Comparison of Sociodemographic and Health-Related Characteristics of UK Biobank Participants With Those of the General Population

Abstract

The UK Biobank cohort is a population-based cohort of 500,000 participants recruited in the United Kingdom (UK) between 2006 and 2010. Approximately 9.2 million individuals aged 40-69 years who lived within 25 miles (40 km) of one of 22 assessment centers in England, Wales, and Scotland were invited to enter the cohort, and 5.5% participated in the baseline assessment. The representativeness of the UK Biobank cohort was investigated by comparing demographic characteristics between nonresponders and responders. Sociodemographic, physical, lifestyle, and health-related characteristics of the cohort were compared with nationally representative data sources. UK Biobank participants were more likely to be older, to be female, and to live in less socioeconomically deprived areas than nonparticipants. Compared with the general population, participants were less likely to be obese, to smoke, and to drink alcohol on a daily basis and had fewer self-reported health conditions. At age 70-74 years, rates of all-cause mortality and total cancer incidence were 46.2% and 11.8% lower, respectively, in men and 55.5% and 18.1% lower, respectively, in women than in the general population of the same age. UK Biobank is not representative of the sampling population; there is evidence of a "healthy volunteer" selection bias. Nonetheless, valid assessment of exposure-disease relationships may be widely generalizable and does not require participants to be representative of the population at large.

Keywords: UK Biobank; cancer; lifestyle; mortality; representativeness; sociodemographic characteristics.

Figure 1.

Rate of participation in the UK Biobank according to sex (A), age at recruitment (B), Townsend deprivation score (C), and region of residence (D), 2006–2010. For numerators and denominators, see Web Table 1. Participants were assigned a Townsend deprivation score corresponding to the output area of their residential postcode (most deprived: ≥2.00; average: −2.00 to 1.99; least deprived: <−2.00). UK, United Kingdom.

Figure 2.

Comparison of smoking status in UK Biobank participants (recruited in 2006–2010) with data from the Health Survey for England (HSE) 2008 for men aged 45–54 years (A), women aged 45–54 years (B), men aged 55–64 years (C), and women aged 55–64 years (D). HSE estimates were weighted for nonresponse bias. The graph excludes 1,899 UK Biobank participants aged 45–64 years who had missing data on smoking status or responded “prefer not to answer.” Numbers of participants: A) UK Biobank, n = 62,004; HSE, n = 1,206; B) UK Biobank, n = 79,755; HSE, n = 1,233; C) UK Biobank, n = 94,907; HSE, n = 1,085; D) UK Biobank, n = 116,246; HSE, n = 1,123. See HSE 2010 (9) for further information about HSE data. UK, United Kingdom.

Figure 3.

Comparison of mortality rates per 1,000 person-years, by age at death, for UK Biobank participants (recruited in 2006–2010) and the population of England and Wales in 2012 (data from the Office for National Statistics) for men (A) and women (B). Total number of deaths in UK Biobank participants aged 45–74 years: men, 8,291; women, 5,380. See United Kingdom Office for National Statistics (13) for further information about death registration data. UK, United Kingdom.

Figure 4.

Comparison of incidence rates for all cancers (excluding nonmelanoma skin cancer) per 100,000 person-years, by age at cancer diagnosis, for UK Biobank participants (recruited in 2006–2010) and the population of England in 2012 (data from the Office for National Statistics) for men (A) and women (B). Total number of all incident cancers (excluding nonmelanoma skin cancer) in UK Biobank participants aged 45–74 years: men, 11,436; women, 10,592. See United Kingdom Office for National Statistics (14) for further information about cancer registration data. UK, United Kingdom.