Plasma fluorescent oxidation products as potential markers of oxidative stress for epidemiologic studies.

Currently lacking are stable and easily measured biomarkers that can reflect oxidative stress in humans. Fluorescent oxidation products may fulfill all three of these criteria. Fasting plasma levels of fluorescent oxidation products were measured in 286 controls in a study of coronary heart disease among US men aged 47-81 years; the study concluded in 2006. Other biomarkers in plasma were also measured, and cardiovascular risk factors such as smoking, hypertension, age, and physical activity were assessed by questionnaire. Indicators of oxidative stress, including smoking, hypertension, and reduced renal function, were associated with greater fluorescent oxidation products in both age- and multivariate-adjusted analyses (for each, p for trend < 0.01). In a multivariate-adjusted analysis, levels of fluorescent oxidation products were 45% higher in current smokers than in never smokers and 61% higher in men who smoked more than 25 cigarettes/day versus 1-4 cigarettes/day. The levels of this marker were 17% higher in hypertensive men than in normotensive men and 20% higher in men in the lowest versus the highest quartile of glomerular filtration rate. Levels were 57% higher in men with both hypertension and reduced renal function than in men with neither. The association of fluorescent oxidation products with several indicators of oxidative stress suggests that this measure could be a useful global marker of oxidative stress for large epidemiologic studies.