Background: Lung cancer is the leading cause of cancer death. Little is known about whether prediagnostic nutritional factors may affect survival. We examined the associations of prediagnostic calcium intake from foods and/or supplements with lung cancer survival. Methods: The present analysis included 23,882 incident, primary lung cancer patients from 12 prospective cohort studies. Dietary calcium intake was assessed using food-frequency questionnaires at baseline in each cohort and standardized to caloric intake of 2000 kcal/d for women and 2500 kcal/d for men. Stratified, multivariable-adjusted Cox regression was applied to compute hazard ratios (HRs) and 95% confidence intervals (CIs). Results: The 5-year survival rates were 56%, 21%, and 5.7% for localized, regional, and distant stage lung cancer. Low prediagnostic dietary calcium intake (<500-600 mg/d, less than half of the recommendation), was associated with a small increase in risk of death compared with recommended calcium intakes (800-1200 mg/d); HR (95% CI) was 1.07 (1.01, 1.13) after adjusting for age, stage, histology, grade, smoking status, pack-years, and other potential prognostic factors. The association between low calcium intake and higher lung cancer mortality was evident primarily among localized/regional stage patients, with HR (95% CI) of 1.15 (1.04, 1.27). No association was found for supplemental calcium with survival in the multivariable-adjusted model. Conclusions: This large pooled analysis is the first, to our knowledge, to indicate that low prediagnostic dietary calcium intake may be associated with poorer survival among early-stage lung cancer patients. Impact: This multinational prospective study linked low calcium intake to lung cancer prognosis.
- Received October 27, 2016.
- Revision received February 24, 2017.
- Accepted February 24, 2017.
- Copyright ©2017, American Association for Cancer Research.