January 2016 Health Bulletin

Menopause and memory – is there a connection?

Sex hormones (estrogens, androgens and progesterone) not only have important actions within the brain but these hormones can actually be made within the brain. The sex hormones made within the brain are called 'neurosteroids'. This is important because even when the production of sex hormones by the ovaries drops off, these hormones continue to be made in the brain. Sex hormones influence brain networks important for memory and appear to protect brain nerve cells from damage.

Estrogen is produced in parts of the brain important for memory when nerve cells 'fire' and send impulses to other nerve cells. So the production and effects of estrogen in the brain are acute. In contrast, fluctuations in blood hormone levels due changes levels across the menstrual cycle have a relatively delayed impact on brain function.

After menopause women experience subtle impairment in verbal learning and memory. It remains unclear whether this is a direct effect of the fall in blood estrogen at menopause. Alternatively, memory effects of menopause may be due to other consequences of low estrogen, such as chronically disrupted sleep and/or anxiety. Quality sleep is important for optimal memory.

If the fall in estrogen production by the ovaries at menopause has direct negative effects on memory then we would expect menopausal estrogen therapy to improve memory. This has not been found to be the case.

In a small study we found no effects of an oral estrogen-progestin combination cognitive function over 6 months, despite the fact that the treatment improved hot flushes, lowered blood pressure and resulted in weight loss compared with placebo1. More recently, the KEEPS study (693 women, aged 42-59 years, and less than 3 years post menopause randomly allocated to treatment with estrogen or placebo for 4 years) reported no beneficial effect of hormone therapy over placebo. Beneficial mood effects were observed after 4 y of oral estrogen therapy2.

In summary, despite studies consistently showing menopause is associated with subtle changes in memory, menopausal hormone therapy has not been shown to prevent these changes.

Further update on vitamin D supplements

A recent study of 200 elderly men and women with Vitmin D levels less that 50 nmol/L were treated with either monthly vitamin D as either higher dose (equivalent to 2000IU/day) or lower dose (equivalent to 800IU/day)3.
The individuals who received the higher dose had an increased risk of falls (66% versus 48%), with the likelihood of falling being greatest in those with the highest Vitamin D blood levels. This is in line with prior studies of high dose Vitamin D. the reason High dose Vitamin D is associated with a greater chance of elderly people falling is unclear.

The accompanying editorial recommends a daily supplementation of 800IU Vitamin D/day for older people without routine measurement of blood levels. There is also a cautionary comment that people should not simply consider higher blood levels of vitamins as automatically being better.

References

  1. Davison SL, Bell RJ, Robinson PJ, et al. Continuous combined oral estradiol plus drospirenone has no detrimental effect on cognitive performance and improves estrogen deficiency symptoms in early postmenopausal women; a randomized placebo controlled trial. Menopause. 2013; 20: 1020-6.
  2. Gleason CE, Dowling NM, Wharton W, et al. Effects of Hormone Therapy on Cognition and Mood in Recently Postmenopausal Women: Findings from the Randomized, Controlled KEEPS-Cognitive and Affective Study. PLoS medicine. 2015; 12: e1001833; discussion e.
  3. Bischoff-Ferrari HA, Dawson-Hughes B, Orav EJ, et al. Monthly High-Dose Vitamin D Treatment for the Prevention of Functional Decline. JAMA internal medicine. 2016; online.



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