Association between dietary calcium and vitamin D intake and cervical carcinogenesis among Japanese women

Background/Objectives: To examine the association between dietary calcium and vitamin D intake and cervical neoplasia risk, we conducted a case-control study. Subjects/Methods: We selected 405 incident cervical neoplasias (333 invasive carcinomas and 72 cervical intraepithelial neoplasias grade III (CIN3)) and 2025 age-matched non-cancer controls. Dietary information was collected using a semiquantitative food-frequency questionnaire (FFQ). The effect on cervical neoplasia risk was evaluated using conditional logistic regression models. Results: The inverse association between invasive carcinoma and milk, yogurt and fish was observed. On the other hand, the marginally significant inverse association between CIN3 and tofu and green leafy vegetables was observed. Compared with the lowest quartile (Q1) of calcium intake, adjusted odds ratios (ORs) for each of the three upper quartiles (Q2, Q3 and Q4) on invasive carcinoma risk were 0.86 (95% confidence interval (CI) 0.63-1.17), 0.50 (95% CI 0.34-0.73) and 0.68 (95% CI 0.48-0.97), respectively (P for trend0.004). However, no association between calcium and cancer risk was evident among CIN3 cases (P for trend0.528). Vitamin D intake showed a similar inverse association (Q2: OR 1.03, 95% CI 0.74-1.44; Q3: OR 0.80, 95% CI 0.56-1.15; and Q4: OR 0.64, 95% CI 0.43-0.94; P for trend0.013). Similar to calcium, no association between vitamin D intake among CIN3 was evident (P for trend0.109). An inverse association with calcium was evident in women whose vitamin D intake was low. However, this combined effect was not significant (invasive carcinoma: interaction P0.819; and CIN3: interaction P0.101). Conclusion: We found an inverse association between dietary calcium and vitamin D intake and cervical neoplasia risk among a group of Japanese women.