Menopause is an important part of women’s reproductive health that is characterised by the loss of ovarian function because of reduced oestrogen secretion, permanent termination of menstruation and the loss of the ability to reproduce (Koo et al., 2017). Menopause can affect biological, psychological and social aspects of a woman’s life (Tan et al., 2014). It is also argued that obesity can impact upon the menopause. Obesity affects both sexes and all ages. Many countries in the western world have extortionate rates of obesity among adults, with women in the United Kingdom having an obesity rate of 26.8% (OECD, 2017a). Obesity is an ever increasing health concern (OECD, 2017b); especially during periods of a persons’ life, where health risks are already increased, such as in the elderly and during menopause for middle-aged women.
Menopause can manifest itself in the form of vasomotor symptoms (VMS), such as hot flushes and night sweats (Thurston and Joffe, 2011), these are episodes of excessive heat, accompanied by sweating and flushing (Goughnour et al., 2016).
Obesity was thought to be protective against VMS as adipose tissue aromatised androgens into oestrogen’s (Ryan et al., 1999 cited in Thurston and Joffe, 2011). However, it has since been argued that adipose tissue instead acts as an insulator (Thurston et al., 2008).
There is evidence to support that obesity is associated with VMS (Tan et al., 2014; Goughnour et al., 2016; Koo et al., 2017).
Peri- and post-menopausal obese women, having a body mass index (BMI) of 30-39.9 kg/m2, experience VMS whereas overweight and normal weight women, having a BMI of 25-29.9 kg/m2 and 18.4-24.9 kg/m2 respectively, only experienced post-menopausal VMS. Post-menopausal obese women are also the most likely to report VMS (Koo et al., 2017). Contrarily, Mirzaiinjmabadi et al. (2006) found no relationship between VMS and BMI.
Vulvovaginal atrophy is also associated with menopausal women and is linked to oestrogen deficiency (Al-Safi and Polotsky, 2015). Symptoms include vaginal dryness and itching.
In addition, evidence shows that obese women are more likely to report moderate or severe vulvovaginal atrophy compared to women with normal BMI (Pastore et al., 2004; Tan et al., 2014). However, Tan et al. (2014) found no significant relationship was found between the groups. A limitation of this study is that obese women were the most represented.
Goughnour et al. (2016) found that there was no significant difference in the “degree of bother” between pre- and post-operation weight loss surgery patients. However, it was noted that there was a small decrease in the prevalence of symptoms.
In turn, menopause is thought to affect a woman’s BMI (Trikudanathan et al., 2013). Women who had had their ovaries removed, experienced accelerated weight gain, which suggests that it is the lack of hormones, as happens as a result of the menopause, in women, which results in increases in BMI (Gibson et al., 2013). Other factors within a woman’s reproductive life, such as the number of pregnancies, are argued to more accurately predict a woman’s risk of obesity after menopause (Zsakai et al., 2015).
As the average age of menopausal onset being 51 (Al-Safi and Polotsky, 2015), age may also play a factor in weight gain. Weight gain during midlife, and hence menopause, could be associated with an energy expenditure (EE) decline (Siervo et al., 2015). This decline could be a result of a decrease in physical activity, losing fat-free mass or no longer experiencing the menstrual cycle, the luteal phase in particular as it is associated with a rise in EE (Duval et al., 2013). Similar to explanations of weight gain for menopausal women, men of a similar age also display an increase in weight and a decrease in EE (Hales et al., 2017; Siervo et al., 2015). Thus, this suggests that chronological age rather than reproductive age is more responsible for the occurrence of obesity than menopause.
Both obesity and menopause have been linked to non-communicable diseases (NCD) and therefore it is logical to question whether they have a synergistic effect. Although disease risk increases with age (Niccoli and Partridge, 2012), the end of a female’s reproductive years, combined with obesity, further increases this risk (Villaverde-Gutierrez et al., 2015).
Post-menopausal obese women have a greater cardiovascular risk than both pre-menopausal obese women and post-menopausal normal weight women (Tufano et al., 2004; Dosi et al., 2014).
Specifically, women with abdominal obesity had the greatest risk for cardiovascular disease (CVD) (Dosi et al., 2014).
Ramezani Tehrani et al. (2014) did not find an association between menopause and CVD, despite increasing BMI during the menopausal transition. Interestingly, after adjustment post-menopausal women were found to have increased levels of variables associated with obesity and therefore increased CVD risk. It should be noted that this study was not conducted for long enough to have a sufficient number of CVD events.
BMI is a well-founded predictor of cancer risk (Calle et al., 2003). Central obesity, instead of obesity as defined by BMI, had no effect upon the risk of developing breast cancer, unlike with the risk of CVD (Sangrajrang et al., 2013). Women who are post-menopausal and obese are more likely to have increased breast cancer risk than pre-menopausal obese women. Mortality rate due to breast cancer also increased two-fold among obese women compared to those with normal weight (Neuhouser et al., 2015; Sangrajrang et al., 2013). Interestingly, Bhaskaran et al. (2014) found that peri-menopausal breast cancer was associated with increasing BMI but only up to a BMI of 22, thereafter the risk decreased, meaning there was no over-all association; differently, post-menopausal breast cancer had a positive association with BMI.
To conclude, body mass index does affect the severity and/or frequency of vasomotor symptoms. The argument of whether body mass index affects vulvovaginal atrophy is more unclear; however, this may be due to a lack of research into this particular menopausal symptom. Body mass index is affected by menopause, though as midlife and menopause go hand in hand, age may have a greater effect upon body mass index than menopause. Menopause and obesity do act synergistically to increase the risk of non-communicable diseases.