A multinational study of sleep disorders during female mid-life
Introduction
Sleep disturbances are highly prevalent in the general population, and may particularly affect women and individuals with physical and/or mental health deterioration [1], [2]. Therefore, it is not of surprise that the climacteric defines a period of high risk for sleep disturbances which may impair female quality of life (QoL). The Study of Women's Health Across the Nation (SWAN), a multiethnic female sample of 12,603, found that 38% of women aged 40–55 reported sleep difficulties significantly related to the menopause [3]. This percentage of affected women is higher than the 17.4% described in the general North-American population [4].
Sleep disturbances constitute a complex phenomenon, which may be primary (endogenously disrupted sleep-vigilance), or secondary (owing to psychological disorders, physical diseases, or the use of drugs) [5]. Therefore during assessment it is important to use methods that aid at determining whether subjects complaining of insomnia suffer a sleep disorder or whether insomnia constitutes a symptom of some other mental disorder. Polysomnography is an objective method for the assessment of sleep disorders, nevertheless it does not allow self-evaluation of sleep quality or the impact that sleep disturbances may have over daytime functioning. Given the heterogeneity of sleep disturbances, various instruments have been developed that allow both quantitative and qualitative assessment of sleep quality and its impact on every-day life [6]. The SWAN also found that the prevalence of sleep disturbances was significantly related to ethnic origin, varying from 28% in Japanese women to 40% in Caucasians [3]. Bearing in mind the aforementioned aspects, our research group was interested in carrying out a multinational study to determine the prevalence of sleep disturbances in mid-aged Latin American women using validated tools. Assessment of determinants capable of influencing the prevalence of insomnia and poor sleep quality was also performed.
Section snippets
Participants and study design
This cross-sectional descriptive study was carried out among otherwise healthy Hispanic women aged 40–59 who accompanied patients attending 20 healthcare centres from cities with more than 500,000 inhabitants in 11 Latin American countries. Healthy status was defined according to criteria of the National Center for Health Statistics [7], as that enabling the performance of daily routine activities. Women with an ethnical origin distinct to Hispanic (i.e. Afro-American or Amerindian) or with a
Results
During the study period a total of 6598 women were invited to participate. A 7.9% denied participation leaving 6079 complete surveys for statistical analysis. Main characteristics of participants are depicted in Table 1. Mean age and educational level of the entire sample was 49.8 ± 5.4 and 10.8 ± 4.9 years, respectively. Mean parity was 2.5, 68.9% had a stable partner, 57.6% were postmenopausal and 15.8% had surgical menopause. Overall, 55.5% of women displayed VMS, 13.2% used HT and 11.5%
Discussion
More than half of the participants of the present research were affected with insomnia and/or poor sleep quality. This slightly differs from a US study that found that 38% of women suffer sleep difficulties [3]. Nevertheless, the latter US finding was based on only one question assessing the previous 2 weeks. Using the Insomnia Severity Index (ISI) a recent study found that 41.5% of Ecuadorian women aged 40–59 suffer insomnia [26], a percentage similar to the 43.6% found in the present series.
Contributors
Juan E. Blumel, Edward Mezones-Holguín, Silvina Witis and Selva Lima were involved in the conception and design of the study. Germán Barón, Ascanio Bencosme, Zully Benítez, Luz M. Bravo, Andrés Calle, Peter Chedraui, Daniel Flores, María T. Espinoza, Gustavo Gómez, José A. Hernández-Bueno, Fiorella Laribezcoa, Mabel Martino, Selva Lima, Alvaro Monterrosa, Desiree Mostajo, Eliana Ojeda, William Onatra, Hugo Sánchez, Konstantinos Tserotas, María S. Vallejo, Silvina Witis, María C. Zuñiga
Competing interests
None declared.
Funding
None.
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