When two sine waves that differ slightly in orientation are presented to the two eyes separately, a single cyclopean sine wave is perceived. However, it is unclear how the brain calculates its orientation. Here, we used a signal detection rating method to estimate the perceived orientation when the two eyes were presented with Gabor patches that differed in both orientation and contrast. We found a nearly linear combination of orientation when both targets had the same contrast. However, the binocular percept shifted away from the linear prediction towards the orientation with the higher contrast, depending on both the base contrast and the contrast ratio. We found that stimuli that differ slightly in orientation are combined into a single percept, similarly for monocular and binocular presentation, with a bias that depends on the interocular contrast ratio. Our results are well fitted by gain-control models, and are consistent with a previous study that favoured the DSKL model that successfully predicts binocular phase and contrast combination and binocular contrast discrimination. In this model, the departures from linearity may be explained on the basis of mutual suppression and mutual enhancement, both of which are stronger under dichoptic than monocular conditions.

We hypothesized that anthropometric measures of abdominal obesity would have a stronger positive association with nonalcoholic fatty liver disease (NAFLD) measured by noncontrast computed tomography versus general measures of obesity. The Multiethnic Study of Atherosclerosis comprised participants aged 45 to 84 years free of known cardiovascular disease. We studied 4,088 participants with adequate liver and spleen computed tomography imaging and no previous use of oral steroids, class 3 antiarrhythmics, moderately heavy alcohol use, or cirrhosis. Prevalent NAFLD was defined as a liver:spleen Hounsfield attenuation ratio of <1. Multivariable log-linear regression modeled the association of 4 obesity measures - weight, body mass index (BMI), waist circumference, and waist-to-hip ratio - with prevalent NAFLD. Receiver-operator curve analysis compared NAFLD discrimination. Median age was 63 years, and 55% were women. For each obesity measure, adjusted prevalence ratios for NAFLD were fourfold to fivefold greater in the highest versus the lowest quartile (p <0.001). Waist circumference and BMI had the highest prevalence ratios, and waist circumference had the best discrimination, for NAFLD in the total population, although an abnormal BMI categorized subjects with NAFLD as well if not better than waist circumference. In ethnic-specific analysis, whites and Chinese had the strongest association of obesity and NAFLD compared with other ethnicities. In conclusion, although waist circumference provided the best discrimination for NAFLD, BMI may perform similarly well in clinical settings to screen for NAFLD.

Aims

Disparities persist on the prevalence of undiagnosed type 2 diabetes in racial/ethnic minorities in the USA. This study evaluated the association between BMI and incident type 2 diabetes risk by racial/ethnic group, to determine whether BMI and presence of type 2 diabetes risk factors may help clinicians better target type 2 diabetes screening.

Methods

This prospective cohort analysis included 5659 adults free of type 2 diabetes at baseline from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort (2000-2011). BMI was measured at baseline and time-updated at subsequent visits. Incident type 2 diabetes was defined as fasting glucose ≥ 7.0 mmol/l, or use of any diabetes medications.

Results

The mean (sd) age was 62 (10) years and 42% of participants were white, 26% African American, 20% Hispanic and 12% Chinese American. During follow-up, 696 (12%) new type 2 diabetes cases were observed. In age- and sex-adjusted models, in the presence of one or more type 2 diabetes risk factors (the most common scenario), a 10% risk of incident type 2 diabetes was observed at a BMI of 21.7 kg/m² [95% confidence interval (CI) 20.1 to 22.8] in Chinese Americans, 23.8 kg/m² (22.7 to 24.9) in Hispanics, 24.7 kg/m² (23.7 to 25.6) in African Americans and 26.2 kg/m² (25.1 to 26.9) in white participants.

Conclusions

This study supports including BMI and presence of type 2 diabetes risk factors as action points for clinicians to prioritize which adults aged ≥ 45 years should be screened. The application of race/ethnicity-specific BMI thresholds may reduce the disparity of undiagnosed type 2 diabetes observed in minority groups.