245, P?=?0.001) 3-mercaptopyruvate sulfurtransferase
(Fig.?1). Among the 180 subjects, 56 were current smokers. After controlling for age, education years and smoking status, the correlation was still significant (r?=??0.261, P?<?0.001). Hb concentrations did not correlate with cognitive tests, including CASI (P?=?0.879), Forward Digit Span (P?=?0.286) and Backward Digit Span (P?=?0.172). After controlling for age, education years and smoking status, the correlation was still insignificant (data not shown). A linear-regression analysis performed with age, education years, and Hb concentrations as the predictor variables identified education years as the only significant predictor of CASI score (P?<?0.001). The results of this study indicate that Hb concentrations negatively correlated with depression, as evaluated using GDS-15, and did not correlate with cognitive function. Our findings are consistent with those of a previous study on English <a href="http://www.selleckchem.com/products/XAV-939.html
">XAV-939 manufacturer community-dwelling older adults (3816 men and women; aged 65.4?��?9.0?years),9 but differed from those from a Japanese analysis that showed no significant association between Hb levels and depressed mood in elderly men at a high risk of requiring care.2 This discrepancy may be caused by sample differences, ethnic differences, or different depression ratings. The underlining mechanism of the link between lower Hb levels and depressive mood still requires full elucidation. Anemia could worsen symptoms of fatigue, irritability, and poor concentration, which are significant components of depression. Furthermore, anemia reduces brain oxygenation,10 which may affect brain function for stress coping. In a large longitudinal prospective study of English community-dwelling older adults, anemia did not predict risk of depression over 2?years of follow up.9 Therefore, the causal correlation may be in the reverse direction (depression causes anemia). For example, lower Hb may be a consequence of poor dietary iron intake among subjects with more depressed moods. Although certain studies demonstrated that lower Hb levels were associated with poorer cognitive function in old age,4,5 the data of the present study did not reveal any significant association between Hb levels and cognition in its elderly healthy male subjects. This result may be caused by differences in sample populations between the histone deacetylase activity
studies and varying cognitive ratings used. This study has several limitations. First, the sample comprised a population of Chinese elderly men living in a veterans' home; therefore, any association between Hb levels and depression in women or other populations requires further confirmation. Second, patient assessments did not include the causes of anemia. Third, this cross-sectional study could not identify the causal correlation between anemia and depression. There are no conflicts of interest to disclose.