Study Chen et al. (2005): study JP 1999
- Public
 - 9-10 aged children followed 3 years, Japan 1999-2002
 - Survey name
 - JP-Toyama Birth Cohort Study
 - Sample
 - Respondents
 - N = 7794
 - Non Response
 - 14,4%
 - Assessment
 - Questionnaire: Paper & Pencil Interview (PAPI)
 
Correlate
- Authors's Label
 - Sleep duration
 - Our Classification
 - 
            
 - 
                        
 - Error Estimates
 - T1-T2 correspondence r=+,15
 - Remarks
 - Assessed at T1 and T2 with 3 year difference
 - Distribution
 - N= 3:476(6,1)%; 2: 3702 (47,5)%; 1:3616(46,4)%
 - Operationalization
 - Self report on question on Sleep duration:
3: ≥9h
2: 8-9h
1:<8h 
Observed Relation with Happiness
vs 8-9h OR = 1,15 CI95[1,04-1,25]
vs <8h OR = 1,29 CI95[1,06-1,58]
OR no controls
vs <8h OR = 1,25 CI95[1,01-1,54]
OR controlled for
- age
- sexe
- T1 BMI
vs <8h OR = 1,21 CI95[0,97-1,51]
OR controlled for
- age
- sexe
- T1 BMI
- Preference for physical activity
- Frequency of physical activity
- Television viewing
- Bedtime
- breakfast eating
T1 sleep duration % happy % unhappy difference
- ≥9h 43,5 56,5 -13
- 8-9h 40,3 59,7 -19,4
- <8h 37,3 62,7 -25,4
in sleep duration %happy %unhappy difference
remained <8 38,0 62,0 -24
<8h to ≥8 h 34,3 65,7 -31,4
≥8h to <8 h 38,9 61,1 -22,2
remained ≥8 h 46,8 53,2 -6,4
Remained Sleep duration ≥8 h
vs ≥8h to <8 h OR = 1,38 CI95[1,26-1,52]
vs <8h to ≥8 h OR = 1,69 CI95[1,13-2,53]
vs remained <8 h OR = 1,44 CI95[1,15-1,89]
OR not controlled
Remained Sleep duration ≥8 h
vs ≥8h to <8 h OR = 1,38 CI95[1,26-1,52]
vs <8h to ≥8 h OR = 1,69 CI95[1,13-2,53]
vs remained <8 h OR = 1,44 CI95[1,15-1,84]
OR controlled for
- age
- sexe
- T1 BMI
T1-T2 difference: 3 years