SmokingDefinition (STATA Implementation) is an algorithm to define smoking status, length of smoking cessation and amount smoked in a cohort of patients from the UK Clinical Practice Research Datalink (CPRD). Overview The smoking status algorithm takes smoking data from various sources within CPRD and outputs three variables: a time-varying smoking status (never, former, current) the duration of cessation (in years, restarting at 0 whenever a new period of cessation begins) the amount smoked (not time varying, single status: 'light' smoker vs heavy smoker, defined based on the highest category recorded within a fixed window of an index date... missing<light<heavy). Requirements Software The files were created using Stata 12.1. Data Standard CPRD datasets saved in STATA format.

Funding: Supported by the Arthritis Research UK Centre for Epidemiology (grant 20380) and the National Institute for Health Research Biomedical Research Unit Funding Scheme. Contributions: Rebecca M. Joseph (designed & implemented the code), Mohammad Movahedi (tested code components), William G Dixon (funding/supervision), Deborah P. M. Symmons (funding/supervision)