Table 2.

Demographic characteristics of the TIDES study population ($N=780$).

Demographic characteristics	$n$ (%) or mean (SD)
Study center
University of California, San Francisco	187 (24)
University of Minnesota	209 (27)
University of Rochester Medical Center	221 (28)
University of Washington	163 (21)
Maternal age (y)	30.5 (5.56)
Missing	2
Maternal race
White	532 (68)
Black	101 (13)
Othera	145 (19)
Missing	2
Maternal education level
High school or less	109 (14)
Any technical school/college	335 (43)
Graduate work	327 (42)
Missing	9
Prepregnancy BMI (kg/m2)	25.7 (6.37)
Missing	11
Ever smoked during pregnancy
No	643 (92)
Yes	57 (8)
Missing	80
Child sex
Female	398 (51)
Male	382 (49)

Note: BMI, body mass index; TIDES, The Infant Development and the Environment Study; SD, standard deviation.

^a Other includes Asian ($n=50$), American Indian or Alaska Native ($n=5$), Native Hawaiian or Pacific Islander ($n=4$), multiracial ($\mathrm{n}=30$), Other ($n=44$), and Unknown ($n=12$).