Restricted cubic splines for modeling the relationship between sleep and sarcopenia

Objective To explore the dose-response relationship between sleep and sarcopenia in elderly patients.Methods From December 2017 to December 2018, elderly people over 60 years old were randomly selected from a medical examination center in Urumqi for relevant investigation. The Pittsburgh Sleep Quality Index(PSQI) was used to investigate sleep information, and sarcopenia was diagnosed using Asian criteria. The relationship between sleep and sarcopenia was modelled by restricted cubic splines.Results A total of 1 391 subjects were included in the study. According to univariate analysis, the effects of sleep quality and sleep duration on sarcopenia were different in the total population and different subgroups(men, women, age <70 years and age ≥70 years)(P<0.05). Restricted cubic splines showed a nonlinear dose-response relationship between sleep quality and sleep duration and the risk of sarcopenia in both the total population and subgroups(P<0.001). For the total population and different subgroups(except men), when PSQI score was≤5 and ≥13, the higher PSQI score was, the higher the risk was; when PSQI score was between 5 and 13, the risk almost no longer increased along with the increase of PSQI score. For the total population and different subgroups(except men), when sleep time≤7 h, the longer the sleep time was, the lower the risk of disease was; when sleep time >7 h, the longer the sleep time was, the higher the risk was in the total population and those older than 70 years, whereas the risk in women almost no longer increased with the increase of sleep duration.Conclusions For elderly people, there is a non-linear dose-response relationship between sleep quality and sleep duration, and the risk of sarcopenia. Both short and long sleep periods may casue an increased risk of sarcopenia.