Discovery and validation of plasma, saliva and multi-fluid plasma-saliva metabolomic scores predicting insulin resistance and diabetes progression or regression among Puerto Rican adults

AIMS/HYPOTHESIS

Many studies have examined the relationship between plasma metabolites and type 2 diabetes progression, but few have explored saliva and multi-fluid metabolites.

METHODS

We used LC/MS to measure plasma (n=1051) and saliva (n=635) metabolites among Puerto Rican adults from the San Juan Overweight Adults Longitudinal Study. We used elastic net regression to identify plasma, saliva and multi-fluid plasma-saliva metabolomic scores predicting baseline HOMA-IR in a training set (n=509) and validated these scores in a testing set (n=340). We used multivariable Cox proportional hazards models to estimate HRs for the association of baseline metabolomic scores predicting insulin resistance with incident type 2 diabetes (n=54) and prediabetes (characterised by impaired glucose tolerance, impaired fasting glucose and/or high HbA1c) (n=130) at 3 years, along with regression from prediabetes to normoglycaemia (n=122), adjusting for traditional diabetes-related risk factors.

RESULTS

Plasma, saliva and multi-fluid plasma-saliva metabolomic scores predicting insulin resistance included highly weighted metabolites from fructose, tyrosine, lipid and amino acid metabolism. Each SD increase in the plasma (HR 1.99 [95% CI 1.18, 3.38]; p=0.01) and multi-fluid (1.80 [1.06, 3.07]; p=0.03) metabolomic scores was associated with higher risk of type 2 diabetes. The saliva metabolomic score was associated with incident prediabetes (1.48 [1.17, 1.86]; p=0.001). All three metabolomic scores were significantly associated with lower likelihood of regressing from prediabetes to normoglycaemia in models adjusting for adiposity (HRs 0.72 for plasma, 0.78 for saliva and 0.72 for multi-fluid), but associations were attenuated when adjusting for lipid and glycaemic measures.

CONCLUSIONS/INTERPRETATION

The plasma metabolomic score predicting insulin resistance was more strongly associated with incident type 2 diabetes than the saliva metabolomic score. Only the saliva metabolomic score was associated with incident prediabetes.

Diabetes Screening and Monitoring Among Older Mexican-Origin Populations in the U.S

OBJECTIVE

The purpose of the study is to examine diabetes screening and monitoring among Latino individuals as compared with non-Latino White individuals and to better understand how we can use neighborhood data to address diabetes care inequities.

RESEARCH DESIGN AND METHODS

This is a retrospective observational study linked with neighborhood-level Latino subgroup data obtained from the American Community Survey. We used generalized estimating equation negative binomial and logistic regression models adjusted for patient-level covariates to compare annual rates of glycated hemoglobin (HbA1c) monitoring for those with diabetes and odds of HbA1c screening for those without diabetes by ethnicity and among Latinos living in neighborhoods with low (0.0-22.0%), medium (22.0-55.7%), and high (55.7-98.0%) population percent of Mexican origin.

RESULTS

Latino individuals with diabetes had 18% higher rates of HbA1c testing than non-Latino White individuals with diabetes (adjusted rate ratio [aRR] 1.18 [95% CI 1.07-1.29]), and Latinos without diabetes had 25% higher odds of screening (adjusted odds ratio 1.25 [95% CI 1.15-1.36]) than non-Latino White individuals without diabetes. In the analyses in which neighborhood-level percent Mexican population was the main independent variable, all Latinos without diabetes had higher odds of HbA1c screening compared with non-Latino White individuals, yet only those living in low percent Mexican-origin neighborhoods had increased monitoring rates (aRR 1.31 [95% CI 1.15-1.49]).

CONCLUSIONS

These findings reveal novel variation in health care utilization according to Latino subgroup neighborhood characteristics and could inform the delivery of diabetes care for a growing and increasingly diverse Latino patient population. Clinicians and researchers whose work focuses on diabetes care should take steps to improve equity in diabetes and prevent inequity in treatment.

Explaining Chronic Illness and Self-Rated Health Among Immigrants of Five Hispanic Ethnicities

The largest racial/ethnic minority group in the United States, Hispanics, especially Hispanic immigrants, have been considered healthier than groups of other ethnicity (including Whites, the majority). However, chronic illnesses such as cancer and diabetes are often seen in this culturally, ethnically diverse group. The present study had two aims. First was to explain two health outcomes, which were presence of chronic illness (any of the five common conditions cardiovascular disease, stroke, hypertension, cancer, and/or diabetes/prediabetes) and self-rated health, in terms of links to certain factors in acculturation, social status, health, social support, and lifestyle. Second was to determine how uniform these links might be across five ethnic groups: Mexican, Puerto Rican, Cuban, Dominican, Central/South American. We combined data from 17 years of the National Health Interview Survey (1999-2015) and subjected these secondary measures to logistic and linear regression, separately by ethnicity, to explain both outcomes. With few exceptions, results generally linked illness/health to the tested independent variables. Additionally, results confirmed ethnicity to moderate the outcomes' associations with the independent variables. Ethnicity-specific analysis showed the two outcomes to exhibit dissimilar relationships with certain independent variables across ethnic groups. Research that (as has been common) lumps together respondents whose Hispanic ethnicities may differ disregards some meaningful variation rather than accounting for it. In future research-and in subsequent evidence-based policy/practice development-all essential sociocultural factors, including ethnicity, should be carefully outlined, advancing good health for the entire Hispanic immigrant population.