title: Diet and Menopause
Creators: name: Grisotto, Giorgia
Publisher: name: Universität Bern
Year: 2024
Subjects: subject: 610 Medicine &amp; health

description: Background: Menopause occurs naturally between the ages of 40 and 60, with 80–90% of women experiencing menopause between ages 45 and 55. Menopausal transition is associated with a drastic drop in oestrogen, an increase in iron concentrations, the appearance of menopausal symptoms, and an increase in the incidence and mortality rates for cardiovascular disease (CVD). Early menopause (at age 45 or younger) is associated with increased risk of type 2 diabetes (T2D), CVDs, bone fractures, mood disorders, and decline in cognitive functions. Conversely, late menopause (at age 55 or older) is associated with an increased risk of ovarian, endometrial, and breast cancer. Understanding modifiable risk factors affecting the age at which menopause occurs may have implications not only for family planning, but also for menopause-related diseases. Aims: I analyse the role diet has on natural menopause onset. In my first article, I evaluate the association between menopausal status and changes in dietary intake among adult women in Switzerland. In the second article, I systematically review and evaluate published research on the associations between diet and the onset of natural menopause (ONM). In the third and fourth articles, by using data from large population-based cohorts, I investigate the association of plant-based diet index (PDI) and dietary iron intake with incidence of early natural menopause. Methods: For the first article, I used data from women enrolled in the first and the second follow-up visits of the CoLaus study—a population-based cohort study in Lausanne, Switzerland. I included women with available data on dietary intake and information on menopause status from two visits in my analysis. I used multivariable and linear models and linear mixed models adjusted for potential confounders to cross-sectionally and longitudinally investigate the association between menopause status and dietary intake. To summarize the evidence on the association between diet and ONM, I used a systematic review and meta‐analysis in the second article. In articles 3 and 4, I used data from premenopausal women enrolled in the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHSII) cohorts—population-based cohorts in the United States. I conducted a Cox proportional hazard model to assess the association of PDI in quintiles with incidence of early natural menopause in NHS and NHSII separately and fixed-effect model to pool the results from both cohorts (article 3). I conducted the same analyses to assess the association of dietary iron intake with incidence of early natural menopause (article 4). Dietary intake was assessed using the food-frequency questionnaire (FFQ), while menopause status and ONM was self-reported for all studies. Results: These studies’ results are presented in 4 articles. In article 1, I included 1,641 women and showed no association of menopause status with total energy intake (TEI), dietary intake, and adherence to the Swiss dietary recommendations, neither cross-sectionally nor longitudinally. Article 2 shows that among the investigated food groups, higher intake of green and yellow vegetables was associated with early age of ONM, while high intakes of some dairy products, such as low-fat, skim milk, and low intake of alcohol were associated with a later onset. I observed no consistent association between
2
macronutrient and micronutrient intake and ONM, although a vegetarian diet was more associated with early ONM. After adjustment for potential confounders, article 3 shows no observed association between PDI and the incidence of early natural menopause in either cohort or when pooling the results from both cohorts. Article 4 shows high intake of iron heme was strongly associated with higher risk to experience early natural menopause among the NHSII cohort. Yet, an association was found between iron non-heme and higher risk of early natural menopause in NHS only in fully adjusted models.
Conclusion: I contribute to scientific knowledge by recognizing the current gaps regarding the role of diet on ONM and by providing new knowledge about components of diet, such as dietary iron intake, that may impact ONM. Despite menopause being associated with elevated risks of T2D and CVD and adhering to a healthy diet during this critical phase of women’s life could help reduce these risks, my research shows that women do not change their diets during menopause transition or when they are in menopause. Also, to be easily understood by a wide range of professionals and the public, I suggest writing dietary guidelines and scientific findings related to menopause in plain language.