Table 2.

Baseline characteristics of cognitive ability score (n = 48,749). Independent samples t-test for sex, and separate one-way ANOVAs for the remainder of the characteristics were conducted for the comparisons between participant characteristics and cognitive ability score.

Characteristics	N	Cognitive ability score M ± SD	p
Sex			< 0.0001
Male	26,623	0.09 ± 10.03
Female	22,126	− 0.07 ± 0.96
Age			< 0.0001
40–44	4998	0.38 ± 0.90
45–49	5273	0.27 ± 0.87
50–54	5838	0.23 ± 0.91
55–59	6548	0.22 ± 0.87
60–64	8303	0.10 ± 0.90
65+	5368	− 0.10 ± 0.94
BMI			< 0.0001
< 18.5 (underweight)	233	− 0.15 ± 1.00
18.5–25 (normal)	16,179	0.08 ± 0.96
25–30 (overweight)	20,435	− 0.003 ± 1.00
30 + (obese)	11,737	− 0.09 ± 1.02
Townsend deprivation index quantiles			< 0.0001
1 (most affluent)	6970	0.24 ± 0.86
2	8474	0.22 ± 0.87
3	8303	0.19 ± 0.90
4	7538	0.17 ± 0.93
5 (most deprived)	5043	− 0.24 ± 1.09
Employment status			< 0.0001
In paid employment or self-employed	23,008	0.25 ± 0.89
Retired	10,621	0.04 ± 0.91
Looking after home and/or family	1008	0.18 ± 0.91
Unable to work because of sickness or disability	780	− 0.22 ± 1.05
Unemployed	653	0.08 ± 0.99
Doing unpaid or voluntary work	145	0.24 ± 0.82
Full-time or part-time student	113	0.18 ± 1.05
Qualifications			< 0.0001
College or University Degree	14,319	0.41 ± 0.88
A levels/AS levels or equivalent	4895	0.31 ± 0.85
O levels/GCSEs or equivalent	9439	0.07 ± 0.85
CSEs or equivalent	2535	− 0.26 ± 0.85
NVQ or HND or HNC or equivalent	2911	− 0.26 ± 0.94
Other professional qualifications	2229	− 0.12 ± 0.92
Total household income			< 0.0001
Less than 18,000	6345	− 0.16 ± 0.98
18,000–30,999	9380	0.03 ± 0.89
31,000–51,999	10,617	0.24 ± 0.86
52,000–100,000	8109	0.42 ± 0.83
Greater than 100,000	1877	0.57 ± 0.86