Objectives The UK Biobank study is a sample of 502,682 people aged 40–70, clustered around 22 assessment centres. As part of a project to investigate the causes of COPD and estimate the UK occupational burden, we have assessed the sample’s representativeness with respect to the UK national population, with a view to accounting for potential biases.

Method We have compared characteristics of the Biobank population (age, education, employment, smoking etc) to that of the UK population as estimated from national data sources.

Results Deprivation index scores indicate that Biobank respondents in more affluent wards are over-represented (52% of Biobank respondents versus 28% nationally have scores of less than -2). The Biobank respondents are also better-educated (33% to degree level, 17% nationally), with similar qualification levels in men and women, whereas more men than women nationally in this age range had higher level qualifications. Fewer were currently employed than nationally (58% vs. 65%), particularly men over 60, with more retired (45% vs. 33%), and fewer disabled or unemployed. There are more in managerial and professional (54% vs. 46%), and fewer in routine and manual occupations (22%, 33% nationally), and fewer smokers (33% vs. 49%). Fewer in the already under-represented unskilled occupations (47% vs. 70% for other occupations), or with reported respiratory ill-health (50% vs. 59%) have a usable email address.

Conclusions As Biobank respondents are on average less deprived, better educated and under-represented in unskilled occupations than the national population, estimating national occupational COPD burden, and collecting further data without bias will require data adjustments.