Table 1 Personal characteristics of the study population by country and location of residence

% Female

47.4

50.9

50.9^**

49.8

51.5

51.8

% Mother with > high school

46.9^*

54.1^*

19.2^{*, **}

19.7

41.9

13.0^***

% Father with > high school

38.8^*

45.7^*

13.4_{*, **}

16.3

32.0

6.8^***

Obesity status

 % Not overweight or obese

87.1

87.8

86.8

88.3

85.9

88.2

 % Overweight

11.5

10.7

11.8

10.0

11.2

10.4

 % Obese

1.4

1.5^*

1.5

1.7

3.0

1.5^***

% Any parental history of allergic disease

14.7^*

11.7^*

30.7^{*, **}

8.8

8.0

20.0^***

% Either parent currently smoking

50.1^*

50.9

46.5^{*, **}

57.8

53.4

43.0^***

% Maternal smoking during pregnancy

2.5

0.9

7.0^{*, **}

2.4

1.1

4.4^***

% Using coal or wood for cooking or heating

4.8^*

1.4^*

10.6^{*, **}

28.3

6.8

28.2^***

% Any mold or dampness in the home

30.5

47.9^*

34.2^{*, **}

29.9

55.8

27.5^***

% With a cat

34.6^*

27.9^*

34.4^{*, **}

61.4

64.2

43.9^***

% With a dog

23.7^*

17.2^*

50.2^{*, **}

45.6

54.2

55.1^***

Mean age, years (SD)

10.2 (1.9)

10.4 (1.9)^*

10.2 (1.9)^**

10.2 (1.9)

10.2 (1.9)

10.3 (1.9)