A prospective study of plasma ascorbic acid concentrations and breast cancer (United States).

OBJECTIVE

To investigate the association between prediagnostic plasma ascorbic acid concentrations and subsequent breast cancer risk in a nested case-control study.

METHODS

Female volunteer residents of Washington County, MD, donated 14,625 non-fasting blood samples in 1989. Incident breast cancer cases (n = 115) and controls (n = 115) were matched by age, menopausal status at donation, and date and hour of blood donation.

RESULTS

Median ascorbic acid concentrations were similar between cases and controls (1.44 mg/dl vs. 1.39 mg/dl. p = 0.78). There was no evidence for a dose-response relationship between higher plasma ascorbic acid concentrations and breast cancer risk [highest vs. lowest fifths: ORadjusted = 0.90, Ptrend = 0.98).

CONCLUSIONS

Findings from this prospective study do not suggest a protective association between prediagnostic plasma ascorbic acid concentrations and breast cancer risk in the subsequent 5 years of follow-up.