Background Although CHD mortality has declined in the UK since the late 1970s, the decline has been particularly marked among more affluent subjects. While the decline substantially reflects improvements in established coronary risk factors, little is known about how these have changed in different socio-economic groups.

Objective To examine whether socio-economic differences in coronary risk factors in Britain have changed over 20 years between 1978–80 and 1998–2000.

Design Prospective study of a socio-economically and geographically representative cohort.

Setting 24 British towns.

Participants 4132 men aged 40–59 years in 1978–80.

Main outcome measures Age-adjusted changes in coronary risk factor levels from 1978-80 to 1998-2000 according to social class were assessed. Coronary risk factors included blood pressure, cholesterol, body mass index (BMI), cigarette smoking and physical activity. Social class, based on longest-held occupation, was grouped as “non-manual” (social classes I, II, III non-manual) and “manual” (III manual, IV and V).

Results Overall, the prevalence of cigarette smoking declined and mean blood pressure and non-HDL cholesterol levels fell, while mean HDL cholesterol and BMI, and physical activity increased. The higher odds of being a current smoker in manual (lower) compared with non-manual (higher) social classes in 2000 (age-adjusted odds ratio 2.04; 95% CI 1.68 to 2.47) had not changed since 1978-80 (p for interaction social class*time 0.51). Men in manual occupations became less likely to be physically inactive compared with non-manual groups (p for interaction 0.04) and more likely to be moderate-vigorously active (p for interaction 0.005). The 20-year increase in mean BMI was 2.34 kg/m² in the manual compared with 2.01 kg/m² in the non-manual group (difference in mean change=0.33 kg/m²; 95% CI 0.14 to 0.53; p for interaction 0.001). Mean systolic blood pressure declined more in manual than non-manual groups (difference in mean change=3.6; 95% CI 2.1 to 5.3, p for interaction <0.0001). Non-manual groups had a greater mean decline in non-HDL cholesterol (difference in mean change=0.18 mmol/l; 95% CI 0.11 to 0.25, p for interaction <0.0001) and a greater mean increase in HDL-cholesterol (difference in mean change 0.04 mmol/l; 95% CI 0.02 to 0.06, p for interaction < 0.0001).

Conclusions Since the 1980s, socio-economic differences in blood pressure and physical activity may have been reduced, while those in cigarette smoking have persisted. Socio-economic differences in BMI, non-HDL and HDL-cholesterol levels appeared to have worsened, with more unfavourable changes in lower socio-economic groups. Continuing priority is needed to improve adverse cardiovascular risk profiles in socially disadvantaged groups in the UK.