birth order, maternal age at birth, month of birth, duration of breast-feeding, and maternal smoking was recorded. Medical records of patients presenting at the respective pediatric gastroenterology departments immediately before or after the patients with inflammatory bowel disease were seen were also abstracted in order to generate a control series. Data concerning 68 patients with Crohn's disease, 39 patients with ulcerative colitis, and 202 control patients were analyzed through multiple logistic regression. Breast-feeding was negatively associated with Crohn's disease (P approximately 0.04) and ulcerative colitis (P approximately 0.07), with relative risk point estimates around 0.5 and with evidence of duration-dependent trends in both instances. There was no evidence of association of either disease with maternal age at birth, birth order, maternal smoking, or season of birth.

Survival and causes of death in patients with inflammatory bowel disease: a population-based study

Relative survival up to December 31, 1986 was analyzed for all patients diagnosed with ulcerative colitis (UC) (n = 2,509) and Crohn's disease (CD) (n = 1,469) within the Uppsala Region, Sweden 1965-1983. After 10 years survival was 96% of that expected for UC and CD. Patients with ulcerative proctitis, left-sided colitis, and pancolitis at diagnosis had relative survival rates of 98%, 96%, and 93% respectively. Survival did not differ by extent at diagnosis for patients with CD. After including prevalent cases, 684 deaths occurred compared with 481.1 expected deaths [standardized mortality ratio (SMR) = 1.4; 95% confidence interval (CI) = 1.3-1.5]. Inflammatory bowel disease was the main reason for this excess mortality. Colorectal cancer increased mortality (50 deaths observed vs. 15.2 expected). Death from other cancers were not greater than expected. Obstructive respiratory diseases, especially bronchitis, emphysema, and asthma increased mortality SMR = 1.5 (95% CI = 1.1-2.2) in UC. Cerebrovascular disease mortality occurred less often than expected (SMR = 0.7; 95% CI = 0.5-1.0). Mortality for other diseases and groups of diseases was close to that expected.

Chemiluminescence assay of mucosal reactive oxygen metabolites in inflammatory bowel disease

Previous studies suggesting increased reactive oxygen metabolite (ROM) production in inflammatory bowel disease have been restricted to peripheral blood and isolated intestinal phagocytes. In the current study, chemiluminescence and the effect of various scavengers, enzymes, and enzyme inhibitors were used to show that ROMs account for the increased production of oxidants by colorectal mucosal biopsy specimens in inflammatory bowel disease. Luminol-amplified chemiluminescence was increased in active ulcerative colitis [macroscopic grade 1: 25 photons.mg-1.min.10(-3) (median), 8-47 (95% confidence intervals), n = 40; grade 2: 89, 65-156, n = 30; grade 3: 247, 133-562, n = 13] and Crohn's disease [mild: 9, 3-84, n = 6; severe: 105, 25-789 (range), n = 5] compared with normal-looking mucosa (ulcerative colitis: 0.8, 0.4-1.4, n = 22, P less than 0.01; Crohn's disease: 0.8, 0.1-2, n = 6, P less than 0.05) and controls (0.6, 0.04-1.4, n = 52, P less than 0.01). In ulcerative colitis, luminol chemiluminescence correlated with microscopic inflammation (Spearman's p = 0.74, P = 0.0001) and was decreased by sodium azide (-89%, P less than 0.05), taurine (-31%, P less than 0.05), catalase (-23%, P less than 0.05), and dimethyl sulfoxide (-29%, P less than 0.05). Superoxide dismutase and oxypurinol decreased lucigenin chemiluminescence in ulcerative colitis by -63% (P less than 0.05) and -27% (P less than 0.05), respectively. Luminol chemiluminescence correlated with lucigenin chemiluminescence (Spearman's rho = 0.72, P = 0.003). These results suggest that neutrophil-derived oxidants (superoxide, hydrogen peroxide, hydroxyl radical, and hypochlorite) are generated in colorectal mucosa in active inflammatory bowel disease and support the hypothesis that production of such metabolites by neutrophils is of major pathogenetic importance.

Has smoking changed the epidemiology of ulcerative colitis?

The influence of smoking on the risk of developing ulcerative colitis is well documented. Compared with lifetime non-smokers, the risk is reduced in smokers and increased in ex-smokers. During the past 50 years general smoking habits have changed considerably. The proportions of smokers and ex-smokers among men and women have undergone significant changes and, consequently, probably also their risk of ulcerative colitis. A review of 56 earlier epidemiologic studies of ulcerative colitis from 1930 to 1990 showed that the sex distribution in ulcerative colitis has changed from an earlier female predominance that has now been replaced by a male predominance. In contemporary pediatric studies no such changes were seen. We propose that these changes in adults are not related to the disease per se but to an extrinsic factor affecting adults but not children--namely smoking.

Cigarette smoking and the risk of colorectal adenoma in men

We evaluated the effect of smoking on the risk of developing colorectal adenoma in men. The data were obtained in a case-control study of 103 men with colorectal biopsy-proven adenoma (cases) and 108 men with normal colonoscopy findings (controls). As compared with men who had never smoked, the estimated relative risk of adenoma increased with the pack-year smoking number, the average number of cigarettes per day, and the total years smoked. The estimated overall relative risk was 2.2 (95% confidence interval, 1.1 to 4.3). Adjustment for age did not alter these results. The data suggest that smokers may have a higher risk of developing colorectal adenoma than non-smokers. If these results are confirmed, they might be of direct importance for public health, since adenomas are precursors of colorectal cancer.

Hydrogen peroxide stimulates phospholipase A2-mediated arachidonic acid release in cultured intestinal epithelial cells (INT 407)

The mechanisms by which hydrogen peroxide and, for comparison, 4-beta-phorbol-12-myristate-13-acetate (PMA) stimulate release of radiolabeled arachidonic acid (14C-AA) in cultured intestinal epithelial cells (INT 407) were investigated. Both hydrogen peroxide and PMA caused a rapid (3 min) and dose-related intracellular release of free 14C-AA, followed by a dose- and time-dependent release of 14C-AA into the extracellular medium, but hydrogen peroxide was about 50,000 times less effective than PMA in releasing 14C-AA. No 14C-AA was released on stimulation with 4-alpha-phorbol-12,13-di-decanoate (PDD), a phorbol ester that does not activate protein kinase C. The 14C-AA release was reduced by the phospholipase A2 inhibitors nordihydroguaiaretic acid and 4-bromophenacyl bromide and by the calmodulin/protein kinase C inhibitor trifluoperazine and the protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7). However, H-7 was less effective than the other inhibitors in reducing the hydrogen peroxide-stimulated 14C-AA release. The hydrogen peroxide-stimulated, but not the PMA-stimulated, rapid (3 min) 14C-AA release was associated with an increased influx of extracellular calcium. Stimulation of the cells with PMA resulted in phosphorylation of a cellular protein of about 32 kDa, whereas no phosphorylation of this protein was detected after stimulation with hydrogen peroxide. Taken together, these findings indicate that (i) both PMA and hydrogen peroxide may stimulate phospholipase A2-mediated AA release from human intestinal epithelial cells; (ii) this stimulation is brought about via protein kinase C and calmodulin-mediated events; (iii) PMA-stimulated 14C-AA release is associated with phosphorylation of a 32-kDa protein, possibly lipocortin, whereas the hydrogen peroxide-stimulated release is not; and (iv) calmodulin is more important for the hydrogen peroxide-stimulated 14C-AA release than is protein kinase C. The possibility that hydrogen peroxide-evoked AA release may contribute to the mucosal abnormality in Crohn's disease is discussed.

Increased risk of preterm birth for women with inflammatory bowel disease

The reproductive histories of 177 women with Crohn's disease and 84 women with ulcerative colitis were compared with those of healthy control subjects. Inflammatory bowel disease was associated with reduced fertility as measured by number of pregnancies, but measures of childlessness, infertility, fecundability, and methods of birth control suggested that this reduced fertility was the patients' choice rather than a consequence of disease-mediated biological impairments. There was no evidence of increased risk of pregnancy loss, but the risk of preterm birth was significantly elevated for patients with Crohn's disease (odds ratio, 3.1; 95% confidence interval, 1.8-5.4) and for those with ulcerative colitis (odds ratio, 2.7; 95% confidence interval, 1.8-5.4). Several plausible biological mechanisms that could explain the link between preterm birth and inflammatory bowel disease are suggested. These results may be useful when counseling patients who desire pregnancy. Physicians can reassure patients about potential fertility problems but should also encourage close obstetrical monitoring during the third trimester of pregnancy.

Inflammatory bowel disease revisited: newer drugs

The development of new drug therapy is an evolutionary process progressing from clinical success with current treatments through an understanding of interactions in the immune and inflammatory events that culminate in the tissue injury of IBD. The basic immunoinflammatory response is reviewed, with identification of the recognized and potential sites of activity of current therapies. Potential sites and implications for future interventions by newer therapies are discussed as we anticipate the discovery of the etiology and eventual cure for ulcerative colitis and Crohn's disease.