Association Between Changes in Hemoglobin Concentration and Cardiovascular Risks and All-Cause Mortality Among Young Women.

Background Anemia is considered to increase the risk of mortality in high-risk populations, but its effect has not been examined among young populations. This study aimed to determine the effect of hemoglobin (Hb) concentration and its changes on the risk of acute myocardial infarction ( AMI ), stroke, cerebrovascular disease and all-cause mortality among young women. Methods and Results We analyzed data from the Korean National Health Information Database on 808 143 women aged 20 to 39 years without any cardiocerebrovascular disease. A 1-time Hb concentration and changes in Hb over a 2-year period were calculated as exposures. Participants were followed for a median of 10 years to determine the risk of AMI , stroke, cerebrovascular disease, and all-cause mortality. There were U- or J-shaped associations between Hb concentration or change in Hb and AMI , stroke, cerebrovascular disease, and all-cause mortality. Increasing the Hb concentration from normal to high increased the risk for AMI (hazard ratio [95% confidence interval]: 1.49 [1.08-2.04]). With regard to the risk for stroke, increasing the Hb concentration from a normal to a high range increased the risk (hazard ratio [95% confidence interval]: 1.10 [1.02-1.35]), and decreasing the Hb concentration from a high to a normal range decreased this risk (hazard ratio [95% confidence interval]: 0.80 [0.60-0.97]). Improving anemia to the normal Hb range decreased all-cause mortality (hazard ratio [95% confidence interval]: 0.81 [0.69-0.94]); however, overcorrection of Hb concentration (Hb≥14.0 g/dL) was not significant. Conclusions These findings suggest that regular Hb analysis may assist in identifying young women who are at risk of AMI , stroke, cerebrovascular disease, and all-cause mortality.