[Is the recent decrease in cholesterolemia in the Czech Republic convincing evidence?].

BACKGROUND: The objective of the study was to evaluate the 8-year trend of serum cholesterol levels in six districts of the Czech Republic, to assess whether the reduction of mean values of total cholesterol recorded during the period between 1985 and 1992 was convincing and to discuss possible causes and consequences of this development. METHODS AND RESULTS: Three cross-sectional surveys of risk factors were implemented in independent random 1% samples of the population aged 25-64 years. In 1985 1256 men (respondence rate 81.5%) and 1317 women (85%) were examined, In 1988 1357 men (85.2%) and 1412 women (88.4%), in 1992 1142 men (73.2%) and 1211 women (76.7%). A detailed check of the deviations in estimations during different time intervals from reference values provided evidence that the analytical method did not have an impact on the revealed changes. In men the mean total cholesterol level was 6.21 (95% confidence limit 6.14-6.28 mmol/l in 1985; 6.29 (6.23-6.35) mmol/l in 1988; 5.99 (5.91-6.06) mmol/l in 1992. In women the mean value of the total cholesterol level was 6.19 (6.12-6.25) mmol/l in 1985; 6.23 (6.17-6.30) mmol/l in 1988; 5.95 (5.88-6.02) mmol/l in 1992. According to variance analysis (ANOVA) the serum cholesterol in 1992 was lower by 0.22 mmol/l (p < 0.0001) than in 1985 and by 0.28 mmol/l (p < 0.0001) lower than in 1988. The drop of cholesterol between 1988-1992 may have been caused by dietary changes recorded in the population. According to nationwide data after 1990 there was a marked drop of the consumption of meat and meat products, milk and dairy products and animal fats, while the consumption of vegetable fats increased. Despite these dietary improvements, in six districts in 1992 fats accounted for 37% of the energy intake, the P/S ratio was only 0.41 in men and 0.46 in women. In these districts in 1992 and 1993 a decline of the standardized mortality rate from IHD in men was recorded. CONCLUSIONS: During an eight-year period the mean serum cholesterol level of men and women decreased significantly in six districts of the Czech Republic. This change was probably associated with a restricted intake of foods which have an impact on the serum cholesterol level.