Sleep time and sleep-related symptoms across two generations – results of the community-based RHINE and RHINESSA studies

Abstract Study Objectives To analyze the association between sleep-related symptoms and sleep length in parents and offspring in relation to other risk factors in both generations. Method The participants were parents (n=5,855, age 54.3 + 6.5 years, 45.2% men) who participated in the community-based RHINE study and one random member of their adult offspring (n=5,855, age 30.2 + 7.7 years, 41.5% men) who participated in the RHINESSA study. Both generations responded to identical questionnaires on sleep symptoms, including difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), early morning awakening (EMA), snoring, nocturnal sweating, nocturnal gastroesophageal reflux (nGER), sleep time and excessive daytime sleepiness (EDS). Insomnia was defined as either, or both, DIS and DMS in combination with EDS. Results All sleep variables except nocturnal sweating were more common in offspring whose parents had reported the same symptom. After adjusting for age, gender, BMI, smoking, physical activity, education, center and having children in offspring, as well as gender, smoking, physical activity, education and total number of children in parents, there were independent associations between sleep symptoms in parents and offspring for DIS (adj. OR, 95% CI: 1.52, 1.20-1.93), DMS (1.34, 1.15-1.56), snoring (1.45, 1.15,1.83), nGER (1.65, 1.15-2.37), insomnia (1.39, 1.13-1.73), short sleep time ( 9h/night). Conclusion The familiar aggregation of many sleep disturbances was not explained by investigated lifestyle and environmental factors. This supports a heritable factor in sleep problems.