No abstract

BackgroundMetformin protection against cancer risk in Orientals is uncertain. We examined the possible metformin effect on total, esophageal, gastric, colorectal (CRC), hepatocellular (HCC) and pancreatic cancers in a Taiwanese cohort.MethodsA representative sample of 800,000 was drawn from the Taiwanese National Health Insurance data of 2000. A cohort of 480,984 participants 20 years or older, diabetes-cancer-free on 1st January 2000 was formed and categorized as four groups by DM and metformin usage status. Eligible incident cancer events had to occur one year after the index date until the end of 2007. The Cox proportional-hazards model evaluated relative risk of cancer for treated DM patients with or without metformin. The covariates included age, gender, other oral anti-hyperglycemic medication, Charlson comorbidity index (CCI) score and metformin exposure dosage and duration.ResultsWith diabetes but no anti-hyperglycemic medication, cancer incidence density increased at least 2-fold for total, CRC and HCC. On metformin, total, CRC and HCC incidences decreased to near non-diabetic levels but to varying degrees depending on gender and cancer type (CRC in women, liver in men). Adjustment for other oral anti-hyperglycemic agents usage and CCI made the benefit of metformin more evident [hazard ratios (95% confidence intervals): total 0.12 (0.08-0.19), CRC 0.36 (0.13-0.98), liver 0.06 (0.02-0.16), pancreas 0.15 (0.03-0.79)]. There was a significant gender interaction with metformin in CRC which favored women. Metformin dosage for a significant decrease in cancer incidence was ≤500 mg/day.ConclusionsMetformin can reduce the incidences of several gastroenterological cancers in treated diabetes.

Objectives: To assess whether overweight Asians, assessed on the basis of WHO criteria, are at greater mortality risk than overweight Caucasians, and to determine whether alternative cut-off points (BMI 5 23?0-24?9 kg/m 2 for overweight and BMI $ 25?0 kg/m 2 for obesity) suggested by the WHO Western Pacific Regional Office are appropriate. Design: The cohort was followed prospectively until the end of 2001. All-cause and CVD mortality risks of the overweight and obese group, relative to the reference group (BMI 5 18?5-24?9 or 18?5-22?9 kg/m 2 ), were assessed using Cox regression analysis, adjusting for age, smoking and gender. Excess deaths were estimated with a method proposed by the US Centers for Disease Control and Prevention. Setting: National Health Interview Survey (NHIS 2001) and a middle-aged perspective cohort in Taiwan. Subjects: Subjects comprised 36 386 civil servants and school teachers, aged 40 years and older, who underwent a medical examination during 1989-1992. Results: In the WHO-defined overweight group, Asians showed a significant increase in all-cause mortality risk compared with Caucasians. Asians showed risks equivalent to Caucasians' at lower BMI (around 5 units). Every unit of BMI increase, at 25?0 kg/m 2 or above, was associated with a 9 % increase in relative mortality risk from all causes. Applying a cut-off point of 25?0 kg/m 2 for obesity would result a prevalence of 27?1 %, while the traditional WHO cut-off point of 30?0 kg/m 2 yielded obesity prevalence of 4?1 %. Excess deaths due to obesity accounted for 8?6 % of all deaths and 21?1 % of CVD deaths, based on the alternative cut-offs. Conclusions: In this Asian population, significant mortality risks started at BMI $ 25?0 kg/m 2 , rather than at BMI $ 30?0 kg/m 2 . The study supports the use of BMI $ 25?0 kg/m 2 as a new cut-off point for obesity and BMI 5 23?0-24?9 kg/m 2 for overweight. The magnitude of obesity-attributable deaths has been hitherto under-appreciated among Asians. Keywords Body mass index Mortality risk Overweight ObesityObesity and smoking are two of the leading causes of preventable diseases in the Western world (1) . Excess deaths from smoking have been well documented in many populations, including Asians (2,3) , but the magnitude of the excess deaths from obesity, an increasingly important burden of disease, is less well publicized (4)(5)(6)(7)(8)(9)(10)(11) , particularly among Asians. At the same BMI level, with BMI defined as weight/height 2 , higher body fat percentage is found in Asians than in Caucasians (12)(13)(14) but their prevalence of obesity is much lower (15) . As a result, some studies have suggested to lower BMI cut-off points for Asians (16)(17)(18)(19)(20) , while others disagree (21,22) or remain non-committal (23)(24)(25) . On reviewing the association of BMI with body fat and morbidity risks among Asian countries, a WHO expert consultation recently concluded that the BMI cut-off points defined by WHO (25?0-29?9 kg/m 2 for overweight, $30?0 kg/m 2 for obesity) should be retained...

No abstract