Associations between supplemental or dietary intake of vitamin C and severity of lower urinary tract symptoms.

To examine the association between long-term dietary vitamin C intake and recent use of vitamin C supplements with the progression and severity of lower urinary tract symptoms (LUTS). Baseline and 5-year follow-up interviews were completed by 2825 black, Hispanic or white men and women aged 30-79 years in the Boston Area Community Health survey. Dietary and supplemental vitamin C intake was assessed using a validated food frequency questionnaire. LUTS were assessed using the validated American Urological Association Symptom Index. Multivariable models were used to test the associations between baseline vitamin C and progression of LUTS over the follow-up period, and between recent vitamin C intake and LUTS severity. In multivariable models, baseline dietary vitamin C was associated with lower odds of progression of daytime storage symptoms in men (e.g. quartile 4 vs 1, odds ratio [OR] = 0.63, 95% confidence interval [CI]: 0.41-0.97), or urgency symptoms in women (P trend = 0.02). Recent vitamin C intake at follow-up was also associated with better symptom scores among men. In contrast, among women, vitamin C supplement intake was associated with worse symptom scores, particularly daytime storage problems (500 mg/day vs none, OR = 1.66, 95% CI: 1.18-2.35, P trend = 0.01). Recent dietary vitamin C was not associated with LUTS in women. Vitamin C intake from foods and beverages was inversely associated with progression of daytime urinary storage symptoms in men or urgency symptoms in women at 5-year follow-up, therefore, the present results do not support a widespread avoidance for patients with LUTS of foods and beverages naturally rich in vitamin C. Supplemental vitamin C use above recommended daily intake levels was associated with higher odds of daytime urinary storage symptoms in women, and this finding is worthy of further attention and confirmation in future clinical trials.