Background In Poland between 1991–2002, total blood cholesterol falls (reflecting better diets) explained approximately 40% of the decline in coronary heart disease mortality. In turn, these dietary improvements reflected major economic changes (stopping meat and fat subsidies plus massive imports of vegetable oils, fresh fruit and vegetables). Our current study aimed to examine the drivers for recent changes in population total cholesterol levels since 2002.
Methods We used data from two independent, national-representative cross-sectional studies in adults aged 18–79 years conducted in 2002 (n = 2993) and 2011 (n = 2413). These surveys included questionnaires and cardiovascular risk factor measurements. Fasting total cholesterol was measured in venous blood samples in one central laboratory using a standardised enzymatic method. For each study participant taking statins in 2011, we calculated the expected therapeutic reduction in total cholesterol level attributable to this medication (based on published meta-analyses of efficacy for specific statins and doses). Change in mean total cholesterol between 2002 and 2011 was measured and calculated, along with estimates of values expected if statins had not been used. Probabilistic sensitivity analyses were then performed to quantify uncertainty. Statins uptake in 2002 was not accounted because this data were not collected. We assumed very low impact of statins use in this year (supported by data from a related survey showing that the total lipid-lowering drugs uptake in 2003 was 3.9%, usually using less effective drugs at lower doses).
Results Statin uptake in Poland in 2011 was 11.0% (95% CI: 9.2–12.8) in men and 11.4% (95% CI: 9.6–13.2) in women overall, rising to approximately 35% and 30% respectively in men and women aged 60–79 years. Mean total cholesterol in Poland in 2002 was 206.7 mg/dL (95% CI: 204.7–208.7). By 2011, this fell by 8.1 mg/dL (95% CI: 5.5–10.7) (7.3 in men and 8.9 in women). The biggest fall, of 22.2mg/dL (95% CI: 16.8–27.6), was observed among older individuals aged 60–79 years (18.9mg/dL in men and 24.5mg/dL in women). The fall in total cholesterol estimated in 2011 if statins had not been used was only 0.8mg/dL (95% CI: 1.8–3.5) for the total adult population and 1.3mg/dL (95% CI:4.4–7.1) in people aged 60–79 years. Thus, statin use explained approximately 90% (95% CI:53–125) of the observed decreases in total cholesterol levels.
Conclusion Statin medications therefore apparently explained a substantial fraction of the observed fall in population total cholesterol level in Poland since 2002, while recent improvement in diet in Poland slowed down. In conclusion, there is a pressing need to introduce more effective dietary policies in Poland.