title: Association between combined lifestyle factors and non-restorative sleep in Japan: a cross-sectional study based on a Japanese health database.
abstract: BACKGROUND
  Although lifestyle factors such as cigarette smoking, excessive drinking, obesity, low or no exercise, and unhealthy dietary habits have each been associated with inadequate sleep, little is known about their combined effect. The aim of this study was to quantify the overall impact of lifestyle-related factors on non-restorative sleep in the general Japanese population.
  
  
  RESULTS
  A cross-sectional study of 243,767 participants (men, 39.8%) was performed using the Specific Health Check and Guidance System in Japan. A healthy lifestyle score was calculated by adding up the number of low-risk lifestyle factors for each participant. Low risk was defined as (1) not smoking, (2) body mass index<25 kg/m², (3) moderate or less alcohol consumption, (4) regular exercise, and (5) better eating patterns. Logistic regression analysis was used to examine the relationship between the score and the prevalence of non-restorative sleep, which was determined from questionnaire responses. Among 97,062 men (mean age, 63.9 years) and 146,705 women (mean age, 63.7 years), 18,678 (19.2%) and 38,539 (26.3%) reported non-restorative sleep, respectively. The prevalence of non-restorative sleep decreased with age for both sexes. Compared to participants with a healthy lifestyle score of 5 (most healthy), those with a score of 0 (least healthy) had a higher prevalence of non-restorative sleep (odds ratio, 1.59 [95% confidence interval, 1.29-1.97] for men and 2.88 [1.74-4.76] for women), independently of hypertension, hypercholesterolemia, diabetes, and chronic kidney disease. The main limitation of the study was the cross-sectional design, which limited causal inferences for the identified associations.
  
  
  CONCLUSIONS
  A combination of several unhealthy lifestyle factors was associated with non-restorative sleep among the general Japanese population. Further studies are needed to establish whether general lifestyle modification improves restorative sleep.
authors.affiliation: Center for Inter-organ Communication Research, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Wakasugi
authors.affiliation: Department of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Junichiro James
authors.initials: JJ
authors.lastname: Kazama
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Ichiei
authors.initials: I
authors.lastname: Narita
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Iseki
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Moriyama
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Yamagata
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Shouichi
authors.initials: S
authors.lastname: Fujimoto
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tsuruya
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Asahi
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Konta
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Masahide
authors.initials: M
authors.lastname: Kondo
authors.affiliation: iAnalysis LLC, Tokyo, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Kurahashi
authors.affiliation: Department of Integrated Science and Engineering for Sustainable Society, Chuo University, Tokyo, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohashi
authors.affiliation: Steering Committee for "Design of the comprehensive health care system for chronic kidney disease (CKD) based on the individual risk assessment by Specific Health Checkups," Fukushima, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015444:Exercise; D005247:Feeding Behavior; D005260:Female; D015438:Health Behavior; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D012892:Sleep Deprivation / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D012907:Smoking / Q000009:adverse effects