認知症における加齢と性差

Age and Sex: Risk Factors for Dementia

認知症の危険因子として加齢，女性，生活習慣病などが挙げられる。また孤発性アルツハイマー病ではアポリポ蛋白Eε4アリルが遺伝的危険因子といわれているが，年齢や性による違いも報告されている。加齢に伴いアンドロゲン，女性ホルモン，男性ホルモンは低下し，認知機能低下や認知症発症とも関連することがわかってきた。予防としてのホルモン補充療法は大変興味深く，今後検討してゆくべき命題だと思われる。

Abstract

Age- and sex-related differences in the incidence and prevalence of dementia are well-known. These may be affected by other risk factors including metabolic syndrome or diabetes mellitus, dietary habits and apolipoprotein E genotypes. Furthermore, cognitive function could be modulated by sex hormones such as estrogen and androgen via their anti-oxidative, neuro-protective and vasoprotective effects. Contrary to the results from basic research and observational studies, clinical trials on hormone replacement therapy (HRT) have been controversial. Overall, HRT with estrogen plus progesterone in older women seemed to increase the risk of dementia. In contrast, testosterone replacement in older men and dehydroepiandrosterone (DHEA) replacement older women may have potential protective effects on cognitive function, although clinical evidence is insufficient at present.