Objective: to study the impact of social, demographic and behavioral factors on 5-year survival rate in persons older than 75 years living in Moscow and the Moscow region.
Materials and methods: We included in this prospective observational study 283 patients (25% men, age 75-98, mean 86.8±4.3 years) after stay at the Russian gerontological clinical research center. To study social and behavioral factors we recorded anthropometric parameters and used questionnaires. Duration of follow-up was 5 years. Endpoint was death from any cause.
Results: One hundred five patients (37.1%) died during the follow-up (median 3.8 years). Survival analysis using the Kaplan-Meier method revealed a number of parameters that affected 5-year survival: age, defcient and excessive body weight, consumption of less than 1 liter of water per day, start of the night sleep after midnight, nightime sleep duration ≥10 h, level of physical activity and history of blood donation. At multivariate analysis adjusted for age and sex the following factors were independently associated with death during follow-up: weight defciency (hazard ratio [HR] 7.36, 95% confdence interval [CI] 2.15-25.26, p=0.001), second degree obesity (HR 0.47, 95% CI 0.25-0.87, p=0.016), start of night sleep after midnight (HR 2.53, 95% CI 1.32-4.85, p=0.005), nightime sleep duration ≥10 h (HR 3.89, 95% CI 1.77-8.59, p=0.001), and history of blood donation (HR 0.24, 95% CI 0.09-0.62, p=0.003).
Conclusion: In people older than 75 years late sleep initiation and long duration of night sleep, and weight loss increase the risk of death in the next 5 by years, 2.5, 3.9 and 7.4 times, respectively, while overweight and history of blood donation are associated with 53% and 76% reduction of the risk of death.
Keywords: demographic factors; elderly; mortality; predictors; social factors; survival.