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Asian Americans Have High Rate of Diabetes

Despite having a low rate of obesity, Asian Americans are more likely to have type 2 diabetes than white Americans, according to a study published online in January 2011 in Diabetes Care. The results are very surprising, given Asian Americans’ much healthier body mass index (BMI) compared with other ethnic groups.

Researchers from The Johns Hopkins University analyzed data from the National Health Interview Survey from 1997 to 2008 of 230,503 American adults 18 years and older. Of these adults, 11,056 identified themselves as Asian Americans and 219,447 as non-Hispanic whites. Adjusted for age and sex, the prevalence of type 2 diabetes was higher in Asian Americans than in whites throughout the study period (4.3%-8.2% versus 3.8%-6%, respectively). Diabetes was highest in Asian Indians, followed by Filipinos, other Asians, and Chinese. The data also confirmed that Asian Americans in this study tended to have healthier BMIs.

Because the results are puzzling, the authors suggest that “additional investigation of this disparity is warranted, with the aim of tailoring optimal diabetes prevention strategies to Asian Americans.” Scientists from the World Health Organization have suggested that instead of 1 definition of obesity for all populations— BMI >30 kg/m2—the cutoff for obesity should be different in different ethnic populations. For Asian individuals, they reasoned, the definition should be ≥23 kg/ m2 because Asian populations have different associations between BMI, percentage of body fat, and health risks than European populations.

Metformin Beneficial in High-Risk Patients

Metformin decreases mortality in patients with preexisting arterial disease, according to a study published in the Archives of Internal Medicine in November 2010. The retrospective study gathered data from the international Reduction of Atherothrombosis for Continued Health (REACH) Registry to include 19,691 patients with type 2 diabetes with a history of coronary artery, cerebrovascular, or peripheral artery disease. The researchers followed these patients for approximately 2 years, recording their baseline characteristics and laboratory results. After conducting statistical analysis adjusted for age, sex, and propensity score, the scientists found that the hazard ratio for death associated with metformin use was 0.76 (95% confidence interval, 0.59-0.75; p <0.001), or metformin use decreased the risk of death by 24% in patients with documented cardiac or arterial disease.

Ronan Roussel, MD, PhD, and colleagues attribute this effect to metformin’s numerous sites of action, including decreasing hepatic insulin resistance, improving lipoprotein levels, and modestly reducing body weight, all “well-established risk factor[s] of cardiovascular death and of noncardiovascular death.” Because metformin is contraindicated in some of the patients included in this study because of the risk of lactic acidosis, like patients with moderate renal failure, the researchers call these results significant.

Although caution must always be used when extrapolating study results to a large population, the authors conclude that “the diversity of countries, geographic regions, practice settings, and types of physicians and patients participating in the REACH Registry, as well as the well-balanced recruitment between specialists and primary care providers, makes the conclusions broadly relevant.” PT

Preventing Diabetes Starts with a Few Small Steps

Researchers from Australia may have come across a new method of preventing diabetes: walking.

Terry Dwyer, AO, MD, MPH, lead director at the Murdoch Children’s Research Institute in Melbourne, and colleagues published an observational cohort study in January’s issue of the British Medical Journal that examined 592 middle-aged adults over a 5-year period.

At the beginning of the study, the participants were given a questionnaire assessing physical activity, and then they were given a pedometer to use for 5 years. Five years later, the researchers measured the participants’ step count according to the pedometer, as well as their body mass index (BMI), waist-tohip ratio, and insulin sensitivity.

Adjusting for many variables including age, weight, socioeconomic status, diet, alcohol use, and smoking, the researchers found inactive participants who increased their step count to 10,000 steps per day (approximately 5 miles) at the end of the 5 years had an improved BMI as well as a 3-fold improvement in insulin sensitivity compared with a similar person who increased to only 3000 steps per day.

Further analysis shows this drastic improvement in insulin sensitivity is related to the change in adiposity; the less fat a person has, the lower his or her risk for developing diabetes. The results demonstrate more of a reason to promote physical activity in middle-aged adults to combat type 2 diabetes and obesity.