Objectives: To study secular trends in cardiovascular risk factors in men aged 50 over a period of 30 years.
Design: Cross-sectional studies of successive cohorts of men from 1963 to 1993.
Setting: City of Göteborg, Sweden.
Subjects: Four random population samples of men born in 1913, 1923, 1933 and 1943, aged 50 when they were examined in 1963, 1973, 1983, and 1993 (n = 855, 226, 776, and 798, respectively).
Main outcome measures: Anthropometric measurements, blood pressure, serum cholesterol and triglycerides and smoking habits over three decades.
Results: Over 30 years, men increased in weight from a mean (SD) of 75.9 (11.0) kg to 82.8 (12.1) kg and gained 3.4 cm in height, with a net increase in body mass index from 24.8 (3.2) to 26.0 (3.4) kg m-2 (P < 0.0001), and a concomitant increase in waist circumference. The proportion of men who were overweight but not obese (BMI = 25-30 kg m-2) increased from 38 to 47%, whereas the prevalence of frank obesity (more than 30 kg m-2) increased from 6% in 1963 to 11% in 1993. Despite the increase in weight, mean systolic blood pressure fell by almost 10 mmHg (P < 0.0001). Mean serum cholesterol concentration decreased from 6.42 (1.12) to 5.88 (1.04) (P < 0.0001). Serum triglycerides increased from 1.26 (0.77) to 1.69 (1.04) mmol L-1 (P = 0.001). The proportion of men who smoked decreased from 56% in 1963 to 30% in 1993 (P < 0.0001). This was due more to an increase in smoking cessation rates than to an increase in the proportion of men who had never smoked. In particular, smokers and former smokers are now more obese than the corresponding categories 30 years ago and smokers are no longer leaner than men who have never smoked.
Conclusions: Over a period of 30 years, serum cholesterol as well as systolic blood pressure and the prevalence of smoking decreased. This favourable decline in coronary risk factors was offset by an appreciable increase in body mass index and waist circumference.