RESUMO
Objective:To investigate the individual and combined effects of calf circumference and vitamin D levels on all-cause mortality risk in community-dwelling older adults based on the Chinese Longitudinal Healthy Longevity Survey.Methods:The calf circumference was measured in the baseline survey in 2012 and 2014.Low calf circumference was defined as <34 cm for men or 33 cm for women at screening.Vitamin D deficiency was defined as plasma 25-hydroxyvitamin D[25(OH)D]levels <50 nmol/L.All participants were followed up until 2018, when death outcomes and survival time were collected.Cox proportional hazard regression models were used to analyze the effects of calf circumference and 25(OH)D levels on the risk of all-cause mortality.Results:A total of 3 052 older adults were included in the analysis, of which 1 960(64.22%)had low calf circumference and 2 245(73.56%)had vitamin D deficiency.After 10 559.9 person-years of follow-up period, 1 312 death events were recorded.After adjusting for sociodemographic characteristics, physical activities, cognitive function, and multiple chronic diseases, calf circumference and 25(OH)D levels were negatively associated with the risk of all-cause mortality(both P<0.05). In the combined analysis, compared with the normal group, the risk of death was highest in the participants with both low calf circumference and vitamin D deficiency, which was higher than those with low calf circumference or vitamin D deficiency alone, with a hazard ratios( HR)(95% CI)of 2.51(1.81-3.45), 1.71(1.22-2.42)and 1.53(1.09-2.15), respectively.There was a significant additive interaction between low calf circumference and vitamin D deficiency on mortality(RERI>0). Conclusions:Low calf circumference and vitamin D deficiency are associated with higher mortality.Older adults with combined conditions had a even higher risk of death.Attention should be paid to joint screening and comprehensive intervention for older adults with both low calf circumference and vitamin D deficiency.