Table 1 Characteristics of samples included in the MINERvA cohort

Sex^a (%)

Male

52.0

49.8

0.933

Birth year^a (%)

1998

31.8

30.6

1999

28.3

29

2000

7

6.78

2001

13.7

14.2

2002

19.2

19.4

Gestational age^b (mean (sd))

Weeks

39.6 (1.82)

39.6 (1.72)

0.96

Urbanicity^b (%)

1: Capital

18.1

17

2: Suburb of the capital

14.9

13.4

3: Municipalities having a town with more than 100,000 inhabitants

8.27

8.68

4: Municipalities having a town with between 10,000 and 100,000 inhabitants

27.3

29.2

5: Other municipalities in Denmark (largest town has less than 10,000 inhabitants)

31.3

31.7

Time to sampling (mean (sd))

Days

6.01 (3.15)

6.15 (3.33)

0.46

Maternal age (mean (sd))

Years

29.2 (4.94)

29.7 (4.57)

0.07

Paternal age (mean (sd))

Years

32.1 (6.04)

31.9 (5.40)

0.476

Maternal smoking during pregnancy (%)

Smoke at any time

29.0

21.2

Non-smoker

71.0

78.8

Maternal smoking amount during pregnancy (%)

5 or less cigarettes per day

6.46

7.25

6–10 cigarettes per day

11.2

7.59

11–20 cigarettes per day

9.6

5.06

21 or more cigarettes per day

1.05

1.18

Birth weight (mean (sd))

Grams

3512 (581)

3541 (542)

0.355