Participants were drawn from 9 cross-sectional UK surveys comprising of the Scottish Health Surveys (SHS, 3 cohorts) and the Health Survey for England (HSE, 6 cohorts). Sampling individuals living in households in each country, all studies are representative of the general population. The characteristics of the individual cohorts are presented in table 1 . The mean age at baseline ranged between 49 and 57 years, with women marginally comprising the majority of study members (range: 54-62%). Study participants gave full informed consent and ethical approval was obtained from the London Research Ethics Council or the Local Research Ethics Councils.
The full protocols for the HSE and SHS data collection have been described in detail elsewhere(15 ;16 ). In brief, study members were visited twice in their homes. During the first visit, trained interviewers collected data on demographics and health behaviours, including socioeconomic status (as indexed by occupational social class), self-reported smoking, and physical activity. During the second visit, conducted within a few days of the first, nurses gathered clinical data. In the seated position and after five minutes rest, systolic and diastolic blood pressure was measured on three occasions using an Omron HEM-907; an average of the second and third readings was used in the present analyses. Nurses also collected information about physician-diagnosed CVD (stroke, ischemic heart disease, angina symptoms), other medical conditions (hypertension and diabetes), and blood-pressure lowering medication (beta-blockers, angiotensin converting enzyme-inhibitors, diuretics, calcium blockers).
Height and weight were measured directly by the interviewers using Chasmors stadiometers (Chasmors Ltd., London, UK) and Tanita electronic digital scales (Tanita Incorporation, Japan), respectively. Body mass index (BMI) was calculated using the usual formulae (weight [kg]/height[m]2). Waist and hip circumferences were measured using a tape with an insertion buckle at one end. Waist circumference was measured at the midpoint between the lower rib and the upper margin of the iliac crest. Hip circumference was denoted by the widest circumference around the buttocks, below the iliac crest. Both measurements were taken twice, using the same tape, and were recorded to the nearest even millimetre. Those whose two waist or hip measurements differed by more than 3 cm had a third measurement taken. The mean of the two valid measurements was used in our analysis. For waist and hip measurements all those who reported that they had a colostomy or ileostomy, or were chairbound or pregnant, were excluded from the measurement. All those with measurements considered invalid by the nurse, for example due to refusals to remove excessive clothing or movement, were excluded from the analysis.
The full protocols for the HSE and SHS data collection have been described in detail elsewhere(15 ;16 ). In brief, study members were visited twice in their homes. During the first visit, trained interviewers collected data on demographics and health behaviours, including socioeconomic status (as indexed by occupational social class), self-reported smoking, and physical activity. During the second visit, conducted within a few days of the first, nurses gathered clinical data. In the seated position and after five minutes rest, systolic and diastolic blood pressure was measured on three occasions using an Omron HEM-907; an average of the second and third readings was used in the present analyses. Nurses also collected information about physician-diagnosed CVD (stroke, ischemic heart disease, angina symptoms), other medical conditions (hypertension and diabetes), and blood-pressure lowering medication (beta-blockers, angiotensin converting enzyme-inhibitors, diuretics, calcium blockers).
Height and weight were measured directly by the interviewers using Chasmors stadiometers (Chasmors Ltd., London, UK) and Tanita electronic digital scales (Tanita Incorporation, Japan), respectively. Body mass index (BMI) was calculated using the usual formulae (weight [kg]/height[m]2). Waist and hip circumferences were measured using a tape with an insertion buckle at one end. Waist circumference was measured at the midpoint between the lower rib and the upper margin of the iliac crest. Hip circumference was denoted by the widest circumference around the buttocks, below the iliac crest. Both measurements were taken twice, using the same tape, and were recorded to the nearest even millimetre. Those whose two waist or hip measurements differed by more than 3 cm had a third measurement taken. The mean of the two valid measurements was used in our analysis. For waist and hip measurements all those who reported that they had a colostomy or ileostomy, or were chairbound or pregnant, were excluded from the measurement. All those with measurements considered invalid by the nurse, for example due to refusals to remove excessive clothing or movement, were excluded from the analysis.