Estimation of Familial Combined Hyperlipoproteinemia prevalence in a large rural population: the Brisighella Heart Study.

Objective: Familial Combined Hyperlipoproteinemic (FCH) is a disorder of lipid metabolism characterized by an increased risk of premature coronary heart disease. Our aim is to estimate the prevalence of FCH subjects in a large North-Italian rural population monitored for 32 years (1972-2004). Methods: In the 2004 Brisighella Heart Study (BHS) survey, 1303 subjects were tested in five or more four-yearly surveys (mean age: 63.7±14.9 years). The individual plasma lipid phenotype by Fredrickson classification was attributed for each survey on the basis of low density lipoprotein (LDL)-cholesterol and triglycerides. A primary dyslipoproteinemia was suspected on the basis of personal and family history, body mass index and dietary habits. Results: At the end of the longitudinal study, the subjects with variable phenotype in the studied population were 17.2% and among primary hyperlipoproteinemics 36.3%. Mean IIb phenotype prevalence was 12.3 ± 6.3% in all hyperlipoproteinemics, while it was 33.4 ± 11.9% in potential FCH subjects. Only 7 subjects were constantly IIb during the observation time and four of them are certainly secondary hyperlipoproteinemics. The Ilb phenotype prevalence was significantly more variable than the Ila phenotypes. The 3.1% of the studied subjects have been selected as candidates for a FCH diagnosis without significant differences between sexes. Conclusion: Our data suggest the existence of a long-term primary variability of the individual plasma lipid phenotype. The prevalence of FCH in the general population appears to be near 2%.