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

TLDR

The study examined UK Biobank’s representativeness by comparing demographic characteristics of responders and non‑responders. The UK Biobank recruited 500,000 participants aged 40–69 from 22 assessment centers, representing 5.5 % of 9.2 million invited individuals, and compared their sociodemographic, lifestyle, and health characteristics with nationally representative data. UK Biobank participants were older, more often female, less socioeconomically deprived, less obese, less likely to smoke or drink daily, and had fewer health conditions, resulting in 46–55 % lower all‑cause mortality and 11–18 % lower cancer incidence at ages 70–74 compared to the general population, indicating a healthy‑volunteer bias yet still permitting broadly generalizable exposure‑disease analyses.

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.