Accumulating evidence suggests a cross-sectional association between oxidative stress and type 2 diabetes (T2D). Systemic oxidative stress, as measured by oxidized LDL (oxLDL), has been correlated with visceral fat. We examined the relationship between oxLDL, and T2D- and obesity-related traits in a bi-racial sample of 2,985 subjects at baseline and after 7 years of follow-up.
We examined six T2D-related traits (T2D status, HbA1c, fasting glucose, insulin, adiponectin and HOMA-IR) as well as six obesity-related traits (obesity status, BMI, leptin, % body fat, visceral and subcutaneous fat mass) using logistic and linear regression models.
In all subjects at baseline, oxLDL was positively associated with T2D (OR=1.3,95% CI:1.1–1.5), fasting glucose (β=0.03±0.006), HbA1c (β=0.02±0.004), fasting insulin (β=0.12±0.02), HOMA-IR (β=0.13±0.02) and negatively with adiponectin (β=−0.16±0.03), (all p<0.001). The strength and magnitude of these associations did not differ much between blacks and whites. In both blacks and whites, oxLDL was also associated with obesity (OR=1.3, 95% CI:1.1–1.4) and 3 of its related traits (β=0.60±0.14 for BMI, β=0.74±0.17 for % body fat, β=0.29±0.06 for visceral fat;
all p<0.001). Furthermore, of 4 traits measured after 7 years of follow-up (fasting glucose, HbA1c, BMI and % fat), their relationship with oxLDL were similar to baseline observations. No significant association was found between oxLDL and incident T2D. Interestingly, oxLDL was significantly associated with % change in T2D- and obesity-related traits in whites but not in blacks.
Our data suggest that systemic oxidative stress may be a novel risk factor for T2D and obesity.