Serum klotho modifies the associations of 25-hydroxy vitamin D with all-cause and cardiovascular mortality.

Vitamin D-associated mortality risk is observed only with concurrently decreasing klotho, indicating that vitamin D metabolism dysfunction cause the high risk of mortality. Klotho levels could help predict long-term mortality outcomes, thus may be useful concurrently for guiding vitamin D supplementation therapy decision-making in populations with vitamin D deficiency.