Table 1

Characteristics (%) of the study population by maternal educational qualification at birth (N=7487)

%	Degree plus	Diploma	A levels	GCSE A–C	GCSE D–G	None	Total
Asthma
None	79.0	78.8	77.7	75.7	70.7	72.7	76.8
Transient	8.2	7.3	8.0	8.5	10.4	6.9	8.0
Persistent	12.8	13.9	14.3	15.8	18.9	20.3	15.2
Child’s sex
Boys	48.5	50.7	48.5	46.8	50.7	50.4	49.3
Girls	51.5	49.3	51.5	53.2	49.3	49.6	50.7
Maternal age at birth
≥25 years	97.8	93.1	74.6	75.7	60.5	63.6	84.3
14–24 years	2.2	6.9	25.4	24.3	39.5	36.4	15.7
Maternal ethnicity
White	89.0	93.4	93.5	94.0	92.2	71.9	92.2
Mixed	0.9	0.6	0.5	0.4	0.6	1.1	0.6
Indian	4.1	1.8	1.0	1.0	1.1	2.7	1.8
Pakistani	2.0	1.2	2.9	2.8	5.4	16.6	2.7
Black	2.2	1.9	1.3	1.3	0.8	4.5	1.7
Other	1.7	1.1	0.4	0.4	0.1	3.2	1.0
Maternal atopy
None	75.1	69.9	69.6	69.7	67.8	73.2	70.3
Eczema or asthma	19.8	24.5	23.0	24.1	24.2	20.9	23.5
Both	4.3	5.9	7.5	7.0	11.4	5.8	6.7
Maternal pre-pregnancy body mass index
Healthy weight	71.0	61.5	53.9	52.8	51.0	46.2	58.2
Underweight	2.8	2.7	3.8	3.9	5.6	7.6	3.5
Overweight	18.8	24.8	27.4	27.4	23.8	29.9	25.4
Obese	7.4	11.1	14.9	15.9	19.5	16.3	13.0
Breast fed for at least 3 months
No	59.5	62.4	74.3	78.3	91.4	87.2	69.7
Yes	40.5	37.6	25.7	21.7	8.6	12.8	30.3
Child’s birth weight
Low weight	2.8	4.8	5.7	6.5	5.4	1.2	5.5
Healthy weight	97.2	95.2	94.3	93.5	94.6	88.2	94.5
Gestational age at birth
Not preterm	95.2	93.8	93.5	92.6	94.2	90.0	93.5
Preterm	4.8	6.2	6.5	7.4	5.8	10.1	6.5
Maternal smoking in pregnancy
No	88.0	82.3	67.3	55.5	48.0	46.6	71.7
Yes	12.0	17.7	32.7	44.5	52.0	53.4	28.3
Alcohol consumption during pregnancy
≤1 unit per week	85.4	86.1	90.9	92.1	93.1	92.7	88.7
Any unit per week	14.6	13.9	9.1	7.9	6.9	7.3	11.3
Wheeze at 9 months
No	97.6	96.8	96.9	96.5	96.0	93.3	96.7
Yes	2.4	3.2	3.1	3.5	4.0	6.7	3.3
Damp in the house
No	89.8	89.4	87.5	86.6	79.7	75.8	87.6
Yes	10.2	10.6	12.5	13.4	20.3	24.3	12.5
Tenure
Own outright	8.1	5.1	4.3	3.7	5.2	6.6	5.0
Own mortgage	87.1	84.2	69.2	59.8	34.1	21.2	72.1
Part rent/mortgage	0.2	0.4	1.5	0.6	0.6	0.1	5.9
Local authority	0.5	2.5	10.4	15.7	32.3	40.1	9.2
Housing association	0.1	2.2	6.0	11.0	15.0	19.2	5.7
Privately rented	2.3	4.1	6.0	7.0	10.8	10.9	5.4
Living with parents	1.0	1.0	2.1	1.9	1.4	1.3	1.4
Rent free	0.8	0.6	0.5	0.3	0.6	0.7	0.5
Furry pets
None	59.7	52.2	46.8	42.5	45.5	54.3	49.7
Not furry	7.1	9.3	9.3	10.2	7.4	11.9	9.4
Yes	33.2	38.4	43.9	47.2	47.1	33.8	40.9
Environmental tobacco smoke
No	97.6	93.3	84.8	79.3	67.8	62.8	87.0
Yes	2.4	6.7	15.2	20.7	32.3	37.2	13.0
Garden access
Yes, sole access	94.3	93.7	89.0	87.1	82.3	78.3	90.4
Yes, shared	2.6	2.2	3.0	2.4	4.3	4.0	2.6
No	3.1	4.2	8.0	10.5	13.4	17.7	7.0
Sibling number
0	18.2	24.0	29.3	24.8	22.7	18.0	24.2
1	58.7	53.9	49.1	45.4	41.3	35.0	50.4
2 or more	23.1	22.2	21.6	29.8	36.1	47.0	25.4
Childcare
Informal	62.0	76.7	88.6	91.8	96.7	99.5	82.3
Formal	38.0	23.3	11.4	8.2	3.3	0.5	17.7
Condition of buildings
Good condition	78.6	75.2	59.5	52.1	35.0	22.3	64.2
Fair condition	20.9	23.4	37.6	42.4	56.0	63.5	32.5
Poor condition	0.5	1.3	2.9	5.1	8.8	13.4	3.1
Bad condition	0.1	0.1	0.1	0.5	0.2	0.8	0.2
Volume of traffic
None	3.7	4.7	5.8	4.3	5.8	5.5	4.8
Light	75.6	76.1	75.2	77.2	70.8	72.2	75.8
Moderate	15.8	14.3	14.4	13.9	17.0	16.1	14.5
Heavy	4.9	4.9	4.6	4.6	6.3	6.2	4.9
Litter in the street
None	92.7	90.2	81.4	73.2	58.4	45.3	82.2
Some	7.2	9.3	17.7	24.7	38.2	47.4	16.5
Everywhere	0.1	0.6	0.9	2.1	3.4	7.3	1.3
Good area
Excellent	50.0	44.0	31.6	27.9	17.1	16.0	36.8
Good	38.0	40.8	40.7	39.5	40.1	35.6	40.0
Average	9.9	12.8	20.5	24.0	29.1	31.5	17.6
Poor	2.1	1.9	5.1	5.6	8.0	10.1	3.8
Very poor	0.1	0.6	2.2	3.0	5.7	6.8	1.8

GCSE, General Certificate of Secondary Education .