Association of Vitamin D Status With Total and Site-Specific Cancer Mortality From Tropical to Subantarctic Latitudes: A Nationwide Population-Based Study in Chile.

BACKGROUND: An association of low vitamin D (VD) status with increased cancer mortality has been described, and Chile provides an ideal setting to evaluate this association given its extensive latitude span (17°S-56°S). METHODS: We performed a nationwide population-based ecological study of all and specific cancer deaths from 2002 to 2020, in which mean 25(OH)D concentrations were obtained from the 2017 Chilean National Health Survey and associations with cancer deaths were assessed across 48 provinces. Multiple regression models including body mass index and tobacco use were performed to account for other carcinogenic factors. RESULTS: For the studied period, 446,237 cancer-associated deaths were reported. Provincial mean 25(OH)D ranged between 11.8 and 25.8 ng/mL, displaying a significant north-south decreasing gradient, and provincial mean 25(OH)D concentrations were inversely correlated with age-standardized death rates for multiple cancer types, being strongest for breast, kidney, and liver cancer. Multiple regression models revealed significant inverse associations for 21 of the 27 cancer types analyzed, being strongest for endometrial, thyroid, colorectal, liver, kidney, and larynx cancer. CONCLUSIONS: Significant inverse associations between 25(OH)D concentrations and multiple cancer-type mortality were found across Chile, confirming the association of low VD status with colorectal and breast cancer mortality, while providing novel ecological evidence of an inverse association between 25(OH)D concentrations and several cancer types for which a relationship with VD has been less established. These findings should inform public policies regarding cancer screening and treatment across different latitudes, and prompt evaluation of VD supplementation and fortification for reduction of site-specific cancer mortality.