Haptoglobin polymorphism as a risk factor for coronary heart disease mortality

Objectives: the aim of our study was to evaluate the independent role of th e haptoglobin (Hp) polymorphism as a risk factor for coronary heart disease (CHD) mortality. Methods: within the framework of the longitudinal part of the Belgian Interuniversity Research on Nutrition and Health (BIRNH) surve y, a nested case-control study design was performed through matching the 10 7 deaths from CHD, occurring within a 10-year follow-up period, with three controls for age and gender. Results: the distribution of the Hp types was found to be in Hardy-Weinberg equilibrium. Conditional logistic regression analysis for matched sets revealed that the Hp polymorphism was significant ly associated with CHD death. Rather surprisingly, the finding was that Hp 1-1 individuals were at doubled risk for CHD mortality compared with the ot hers, the odds ratio being 2.09 (95% CI. 1.22-3.60). The association was in dependent from other classical cardiovascular risk factors and the Hp conce ntration, and of comparable magnitude between men and women. Moreover, eval uating the interaction term in a multiplicative model showed that the Hp ty pe did not play a synergistic role in the prognostic value of established c ardiovascular risk factors. Conclusion: in contrast to the findings from cr oss-sectionally based studies, the results from this longitudinal study sho w that Hp 1-1 individuals are at elevated risk for CHD mortality. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.