Liu L, Chen C, Lo K, et al. - Researchers investigated if frailty status has any impact on the links of serum 25(OH)D concentrations with all-cause and cause-specific mortality in the oldest old Chinese. From the Chinese Longitudinal Healthy Longevity Survey, 1,411 participants aged at least 80 were included. At baseline, data regarding serum 25(OH)D level, frailty status and covariates were assessed. During the follow-up survey in 2017-2018, all-cause and cause-specific mortality status were determined using ICD-10 codes. Findings revealed higher risk of all-cause and cause-specific mortality in relation to low serum 25(OH)D levels in the Chinese oldest old, and people with frailty exhibited significantly stronger associations.