Influences of hormone replacement therapy on olfactory and cognitive function in postmenopausal women

Abstract

Olfactory dysfunction can be an early sign of Alzheimer’s disease (AD). Since hormone replacement therapy (HRT) may protect against developing AD in postmenopausal women, the question arises as to whether it also protects against olfactory dysfunction in such women. Three olfactory and 12 neurocognitive tests were administered to 432 healthy postmenopausal women with varied HRT histories. Serum levels of reproductive hormones were obtained for all subjects; APOE-ε4 haplotype was determined for 77. National Adult Reading Test and Odor Memory/Discrimination Test (OMT) scores were positively influenced by HRT. Odor identification and OMT test scores were lower for women who scored poorly on a delayed recall test, a surrogate for mild cognitive impairment. WAIS-R NI Spatial Span Backwards Test scores were higher in women receiving estrogen plus progestin HRT and directly correlated with serum testosterone levels, the latter implying a positive effect of testosterone on spatial memory. APOE-ε4 was associated with poorer odor threshold test scores. These data suggest that HRT positively influences a limited number of olfactory and cognitive measures in the menopause.

Correspondence between colour and odour for women in pre‐menopause and post‐menopause

“…It is known that women are greatly influenced by changes of female hormones, particularly during the menstrual cycle and menopause, and some women experience perceptual, cognitive and mental changes. In particular, for women in menopause, visual perception and the response to visual stimuli decline, and olfactory perception is likely to be decreased . Some studies about colour perception showed that female hormones could affect short‐wavelength light sensitivity, by which humans perceive bluish colour .…”

“…14,15 Regarding perception, women are likely to have decreased abilities of visual perception, as shown by such indicators as declines of reaction time, [16][17][18] and also to have changes of olfactory senses, according to the hormonal changes in menopause. [19][20][21][22] However, some studies showed no strong associations between menopause and perceptual or cognitive functioning, 23,24 and menopausal symptoms can vary according to their individuals' health conditions and experiences. 13,25 Menopausal women may also have deficits in colour perception, particularly perception related to short-wavelength cones, 26 but the colour perceptual and cognitive functions affected by menopause have not been clearly identified.…”

“…In particular, for women in menopause, visual perception and the response to visual stimuli decline, and olfactory perception is likely to be decreased. 14,15,[19][20][21]32 Some studies about colour perception showed that female hormones could affect shortwavelength light sensitivity, by which humans perceive bluish colour. 26,[33][34][35][36] Our study also revealed that women in menopause had a difference in colour perception in a study comparing premenopausal and postmenopausal women, and that postmenopausal women had slower responses to blue.…”

“…In addition, during menopausal transition following aging, cognitive dysfunction, including decreased verbal fluency and word‐narrative memory, appears in women . Regarding perception, women are likely to have decreased abilities of visual perception, as shown by such indicators as declines of reaction time, and also to have changes of olfactory senses, according to the hormonal changes in menopause . However, some studies showed no strong associations between menopause and perceptual or cognitive functioning, and menopausal symptoms can vary according to their individuals’ health conditions and experiences .…”

Contraceptive Use Affects Overall Olfactory Performance: Investigation of Estradiol Dosage and Duration of Intake

“…In this research field, the results were also contradictory. Whereas some studies provided evidence of a positive impact of HRT in postmenopausal women in various cognitive domains (for review see [30]) as well as olfactory sensitivity [31,32], there are also investigations that have shown a lack of significant differences in individuals using HRT [33]. Due to a huge increase in OC use within the last decades, numerous studies have been performed to investigate the influence of hormones in premenopausal women on various cognitive functions, such as verbal memory [34] or mental rotation [35].…”