Bruce A. Chapman

High incidence of Crohn's disease in Canterbury, New Zealand: Results of an epidemiologic study

Background: Inflammatory bowel disease (IBD) has increased exponentially in industrialized nations over the last 50 years. Previous New Zealand studies have shown that IBD is less common than in other countries; however, clinical observations suggested a high incidence and prevalence of IBD in Canterbury, particularly Crohns disease (CD). Aim: This study aimed to determine the descriptive epidemiology of IBD in Canterbury. Methods: Canterbury IBD patients, recruited using multiple strategies, gave informed consent, permission for clinical record review, completed a questionnaire, and were bled for DNA extraction as part of the Canterbury IBD Project. Cases were confirmed using standard criteria, and completeness of recruitment was validated using capture‐recapture methods. Demographic and phenotypic data were extracted from case notes. One thousand four hundred twenty patients (715 CD, 668 ulcerative colitis [UC]) were recruited (>91% of Canterbury IBD patients). Results: In 2004, age‐standardized (World Health Organization World Standard Population) IBD, CD, and UC incidence rates were 25.2, 16.5, and 7.6/100,000/year, respectively. The IBD, CD, and UC point prevalences on 1 June, 2005 were 308.3, 155.2, and 145.0/100,000, respectively. CD patients were more likely than UC patients to be female (61.4% vs. 47.1%) and to be younger (median age, 39.9 years vs. 43.7 years). The percent of IBD patients who were white was 97.5%. Conclusion: IBD is at least as common in Canterbury as in other western regions. CD incidence and prevalence are amongst the highest ever reported and are higher than for UC. IBD population characteristics are otherwise similar to other countries. The Canterbury IBD Project will be a valuable tool for future population‐based IBD epidemiology and genetics research.

The significance of haemochromatosis gene mutations in the general population: implications for screening

Background—Haemochromatosis is associated with mutations in the HFE gene but the significance of these mutations in the general population is unknown. Aims—To determine the frequency ofHFE gene mutations in the general population, their effect on serum iron indexes, and their role in screening for haemochromatosis. Methods—Deoxyribonucleic acid (DNA) from 1064 randomly selected subjects was analysed for the C282Y and H63D mutations in the HFE gene. Serum iron, transferrin saturation, and ferritin were measured and individuals with increased iron indexes were investigated to confirm or exclude a clinical diagnosis of haemochromatosis. Results—Mutations were identified in 409 individuals (38.4%) with heterozygote (carrier) frequencies of 13.2% and 24.3% for the C282Y and H63D mutations respectively. Heterozygosity for either mutation significantly increased serum iron and transferrin saturation but despite a similar trend for ferritin, this was only significant for C282Y homozygotes. Five individuals (0.47%) were homozygous for the C282Y mutation, three of whom had haemochromatosis confirmed by liver biopsy (0.28%). The other two C282Y homozygotes would not have been detected by phenotypic screening alone. Conclusions—HFE mutations are present in 38.4% of the population, affect serum iron indexes, and are important determinants of iron status. The population frequency of genetically defined haemochromatosis (C282Y homozygosity) is approximately one in 200 and is higher than the prevalence of clinically apparent haemochromatosis.

The low FODMAP diet improves gastrointestinal symptoms in patients with irritable bowel syndrome: a prospective study.

Current treatment for irritable bowel syndrome (IBS) is suboptimal. Fermentable oligo‐, di‐, mono‐saccharides and polyols (FODMAPs) may trigger gastrointestinal symptoms in IBS patients. Our aim was to determine whether a low FODMAP diet improves symptoms in IBS patients.

Adult coeliac disease: prevalence and clinical significance.

Background and Aims : Although coeliac disease is a common condition, the role of population screening is not clear. The aim of this study was to determine the prevalence and clinical significance of coeliac disease in the adult population of Christchurch, New Zealand.

Population-based epidemiology study of autoimmune hepatitis: A disease of older women?

Background and Aim:  The etiology of autoimmune hepatitis (AIH) is unknown, and limited epidemiological data are available. Our aim was to perform a population based epidemiological study of AIH in Canterbury, New Zealand.

Prevalence of gallbladder disease in diabetes mellitus

A study was undertaken to compare the prevalence of gallstone disease (gallstones observed on ultrasound or history of cholecystectomy) in 308 diabetics and 318 controls. There was a higher prevalence of gallstone disease (GSD) in diabetics (32.7%) compared to controls (20.8%;P<0.001 chi-squared test). However, when gender was taken into account, the difference was only significant in females (diabetics 41.8% versus controls 23.1%;P<0.001). Analysis by type of diabetes revealed that subjects with non-insulin-dependent diabetes mellitus (NIDDM) had a higher prevalence of GSD than controls for both genders: males—controls 18.1%, NIDDM 33.3% (P<0.05), IDDM 15.6% ns; females—controls 23.1%, NIDDM 48.6% (P<0.001), IDDM 36.3% (P<0.05). On univariate analysis the following risk factors were associated with gallstones (P<0.1): increased age, body mass index (BMI), triglycerides, LDL cholesterol, decreased HDL cholesterol, alcohol intake, family history of GSD, and female parity >3. Using stepwise multiple logistic regression, the following variables were identified as independently predictive of gallstones for each gender/diabetic combination: Males—NIDDM (N=54), increased age, and decreased HDL; IDDM (N=90), age and family history; Females—NIDDM (N=74), increased age, diabetes, increased BMI, and decreased alcohol; IDDM (N=91), increased BMI, age, decreased alcohol and family history. The proportion of subjects who underwent cholecystectomy was higher in females (46.7%) compared to males (21.7%;P<0.01) but there were no differences between diabetics and controls in either sex. In conclusion, there was a higher prevalence of GSD in diabetics compared to controls. However, GSD is multifactorial and only in NIDDM females was diabetes an independent risk factor. The proportion of diabetics and controls with GSD who underwent cholecystectomy was equivalent.

Thiopurine S‐methyltransferase (TPMT) genotype does not predict adverse drug reactions to thiopurine drugs in patients with inflammatory bowel disease

Background : Azathioprine and mercaptopurine (MP) are well established treatments for inflammatory bowel disease but they have severe adverse effects that prevent their use in some patients. The likelihood and type of adverse effect may relate to thiopurine methyltransferase (TPMT) enzyme activity and genotype.

Gallbladder Polyps: Prospective Study

The aim of this study was to describe the natural history of gallbladder polyps. Thirty‐eight subjects who had been previously identified as having gallbladder polyps in an epidemiologic study of gallstone prevalence in 627 diabetic subjects and matched controls were followed longitudinally. Follow‐up sonograms were obtained on 33 and 22 of the 38 subjects at 2 and 5 years, respectively. Prevalence for gallbladder polyps in this population was 6.7%, with a marked male predominance (odds ratio 2.3). No statistical difference in prevalence was found between diabetic subjects and nondiabetic controls. Ninety percent of the polyps were less than 10 mm in diameter, with no polyp being larger than 12 mm. During the follow‐up period no changes suggestive of malignant transformation were observed. In conclusion, we found that gallbladder polyps were relatively common and that few significant changes occurred over a 5 year period. In asymptomatic subjects in whom gallbladder polyps less than 10 mm in diameter are found incidentally, the likelihood of malignant transformation is low.

Interferon treatment is not associated with a worsening of psychiatric symptoms in patients with hepatitis C

Aim : To study prospectively the psychiatric side effects of interferon‐α in patients with hepatitis C.

Use of 99mTc-DISIDA biliary scanning with morphine provocation for the detection of elevated sphincter of Oddi basal pressure

BACKGROUND Endoscopic biliary manometry is useful in the assessment of patients with types II and III sphincter of Oddi dysfunction, but it is time consuming and invasive. AIM To investigate the role of 99mTc-DISIDA scanning, with and without morphine provocation, as a non-invasive investigation in these patients compared with endoscopic biliary manometry. SUBJECTS AND METHODS A total of 34 patients with a clinical diagnosis of type II (n=21) or III (n=13) sphincter of Oddi dysfunction were studied. Biliary scintigraphy with 100 MBq of 99mTc-DISIDA was carried out with and without morphine provocation (0.04 mg/kg intravenously) and time/activity curves were compared with the results of subsequent endoscopic biliary manometry. RESULTS Eighteen (nine type II, nine type III) of the 34 (53%) patients had sphincter of Oddi basal pressures above the upper limit of normal (40 mm Hg). In the standard DISIDA scan without morphine, no significant differences were observed in time to maximal activity (Tmax) or percentage excretion at 45 or 60 minutes between those with normal and those with abnormal biliary manometry. However, following morphine provocation, median percentage excretion at 60 minutes was 4.9% in those with abnormal manometry and 28.2% in the normal manometry group (p=0.002). Using a cut off value of 15% excretion at 60 minutes, the sensitivity for detecting elevated sphincter of Oddi basal pressure by the morphine augmented DISIDA scan was 83% and specificity was 81%. Also, 14 of the 18 patients with abnormal manometry complained of biliary-type pain after morphine infusion compared with only two of 16 patients in the normal manometry group (p=0.001). CONCLUSIONS 99mTc-DISIDA with morphine provocation is a useful non-invasive investigation for types II and III sphincter of Oddi dysfunction to detect those with elevated sphincter basal pressures who may respond to endoscopic sphincterotomy.