TABLE 1.

Estimates of ordinary least square (OLS) coefficients examining sibling effects on body mass index (BMI) and lifestyle factors

	Sibling status and BMI					Sibling status and lifestyle factors
First-wave single children	BMI					Screen time		Fast food
Dependent variable	%	Wave II	Wave III	Wave IV	Wave V	Wave II	Wave III	Wave II	Wave III
Birth order (Ref: single-child)	17.6%
First born	33.0%	−0.07 [0.04]	−0.07 [0.04]	−0.14** [0.05]	−0.14** [0.05]	−1.42** [0.46]	−1.5** [0.53]	−0.28* [0.13]	−0.34 [0.16]
Middle born	18.9%	−0.11* [0.04]	−0.11* [0.05]	−0.21** [0.06]	−0.18** [0.06]	−1.90** [0.54]	−1.45* [0.58]	−0.17 [0.16]	−0.24 [0.18]
Last born	30.6%	−0.02 [0.04]	−0.04 [0.05]	−0.07 [0.06]	−0.09 [0.06]	−0.48 [0.49]	−0.11 [0.51]	−0.07 [0.13]	−0.06 [0.18]
	Sibling status and BMI					Sibling status and lifestyle factors
Fifth-wave single children	BMI					Screen time		Fast food
Dependent variable	%	Wave II	Wave III	Wave IV	Wave V	Wave II	Wave III	Wave II	Wave III
Sibship size (Ref: single-child)	4.3%
One sibling	27.4%	−0.17* [0.07]	−0.28** [0.10]	−0.18* [0.09]	−0.17* [0.08]	−0.21 [0.79]	0.40 [0.90]	−0.48* [0.20]	−0.31 [0.34]
Two siblings	28.2%	−0.20** [0.06]	−0.28** [0.09]	−0.25** [0.09]	−0.22** [0.08]	−0.39 [0.78]	0.28 [0.89]	−0.56* [0.22]	−0.06 [0.33]
Three or more siblings	40.2%	−0.16** [0.06]	−0.24** [0.08]	−0.21* [0.08]	−0.18* [0.08]	−0.31 [0.75]	0.74 [0.91]	−0.47* [0.22]	−0.34 [0.32]

Note: BMI = kg/m²; estimates are OLS coefficients with SEs in brackets. The covariates include age, gender, race/ethnicity, Special Education status, family income, family structure, and financial distress fromWave I.

^*p < 0.05.

^**p < 0.01.