Pre-diagnostic dietary consumption of calcium and magnesium and calcium-to-magnesium intake ratio and ovarian cancer mortality: results from the ovarian cancer follow-up study (OOPS).

ABSTRACT

PURPOSE: Previous studies have indicated that dietary consumption of calcium (Ca), magnesium (Mg), and the Ca-to-Mg (CaMg) ratio were associated with different health outcomes. However, no study has evaluated the association of pre-diagnostic Ca, Mg, and CaMg ratio consumption with ovarian cancer (OC) survival. METHODS: The aforementioned associations were investigated in a cohort of 853 Chinese women diagnosed with OC between 2015 and 2020. A validated food frequency questionnaire was used to evaluate pre-diagnostic diet information. Deaths were recorded until March 31, 2021 via medical records and active follow-up. Cox proportional hazards model was applied to calculate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: A total of 130 deaths were observed during a median follow-up of 37.2 months. After adjustment for potential confounders, pre-diagnostic Ca (HR< 600 vs. > 1000 = 1.45, 95% CI = 0.47-4.46, p for trend = 0.69) and Mg (HR< 250 vs. > 330 = 0.90, 95% CI = 0.39-2.08, p for trend = 0.77) intakes were found to be unrelated to OC survival, whereas a higher CaMg intake ratio was significantly associated with worse survival (HR< 1.7 vs. > 2.5 = 2.72, 95% CI = 1.28-5.78, p for trend < 0.05). A significant result was also observed when treating the CaMg ratio as a continuous variable (HR = 1.69, 95% CI = 1.12-2.55) for one-unit increment. CONCLUSION: Pre-diagnostic consumption of Ca and Mg was unrelated to OC survival, while a higher CaMg intake ratio was strongly associated with worse survival among OC patients.