Ozone Exposure, Glucose Homeostasis and Insulin Resistance in the U.S.A.

Abstract

Ozone Exposure, Glucose Homeostasis and Insulin Resistance in the USABackground: Epidemiological studies have suggested the associations between ambient air pollution levels and metabolic syndrome as well as diabetes. However, studies based on a national-wide sample are limited.Materials and Methods: In this study, we used the 1999-2002 restricted-access National Health and Nutrition Survey data (n=4,341 adults) to investigate the effects of air pollutants including fine particles (PM2.5) and ozone (O3) on glucose homeostasis and insulin resistance. We calculated daily average levels of air pollutants on each day in the preceding week and the preceding 1-month, 3-month, and annual averages of air pollutants at participants’ geocoded home address. Linear regression models were applied for fast glucose, insulin, hemoglobin A1c (HbA1c), homeostasis model assessment of β cell function (HOMA- β), and insulin resistance (HOMA-IR). Logarithm transformation was applied to skewed variables.Results: We found that exposure to O3 was significantly positively associated with fasting glucose level at lag days (β=1.18-1.69 per 1 ppm change in O3, P <0.05), one month (β=1.97, P = 0.02), three months (β=2.29, P = 0.03) and one year window of exposure (β=3.47, P = 0.01). Additionally, O3 exposure was significantly negatively associated with and HOMA- β for all lag times. Monthly, 3-month and annual averages of O3 were also positively associated with HbA1c. However, PM2.5 was shown to have no strong relationship with these outcome measurements.Conclusions: Our study suggested that exposure to O3 may have adverse effects on glucose homeostasis and β-cell function. The findings warrant further investigation.