Objective: To examine the effects of dietary supplements on high-risk human papillomavirus (HPV) infection and cervical carcinogenesis.

Methods: A multi-institutional cross-sectional study was carried out to examine whether dietary supplements were associated with the risk of cervical intraepithelial neoplasia (CIN). We enrolled 1096 women aged 18 to 65 years to participate in an HPV cohort study from March 2006 up to present. For this analysis, we included 328 HPV-positive women (166 controls; 90 CIN I and 72 CIN II/III). The details of each participant's routine dietary intake during the prior year were collected. Specific dietary supplements were classified into 5 categories, namely, multivitamins, multinutrients, vitamin C, calcium, and miscellaneous.

Results: A higher HPV viral load was associated with an increased risk of CIN II/III (odds ratio [OR], 3.32; 95% confidence interval [CI], 1.54-7.16; P for trend 0.002). Dietary supplement use including multivitamins (OR, 0.21; 95% CI, 0.09-0.48), vitamins A (OR, 0.19; 95% CI, 0.07-0.53), C (OR, 0.24; 95% CI, 0.10-0.56), E (OR, 0.20; 95% CI, 0.07-0.53), and calcium (OR, 0.21; 95% CI, 0.08-0.50) was significantly associated with a lower risk of CIN II/III. The patients who took multivitamins and had a lower HPV viral load (<15.5 relative light units/positive control) had a significantly decreased frequency of CIN I (OR, 0.35; 95% CI, 0.14-0.87; interaction P = 0.925) and CIN II/III (OR, 0.11; 95% CI, 0.04-0.37; interaction P = 0.304).

Conclusions: The findings of this study suggest that dietary supplements may reduce the risk of CINs in women with high-risk HPV infection.