“…Data collection involved the completion of a study questionnaire and participation in a medical examination, both of which have been described in detail elsewhere (Reid et al, 1974). In brief, the questionnaire included enquiries regarding civil service employment grade (our indicator of socioeconomic position) (Marmot et al, 1978), smoking habits (Reid et al, 1976), intermittent claudication (Rose, 1962;Davey Smith et al, 1990), angina (Rose, 1962;Rose et al, 1977b), chronic bronchitis (Committee on the Aetiology of Chronic Bronchitis, 1965) and use of medication, including blood pressure-lowering drugs. Forced expiratory volume in 1 s (FEV 1 ) (adjusted for height (Batty et al, 2002)), ischaemia (Rose et al, 1977a), fasting plasma cholesterol (Davey Smith et al, 1992), 2-h blood glucose (Jarrett et al, 1986), height (Leon et al, 1995), and weight (Jarrett et al, 1982) were determined using standardised protocols.…”