The present study results indicated that there is a direct meaningful relationship between menopause symptoms and musculoskeletal pains in a way that women with severe climacteric symptoms reported higher rates of musculoskeletal pains. The women with mild or without menopause symptoms were not at high risk for long-term disability due to musculoskeletal pains, whereas in the women with severe menopause symptoms, this rate was 59.4%. In a cross-sectional study by Juan E. Blumel, the prevalence of muscle and joint aches was 63%, and 15.6% of which has severe and very severe musculoskeletal pain scores. In this large sample of mid-aged women, the prevalence of musculoskeletal pains was high, which was significantly related to menopausal variables; especially vasomotor symptoms. Also, only 8.2% of the women with no vasomotor symptoms suffered from severe/very severe muscle and joint aches, whereas in the women with very severe vasomotor symptoms, the prevalence of muscle and joint aches increased up to 60.2% (5). Korean research reported that climacteric symptoms and leisure time inactivity were statistically effective factors for low back pain in postmenopausal women. Women with backache expressed more severe climacteric symptoms than those without backache (4). Both of the above studies are relatively in accordance with our study. Similarly, in the study by Mitchell et al., a significant increase in backache was observed during the early postmenopause and women with vasomotor symptoms, depressed mood, anxiety, difficulty in concentrating and insomnia reported more back pain (12).
The results of these studies and our study highlight the fact that climacteric symptoms are directly associated with increases in musculoskeletal pains, which probably indicate the role of hormonal changes in this period. In our study, another factor related to musculoskeletal pains was serum estradiol level such that the declining serum estradiol level in the postmenopausal females promoted the development of musculoskeletal pains. By contrast, in Akkus’s et al.’s study, no significant difference was seen in the measured values for estradiol between fibromyalgia patients and healthy females. Since the subjects' population consisted of both pre- and post-menopausal women, no significant difference between the groups appears to be influenced by hormonal fluctuations in pre-menopausal women (17). Sambrook et al. measured estrogen concentrations in 49 postmenopausal women with rheumatoid arthritis and 49 women without rheumatoid arthritis. In this study, compared with the control group, estrogen levels declined in the females with rheumatoid arthritis significantly (18).
In line with our findings, in Nikolv et al.’s study, there was a significant difference in the severity of back pain between women with low and women with normal levels of estrogen. In these women, plasma estrogen levels, as a hormonal and reproductive factor, had a significant negative relationship with low back pain (19).
Similarly, in Sowers et al.’s study, there was a significant association between low estradiol level, 2-hydroxy estrone, and the development of knee osteoarthritis (20).
Estrogen is an important factor in maintaining the integration of the musculoskeletal system (21). The inability to produce estrogen in the menopausal status is associated with decreasing the skeletal muscle mass, muscle performance, and functional capacity (22). At present, there is growing evidence on the role of estrogen in increasing the activity of joint tissues via complex molecular pathways. Estrogen therapy plays an influential role in maintaining and restoring joint tissues in osteoarthritis (23). Stening et al conducted a clinical trial study involving 29 postmenopausal women. In this study, after six weeks of treatment with transdermal estrogen, no relief of pain was observed (24), which could be expectable because of the small sample size and short duration of estrogen therapy. Indeed, the effect of hormone therapy on pain possibly depends on the dose or duration of hormone therapy and also its different effects on the target organs such as the joints, spine, etc (25). Contrary to this, in a clinical trial study, 16,608 postmenopausal women were classified into conjugated estrogen plus medroxyprogesterone acetate or placebo. It was seen that the hormone therapy group reported relief of joint pain and joint stiffness (26).
As estrogen level decreases during menopause, this can induce musculoskeletal pains and joint stiffness; as a result, estrogen replacement therapy may decrease the risk of musculoskeletal pains.
Since menopause is not essentially a risk factor for musculoskeletal pains, it is important to identify other factors for this among menopausal women. In the present study, in addition to climacteric symptoms and serum estradiol level, older age, high parity, and high BMI were related to the higher risk of musculoskeletal pains. Furthermore, with the increase of marriage age, young maternal age, and physical activity, musculoskeletal pains decreased. In Wijnhoven et al.’s cross-sectional study, young maternal age and estrogen therapy during menopause were related to low back pain. The findings suggest that hormonal and reproductive factors are related to musculoskeletal pains (27). In explaining this finding, it seems that women have more severe menopausal symptoms, seek different treatments such as hormone therapy.
Meanwhile, in Sievert et al.’s study, menopausal women with back pain were more likely to be older, have less educational level, and have higher BMI, whereas women with joint pain were more likely to be post-menopause, with less educational level, more children and higher BMI (28). In Gao HL et al.’s study, menopause was regarded as a period for the increase of musculoskeletal symptoms. In addition, higher BMI and age were associated with increased prevalence of knee pain and joint stiffness (29).
The consistent message in the literature is that exercise is a safe and powerful tool to prevent and treat many medical, psychological, and musculoskeletal conditions in females at midlife and beyond (30).
Conversely, Mitchell et al. observed that more physical activity was associated with joint pain among menopausal women (12). The feasible explanation of this contradictory result may be due to the lack of international questionnaire to assess musculoskeletal pains in inactive women.
Females with low back pain avoid doing physical activity due to fear of pain; this can lead to a faulty cycle. Sedentary lifestyles promote muscle weakness and backache (4).
In our study, the results derived from stepwise linear multiple regression analysis showed menopause symptoms are a strong predictor of musculoskeletal pains among all the variables. As stated before, a few studies have been conducted on the relationship between climacteric symptoms and musculoskeletal pains but none of them has investigated the impact of climacteric symptoms in comparison with other factors such as serum estradiol level as well as reproductive and demographic data, and this may be seen as a potential strength of our study. However, some limitations were identified in this study. This work was a cross-sectional study, so we could not recognize the causality; rather only the relationship between climacteric symptoms, serum estradiol level, and musculoskeletal pains was targeted.