Correlation of a [13C]glucose breath test with surrogate markers of insulin resistance in urban and rural Asian Indians.

BACKGROUND

High rates of insulin resistance (IR), which contribute to a high prevalence of cardiovascular disease (CVD), have been noted in Asian Indians. Rapid, effective measures of IR could identify individuals at risk for CVD in this population. A [(13)C]glucose breath test has been shown to correlate significantly with invasive measures of IR in a Caucasian cohort. We hypothesized that the breath test would correlate significantly with surrogate measures of IR in Asian Indians.

METHODS

A total of 49 urban and 49 rural Asian Indian subjects underwent the (13)C breath test and 2-hour oral glucose tolerance testing. Correlations were performed between the breath test results and surrogate measures of IR including the homeostasis model of insulin resistance (HOMA). These two indices were also correlated with body mass index (BMI).

RESULTS

In the overall cohort, the breath test correlated significantly with HOMA (r = -0.40; P < 0.0001), waist circumference (WC) (r = -0.70; P < 0.0001), and BMI (r = -0.59; P < 0.0001). The breath test correlated significantly with BMI in the urban and rural cohorts (r = -0.65; P < 0.0001 and r = -0.36; P = 0.01) and with HOMA (r = -0.55; P = 0.0001) in the urban cohort. There was no significant correlation between the breath test and HOMA (r = -0.07; P = 0.61) in the rural cohort. When corrected for WC and BMI, the correlation between the breath test and HOMA in the urban cohort was no longer significant (r = -0.08; P = 0.57).

CONCLUSIONS

The (13)C breath test correlated significantly with HOMA values in urban but not in more insulin-sensitive rural subjects and yielded no incremental information over BMI. Further refinement of the [(13)C]glucose breath test is necessary prior to its use as a screening test for IR in Asian Indians.