Faculty Bibliography

OBJECTIVE: Metformin is the first-line oral medication recommended for glycemic control in patients with type 2 diabetes. We reviewed the literature to quantify the effect of metformin treatment on glycated hemoglobin (HbA(1c)) levels in all types of diabetes and examine the impact of differing doses on glycemic control. RESEARCH DESIGN AND METHODS: MEDLINE, EMBASE, and the Cochrane Library were searched from 1950 to June 2010 for trials of at least 12 weeks' duration in which diabetic patients were treated with either metformin monotherapy or as an add-on therapy. Data on change in HbA(1c) were pooled in a meta-analysis. Data from dose-comparison trials were separately pooled. RESULTS: A total of 35 trials were identified for the main analysis and 7 for the dose-comparison analysis. Metformin monotherapy lowered HbA(1c) by 1.12% (95% CI 0.92-1.32; I(2) = 80%) versus placebo, metformin added to oral therapy lowered HbA(1c) by 0.95% (0.77-1.13; I(2) = 77%) versus placebo added to oral therapy, and metformin added to insulin therapy lowered HbA(1c) by 0.60% (0.30-0.91; I(2) = 79.8%) versus insulin only. There was a significantly greater reduction in HbA(1c) using higher doses of metformin compared with lower doses of metformin with no significant increase in side effects. CONCLUSIONS: Evidence supports the effectiveness of metformin therapy in a clinically important lowering of HbA(1c) used as monotherapy and in combination with other therapeutic agents. There is potential for using higher doses of metformin to maximize glycemic control in diabetic patients without increasing gastrointestinal effects.

INTRODUCTION: Accurate information about the prevalence and types of tobacco use is essential to deliver effective public health policy. We aimed to study the prevalence and modes of tobacco consumption in the United Arab Emirates (UAE), particularly focusing on the use of Midwakh (Arabic traditional pipe). METHODS: We studied 170,430 UAE nationals aged >/= 18 years (44% males and 56% females) in the Weqaya population-based screening program in Abu Dhabi residents during the period April 2008-June 2010. Self-reported smoking status, type, quantity and duration of tobacco smoked were recorded. Descriptive statistics were used to describe the study findings; prevalence rates used the screened sample as the denominator. RESULT: The prevalence of smoking overall was 24.3% in males and 0.8% in females and highest in males aged 20-39. Mean age (SD) of smokers was 32.8 (11.1) years, 32.7 (11.1) in males and 35.7 (12.1) in females. Cigarette smoking was the commonest form of tobacco use (77.4% of smokers), followed by Midwakh (15.0%), shisha (waterpipe) (6.8%), and cigar (0.66%). The mean durations of smoking for cigarettes, Midwakh, shisha and cigars were 11.4, 9.3, 7.6 and 11.0 years, respectively. CONCLUSIONS: Smoking is most common among younger UAE national men. The use of Midwakh and the relatively young age of onset of Midwakh smokers is of particular concern as is the possibility of the habit spreading to other countries. Comprehensive tobacco control laws targeting the young and the use of Midwakh are needed.

Transnational Organisations increasingly prioritise the need to support local research capacity in low and middle income countries in order that local priorities are addressed with due consideration of contextual issues. There remains limited evidence on the best way in which this should be done or the ways in which external agencies can support this process.We present an analysis of the learning from the INDOX Research Network, established in 2005 as a partnership between the Institute of Cancer Medicine at the University of Oxford and India's top nine comprehensive cancer centres. INDOX aims to enable Indian centres to conduct clinical research to the highest international standards; to ensure that trials are developed to address the specific needs of Indian patients by involving Indian investigators from the outset; and to provide the training to enable them to design and conduct their own studies. We report on the implementation, outputs and challenges of simultaneously trying to build capacity and deliver meaningful research output.

BACKGROUND: High quality evidence indicates that aspirin is effective in reducing colorectal polyps; and numerous epidemiological studies point towards an ability to prevent colorectal cancer. However the role of Aspirin as an adjuvant agent in patients with established cancers remains to be defined. Recently a nested case-control study within the Nurses Health cohort suggested that the initiation of Aspirin after the diagnosis of colon cancer reduced overall colorectal cancer specific mortality. Although this data is supportive of Aspirin's biological activity in this disease and possible role in adjuvant therapy, it needs to be confirmed in a randomized prospective trial. METHODS/DESIGN: We hypothesize through this randomized, placebo-controlled adjuvant study, that Aspirin in patients with dukes C or high risk dukes B colorectal cancer (ASCOLT) can improve survival in this patient population over placebo control. The primary endpoint of this study is Disease Free Survival and the secondary Endpoint is 5 yr Overall Survival. This study will randomize eligible patients with Dukes C or high risk Dukes B colorectal cancer, after completion of surgery and standard adjuvant chemotherapy (+/- radiation therapy for rectal cancer patients) to 200 mg Aspirin or Placebo for 3 years. Stratification factors include study centre, rectal or colon cancer stage, and type of adjuvant chemotherapy (exposed/not exposed to oxaliplatin). After randomization, patient will be followed up with 3 monthly assessments whilst on study drug and for a total of 5 years. Patients with active peptic ulcer disease, bleeding diathesis or on treatment with aspirin or anti-platelet agents will be excluded from the study. DISCUSSION: This study aims to evaluate Aspirin's role as an adjuvant treatment in colorectal cancer. If indeed found to be beneficial, because aspirin is cheap, accessible and easy to administer, it will positively impact the lives of many individuals in Asia and globally. TRIALS REGISTRATION: Clinicaltrials.gov: NCT00565708.

DNA-damaging agents are widely used in cancer treatment despite their lack of tumor specificity. Human NQO2 (quinone oxidoreductase-2) is an atypical oxidoreductase because no endogenous electron donor has been identified to date. The enzyme converts CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide], in the presence of the synthetic nicotinamide cofactor analog EP0152R, to a cytotoxic bifunctional alkylating agent. NQO2 activity in hepatocellular tumor tissue is higher than that in other cancer types by a factor of 6 and higher than that in bone marrow by a factor of 20. Structural data from x-ray crystallography and nuclear magnetic resonance spectroscopy allowed us to construct a model of CB1954 and EP0152R binding to NQO2, which suggested an optimal infusion schedule for a phase I trial combining the two agents. Thirty-two patients were treated, and diarrhea and serum transaminase concentrations defined a maximum tolerated dose for the drug combination. There was a clear pharmacokinetic interaction, with EP0152R inducing a marked increase in clearance of CB1954, in keeping with model predictions. We detected DNA interstrand cross-links caused by nitroreduced CB1954 in tumor biopsies from treated patients, demonstrating that the activated prodrug exerts its cytotoxic properties through DNA base alkylation.

BACKGROUND: Associations between family history of colorectal cancer (CRC) in first degree relatives and risk of developing cancer have been well defined, but interactions with environmental, lifestyle and dietary factors are much less clear. AIM: The aim of this study was to evaluate family history, lifestyle and dietary factors associated with developing colorectal cancer in an Arab population. DESIGN: This matched case-control study was conducted from August 2008 to February 2009 in Al-Amal Hospital and Primary Health Care Centers in Qatar. SUBJECTS AND METHODS: The study covered 146 colorectal cancer patients from Al-Amal hospital and 282 healthy subjects matched by age and gender as controls from primary health care centers. The questionnaire included socio-demographic information, type of consanguinity, medical history, lifestyle habits, and dietary intake. Of the selected 185 colorectal cancer cases, 146 (78.9%) agreed to participate in the study, whereas from the 350 selected controls, 282 (80.6%) gave consent. RESULTS: The mean age of cases was 54.1+/-12.4 and of controls 53.1+/-13.1. Among the life style factors, being overweight and obese (60.2%; 30.1% p=0.006), having a smoking habit (26.7%, p=0.025), and consuming bakery items (78.8% p<0.001) and soft drinks (28.7% p<0.02), were positively associated with CRC. The majority of the studied cases and controls were consuming fresh fruits (87.7% vs 85.5%), fresh vegetables (95.2% vs 95%) and green salad (91.1% vs 89.4%) regularly. Family history of CRC (41.8%) was significantly higher in colorectal patients than in controls (29.1%) (p<0.01). Parental consanguinity was observed more frequently in colorectal cancer patients (35.6%). Multivariate stepwise logistic regression analysis showed that smoking, BMI, family history, consuming bakery and soft drinks were significant predictors of development of colorectal cancer. CONCLUSION: The present study revealed family history and parental consanguinity to be strongly associated with the development of colorectal cancer. Age, gender, a sedentary lifestyle, and being overweight were also positively linked with CRC risk.