A U-shaped relationship between haematocrit and mortality in a large prospective cohort study

Background: Only a limited number of studies have investigated the correlation between haematocrit (HCT) and mortality in the general population, and few of those studies have had data on a wide range of low and high levels of HCT. We investigated the association between baseline HCT and mortality in a prospective cohort study of 49 983 adult subjects in Iran with a broad spectrum of HCT values. Methods: Data on socio-demographic and life-style factors, past medical history, and levels of HCT were collected at enrollment. During a mean follow-up of 5 years (follow-up success rate ±99%), 2262 deaths were reported. Cox proportional hazards regression models were used to estimate hazard ratios and corresponding 95% confidence intervals. Results: There was a U-shaped relationship between categories of HCT and mortality in both sexes: both low and high levels of HCT were associated with increased overall mortality and mortality from cardiovascular disease. The U-shaped relationship persisted after several sensitivity analyses were done, including analyses restricted to non-smokers and non-users of opium; analyses excluding deaths from accidents and other external causes as well as deaths of persons with self-reported ischemic heart disease at the baseline interview for the study; and analyses excluding the first 2 years of follow-up. Self-reported past medical history and lack of data about lipids and other cellular blood components were the major limitations of the study. Conclusions: Low and high levels of HCT are associated with increased mortality in the general population. The findings in the present study can be of particular importance for low- and middle-income countries in which a substantial proportion of the population lives with suboptimal levels of HCT. © Published by Oxford University Press on behalf of the International Epidemiological Association 2013

Impact des estrogènes et de leurs récepteurs sur le risque eschémique chez les femmes ménopausées : une approche cas-cohorte

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF

High Level of Plasma Estradiol as a New Predictor of Ischemic Arterial Disease in Older Postmenopausal Women: The Three-City Cohort Study

BACKGROUND: Despite evidence that estrogens may be involved in atherothrombosis, the role of endogenous sex steroid hormones in ischemic arterial disease among postmenopausal women remains uncertain. METHODS AND RESULTS: In the Three-City prospective cohort study of subjects (n=9294) >65 years of age, we investigated the association of total 17β-estradiol, bioavailable 17β-estradiol, and total testosterone with the 4-year incidence of ischemic arterial disease among postmenopausal women who did not use any hormone therapy. We designed a case-cohort study including a random sample of 537 subjects and 106 incident cases of first cardiovascular events. Weighted Cox proportional-hazards models with age as the time scale were used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for ischemic arterial disease by a 1-standard deviation increase in sex steroid hormones. In univariate analysis, HR of ischemic arterial disease was positively and significantly associated with both total and bioavailable estradiol levels. These associations remained significant after adjustment for traditional cardiovascular risk factors, including body mass index, diabetes, hypercholesterolemia, hypertension, and smoking status (HR: 1.42, 95% CI: 1.12-1.79, P<0.01; and HR: 1.42, 95% CI: 1.12-1.78, P<0.01, respectively). Separate analysis for coronary heart disease yielded similar results (adjusted HR: 1.49, 95% CI: 1.10-2.02, P=0.01; and adjusted HR: 1.50, 95% CI: 1.11-2.04, P<0.01, respectively), and a borderline significant trend was observed for ischemic stroke (HR: 1.34, 95% CI: 0.95-1.89, P=0.08; and HR: 1.32, 95% CI: 0.94-1.84, P=0.11, respectively). By contrast, no significant association was found between total testosterone and ischemic arterial disease in both univariate and adjusted analyses. CONCLUSIONS: High plasma level of endogenous estradiol emerges as a new predictor of ischemic arterial disease in older postmenopausal women. (J Am Heart Assoc. 2012;1:e001388 doi: 10.1161/JAHA.112.001388.)

Clin Endocrinol (Oxf)

CONTEXT: Although endogenous estradiol, 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 estrogen 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 estradiol (tE2) was measured and ER genotyped in a random subsample of 472 men without hormonal treatment. Free estradiol (fE2) was estimated using Vermeulen and Sodergard algorithms. MAIN OUTCOME: Mortality data were obtained from death certificates. We used inverse probability weighted Cox models to examine the association of estradiol with all-cause and cause-specific mortality and its interaction with ER genetic polymorphisms. RESULTS: 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 estradiol 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. This article is protected by copyright. All rights reserved