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YIA 03-07 REACTIVE OXYGEN SPECIES ADVERSELY RELATES TO EARLY VASCULAR CHANGES AND ARTERIAL STIFFNESS IN BLACK NORMOTENSIVE SMOKERS: THE AFRICAN-PREDICT STUDY.

OBJECTIVE
Cigarette smoking weakens the antioxidant defence system and is considered a lifestyle risk factor contributing to cardiovascular disease progression. Little information exists on these links in non-smoking versus smoking populations. We aimed to explore the associations of oxidative stress with markers of vascular function in a young, normotensive bi-ethnic population.


DESIGN AND METHOD
We included 237 non-smokers (108 black and 129 white) and 145 smokers (78 black and 67 white) from South Africa between ages 20 and 30 years. We performed cardiovascular measurements including retinal microvascular imaging and femoral pulse wave velocity (PWV). Serum cotinine levels were measured to define smoking status and reactive oxygen species (ROS) to define oxidative stress.


RESULTS
In smokers, the arteriole-to-venule ratio was lower in black compared to white individuals (p = 0.032), but PWV and ROS were similar. In single regression analysis, ROS correlated inversely with arteriole-to-venule ratio (r = -0.37; p = 0.002) in black smokers only. After partially correcting for age, sex and body mass index we confirmed this relationship, but a positive correlation emerged with ROS and PWV in black smokers (r = 0.24; p = 0.042) and systolic blood pressure in white smokers (r = 0.28; p = 0.027). In multivariate analysis, we confirmed the associations of ROS with arteriole-to-venule ratio (Adj. R = 0.19; β = -0.33; p = 0.004) and PWV (Adj. R = 0.35; β = -0.24; p = 0.042) in black smokers only.


CONCLUSIONS
Our results suggest that early vascular changes are evident in young, normotensive black individuals that are exposed to cigarette smoking and related oxidative stress augmenting their vulnerability to develop early onset arterial stiffness.