Ascorbate is depleted by smoking and replaced by moderate supplementation: a study in male smokers and nonsmokers with matched dietary antioxidant intakes.

Our findings appear independent of the potential confounding effect of numerous and well measured factors (i.e. smoking, weight, socioeconomic status, dietary antioxidant intake); however we cannot exclude the potential of residual confounding.

Montonen J, Knekt P, Jarvinen R, Reunanen A. Dietary antioxidant intake and risk of type 2 diabetes.

Speizer FE, Colditz GA, Hunter DJ, et al.: Prospective study of smoking, antioxidant intake, and lung cancer in middle-aged women (USA).

Dietary antioxidant intake and incidence of early age-related maculopathy: the Blue Mountains Eye Study.