Fig. 2
From: Sleep duration and all-cause mortality in the elderly in China: a population-based cohort study
Adjusted dose-response association between sleep duration and risk of all-cause mortality among the elderly population in China, based on model 3. Sleep duration was modeled using a restricted cubic spline function with knots at 25th, 50th, and 75th percentiles of its distribution. The inset showed the HR of all-cause mortality risk based on different knots selection. The reference value was all set at 7 hours