These results from SWAN provide seven years of longitudinal HRQL data on a large cohort of middle-aged women as they experience the menopausal transition. Final results show that after adjustment for a wide range of variables, menopausal status is independently related to physical limitations in role functioning, but not other HRQL domains. In analyses only adjusting for baseline chronological age and time, menopausal status was significant for all SF-36 domains assessed with women having greater odds of reduced functioning at early peri, late peri, and postmenopause than when premenopausal. Except for role-physical, the odds of reduced functioning were greatest at early and late perimenopause. However, symptoms that often co-occur with menopause (VMS, vaginal dryness, urine leakage, and poor sleep) accounted for the effect of status (when excluding HT users) on role-emotional, bodily pain, and vitality. With the addition of medical conditions, depression, and stress to the model, the social functioning domain was no longer related to menopausal status. These findings highlight the importance of controlling for important covariates in assessing the impact of the menopausal transition on HRQL. However, even controlling for this wide range of variables, late-peri and postmenopausal women were more likely to report reduced functioning on the role-physical domain than when premenopausal. These findings are consistent with Mishra et al.22
who found significant declines in the physical health domains of the SF-36 among women who remained perimenopausal over two years, compared to women who remained premenopausal. It is possible that these results are due to health problems that may co-occur with menopause and/or aging. Our analyses only included medical conditions that were reported with a high prevalence (i.e. arthritis and migraines) and Mishra et al. did not include any health variables. A more comprehensive look at co-morbidities might explain this effect.
Despite the significant finding for role-physical, it is important to note that the actual changes in HRQL are quite small and may not be meaningful. The unadjusted SF-36 scores shown in vary only slightly by menopausal status. The percent of women classified in the reduced functioning percentile increases between pre and late perimenopause by only 3.8% for role-physical.
With respect to HT users, our results show that both current and former HT users were more likely to report poor functioning on all domains than women who never used HT. This was significant for bodily pain, vitality, and role-physical. Separate SWAN analyses explored HT users in greater depth and did not find that HRQL was related to initiation of HT or that HRQL improved following initiation of HT.33
Our results are also consistent with Mishra et al.22
who found that women taking HT reported greater decline on all aspects of the SF-36 except role emotional. These findings are somewhat in contrast to research showing that HT users tend to be healthier than non users. It is possible that HT users may be healthier by more objective measures (e.g., cardiovascular risk factors), but perceive themselves as more impaired. HT users in SWAN did not report more comorbidities.33
Our findings support the role of symptoms in relation to HRQL. We found that vaginal dryness, urine leakage, poor sleep, and depression were highly related to all SF-36 domains. Results are consistent with our baseline findings13
and Kumari et al.23
who found that women who experienced vasomotor symptoms or depression showed significant declines on the SF-36.
Our results for race/ethnicity are generally consistent with our earlier baseline report of pre and early perimenopausal women.13
We found no effect of race/ethnicity on the role-physical domain when analyses adjusted for socioeconomic status, health, and social circumstances. Despite adjusting for a wide range of variables, both analyses found significant racial/ethnic group differences for the bodily pain and social functioning domains. African-American and particularly Hispanic women, reported more bodily pain and reduced social functioning than Caucasians.
Unlike our earlier report, our present analyses found significant race/ethnicity effects for both vitality and role-emotional. African-American women were less likely to report reduced vitality than Caucasian women. African-American, Hispanic, and Japanese women reported less reduced functioning for role-emotional than Caucasian women. However, the pattern of results was similar in both analyses and the statistical differences may be due to a larger N in the present analyses.
There are several limitations to this study. First, SWAN is not composed of a true national probability sample. Women in the cohort had more education, higher incomes, were less likely to be smokers, and rated themselves higher on perceived health than eligible women who did not enroll. Since the study excluded women with past hysterectomy, bilateral oophorectomy or recent hormone use, cohort participants were less likely to have already experienced reproductive or perimenopausal problems. Second, the SF-36 has some limitations. The study did not include the SF-36 physical functioning, mental health, and general health perceptions subscales and the subscales that were included were not administered at every visit. However, this latter limitation should not impact the associations between change in menopausal status and HRQL. Although the SF-36 is viewed as a generic quality of life measure and may not tap specific quality of life issues relevant to women over the menopausal transition, it is the most widely used scale and considered appropriate for a healthy population. We should also note that the present study was not designed to determine the effect of hormone therapy on HRQL, a question best addressed in a randomized clinical trial. Finally, our analyses only included limited medical conditions and it is possible that a more comprehensive look at co-morbidities would explain the effect of menopausal status on role physical.
In conclusion, in this large multiethnic cohort of women, we found that changes in HRQL over the menopausal transition are largely explained by symptoms related to menopause and/or aging such as vasomotor symptoms, vaginal dryness, urine leakage, and trouble sleeping; health conditions such as arthritis; and depressed mood and stress. Our continued follow-up of the SWAN cohort will allow us to determine the HRQL trajectory in the early postmenopausal years.