I D Norton

Royal North Shore Hospital, Sydney, New South Wales, Australia

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Publications (74)344.48 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND:: Data from the northern hemisphere suggest that patients with ulcerative colitis (UC) have similar survival to the general population, whereas mortality in Crohn's disease (CD) is increased by up to 50%. There is a paucity of data from the southern hemisphere, especially in Australia. METHODS:: A prevalence cohort (1977-1992) of patients with inflammatory bowel disease (IBD) diagnosed after 1970 was studied. Survival status data and causes of death up to December 2010 were extracted from the National Death Index. Relative survival analysis was carried out separately for men and women. RESULTS:: Of 816 cases (384 men, 432 women; 373 CD, 401 UC, 42 indeterminate colitis), 211 (25.9%) had died by December 2010. Median follow-up was 22.2 years. Relative survival of all patients with IBD was not significantly different from the general population at 10, 20, and 30 years of follow-up. Separate analyses of survival in CD and UC also showed no differences from the general population. There was no difference in survival between patients diagnosed earlier (1971-1979) or later (1980-1992). At least 17% of the deaths were caused by IBD. Fatal cholangiocarcinomas were more common in IBD (P < 0.001), and fatal colorectal cancers more common in UC (P = 0.047). CONCLUSIONS:: In Australia, IBD patient survival is similar to the general population. In contrast to data from Europe and North America, survival in CD is not diminished in Australia. IBD caused direct mortality in 17%, especially as biliary and colorectal cancers are significant causes of death.
    Inflammatory Bowel Diseases 06/2013; · 5.12 Impact Factor
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    ABSTRACT: BACKGROUND: & Aims: Inflammatory bowel disease (IBD) can require surgical resection and also lead to colorectal cancer (CRC). We investigated the cumulative incidence of resection surgeries and CRC among patients with ulcerative colitis (UC) or Crohn's disease (CD). METHODS: We analyzed data from a cohort of patients who participated in an IBD study (504 with UC and 377 with CD) at 2 academic medical centers in Sydney, Australia from 1977 to 1992 (before the development of biologic therapies). We collected follow-up data on surgeries and development of CRC from hospital and community medical records or via direct contact with patients, over a median time period of 14 y. Cumulative incidences of resection surgeries and CRC were calculated by competing risk survival analysis. RESULTS: Among patients with UC, CRC developed in 24, for a cumulative incidence of 1% at 10 y (95% confidence interval [CI], 0-2%), 3% at 20 y (95% CI, 1%-5%), and 7% at 30 y (95% CI, 4%-10%). Their cumulative incidence of colectomy was 15% at 10 y (95% CI, 11%-19%), 26% at 20 y (95% CI, 21%-30%) and 31% at 30 y (95% CI, 25%-36%). Among patients with CD, 5 of 327 with colon disease developed CRC, with a cumulative incidence of CRC of 1% at 10 y (95% CI, 0-2%), 1% at 20 y (95% CI, 0-2%), and 2% at 30 y (95% CI, 0-4%). Among all patients with CD, the cumulative incidence of resection was 32% at 5 y (95% CI, 27%-37%), 43% at 10 y (95% CI, 37%-49%), and 53% at 15 y (95% CI, 46%-58%). Of these 168 subjects, 42% required a 2nd resection within 15 y of the first surgery (95% CI, 33%-50%). CONCLUSION: Patients with UC have a low incidence of CRC over a 30 y period (7% or less); the incidence among patients with CD is even lower. However, almost one third of patients with UC and about 50% of those with CD will require surgery.
    Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 05/2013; · 5.64 Impact Factor
  • Ian D. Norton, Jonathan E. Clain
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    ABSTRACT: Many technical advances have offered enhanced capabilities in noninvasive imaging of the pancreas. Although these technical advances are impressive, current studies do not always define clearly the benefits that these advances will confer in patient management. A critical overview of these imaging modalities is offered here, with respect to diagnosis and patient management. Outcomes from various studies are summarized for modalities including transabdominal ultrasound, computed tomography, magnetic resonance imaging with and without pancreatography, and positron emission tomography.
    Current Gastroenterology Reports 04/2012; 2(2):120-124.
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    ABSTRACT: Pancreatitis and pancreatic insufficiency are associated with both cystic fibrosis and alcoholism. The pathogenesis of alcoholic pancreatitis is unknown, but only a minority of alcoholics develop pancreatitis, and it has been suggested that a genetic predisposition may play a role in this disease. Two observations led to the hypothesis that this genetic predisposition could result from mutations in the cystic fibrosis gene. First, the prevalence of cystic fibrosis mutations in the Caucasian population (approximately 5%) is similar to the prevalence of pancreatitis among heavy drinkers. Second, in both diseases, pancreatic duct damage is a prominent feature and has been postulated to be the initial site of injury. Therefore, the aim of this study was to determine whether an increased frequency of mutations in the cystic fibrosis gene occurs in alcoholic pancreatitis. The 15 most common cystic fibrosis mutations in a Caucasian community were sought in 24 subjects with alcoholic pancreatitis. None were homozygous or heterozygous for these mutations. These findings suggest that cystic fibrosis mutations are not a major genetic factor predisposing to pancreatic injury in alcoholics.
    Journal of Gastroenterology and Hepatology 06/2008; 13(5):496 - 499. · 3.33 Impact Factor
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    ABSTRACT: Considerable variability has been reported in the frequency and specificity of anti-neutrophil cytoplasmic antibody with a perinuclear staining pattern (pANCA) in patients with chronic liver disease, especially in primary sclerosing cholangitis (PSC), and in inflammatory bowel disease. This study examines the presence of pANCA in patients with these disorders, in particular those with PSC complicated by other biliary disease, and also patients who had undergone orthotopic liver transplantation. An indirect immunofluorescent technique was used to measure pANCA with serum diluted 1:20. Ten of 39 (26%) patients with PSC had detectable pANCA, as did two of nine (22%) with autoimmune chronic active hepatitis (AICAH) but none of the 51 patients with other forms of chronic liver disease. The presence of pANCA was significantly more frequent in patients who had PSC with biliary tract complications, in particular calculi (seven of 16 with vs three of 23 without; P = 0.03). Eight of the 12 pANCA-positive patients with PSC or AICAH had undergone hepatic transplantation. This was more likely than in patients with PSC or AICAH who were pANCA negative (10 of 36; P = 0.02). To date, pANCA has been detected after transplantation in four patients with PSC and one with AICAH. In patients with PSC or AICAH, pANCA should be sought as a marker of prognosis.
    Journal of Gastroenterology and Hepatology 01/2008; 9(1):40-4. · 3.33 Impact Factor
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    ABSTRACT: Recent studies showed that endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) is a low-risk procedure for causing bacteremia and infectious complications when sampling solid lesions of the upper gastrointestinal (GI) tract. As a result, antibiotics are not recommended for prophylaxis against endocarditis. Our aim was to prospectively evaluate the risk of bacteremia and other infectious complications in patients undergoing EUS FNA of lower GI tract lesions. Patients referred for EUS FNA of lower GI tract lesions were considered for enrollment. Patients were excluded if there was an indication for preprocedure antibiotic administration based on American Society for Gastrointestinal Endoscopy guidelines, had taken antibiotics within the prior 7 days, or if they had a cystic lesion. Blood cultures were obtained immediately before the procedure, after flexible sigmoidoscopy/radial EUS, and 15 minutes after EUS FNA. One hundred patients underwent a total of 471 FNAs (mean, 4.7 FNAs/patient; range, 1-10 FNAs/patient). Blood cultures were positive in 6 patients. Cultures from 4 patients (4.0%, 95% confidence interval, 1.6%-9.8%) grew coagulase-negative Staphylococcus (n = 2), Peptostreptococcus stomatis (n = 1), or Moraxella (n = 1), which were considered contaminants. Two patients (2.0%, 95% confidence interval, 0.6%-7%) developed bacteremia: Bacteroides fragilis (n = 1) and Gemella morbillorum (n = 1). No signs or symptoms of infection developed in any patient. EUS FNA of solid lesions in the lower GI tract should be considered a low-risk procedure for infectious complications that does not warrant prophylactic administration of antibiotics for the prevention of bacterial endocarditis.
    Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 07/2007; 5(6):684-9. · 5.64 Impact Factor
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    ABSTRACT: Background: The observation that only a minority of alcoholics develops clinical pancreatic disease has led to a search for a predisposing factor to the disease. One possible predisposing factor is mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene as cystic fibrosis leads to pancreatic injury. We have recently demonstrated that 15 common CFTR mutations are not found in patients with alcoholic pancreatitis. Another common polymorphism of the CFTR gene has recently been implicated in the pathogenesis of idiopathic chronic pancreatitis, the 5T variant of the variable length polythymidine tract in intron 8 (the normal genotypes are 7T and 9T). The 5T variant inhibits transcription of exon 9 resulting in a CFTR protein lacking chloride channel activity. The aim of this study was to determine whether the 5T variant is associated with alcoholic pancreatitis. Methods: Fifty-two patients with alcoholic pancreatitis were identified using standardized diagnostic criteria. Fifty alcoholics without pancreatitis were also studied as controls. Genomic DNA was extracted from peripheral blood leukocytes and the polythymidine tract of intron 8 was amplified by nested polymerase chain reaction using established primers. The polymerase chain reaction products were digested with Msel, separated by electrophoresis on 15% polyacrylamide gels and genotypes assigned by comparison with known positive controls. Results: The 5T allele was found in only two patients with alcoholic pancreatitis (3.9% of the index group; 95% confidence intervals 0-10%) and in seven alcoholic controls. Allele frequencies for 5T, 7T, and 9T in patients with alcoholic pancreatitis were 1.9%, 85.6%, and 12.5%, respectively. These did not differ from the allele frequencies in alcoholic controls (7%, 79%, and 14% for 5T, 7T, and 9T, respectively). Conclusion: The 5T allele was not associated with alcoholic pancreatitis. Individual susceptibility to this disease remains unexplained.
    Alcoholism Clinical and Experimental Research 05/2006; 23(3):509 - 512. · 3.42 Impact Factor
  • Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2006; 63(5).
  • Ian D. Norton
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    ABSTRACT: The optimal approach has yet to emerge for the management of sporadic periampullary adenomas and upper gastrointestinal (GI) neoplasia complicating familial adenomatous polyposis (FAP). There are no randomized trials comparing different surgical and/or endoscopic modalities. Such studies may not be feasible given the infrequency of these conditions and the long follow-up period required for such a study. In the meantime, selection of the optimal approach for an individual patient will rely on a careful evaluation of the disease severity and extent in that patient and the utilization of the best available endoscopic and surgical expertise.
    12/2005: pages 337-344;
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    ABSTRACT: The aim of the study was to examine whether endoscopic intralesional corticosteroid injection into recalcitrant peptic esophageal strictures reduces the need for repeat stricture dilation. Patients with a peptic esophageal stricture and recurrent dysphagia having had at least one dilation in the preceding 18 months were enrolled in a prospective randomized, double-blind study comparing steroid and sham injection. After endoscopic confirmation of recurrent stricture, patients were randomized to receive either 0.5 cc/quadrant triamcinolone (40 mg/cc) or sham injection into the stricture followed by balloon dilation of the stricture. Patients were stratified by the number of dilations required in the preceding 18 months, severity of dysphagia, the presence of esophagitis, stricture severity, and prior therapy with a proton-pump inhibitor. Patients and their physicians were blinded to the type of intervention received. Baseline dysphagia questionnaires were completed. Post-procedurally all patients were placed on a standardized proton-pump inhibitor regimen and standardized telephone follow-up questionnaires were completed at 1 wk and at 1, 3, 6, 9, and 12 months. The original sample-size calculation of 60 patients could not be met in a timely fashion because of a low incidence of recalcitrant peptic stricture patients. A total of 30 patients were enrolled, 15 in the steroid group (10 men, mean age 66 yr) and 15 in the sham group (11 M, mean age 67 yr). Patients were followed for 1 yr, unless they underwent an antireflux operation or died. Two patients, one per group, died of non-esophageal causes at 1 and 12 months. Four patients had fundoplication, two in each group, unrelated to stricture or dysphagia. Two patients in the steroid group (13%) and nine in the sham group (60%) required repeat dilation (p= 0.011). In patients with recalcitrant peptic esophageal stricture, steroid injection into the stricture combined with acid suppression significantly diminishes both the need for repeat dilation and the average time to repeat dilation compared to sham injection and acid suppression alone.
    The American Journal of Gastroenterology 12/2005; 100(11):2419-25. · 9.21 Impact Factor
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    ABSTRACT: Endoscopic biliary sphincterotomy has complication rates of 5%-12%. The output from the electrosurgical generator may influence the degree of coagulation and the rapidity of the incision, and thus rates of pancreatitis, hemorrhage, and perforation. Some modern generators incorporate feedback control to standardize output and automate the alternating cut and coagulation modes. Our aim was to compare 2 feedback-controlled generators, one with constant pure cutting-type output and the other with an alternating cut and coagulation mode. In this multicenter randomized study, 133 patients were assigned to the alternating cut/coag output and 134 patients were assigned to constant pure-cut output. Patients were stratified by their risk for pancreatitis. The overall pancreatitis rate was 1.5%, including 3 patients in the cut/coag group and 1 patient in the pure-cut group (P>.05). There were 11 poorly controlled (zipper) incisions in the pure-cut group and none in the cut/coag group (P=.02). The incision was completed in all patients without stalling. Immediate hemorrhage occurred in 35 pure-cut patients and 8 cut/coag patients output (P=.002). There were no episodes of clinically significant bleeding, delayed bleeding, or perforation. Biliary sphincterotomy using feedback-controlled generators results in dependable progression of incision with a low pancreatitis rate. Control of the incision is improved subjectively with the cut/coagulation output, but this did not translate into a difference in clinically significant complications.
    Clinical Gastroenterology and Hepatology 11/2005; 3(10):1029-33. · 6.65 Impact Factor
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    ABSTRACT: EUS is an important modality for the diagnosis of pancreatic disease. An understanding of normal pancreatic ductal and parenchymal variation in asymptomatic individuals is essential to improve EUS accuracy. The primary aim of this study was to determine age-related pancreatic parenchymal and ductular changes identifiable on EUS in individuals with no history or symptoms of pancreaticobiliary disease. Secondary aims were to define demographic and clinical factors associated with identifiable pancreatic parenchymal and ductular changes, and to determine the main pancreatic-duct diameter and pancreatic-gland width according to age. Patients referred for either upper endoscopy or EUS for an indication unrelated to pancreaticobiliary disease were prospectively enrolled. Patients were stratified by age (<40, 40-60, >60 years). Each patient was assessed for the presence of EUS findings for chronic pancreatitis. Logistic regression was used to identify factors associated with an abnormality. A total of 120 patients (63 men, 57 women; median age, 52 years, interquartile range [IQR] 40-61 years) were prospectively evaluated. At least one parenchymal and/or ductular abnormality was identified in 28% of the patients, with a trend of increasing abnormality with age: <40 years (23%), 40 to 60 years (25%), and >60 years (39%); p = 0.13. No patient had more than 3 abnormal EUS features. Hyperechoic stranding (n = 22) was the most common finding in all age groups. The odds for any abnormality in men (relative to women) was significantly higher (OR 2.9: 95% CI[1.2, 6.8], p = 0.01), with 38% of men and 18% of women having an abnormality. Smoking, low alcohol intake, body mass index, and endoscopic finding were not significantly associated with an abnormal EUS. The overall median pancreatic-gland width and main pancreatic duct diameter were 15 mm (IQR 6-25 mm) and 1.7 mm (IQR 0.9-4.3 mm), respectively. The frequency of EUS abnormalities in patients without clinical evidence of chronic pancreatitis increases with age, particularly after 60 years of age. The threshold number of EUS criteria for the diagnosis of chronic pancreatitis is variable. However, the typically used standard of 3 or more criteria appears appropriate. A higher number of threshold criteria may be needed in males and to a lesser extent in patients over 40 years of age, which should be related to clinical history and other structural or functional studies. Ductal or parenchymal calculi, ductal narrowing, ductal dilatation, or more than 3 abnormalities appear to be more specific features for the EUS diagnosis of chronic pancreatitis at any age.
    Gastrointestinal Endoscopy 03/2005; 61(3):401-6. · 5.21 Impact Factor
  • Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2005; 61(5).
  • I D Norton, W S Selby
    Internal Medicine Journal 01/2004; 34(1-2):8-9. · 1.82 Impact Factor
  • Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2004; 59(5).
  • Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2004; 59(5).
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    ABSTRACT: Therapy of esophageal carcinoma is stage dependent. The role of EUS-guided fine-needle aspiration (EUS FNA) in this setting is unclear. The aims of this study were to compare the performance characteristics of CT, EUS, and EUS FNA for preoperative nodal staging of esophageal carcinoma and to measure the impact of each staging test on treatment decisions. From December 1999 to March 2001, all patients with esophageal carcinoma seen at the Mayo Clinic Rochester were prospectively evaluated with CT, EUS, and EUS FNA. The impact of tumor stage on final therapy was assessed. A total of 125 patients with esophageal carcinoma were enrolled. EUS FNA was more sensitive (83% vs. 29%; P < 0.001) than CT and more accurate than CT (87% vs. 51%; P < 0.001) or EUS (87% vs. 74%; P = 0.012) for nodal staging. Direct surgical resection was contraindicated in 77% of patients evaluated due to advanced locoregional/metastatic disease. Tumor location, patient age, comorbidities, and tumor stage determined by CT, EUS, and EUS FNA were associated with treatment decisions (P < 0.05). EUS FNA resulting in a higher/worse stage than CT (41 patients) was associated with a greater rate of treatments that were not direct surgeries compared with cases in which the stage was the same or better. EUS FNA is more accurate for nodal staging and impacts on therapy of patients with esophageal carcinoma. EUS FNA should be included in the preoperative staging algorithm of these patients.
    Gastroenterology 12/2003; 125(6):1626-35. · 12.82 Impact Factor
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    ABSTRACT: There are few data regarding the risk of bacteremia with EUS-guided FNA. This study prospectively evaluated the frequency of bacteremia and other infectious complications after EUS-guided FNA. Patients referred for EUS-guided FNA of the upper GI tract lesions were considered for enrollment. Patients were excluded if there was an indication for preprocedure administration of antibiotics based on ASGE guidelines, had taken antibiotics within the prior 7 days, or if they had a pancreatic cystic lesion. Blood cultures were obtained immediately before the procedure, after routine endoscopy/radial EUS, and 15 minutes after EUS-guided FNA. Fifty-two patients underwent EUS-guided FNA at 74 sites (mean 1.4 sites/patient) totaling 266 passes of the fine needle (mean 5.1 FNA/patient). Coagulase negative Staphylococcus was grown in cultures from 3 patients (5.8%; 95% CI [1%, 15%]) and was considered a contaminant. Three patients (5.8%; 95% CI [1%, 15%]) developed bacteremia: Streptococcus viridans (n = 2), unidentified gram-negative bacillus (n = 1). No signs or symptoms of infection developed in any patient. EUS-guided FNA of solid lesions in the upper GI tract should be considered a low-risk procedure for infectious complications that does not warrant prophylactic administration of antibiotics for prevention of bacterial endocarditis.
    Gastrointestinal Endoscopy 06/2003; 57(6):672-8. · 5.21 Impact Factor
  • I D Norton, D B Jones
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    ABSTRACT: Endoscopic ultrasound (EUS) comprises several techniques of performing high-frequency ultrasound via an endoscope placed in the gastrointestinal tract (oesophagus, stomach, duodenum and pancreaticobiliary tree and rectum). It has rapidly become an important tool in the investigation of a variety of lumenal disorders as well as locoregional staging of gastrointestinal malignancies. Needle biopsy of peri-intestinal structures, such as lymph nodes and pancreatic masses, can also be performed under real-time ultrasound control. To date, the utilization of this technology in Australia has been limited by cost constraints and a paucity of training opportunities. EUS continues to be a rapidly growing area in clinical gastroenterology. Recent studies continue to define its role, particularly in the loco-regional staging of a variety of malignancies. In addition, new instruments permit tissue sampling and a variety of therapeutic manoeuvres under direct ultrasound guidance.33; 26-32)
    Internal Medicine Journal 01/2003; 33(1-2):26-32. · 1.82 Impact Factor
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    ABSTRACT: Before endoscopic mucosal resection and polypectomy of sessile lesions, injection of fluid into the submucosa cushions and isolates the tissue and thereby reduces thermal injury and the risk for perforation and hemorrhage. This study investigated the performance of 5 different solutions when used to form submucosal fluid cushions in the porcine esophagus. Five groups of 5 pigs were studied. In each pig, 6 separate submucosal injections of 5 mL of a single test solution were performed within the distal third of the esophagus. The time required for the submucosal bleb to flatten completely was recorded after each injection. The solutions used were as follows: normal saline solution, normal saline plus epinephrine solution, 50% dextrose, 10% glycerine/5% fructose in normal saline solution, and 1% rooster comb hyaluronic acid. The normal saline solution and normal saline plus epinephrine solutions had the shortest disappearance times (respectively, median 2.4 and 3.0 minutes), which were significantly shorter compared with the other test solutions. The mean disappearance times for 50% dextrose and 10% glycerine were, respectively, 4.7 and 4.2 minutes. The mean disappearance time for hyaluronic acid was 22.1 minutes. A solution of hyaluronic acid appears to be ideal for producing a lasting submucosal cushion for prolonged procedures. Dextrose 50% is superior to normal saline solution and may serve as an alternative to hyaluronic acid in terms of availability and cost.
    Gastrointestinal Endoscopy 11/2002; 56(4):513-6. · 5.21 Impact Factor

Publication Stats

3k Citations
344.48 Total Impact Points

Institutions

  • 2013
    • Royal North Shore Hospital
      Sydney, New South Wales, Australia
  • 2004–2008
    • Royal Prince Alfred Hospital
      • Department of Surgery
      Camperdown, New South Wales, Australia
  • 1996–2008
    • University of New South Wales
      • • Prince of Wales Hospital
      • • Pancreatic Research Group
      Kensington, New South Wales, Australia
  • 1998–2007
    • Mayo Clinic - Rochester
      • Department of Gastroenterology and Hepatology
      Rochester, Minnesota, United States
  • 2006
    • The Queen Elizabeth Hospital
      Tarndarnya, South Australia, Australia
  • 2005
    • University of Minnesota Rochester
      Rochester, Minnesota, United States
  • 1998–2005
    • Mayo Foundation for Medical Education and Research
      • Division of Gastroenterology and Hepatology
      Scottsdale, AZ, United States
  • 2003
    • Concord Repatriation General Hospital
      Sydney, New South Wales, Australia
  • 1994–2002
    • Prince of Wales Hospital and Community Health Services
      • Department of Gastroenterology
      Sydney, New South Wales, Australia