Table 1

Sample characteristics
All twins
(n = 692)
Children’s sex
 Boys 48.0%
 Girls 52.0%
Zygosity
 MZ 42.5%
 DZ 57.5%
Children’s age (years)1
 T1 2.65 ± 0.08
 T2 8.97 ± 0.54
Ethnicity (mother)
 White 89.9%
 Non-white 6.4%
 Ethnicity missing 3.8%
Parental education2 – T1
 No high school diploma 10.4%
 High school diploma 7.2%
 College diploma 35.3%
 University diploma 41.9%
 Education missing 5.2%
Annual family income ($Can) – T1
 < 20,000 9.2%
 20,000-39,999 20.2%
 40,000-59,999 22.5%
 ≥ 60,000 41.3%
 Income missing 6.6%

1Mean ± SD.

2Represents the highest educational level for either parent.

Dubois et al.

Dubois et al. International Journal of Behavioral Nutrition and Physical Activity 2013 10:134   doi:10.1186/1479-5868-10-134

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