Haptoglobin (HP) polymorphisms and human longevity: a cross-sectional association study in a Central Italy population.

Background: Haptoglobin (HP), which scavenges free, cell-toxic hemoglobin and has anti-inflammatory and immune-modulatory function in extravascular tissues, may represent an excellent candidate gene to investigate the life-span expectancy.

Methods: HP 1/2 polymorphism has been determined for 1072 (569 females, 503 males) unrelated healthy individuals from Central Italy, 18-106 years old, divided into three gender-specific age classes defined according to demographic information and accounting for the different survivals between sexes. HP*1F/S subtyping was also performed to check the possible existence for a preferential advantage of HP*1F or HP*1S allele.

Results: HP*1/*1 genotype results associated to increased probability of young subjects of attaining longevity (Comparison 1: O.R. 1.709, p=0.0114) with a concomitant advantage of HP*1 allele (Comparison 1: O.R. 1.273, p=0.0194). On the other side, carriers of HP*2 allele displayed an overall significant disadvantage in reaching Age Class 2 (O.R. 0.585, p=0.0092). No significant differences were noticed between age groups either considering total HP*1F and HP*1S allele frequencies or according to HP 1/2 genotypes.

Conclusion: The crucial role played by HP in aging process is warranted by its many established functions and its related phenotypes so that it may be considered an important gene involved in the determination of human survival.