letter to tHe eDitor

Bhat M, Lu Y, Marcil V, et al. Tumour necrosis factor-alpha polymorphism increases the risk for nonvariceal upper gastrointestinal bleeding in patients taking proton pump inhibitors. Can J Gastroenterol Hepatol 2014;28(9):488. To the Editor: Nonvariceal upper gastrointestinal bleeding (NVUGIB) is associated with significant morbidity, affecting 50 to 150 per 100,000 adults annually (1). Patients with NVUGIB may present with melena, hematochezia or coffee-ground emesis, often accompanied by a decrease in hemoglobin levels and even hemodynamic instability. Nonsteroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori infection are the principal risk factors for NVUGIB, accounting for >95% of cases. Taking proton pump inhibitors (PPIs) is a known protective factor against NVUGIB. There has recently been growing interest in a possible genetic predisposition to NVUGIB, with investigation of single nucleotide polymorphisms (SNPs) associated with bleeding events. Of particular interest have been mutations in proinflammatory genes or genes that regulate NSAID/PPI metabolism, which may contribute to excessive inflammation and ulceration in the context of H pylori infection and NSAID use. A recent pharmacogenomic study The above literature describing a genetic predisposition for bleeding events applies principally to East Asian patient populations. Therefore, we decided to study whether such genetic associations could be elicited in the Canadian context. We performed a pilot study to assess the association of SNPs involved in NSAID metabolism (CYP2C9) and inflammatory response (TNF-α) with NVUGIB events. Patients who were part of the REASON-II NVUGIB study population at the McGill University Health Centre (Montreal, Quebec) were recruited (5). Study controls were asymptomatic patients undergoing screening colonoscopy, and excluded if there was any history of NVUGIB. DNA extracted from serum was genotyped for SNPs in the proinflammatory TNF-α (rs1799724, rs1800630, rs1799964) and NSAID-metabolizing CYP2C9 genes (rs1799853, rs1057910). Using STATA version 10, we assessed for any association between SNPs and NVUGIB events using logistic regression analysis and stratifying according to H pylori status, NSAID and PPI use. Our study included 23 patients and 46 controls of comparable age and sex, with NSAID (26.1% versus 6.7%) and PPI use (21.7% versus 13.0%) being more prevalent among patients. The TNFα1031C SNP, a proinflammatory cytokine polymorphism, was more common among patients with NVUGIB (OR 2.2 [95% CI 0.9 to 5.1]; P=0.084), particularly among those using PPIs (OR 20.0 [95% CI 0.9 to 429.9]; P=0.056) or not taking NSAIDs (OR 3.2 [95% CI 1.1 to 9.0]; P=0.027) at the time of the bleeding event. There was a trend in association of the TNF-α863A SNP with NVUGIB in patients not taking NSAIDs (OR 2.7 [95% CI 0.9 to 8.6]; P=0.071). We did not detect an association between CYP2C9 polymorphisms and NVUGIB, a result similar to that obtained in the study by Musumba et al (2). In conclusion, our pilot study demonstrates that TNF-α1031C SNP confers a risk for NVUGIB events among patients taking PPIs, a finding compatible with previous studies showing increased risk for peptic ulceration with this particular SNP (3

Age-specific association between blood pressure and vascular and non-vascular chronic diseases in 0·5 million adults in China: a prospective cohort study

Summary: Background: The age-specific association between blood pressure and vascular disease has been studied mostly in high-income countries, and before the widespread use of brain imaging for diagnosis of the main stroke types (ischaemic stroke and intracerebral haemorrhage). We aimed to investigate this relationship among adults in China. Methods: 512 891 adults (59% women) aged 30–79 years were recruited into a prospective study from ten areas of China between June 25, 2004, and July 15, 2008. Participants attended assessment centres where they were interviewed about demographic and lifestyle characteristics, and their blood pressure, height, and weight were measured. Incident disease was identified through linkage to local mortality records, chronic disease registries, and claims to the national health insurance system. We used Cox regression analysis to produce adjusted hazard ratios (HRs) relating systolic blood pressure to disease incidence. HRs were corrected for regression dilution to estimate associations with long-term average (usual) systolic blood pressure. Findings: During a median follow-up of 9 years (IQR 8–10), there were 88 105 incident vascular and non-vascular chronic disease events (about 90% of strokes events were diagnosed using brain imaging). At ages 40–79 years (mean age at event 64 years [SD 9]), usual systolic blood pressure was continuously and positively associated with incident major vascular disease throughout the range 120–180 mm Hg: each 10 mm Hg higher usual systolic blood pressure was associated with an approximately 30% higher risk of ischaemic heart disease (HR 1·31 [95% CI 1·28–1·34]) and ischaemic stroke (1·30 [1·29–1·31]), but the association with intracerebral haemorrhage was about twice as steep (1·68 [1·65–1·71]). HRs for vascular disease were twice as steep at ages 40–49 years than at ages 70–79 years. Usual systolic blood pressure was also positively associated with incident chronic kidney disease (1·40 [1·35–1·44]) and diabetes (1·14 [1·12–1·15]). About half of all vascular deaths in China were attributable to elevated blood pressure (ie, systolic blood pressure >120 mm Hg), accounting for approximately 1 million deaths (<80 years of age) annually. Interpretation: Among adults in China, systolic blood pressure was continuously related to major vascular disease with no evidence of a threshold down to 120 mm Hg. Unlike previous studies in high-income countries, blood pressure was more strongly associated with intracerebral haemorrhage than with ischaemic stroke. Even small reductions in mean blood pressure at a population level could be expected to have a major impact on vascular morbidity and mortality. Funding: UK Wellcome Trust, UK Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, Chinese Ministry of Science and Technology, and the National Science Foundation of China