Table 1

Descriptive characteristics of the sample (n=412 299)

	Males		Females		All
	n	%	n	%	n	%
Total	195 131	47.3	217 168	52.7	412 299	100.0
Age at baseline (years) *
38–44	20 476	10.5	23 892	11.0	44 368	10.8
45–49	25 246	12.9	31 543	14.5	56 789	13.8
50–54	28 821	14.8	36 394	16.8	65 215	15.8
55–59	34 774	17.8	40 910	18.8	75 684	18.4
60–64	46 955	24.1	50 174	23.1	97 129	23.6
65–73	38 859	19.9	34 255	15.8	73 114	17.7
Ethnic group
White British	175 294	89.8	193 220	89.0	368 514	89.4
Other White	10 855	5.6	13 903	6.4	24 758	6.0
South Asian	3835	2.0	2870	1.3	6705	1.6
Black	2403	1.2	3306	1.5	5709	1.4
Chinese	450	0.2	720	0.3	1170	0.3
Mixed	891	0.5	1448	0.7	2339	0.6
Other	1403	0.7	1701	0.8	3104	0.8
Highest qualification †
College or university degree	70 136	35.9	74 613	34.4	144 749	35.1
A levels or equivalent	20 898	10.7	27 183	12.5	48 081	11.7
GCSEs or equivalent	36 862	18.9	51 055	23.5	87 917	21.3
CSEs or equivalent	10 560	5.4	11 730	5.4	22 290	5.4
NVQ or HND or HNC or equivalent	17 732	9.1	9607	4.4	27 339	6.6
Other professional qualifications	8560	4.4	12 375	5.7	20 935	5.1
No qualifications	30 383	15.6	30 605	14.1	60 988	14.8
Occupational class ‡
Higher managerial and professional	48 981	25.1	25 058	11.5	74 039	18.0
Lower managerial and professional	34 686	17.8	54 458	25.1	89 144	21.6
Intermediate occupations	14 933	7.7	36 723	16.9	51 656	12.5
Small employers and own accounts	9345	4.8	4958	2.3	14 303	3.5
Lower supervisory and technical	10 702	5.5	1019	0.5	11 721	2.8
Semiroutine occupations	10 986	5.6	20 181	9.3	31 167	7.6
Routine occupations	10 162	5.2	5365	2.5	15 527	3.8
Not classified	55 336	28.4	69 406	32.0	124 742	30.3
Household income (before tax)
Less than £18 000	39 184	20.1	52 863	24.3	92 047	22.3
£18 000–£30 999	47 701	24.5	57 347	26.4	105 048	25.5
£31 000–£51 999	52 674	27.0	55 578	25.6	108 252	26.3
£52 000–£100 000	43 674	22.4	40 867	18.8	84 541	20.5
Greater than £100 000	11 898	6.1	10 513	4.8	22 411	5.4
Household size
1	33 345	17.1	45 334	20.9	78 679	19.1
2	90 130	46.2	98 297	45.3	188 427	45.7
3	30 803	15.8	33 989	15.7	64 792	15.7
4	29 408	15.1	28 809	13.3	58 217	14.1
5+	11 445	5.9	10 739	4.9	22 184	5.4
Number of cars per household
0	14 877	7.6	19 055	8.8	33 932	8.2
1	77 536	39.7	95 160	43.8	172 696	41.9
2	79 161	40.6	79 599	36.7	158 760	38.5
3	17 829	9.1	17 994	8.3	35 823	8.7
4+	5728	2.9	5360	2.5	11 088	2.7
Region§
London	25 333	13.0	30 273	13.9	55 606	13.5
South-East England	17 007	8.7	19 402	8.9	36 409	8.8
South-West England	16 764	8.6	19 613	9.0	36 377	8.8
East Midlands	13 120	6.7	14 559	6.7	27 679	6.7
West Midlands	18 383	9.4	18 020	8.3	36 403	8.8
Yorkshire and the Humber	29 615	15.2	32 479	15.0	62 094	15.1
North-East England	23 110	11.8	25 606	11.8	48 716	11.8
North-West England	29 599	15.2	31 717	14.6	61 316	14.9
Wales	8265	4.2	9048	4.2	17 313	4.2
Scotland	13 935	7.1	16 451	7.6	30 386	7.4
Urban residence	167 547	85.9	186 617	85.9	354 164	85.9
Townsend score (mean, SD)¶	−1.37	3.1	−1.37	3.0	−1.37	3.0

*Continuous variable in models
†A levels: academic advanced levels, postcompulsory education. GCSE: academic General Certificate of Secondary Education, formerly ordinary levels, taken at ages 15–16 years and the end of compulsory education. CSE: vocational Certificate of Secondary Education, formerly taken at ages 15–16 years. NVQ, HND, HNC: National Vocational Qualifications, Higher National Diploma, Higher National Certificate, all intermediate semivocational qualifications.
‡Based on National Statistics Socio-economic Classification (NS-SEC), where not classified=those who were retired, unemployed, looking after home/family, unable to work because of sickness/disability, doing unpaid/voluntary work, or full-time students.
§Grouped based on assessment centre: London=St Barts, Croydon, Hounslow; South-East England=Oxford, Reading; South-West England=Bristol; East Midlands=Nottingham; West Midlands=Birmingham; Yorkshire and the Humber=Leeds, Sheffield; North-East England=Middlesbrough, Newcastle; North-West England=Liverpool, Manchester, Bury; Wales=Cardiff, Swansea, Wrexham; Scotland=Glasgow, Edinburgh.
¶Lower score=less deprived (min: −6.3; max: 11.0).