# Correlational findings

## 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

Happiness Measure Statistics Elaboration / Remarks O-QOL-cm-sq-v-5-a = + p < .05 T1 sleep duration ≥9h by T2 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
O-QOL-cm-sq-v-5-a = + p < .05 vs 8-9h          OR = 1,15 CI95[1,04-1,25]
vs <8h           OR = 1,25 CI95[1,01-1,54]
OR controlled for
- age
- sexe
- T1 BMI
O-QOL-cm-sq-v-5-a = + p < .05 vs 8-9h          OR = 1,13 CI95[1,03-1,25]
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
O-QOL-cm-sq-v-5-a = -                       T2 happiness
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
O-QOL-cm-sq-v-5-a = - T1-T2 CHANGE          T2 happiness
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
O-QOL-cm-sq-v-5-a = + p < .05 T1-T2 CHANGE sleep duration by T2 happiness

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
O-QOL-cm-sq-v-5-a = + p < .05 T1-T2 CHANGE sleep duration by T2 happiness

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