# 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
Bedtime
Our Classification
Error Estimates
T1-T2 correspondence r=+,24
Remarks
Assessed at T1 and T2 with 3 year difference
Distribution
N= 4:5713(73,3)%;  3: 1465(18,8)%; 2:514(6,6)% ;1:102 (1,3)%
Operationalization
Self report on question on Bedtime:
4: <10 PM (early)
3: 10-10,5 PM
2: 10,5-11PM
1: ≥11PM (late)

## Observed Relation with Happiness

Happiness Measure Statistics Elaboration / Remarks O-QOL-cm-sq-v-5-a = + p < .05 T1 Early bedtime by T2 happiness

vs 10-10,5 PM      OR = 1,11 CI95[0,99-1,25]
vs 10,5-11PM       OR = 1,19 CI95[0,98-1,43]
vs ≥11PM           OR = 1.28 CI95[0,86-1,92]
OR no controls
O-QOL-cm-sq-v-5-a = + p < .05 vs 10-10,5 PM      OR = 1,13 CI95[1,00-1,27]
vs 10,5-11PM       OR = 1,17 CI95[0,96-1,42]
vs ≥11PM           OR = 1,34 CI95[0,88-2,05]
OR controlled for
- age
- sexe
- T1 BMI
O-QOL-cm-sq-v-5-a =                      T2 happiness
T1 bedtime     % happy  % unhappy difference
- <10PM           42,4     57,6     -15,2
- 10-10,5         39,9     60,1      -20,2
- 10,5-11PM       38,4     61,6      -23,2
- ≥11PM           36,5     63,5       -27
O-QOL-cm-sq-v-5-a = + T1-T2 CHANGE bedtime by T2 happiness
%happy  %unhappy difference
- Remained<10PM     49,0    51,0       -2
- <10PMto≥10PM      40,5    59,5       -19
- ≥10PMto<10PM      48,5    51,5       -3
- remined ≥10PM     38,3    61,7      -23,4
O-QOL-cm-sq-v-5-a = + p < .05 T1-T2 CHANGE bedtime by T2 happiness

Remained <10PM
vs <10PM to≥10PM    OR = 1,41 CI95[1,25-1,60]
vs ≥10PM to<10PM    OR = 1,02 CI95[0,76-1,38]
vs remained ≥10PM    OR = 1,55 CI95[1,34-1,78]
OR not controlled
O-QOL-cm-sq-v-5-a = + p < .05 T1-T2 CHANGE bedtime by T2 happiness

Remained <10PM
vs <10PM to≥10PM    OR = 1,41 CI95[1,24-1,61]
vs ≥10PM to<10PM    OR = 1,07 CI95[0,78-1,47]
vs remained ≥10PM    OR = 1,55 CI95[1,34-1,80]
OR controlled for
- age
- sexe
- T1 BMI
O-QOL-cm-sq-v-5-a = + p < .05 T1-T2 CHANGE bedtime by T2 happiness

Remained <10PM
vs <10PM to≥10PM    OR = 1,29 CI95[1,11-1,49]
vs ≥10PM to<10PM    OR = 0,97 CI95[0,68-1,38]
vs remaind ≥10PM    OR = 1,41 CI95[1,19-1,66]
OR controled for
- age
- sexe
- T1 BMI
- Preference for physical activity
- Frequency of physical activity
- Televisoon viewing
- breakfast eating
- Sleep duration
- video gameplaying

T1-T2 difference: 3 years