Variation and significance of sex hormone levels in Alzheimer's disease patients

Background: The incidence of Alzheimer's disease (AD) obviously increases in females than in males. Estrogen replacement can prevent and/or delay AD onset. Therefore, it can be presumed that AD onset has a certain relationship with the deficiency of estrogen. Objective: To discuss the variation and significance of serum sex hormone levels, especially estrogen levels in AD patients. Design: A case-control study at a ratio of 1: 1. Setting and participants: The study was completed in Neurology Department of the First Affiliated Hospital of Xi' an Jiaotong University. AD patients and healthy elderly from the population of the survey of the incidence of elderly dementia in Xi'an area were enrolled. There were 27 cases in AD group with a mean age of (71.9 ± 10.8) years old, in which there were 9 males and 18 females. There were 27 healthy elders in control group, which were selected strictly according to 1: 1 matching policy of same sex, age difference less than 3 years old, same education background, same residences, no cognitive damage and psychiatric symptoms. Interventions: 3 mL of venous bloods were drawn at 8.00 - 9.00 a. m. with empty stomach in both groups. Sex hormones were assayed by radioimmunology. Main outcome measures: Serum sex hormone levels were measured, including serum follicle-stimulating hormone (FSH), luteinizint hormone (LH), prolactin (PRL), progesterone (P), testosterone (T), and estradiol(E2). The correlations between serum estradiol level and the severity of AD were analyzed, as well as between serum estradiol level and scores of mini-mental state examination (MMSE). Results: There were no significant differences in the levels of serum FSH, LH, PRL, P and T between the two groups (P > 0.05). The serum E2 level in the AD group[ (119.54 ± 44.15) μg/L] was significantly lower than that of the control group [ (154.55 ± 63.62) μg/L, t = 2.756, P < 0.05]. There was a significant positive correlation between serum E2 level and the severity of AD(r = 0.412, P = 0.013). In the AD group, the serum level of E2 was positively correlated with MMSE scores (r = 0.59, P = 0.25) but without statistical significance. Conclusion: The decrease of estrogen level may be one of the risk factor in AD onset.