Skip to main content

Advertisement

Table 1 Study population characteristics

From: Placental mitochondrial DNA content is associated with childhood intelligence

Parental characteristics(n = 201)
Education
 Low16 (8.0)
 Middle71 (35.3)
 High114 (56.7)
Neighbourhood income, euro18,483 ± 2474
Smoking during pregnancy16 (8.0)
Cigarettes/day during pregnancy1.5 ± 3.7
Urban environment within 5 km, %32 ± 12
Characteristics of twins(n = 375)
Birth 
Birth weight (g)2525 ± 514
Gestational age, weeks36.8 ± 2.3
Birth year1986 ± 2.5
Sex 
 Male–male143 (38.1)
 Female–female131 (34.9)
 Male–female101 (26.9)
Zygosity–chorionicity 
 Dizygotic-dichorionic212 (56.5)
 Monozygotic-dichorionic73 (19.5)
 Monozygotic-monochorionic90 (24.0)
Twins in final study 
 Twin with 1 individual in study27 (7.0)
 Twin with 2 individuals in study348 (93.0)
Childhood 
Age11.5 ± 1.6
Intelligence score (IQ) 
 Total IQ106.0 ± 15.1
 Verbal106.6 ± 14.6
 Performance103.9 ± 15.3
  1. Data presented are mean ± standard deviation or number (percentage)