Socio-demographic and lifestyle factors for child’s physical growth and adiposity rebound of Japanese children: a longitudinal study of the 21st century longitudinal survey in newborns

Table 5 The generalized estimating equation (GEE) of BMI for six-year surveys retaining significant exploratory factors

Variable	Category	Estimate	95% confidence interval		P value	P value in type 3 effect analysis^‡
BMI^† at baseline survey		0.151	0.141	0.161	<.01*	<.01*
Age		-0.263	-0.268	-0.258	<.01*	<.01*
Overweight at age 5 ½ years		1.742	1.710	1.775	<.01*	<.01*
(Base category; < 85^th percentile)
Gender (base category; boy)	Girl	-0.160	-0.181	-0.139	<.01*	<.01*
Gestational period	< 22–36 weeks	0.160	0.106	0.214	<.01*	<.01*
(Base category; < 37–41 weeks)	≥ 42 weeks	-0.144	-0.262	-0.003	<.01*
Main parental care provider at age 6 months	Father	-0.107	-0.389	0.175	.46	<.01*
(Base category; mother)	Grandmother	0.024	-0.038	0.087	.44
	Grandfather	0.013	-0.321	0.347	.94
	Others	0.122	0.063	0.181	<.01*
Main parental care provider across the surveys	Father	-0.039	-0.186	0.108	.60	<.01*
(Base category; mother)	Grandmother	-0.055	-0.100	-0.010	.02*
	Grandfather	0.108	-0.053	0.268	.19
	Others	0.087	0.071	0.102	<.01*
Wake-up time (base time; 0 am)		-0.044	-0.062	-0.026	<.01*	<.01*
Video game playing	< 1 hour	0.014	-0.010	0.037	.25	.02*
	1 hour -	0.068	0.029	0.107	<.01*
	2 hour -	0.009	-0.104	0.122	.88
	3 hour -	-0.020	-0.265	0.225	.87
Snack at age 4 ½ years	Eating irregularly	-0.047	-0.083	-0.010	.01*	.03*
(Base category; eating regularly)	Don’t eat	-0.044	-0.148	0.059	.40

*Statistically significant at the level of P < .05.
^†BMI: body mass index.
^‡Type 3 effect test is based on an asymptotic chi-square distribution of the likelihood ratio statistic computed from GEE models and it allows one to test for an effect of interest provided all the other variables are included in the GEE model.

ISSN: 1471-2458