Lower serum levels of total cholesterol are associated with higher urinary levels of 8-hydroxydeoxyguanosine

BACKGROUND Lower serum total (TC), high-density lipoprotein (HDL-C) and low-density lipoprotein cholesterols (LDL-C) have been linked to an increased risk of cancer in various sites, but its underlying mechanism remains unclear. In an attempt to clarify the association between cholesterol levels and oxidative DNA damage, we investigated the relationship between serum cholesterol and urinary 8-hydroxydeoxyguanosine levels in a Japanese working population. METHODS The study subjects were 294 men and 209 women aged 21-66 years in two Japanese municipal offices. Urinary 8-hydroxydeoxyguanosine (8-OHdG) was measured using an automated high-pressure liquid chromatography. Linear regression analysis was used to examine the associations of urinary 8-OHdG with TC, HDL-C and LDL-C levels with adjustment for sex, age, smoking and body mass index. Subgroup analyses were conducted by smoking status in men and age in women. Analysis of covariance was employed to estimate adjusted means of urinary 8-OHdG across TC category. RESULTS After multivariate adjustment, urinary 8-OHdG levels were inversely associated with serum TC levels (β = -0.0015, p < 0.05) and LDL-C levels (β = -0.0012, p = 0.07). The inverse association with TC was apparent among smoking men (β = -0.0017, p < 0.05) and among women aged less than 48 years (β = -0.0040, p < 0.01). 8-OHdG decreased as TC increased (up to 219 mg/dL); subjects with TC levels of <160 mg/dL had a 17.4% higher adjusted mean of 8-OHdG than did those with TC levels of 200-219 mg/dL. CONCLUSION Results suggest that circulating low TC levels are associated with higher oxidative DNA damage.