Sleep quality and its association with postural stability and fear of falling among Spanish postmenopausal women

Objective: To analyze the association of sleep quality with postural balance, as measured with objective stabilometric parameters, and fear of falling (FoF), among Spanish postmenopausal women. Methods: In all, 250 women (60 +/- 8 years) took part in this cross-sectional study. Sociodemographic and anthropometric data were collected, as well as information concerning history of falls and FoF. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale, and the Pittsburgh Sleep Quality Index was used to analyze sleep quality. Measurements of sway area (S), velocity (V), and mediolateral (RMSX) and anteroposterior (RMSY) displacements of the center of pressure were obtained with a resistive multisensor platform under both eyes-open (EO) and eyes-closed (EC) conditions to assess postural control. The independent associations of sleep quality with FoF and postural control were evaluated by multivariate linear and logistic regressions, respectively, adjusting for potential confounding variables. Results: SEO was independently associated (adjusted R-2 = 0.073) with sleep duration (P<0.001) and subjective sleep quality (P = 0.001), VEO (adjusted R-2 = 0.156) with daytime dysfunction (P = 0.006) and sleep duration (P = 0.013), RMSXEO (adjusted R-2 = 0.118) with subjective sleep quality (P = 0.005), and RMSYEO (adjusted R-2 = 0.166) with sleep duration (P = 0.001) and daytime dysfunction (P = 0.046). Under EC condition, SEC (adjusted R-2 = 0.014) was independently related with anxiety (P = 0.034), VEC (adjusted R-2 = 0.148) with daytime dysfunction (P = 0.002) and sleep duration (P = 0.024), RMSXEC (adjusted R-2 = 0.134) with subjective sleep quality (P< 0.001), and RMSYEC (adjusted R-2 = 0.128) with sleep duration (P = 0.013) and daytime dysfunction (P = 0.033). Logistic regression showed that time since menopause (P = 0.003), body mass index (P = 0.001), and anxiety (P< 0.001), unlike sleep quality, were independently associated with FoF. The effect size of the model was medium (adjusted R-2 = 0.162). Conclusions: In Spanish postmenopausal women, sleep duration, subjective sleep quality, and daytime dysfunction were independent risk factors for worsened postural stability. FoF, anxiety, time since menopause onset, and body mass index, unlike sleep quality, were independently associated with poor postural stability.