Background & aims

Early recognition of prediabetes can lead to timely clinical interventions to prevent type 2 diabetes. Both Latino ethnicity and chronic hepatitis C (HCV) have been identified as diabetic risk factors. We aimed to investigate predictors of impaired fasting glucose (IFG), a common prediabetic state, among Latinos with and without HCV.

Methods

One hundred Latino adults with no history of diabetes or cirrhosis underwent clinical, laboratory, and metabolic evaluation, including oral glucose tolerance testing (OGTT) and insulin suppression testing to quantify directly measured insulin resistance (IR). Isolated IFG was defined as fasting glucose ≥100 mg/dl and <140 mg/dl at 2 h during normal glucose tolerance during OGTT.

Results

Overall subject characteristics included median age 44 years, 64% male, 40% HCV-positive and 32% with isolated IFG. Factors associated with isolated IFG included subject age (OR 2.42 per decade, 95%CI 1.40-3.90, P = 0.001), HCV infection (OR 4.0, 95%CI 1.71-9.72, P = 0.002) and alanine aminotransferase (ALT) (OR 2.35 per doubling, 95%CI 1.46-3.77, P < 0.0001). Multipredictor logistic regression analysis identified ALT (OR 2.05 per doubling, P = 0.005, 95% CI 1.24-3.40) and age (OR 2.20 per 10 years, P = 0.005, 95%CI 1.27-3.80) as factors independently associated with IFG. While HCV was associated with 4-fold higher odds of IFG, this entire effect was mediated by ALT.

Conclusions

We found strong evidence that liver inflammation is a risk factor for prediabetes among Latinos with and without HCV. Among HCV-infected individuals, early antiviral therapy could mitigate the effect of inflammation and represent an important intervention to prevent diabetes in this at-risk population.

Background and aims

Studies investigating insulin resistance (IR) in chronic hepatitis C virus (HCV) infection have used surrogate measures of IR that have limited reliability. We aimed to describe the distribution and risk factors associated with IR and its change over time in HCV using direct measurement.

Methods

One hundred two non-cirrhotic, non-diabetic, HCV-infected subjects underwent clinical, histologic, and metabolic evaluation, and 27 completed repeat evaluation at 6 months. Insulin-mediated glucose uptake was measured by steady-state plasma glucose (SSPG) concentration during the insulin suppression test.

Results

Three subjects with diabetes were excluded and 95 completed all testing. SSPG ranged from 39 to 328 mg/dL (mean 135 mg/dL) and was stable over time (mean SSPG change -0.3 mg/dL). SSPG was associated with Latino ethnicity (Coef 67, 95 % CI 37-96), BMI (Coef 19 per 5 kg/m(2), 95 % CI 5-32), ferritin (Coef 1.4 per 10 ng/ml, 95 % CI 0.2-2.5), male gender (Coef -48, 95 % CI -80 to -16), and HDL (Coef -16, 95 % CI -28 to -5 mg/dL). Current tobacco use (Coef 55, 95 % CI 19-90), steatosis (Coef -44, 95 % CI -86 to -3), and increases in BMI (Coef 30 per 5 kg/m(2), 95 % CI 6-53) and triglyceride (Coef 3.5 per 10 mg/dL, 95 % CI 0.3-6.7) predicted change in SSPG.

Conclusions

There was a wide spectrum of insulin resistance in our HCV population. Host factors, rather than viral factors, appeared to more greatly influence insulin action and its change in HCV.

In the Americas, women with Indigenous American ancestry are at increased risk of intrahepatic cholestasis of pregnancy (ICP), relative to women of other ethnicities. We hypothesized that ancestry-related genetic factors contribute to this increased risk. We collected clinical and laboratory data, and performed biochemical assays on samples from U.S. Latinas and Chilean women, with and without ICP. The study sample included 198 women with ICP (90 from California, U.S., and 108 from Chile) and 174 pregnant control women (69 from California, U.S., and 105 from Chile). SNP genotyping was performed using Affymetrix arrays. We compared overall genetic ancestry between cases and controls, and used a genome-wide admixture mapping approach to screen for ICP susceptibility loci. We identified commonalities and differences in features of ICP between the 2 countries and determined that cases had a greater proportion of Indigenous American ancestry than did controls (p = 0.034). We performed admixture mapping, taking country of origin into account, and identified one locus for which Native American ancestry was associated with increased risk of ICP at a genome-wide level of significance (P = 3.1 x 10(-5), Pcorrected = 0.035). This locus has an odds ratio of 4.48 (95% CI: 2.21-9.06) for 2 versus zero Indigenous American chromosomes. This locus lies on chromosome 2, with a 10 Mb 95% confidence interval which does not contain any previously identified hereditary 'cholestasis genes.' Our results indicate that genetic factors contribute to the risk of developing ICP in the Americas, and support the utility of clinical and genetic studies of ethnically mixed populations for increasing our understanding of ICP.