Menopausal hormone therapy (MHT) reportedly increases the risk of cognitive decline in women over age 65 y. It is unknown whether similar risks exist for recently postmenopausal women, and whether MHT affects mood in younger women. The ancillary Cognitive and Affective Study (KEEPS-Cog) of the Kronos Early Estrogen Prevention Study (KEEPS) examined the effects of up to 4 y of MHT on cognition and mood in recently postmenopausal women.
Methods and Findings
KEEPS, a randomized, double-blinded, placebo-controlled clinical trial, was conducted at nine US academic centers. Of the 727 women enrolled in KEEPS, 693 (95.3%) participated in the ancillary KEEPS-Cog, with 220 women randomized to receive 4 y of 0.45 mg/d oral conjugated equine estrogens (o-CEE) plus 200 mg/d micronized progesterone (m-P) for the first 12 d of each month, 211 women randomized to receive 50 μg/d transdermal estradiol (t-E2) plus 200 mg/d m-P for the first 12 d of each month, and 262 women randomized to receive placebo pills and patches. Primary outcomes included the Modified Mini-Mental State examination; four cognitive factors: verbal learning/memory, auditory attention/working memory, visual attention/executive function, and speeded language/mental flexibility; and a mood measure, the Profile of Mood States (POMS). MHT effects were analyzed using linear mixed-effects (LME) models, which make full use of all available data from each participant, including those with missing data. Data from those with and without full data were compared to assess for potential biases resulting from missing observations. For statistically significant results, we calculated effect sizes (ESs) to evaluate the magnitude of changes.
On average, participants were 52.6 y old, and 1.4 y past their last menstrual period. By month 48, 169 (24.4%) and 158 (22.8%) of the 693 women who consented for ancillary KEEPS-Cog were lost to follow-up for cognitive assessment (3MS and cognitive factors) and mood evaluations (POMS), respectively. However, because LME models make full use all available data, including data from women with missing data, 95.5% of participants were included in the final analysis (n = 662 in cognitive analyses, and n = 661 in mood analyses). To be included in analyses, women must have provided baseline data, and data from at least one post-baseline visit. The mean length of follow-up was 2.85 y (standard deviation [SD] = 0.49) for cognitive outcomes and 2.76 (SD = 0.57) for mood outcomes. No treatment-related benefits were found on cognitive outcomes. For mood, model estimates indicated that women treated with o-CEE showed improvements in depression and anxiety symptoms over the 48 mo of treatment, compared to women on placebo. The model estimate for the depression subscale was −5.36 × 10−2 (95% CI, −8.27 × 10−2 to −2.44 × 10−2; ES = 0.49, p < 0.001) and for the anxiety subscale was −3.01 × 10−2 (95% CI, −5.09 × 10−2 to −9.34 × 10−3; ES = 0.26, p < 0.001). Mood outcomes for women randomized to t-E2 were similar to those for women on placebo. Importantly, the KEEPS-Cog results cannot be extrapolated to treatment longer than 4 y.
The KEEPS-Cog findings suggest that for recently postmenopausal women, MHT did not alter cognition as hypothesized. However, beneficial mood effects with small to medium ESs were noted with 4 y of o-CEE, but not with 4 y of t-E2. The generalizability of these findings is limited to recently postmenopausal women with low cardiovascular risk profiles.
ClinicalTrials.gov NCT00154180 and NCT00623311
In a randomized, controlled trial, Carey Gleason and colleagues examine the effects of hormone therapies on cognitive and mood outcomes in recently postmenopausal women.
Menopause (“change of life”)—the time in a woman’s life when her menstrual periods stop—is a normal part of aging and usually occurs around the age of 50. In the years before menopause (the menopausal transition or perimenopause), the levels of estrogen and progesterone—sex hormones produced by the ovaries that prepare the woman’s body every month for a possible pregnancy—go up and down irregularly. This variation in hormone levels changes the frequency and characteristics of a woman’s periods but can also cause hot flashes (feeling hot on and off during the day), night sweats, vaginal dryness, bone thinning, and mood swings. Some women sail through menopause without experiencing any of these symptoms, but for other women menopausal symptoms, which can continue for several years after menopause, can be debilitating. For these women, menopausal hormone therapy (MHT, previously known as hormone replacement therapy, or HRT)—treatment with various combinations and types of estrogen and progesterone—can be prescribed during or after the menopausal transition to manage their troublesome symptoms.
Why Was This Study Done?
Although MHT has helped many women deal with their menopausal symptoms, it can increase a woman’s risk of heart disease, stroke, blood clots, and breast cancer. There is also some evidence that MHT increases the risk of cognitive decline (decline in thinking, language, memory, understanding, and judgment) and dementia in women who start taking MHT after the age of 65. However, other evidence suggests that MHT might enhance cognition and mood if it is given at menopause rather than later. In this randomized, double-blinded, placebo-controlled clinical trial (the KEEPS-Cog trial, an ancillary study of the Kronos Early Estrogen Prevention Study, which examined the effect of MHT on cardiovascular health), the researchers investigate the effects of up to four years of MHT on cognition and mood in recently postmenopausal women living in the US. A randomized, placebo-controlled clinical trial compares the outcomes of participants assigned an active intervention or a placebo (dummy) intervention through the play of chance; in a double-blinded trial, neither the researchers nor the participants know who is receiving which treatment until the trial ends.
What Did the Researchers Do and Find?
In the KEEPS-Cog trial, 220 healthy recently postmenopausal women took an estrogen pill every day and a progesterone pill for the first 12 days of each month, 211 women wore an estradiol patch (transdermal estradiol) and took a progesterone pill for the first 12 days of each month, and 262 women received placebo patches and pills for up to four years (the average follow-up was a little less than three years). The researchers assessed the trial participants for their overall cognitive health using an instrument called the Modified Mini-Mental State Examination, for four specific cognitive functions using several established instruments, for depression symptoms using the Beck Depression Inventory, and for mood using the Profile of Mood States instrument at baseline and at 18, 36, and 48 months. Statistical analysis of the data collected indicates that, during the trial, there were no treatment-related effects on cognition or depression symptoms. However, women treated with estrogen pills and progesterone (but not those treated with estradiol patches and progesterone) showed improvements in some mood symptoms compared to women in the placebo group.
What Do These Findings Mean?
Before starting their trial, the researchers hypothesized that, because the body handles different formulations and types of estrogen in different ways, transdermal estradiol but not oral estrogen would improve cognition and mood in recently postmenopausal women when compared to placebo. Notably, the findings suggest that MHT does not alter cognition as hypothesized and that oral rather than transdermal estrogen has a small to moderate beneficial effect on mood. Importantly, these findings provide no information about the effects of MHT beyond four years and, because most of the women in the study were white, well-educated, and at low risk of cardiovascular disease, may not be applicable to the general postmenopausal population of the US and of other countries. Moreover, because MHT improved menopausal symptoms in the women receiving hormones, the trial was not truly double-blinded. However, despite these and other study limitations, the researchers suggest that their findings could now be used to help women make more informed decisions about whether to use MHT to manage their menopausal symptoms.
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001833.
The US National Institute on Aging provides detailed information for women about menopause (in English and Spanish) and about hormones and menopause
The UK National Health Service Choices website also provides detailed information about menopause and about menopausal hormone therapy, including some personal stories
The US Food and Drug Administration provides answers to common questions about menopause and hormones (in English and Spanish)
MedlinePlus provides links to further resources and advice about menopause and about menopausal hormone therapy (in English and Spanish)
More information about the KEEPS-Cog trial is available