Table 1 Demographic characteristics for questionnaire and time-use diary samples at 2, 4, and 6 months of age

Infant age (days)

66.58(5.79)

127.39(8.10)

186.40(7.14)

67.09(5.62)

126.49(7.22)^c

185.29(5.51)^c

Infant sex

 Male

109(43.6)

-

-

41(43.6)

-

-

 Female

141(56.4)

-

-

53(56.4)

-

-

Infant race/ethnicity

 Caucasian

132(52.8)

-

-

59(62.8)

-

-

 Other

118(47.2)

-

-

35(37.2)

-

-

Number of siblings

 Zero

116(46.4)

-

-

53(56.4)

-

-

 One

98(39.2)

-

-

31(33.0)

-

-

 Two or more

36(14.4)

-

-

10(10.6)

-

-

 Non-parental care (hours)

1.95(10.10)

2.43(7.26)

2.67(6.65)

1.14(3.35)

1.69(3.90)^c

2.07(4.51)^c

 Parental age (years)

32.62(5.03)^a

32.56(4.85)^b

32.69(4.78)^b

32.29(4.22)

32.44(4.15)^d

32.52(4.00)^d

Parental marital status

 Married or living common-law

241(96.4)

-

-

90(95.7)

-

-

 Not married or living common-law

9(3.6)

-

-

4(4.3)

-

-

Parental education

 Above bachelor’s degree

62(24.8)

-

-

25(26.6)

-

-

 A bachelor’s degree

98(39.2)

-

-

41(43.6)

-

-

 Below a bachelor’s degree

90(36.0)

-

-

28(29.8)

-

-

Parental country of birth

 Canada

173(69.2)

-

-

75(79.8)

-

-

 Other country

77(30.8)

-

-

19(20.2)

-

-