Urban-rural differences in asthma prevalence among young people in Canada: the roles of health behaviors and obesity.

BACKGROUND: Asthma prevalence has been reported to be lower in rural regions, but the reasons for this are not known. OBJECTIVE: To confirm the existence of an urban-rural geographic gradient in asthma prevalence among Canadian youths and to evaluate whether this gradient was mediated by health behaviors. METHODS: Cross-sectional data from 4,726 Canadian youth (grades 6-10) were collected during the 2001-02 Health Behaviour in School-Aged Children survey. Geographic region was categorized as metro (urbanized), non-metro but adjacent to metro, and rural. Asthma was defined via self-report of doctors' diagnoses and at least 1 of: (1) asthma symptoms or (2) a health care visit for asthma in the past year. Health behaviors (diet and physical activity) as well as obesity were also assessed. RESULTS: Asthma prevalence was lowest in rural regions (metro = 17.7%, non-metro-adjacent = 15.6%, rural = 14.8%). A lower risk of asthma was associated with rural region (adjusted odds ratio [OR] = 0.76, 95% CI = 0.61-0.95) and living in non-metro-adjacent regions (adjusted OR = 0.81, 95% CI = 0.65-1.01). Health behaviors and obesity status did not mediate the association between geographic region and asthma. Being overweight or obese, having a high physical activity level, and exposure to passive smoking independently elevated the risk of asthma, whereas increased consumption of whole milk or vegetables were each protective. CONCLUSIONS: Although asthma prevalence among youth was lower in rural areas, this association was not mediated by health behaviors or obesity. Other exposures, likely environmental, are the logical mechanisms through which rural geographic status is related to lower asthma prevalence.

Obesity is not associated with adverse outcome following surgical resection of oesophageal adenocarcinoma.

OBJECTIVE: To study the impact of obesity on postoperative morbidity and outcome following surgical resection of primary oesophageal adenocarcinoma (EADC). METHODS: From a prospective database, we compared clinicopathological findings (age, gender, surgical approach, tumour differentiation and stage), postoperative mortality, morbidity, length of hospitalisation, disease-free survival (DFS) and overall survival (OS) between 56 obese (body mass index (BMI)≥30 mgkg(-2)) and 86 non-obese (BMI<30 mgkg(-2)) patients with EADC. RESULTS: In this consecutive series, there were 118 male and 24 female patients with a median age of 63 years (range, 36-85 years). For all patients, the 5-year OS was 26.9%, with a median survival of 20 months. No significant differences (P>0.05) were found between obese and non-obese patients, with respect to age, gender, surgical approach (transthoracic vs transhiatal), pT-stage, duration of hospital stay, postoperative mortality or morbidity. However, compared with non-obese patients, obese patients had a higher frequency of postoperative respiratory complications (odds ratio (OR), 3.05; 95% confidence intervals (CIs), 1.29-7.17). DFS and OS at 5 years were increased for patients who were obese at the time of oesophageal resection (P=0.008). CONCLUSIONS: Obesity is not associated with increased postoperative complication rates or adverse outcome following oesophageal resection, and should therefore not be considered a relative contraindication to the surgical management of EADC. The improved survival of obese patients who underwent oesophageal resection for EADC suggests that further investigation of the association between obesity and oesophageal malignancy is now warranted.

Prognostic value of p53 mutations in oesophageal adenocarcinoma: final results of a 15-year prospective study.

OBJECTIVE: This study evaluates the clinical significance of p53 mutations in oesophageal adenocarcinoma (EADC). METHODS: Between February 1991 and February 2006, 142 consecutive patients with EADC underwent potentially curative oesophageal resection. No patient received induction therapy. Strict clinicopathologic criteria were used to define primary EADC (Type I), excluding gastric cardia adenocarcinoma (Type II). Genomic DNA was extracted from oesophageal tumours, each with matched histologically normal oesophageal epithelium (internal control) from the resection margin. Polymerase chain reaction was used to amplify p53 exons 4-10, and mutations were characterised by direct DNA sequencing. The p53 mutations were correlated with clinicopathologic findings, p53 protein expression determined using immunohistochemistry, and outcome using Kaplan-Meier and Cox proportional hazards models. RESULTS: For all patients, 5-year overall survival (OS) was 26.9%. Conventional predictors of reduced OS included advanced pathological tumour-node-metastasis (pTNM) stage (P<0.0001) and number of involved lymph nodes (0, 1-3, >3; P<0.0001). No p53 mutations were found in normal oesophageal epithelia. A total of 47% of tumours (67/142) had p53 mutations, predominantly G:C to A:T transitions at CpG dinucleotides (36/67). The p53 mutations were associated with p53 protein overexpression (P<0.0001) and poor tumour differentiation (P=0.037). Patients whose tumours had p53 mutations had significantly reduced 5-year OS (hazard ratio (HR): 1.54; 95% confidence interval (CI): 1.03-2.3; P=0.03). CONCLUSIONS: Patterns of p53 mutations in EADC suggest endogenous molecular mechanisms. The p53 mutations are a predictor of significantly reduced postoperative survival following surgical resection of EADC, and would appear to be a clinically useful molecular prognostic biomarker.

Does previous fundoplication alter the surgical approach to esophageal adenocarcinoma?

OBJECTIVE: The primary aim of this study was to test the widespread assumption that the viability of the gastric fundus is compromised by fundoplication, thereby limiting the use of stomach to reconstruct the upper gastrointestinal tract after esophageal resection. METHODS: Between February 1991 and February 2006, a consecutive series of 142 patients with esophageal adenocarcinoma (EADC) underwent esophageal resection. To reconstruct the upper gastrointestinal tract, all patients had a narrow gastric tube (greater curvature of stomach based on the right gastroepiploic artery) transposed through the posterior mediastinum to the left neck where an anastomosis to the cervical esophagus was performed. From a prospective database, 15 patients were identified to have undergone an 'open' fundoplication (transabdominal Nissen, n=11; transthoracic Belsey, n=4) from 12 to 23 years earlier. Outcomes were compared between patients with EADC who had undergone previous fundoplication, and patients with EADC who never had antireflux surgery. RESULTS: Gastric transposition and cervical esophagogastrostomy were technically feasible in all patients. No significant differences in outcome were found between patient groups. Gastric necrosis developed in only one patient, who had not undergone previous fundoplication. Anastomotic leak rates after esophageal resection and reconstruction were not statistically different based on whether patients had undergone previous fundoplication (2/15, 13.3%) or not (16/127, 12.6%; p=0.99). CONCLUSIONS: With careful attention to surgical technique, previous fundoplication does not preclude the use of stomach to reconstruct the foregut after esophageal resection, refuting the notion that previous antireflux surgery is a relative contraindication to, or alters the approach to esophageal cancer surgery.