Data were collected on years of full time education, occupation, personal and family history, tobacco and alcohol consumption, drug intake, and physical activity. Cumulative tobacco consumption was quantified as pack years. Pack years were calculated by multiplying the number of packs (defined as 20 manufactured cigarettes) of cigarettes smoked a day by the number of years the person had smoked. A questionnaire on personal medical history and the London School of Hygiene & Tropical Medicine Cardiovascular (Rose) Questionnaire for Chest Pain on Effort and Possible Infarction26 were also completed. The Rose questionnaire is a standardised and validated questionnaire that evaluates the usual characteristics of chest pain and discomfort. When a participant responded negatively to the first two questions (chest pain and discomfort), the rest were skipped. If the individual answered positively, the occurrence of chest pain at rest or on exertion, the intensity, location, and duration of the chest pain or discomfort were then documented.
