Table 2.

Demographic Comparison Between Case Populations Defined via Different Data Sources, UK Biobank, 2006–2010^a

	Data Source						P for Difference Between Self-Reported and Hospital Data
	Hospital Data (n = 9,272)		Primary-Care Data (n = 1,441)		Self-Reported (n = 13,727)
Variable	%	Mean (SD)	%	Mean (SD)	%	Mean (SD)
Female sex	45.7		54.0		58.3		<0.0001
Age, years		60.3 (7.2)		60.1 (7.2)		59.7 (7.4)	<0.0001
White race/ethnicity	96.5		97.3		96.0		0.051
Assessment center
Wales	3.9		14.1		4.9		0.0003
Scotland	7.0		11.7		5.8		0.0002
London	11.4		5.3		11.7		0.486
Not working (retired or unemployed)	60.4		61.1		59.9		0.448
Higher educationb	52.7		52.4		53		0.655
Current smoker	12.2		12.3		12.4		0.652
Work history
Heavy manual workc	6.5		6.4		5.9		0.063
Shift workd	4.6		4.4		4.5		0.721
Townsend deprivation index		−0.89 (3.31)		−1.07 (3.17)		−0.93 (3.27)	0.365
Owning one’s house outright	56.8		57.5		55.0		0.007
>1 car in household	40.7		41.2		42.4		0.010
Body mass indexe		29.4 (5.6)		29.2 (5.6)		29.2 (5.7)	0.009

Abbreviation: SD, standard deviation.

^a A larger version of this table can be seen as Web Table 11. P values are reported for independent sample t tests for continuous variables and χ² tests of proportions for binary variables.

^b Answered >18 years to the question, "At what age did you complete your continuous full time education?" or selected "college or university degree" as a response to the question, "Which of the following qualifications do you have?".

^c Answered “usually” or “always” to the question, “Does your work involve heavy manual or physical work?”.

^d Answered “usually” or “always” to the question, “Does your work involve shift work?”.

^e Weight (kg)/height (m)².