1. Introduction
Menopause, marked by the cessation of menstruation and the end of reproductive capacity, typically occurs between the ages of 45 and 55, with the median age around 51
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. The timing of menopause is influenced by a variety of factors, including educational level, occupation, marital status, age at menarche, parity, and smoking habits
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. Notably, the age at which menopause occurs carries its own health implications: early menopause is linked to an increased risk of cardiovascular disease, osteoporosis, and metabolic syndrome, while late menopause heightens the risk of estrogen-sensitive cancers
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The experience of menopause and its accompanying symptoms vary significantly among individuals. Common symptoms include hot flushes, night sweats, mood changes, weight gain, and sleep disturbances
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. Research suggests that ethnicity may influence the severity of vasomotor symptoms such as hot flushes and night sweats
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. However, the term “ethnicity” encompasses a broad range of factors, including body mass index (BMI), educational attainment, parity, diet, socioeconomic status, physical activity, attitudes and beliefs toward menopause, climate, and genetic predispositions
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Studies have reported relatively high frequencies of hot flushes in women from diverse regions, including North America, Europe, Latin America, Africa, the Middle East, and Western countries, compared to lower frequencies observed among Asian women
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. Nonetheless, significant evidence points to the role of environmental factors and geographical location in shaping menopause experiences
[9]
. For instance, women who migrate from eastern to western regions tend to report more severe vasomotor symptoms, suggesting that environmental influences may outweigh ethnic determinants
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. While some evidence hints at climate’s potential impact on menopause, conclusive findings are lacking, likely due to variations in study designs, sampling methods, and populations
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This systematic literature review aims to delve into the existing body of research, focusing on the three studies that have specifically investigated the impact of climate change on menopause
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. It seeks to interpret how climate change may be altering the age of onset, severity of symptoms, and long-term effects of menopause, filling a crucial gap in our understanding of this complex phenomenon. While prior research has broadly examined this association, this review dissects the nuances of the aforementioned factors and how this might exacerbate or mitigate menopausal symptoms.
2. Methods
2.1. Study Design and Participants
This systematic literature review synthesizes findings from three distinct studies exploring the impact of climate change on menopause, with each study employing rigorous methodology to investigate certain associations within different populations and diverse geographical settings
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[16]
. Additionally, the uniqueness in population studies and climate variables make these strong studies for analysis. Criteria for inclusion also emphasized the comprehensive assessment of menopausal symptoms, diversity in climatic exposure, and representation of varying altitudes and temperatures. Our systematic search spanned databases such as PubMed, Web of Science, and Scopus, using keywords related to “menopause,” “climate change,” “geographical factors,” and “menopausal symptoms.” The search, covering literature up to April 2023, followed PRISMA guidelines for systematic reviews. Studies were screened for relevance based on titles, abstracts, and full texts, applying inclusion and exclusion criteria to ensure focus and quality. We assessed the quality of included studies using the Newcastle-Ottawa Scale, considering their design, comparability, and outcome measurement.
Study 1: Multinational Cross-Sectional Survey
The first study targeted Spanish-speaking members of CAMS (South and Central America and Spain), aiming for a diverse sample in terms of temperature, humidity, and altitude across urban environments
[14]
. Participants were perimenopausal or postmenopausal women aged 45 - 55 years, primarily from non-clinical settings. Exclusions included severe medical conditions, psychiatric disorders, and non-natural menopause causes. Data collection involved detailed questionnaires on health, lifestyle, and menopausal symptoms, utilizing measures like the Hot Flush Rating Scale (HFRS) and the Women’s Health Questionnaire (WHQ) for symptom assessment.
Study 2: Menopause Clinic Patients
The second study focused on 232 postmenopausal women attending a menopause clinic in a teaching hospital, divided according to the climate of their reproductive years (Continental, Black Sea, Mediterranean)
[17]
. The study investigated natural menopause’s onset age and metabolic factors, adjusting for known contributors like educational status and lifestyle habits. Physical measurements and biochemical analyses were conducted, with statistical analyses determining associations between climatic exposure and menopausal outcomes.
Study 3: Cross-Sectional Survey in the UAE
The third study recruited 200 women per season in the United Arab Emirates, aiming to understand the hyper-arid climate’s effect on vasomotor symptoms among perimenopausal and postmenopausal women
[16]
. Inclusion criteria mirrored those of Study 1, adapted for the native Emirati population. This study also employed the HFRS and WHQ, alongside the Menopause Representations Questionnaire (MRQ) to capture perceptions and beliefs about menopause. Data collection varied seasonally to examine potential differences in symptom reporting.
2.2. Data Collection and Analysis
In all studies, questionnaires were translated into the local language using forward and backward translation techniques to ensure linguistic and cultural appropriateness. The studies utilized a mix of recruitment strategies, from health centers to public places and media outreach, striving for broad representation. Ethical approvals were obtained in accordance with local regulations. Data from completed questionnaires were analyzed at a coordinating center in the UK, employing the SPSS software for statistical analysis. The analysis focused on quantifiable data such as symptom frequency and severity, lifestyle factors, and demographic details. Advanced statistical methods, including ANOVA, chi-square tests, and regression analyses, were used to explore predictors of menopausal symptoms and the influence of climatic factors.
2.3. Synthesis Approach
This review systematically evaluated the methodologies and findings of the three studies to identify common themes and divergent results. By integrating diverse research approaches and outcomes, the review aims to offer a comprehensive understanding of how climate change might influence menopause’s clinical and personal experiences.
3. Results
3.1. Sociodemographic and Health Variables across Studies
Study 1 involved 896 women, mainly married or with a partner, aged 50, with children, and working full-time or part-time
[14]
. The average BMI was in the overweight range. Most consumed meat, fish, and vegetables, with low alcohol intake and exercise levels. Hot flush prevalence varied by location, with an average of 58.5% experiencing vasomotor symptoms. The study found associations between hot flush prevalence and several factors, including temperature, age, general health, and diet, but not BMI or altitude. Hot flush frequency and problem rating were inversely related to altitude and directly related to temperature and humidity.
Study 2’s participants had a mean age of 59.7 years and lived in various climates
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. Differences were noted in the age at menopause, menarche, gravidity, BMI, and HDL levels across climates, with the lowest mean age at menopause in the Mediterranean climate. Climate and cigarette smoking were associated with the age at menopause. The study emphasized the impact of climate, smoking, and other factors on menopausal age and health markers.
Study 3 surveyed 372 women in the UAE, focusing on perimenopausal and postmenopausal women
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. The study highlighted the role of sociodemographics, lifestyle, and health variables on menopause symptoms. Employment, diet, BMI, and psychological factors were significant predictors of hot flushes and night sweats (HFNS) prevalence. The findings underscored the complex interplay of various factors, including diet and lifestyle, on menopause symptoms for each individual.
3.2. Key Findings and Implications
The three studies collectively highlight the multifaceted nature of menopause experiences, influenced by sociodemographic factors, health and lifestyle variables, climate, and geographic altitude
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. While the specific impacts vary across studies, several trends emerge:
The impact of climate change on menopause is a complex issue influenced by a range of factors including geographic location, lifestyle, health status, and sociodemographic variables
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. The reviewed studies provide evidence of the diverse ways in which climate and environmental factors can influence menopause symptoms and experiences. Further research is needed to understand the mechanisms behind these associations and to develop targeted interventions to support women through the menopausal transition in a changing climate.
3.3. Bias and Limitations
Potential biases include variations in sampling methods, participant self-reporting, and the representativeness of the samples
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. The studies may have selection biases, especially in recruitment from clinical settings or specific populations, which could limit generalizability. Publication bias might be present, as studies with significant findings are more likely to be published. Future research should employ longitudinal designs to better capture the long-term effects of climate change on menopause and consider the cultural and societal influences that shape menopause experiences.
4. Discussion
4.1. Synthesis of Findings across Studies
This review synthesizes findings from three studies, providing a comprehensive understanding of how climate change and geographical factors impact menopause
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. The results underscore the complexity of menopause, shaped by an interplay of environmental, physiological, psychological, and sociodemographic factors.
Environmental Influences: Consistently, the studies reveal that higher temperatures and specific climate conditions (e.g., Mediterranean climate) are correlated with increased prevalence and severity of menopausal symptoms, particularly HFNS
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. This association suggests that climatic factors directly influence women’s experiences of menopause, potentially through effects on the body’s thermoregulatory systems.
Altitude and Seasonality: Interestingly, the first study highlighted an inverse relationship between altitude and HFNS frequency and severity, suggesting that women living at higher altitudes experience fewer and less severe symptoms
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. This finding adds a complex layer to understanding menopause, indicating that not only temperature but also altitude and perhaps oxygen levels may play roles in symptom manifestation.
Health and Lifestyle Factors: Across the studies, factors such as BMI, exercise, diet, and psychological health (anxiety and depression) emerged as significant predictors of menopausal symptoms
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. These results affirm the multifaceted nature of menopause, where biological, psychological, and lifestyle factors intersect to shape women’s experiences.
Sociodemographic Variables: The influence of sociodemographic variables such as marital status, employment, and educational level on menopause symptoms was explored, with mixed findings
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. Cultural and societal factors significantly shape menopause experiences. The studies underscore the need to consider cultural attitudes, beliefs, and practices when addressing symptoms. These factors may indirectly impact menopausal experiences through their effects on women’s health, lifestyle choices, and access to care.
4.2. Implications for Future Research and Practice
Future studies should employ longitudinal designs to capture the long-term effects of climate change on menopause through:
5. Conclusions
This systematic literature review highlights the complex interplay between climate change, geographical factors, and the menopause experience
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. The reviewed studies collectively point to significant environmental impacts on menopausal symptoms, with temperature and altitude playing crucial roles
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. They also reaffirm the importance of considering individual health, psychological factors, and lifestyle choices in understanding and managing menopause.
This review acknowledges the potential confounding effects of lifestyle and socioeconomic status on the relationship between climate and menopause symptoms
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. For instance, access to healthcare and diet might mediate the severity of symptoms experienced in different climates, suggesting that future research should incorporate these variables into their analysis. This review is subject to limitations, including potential publication bias and the heterogeneity of study designs. The variability in geographical settings and climatic conditions of the included studies may affect the generalizability of our findings. Future research should aim for more standardized study designs to enhance comparability.
The findings emphasize the necessity for a multifaceted approach in research and healthcare practice, one that considers the holistic environmental, physiological, psychological, and sociodemographic dimensions of menopause
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. Actional public health strategies such as the development of targeted public health campaigns that educate women on the potential impact of climate on menopause as well as healthcare providers considering environmental factors when advising women on managing menopausal symptoms bring awareness and education to the public and policymakers. As climate change continues to alter environmental conditions globally, understanding its impact on health, particularly menopausal health, becomes increasingly vital for developing effective support and interventions for women worldwide.