Oestradiol level, oestrogen receptors, and mortality in elderly men: The three-city cohort study

Context: Although endogenous oestradiol, generally considered as the female hormone, has been little investigated in men, it could play a role in men's health, mortality in particular. The influence of oestrogen receptors (ER) genetic polymorphisms on this relationship has never been studied.

Design and participants: The Three-City cohort study included (1999-2001) 3650 men ≥65 years who were followed for mortality over 12 years. At baseline, total oestradiol (tE2) was measured and ER genotyped in a random subsample of 472 men without hormonal treatment. Free oestradiol (fE2) was estimated using Vermeulen and Södergard algorithms.

Main outcome: Mortality data were obtained from death certificates. We used inverse probability weighted Cox models to examine the association of oestradiol with all-cause and cause-specific mortality and its interaction with ER genetic polymorphisms.

Results: A total of 183 men died over the follow-up (cardiovascular disease (CVD), n = 44; cancer, n = 57; other causes, n = 82). After adjustment, there was a quadratic relationship of all-cause mortality with tE2 and fE2 (P-quadratic = 0.04 and 0.05, respectively), with higher mortality for the top and bottom tertiles compared to the middle one. These associations were stronger for CVD mortality (P-quadratic = 0.01 and 0.02 for tE2 and fE2, respectively) and disappeared for cancer mortality. There was no evidence of an interaction of oestradiol with any ER polymorphisms on all-cause mortality.

Conclusion: In elderly men, we showed a nonlinear association of tE2 and fE2 with all-cause mortality. These quadratic relationships were stronger for CVD mortality and did not exist for cancer mortality. ER genetic polymorphisms did not modify this association.