Sleep Disturbances among Females and Associated Risk Factors: A Nationwide Cohort Study in Iceland

Bakgrunnur: Faraldsfræðilegar lýðgrundaðar ferilrannsóknir hafa sýnt að tíðni skerta svefngæða eru á bilinu 27–52% meðal kvenna víðsvegar um heiminn. Engar faraldsfræðilegar rannsóknir hafa verið framkvæmdar til að meta svefngæði hjá íslenskum konum til þessa. Markmið þessarar rannsóknar er því að meta algengi skerta svefngæða hjá íslenskum konum og tengsl þess við bakgrunnsbreytur og aðra áhættuþætti. Aðferð: Þátttakendur voru samtals 31.811 íslenskar konur (18–69 ára) sem tóku þátt í lýðgrundaðri ferilrannsókn sem heitir Áfallasaga kvenna á árunum 2018–2019. Upplýsingum um bakgrunn, heilsufarslega þætti og skjátíma var safnað með rafrænum sjálfsmatsspurningalista. Svefngæði vorum metin með Pittsburg Sleep Quality Index (PSQI). Poission-aðhvarfsgreining var notuð til að reikna áhættuhlutföll (ÁH) með 95% öryggisbili (ÖB). Leiðrétt var fyrir aldri, menntun, líkamsþyngdarstuðli, áfengisneyslu og reykingum þegar það átti við. Niðurstöður: Í heildina greindu 65,6% kvenna frá skertum svefngæðum (>5 stig á PSQI) síðasta mánuðinn. Samband aldurs og svefngæða var U-laga þar sem yngstu og elstu þátttakendurnir greindu frekar frá skertum svefngæðum. Niðurstöðurnar gáfu til kynna að það að búa á Norðurlandi (leiðrétt ÁH = 1.06 [95% ÖB (1.03–1.09)]), lágt menntunarstig (leiðrétt ÁH = 1.32 [95% ÖB (1.29–1.34)]), lágar tekjur (leiðrétt ÁH = 1.46 [95% ÖB (1.42–1.50)]), að vera einhleyp (leiðrétt ÁH = 1.16 [95% ÖB (1.15–1.18)]) og eiga fimm börn eða fleiri (leiðrétt ÁH = 1.11 [95% ÖB (1.06–1.15)]) tengist aukinni hættu á skertum svefngæðum. Ennfremur tengdust óvirkni á vinnumarkaði (leiðrétt ÁH = 1.38 [95% ÖB (1.36–1.40)]) og vaktavinna (leiðrétt ÁH = 1.21 [95% ÖB (1.18–1.24)]) skertum svefngæðum. Þeir heilsufarslegu þættir sem tengdust skertum svefngæðum voru undirvikt (leiðrétt ÁH = 1.17 [95% ÖB (1.09–1.25)]), offita (leiðrétt ÁH = 1.23 [95% ÖB (1.21–1.25)]), reykingar (leiðrétt ÁH = 1.37 [95% ÖB (1.34–1.40)] fyrir daglegar reykingar) og óhófleg áfengisneysla, sérstaklega einu sinni eða oftar í viku (leiðrétt ÁH = 1.25 [95% ÖB (1.21–1.29)]). Að auki tengdust þrjár klukkustundir eða meira af daglegum tómstundatengdum skjátíma skertum svefngæðum, en áhættan á skertum svefngæðum jókst með aukinni skjánotkun. Ályktanir: Niðurstöður rannsóknarinnar gefa til kynna að algengi skerta svefngæða sé hærra hjá íslenskum konum en annarsstaðar. Jafnframt tengist búseta á Norðurlandi, lág félagshagfræðileg staða og slæm heilsutengd hegðun skertum svefngæðum. Þessar niðurstöður gætu nýst við skipulagninu forvarna og til að bera kennsl á konur sem þurfa á íhlutun að halda til að bæta svefn sinn.Background: International population-based studies have found the prevalence of poor sleep quality among adult females to range from 27% to 52%. However, no epidemiological population-based study has assessed this among Icelandic females. Therefore, the aim of this study is to assess the prevalence of poor sleep quality among the Icelandic female population and associated risk factors. Method: Participants consisted of 31,811 Icelandic females (18–69 yrs. old) who took part in the nationwide Stress and Gene Analysis (SAGA) cohort study in 2018–2019. Information on background characteristics, health-related behavior, and screen-time was assessed with a self-report questionnaire. Past month sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI). Poisson log-linear models were used to obtain relative risks (RRs) with 95% confidence intervals (CIs). Adjustments were made for age, education, BMI, alcohol consumption, and smoking, when relevant. Results: Overall, 65.6% of females were experiencing poor sleep quality (PSQI score > 5) in the past month. The relationship between age and sleep quality was U-shaped, with poor sleep quality being more common among the youngest and oldest participants. In addition, residing in North Iceland (adjusted relative risk [aRR] = 1.06 [95% CI (1.03–1.09)]), low education level (aRR = 1.32 [95% CI (1.29–1.34)]), low income (aRR = 1.46 [95% CI (1.42–1.50)]), not being in a relationship (RR = 1.16 [95% CI (1.15–1.18)]), and having five or more children (aRR = 1.11 [95% CI (1.06–1.15)]) was associated with poor sleep quality. Furthermore, being inactive in the workforce (aRR = 1.38 [95% CI (1.36–1.40)]) and working shifts, compared to regular hours (aRR = 1.21 [95% CI (1.18–1.24)]) was associated with poor sleep quality. Health-related factors associated with poor sleep quality included being underweight (aRR = 1.17 [95% CI (1.09–1.25)]), obese (aRR = 1.23 [95% CI (1.21–1.25)]), smoking (aRR = 1.37 [95% CI (1.34–1.40)] for daily smoking), and binge drinking, particularly once or more a week (aRR = 1.25 [95% CI (1.21–1.29)]). In addition, more than three hours of daily leisure-based screen-time was associated with poor sleep quality, with the risk of poor sleep quality increasing as a function of time spent in front of screens. Conclusion: Our results indicate that the prevalence of poor sleep quality in the Icelandic female population is higher than elsewhere. In addition, residing in North Iceland, low socioeconomic status, shift work, and adverse health-related behavior were associated with poor sleep quality. These findings could be valuable in the development of preventive strategies and identifying females who could benefit from interventions to improve sleep

Psychometric properties of the Satisfaction with life scale (SWLS) in a sample of individuals over the age of 40 years old from the Icelandic population

Background: The psychometric properties of different language versions of the Satisfaction with Life Scale (SWLS) has been shown to be good to excellent in general populations and clinical samples. The current study estimated the psychometric properties of the Icelandic version of the SWLS as well as general life satisfaction for a large, population based sample of Icelandic individuals over the age of 40. The current study is part of the largest scientific study to date conducted in Iceland, which evaluates the value of screening for a precursor of myeloma in Icelanders over the age of 40. Methods: All Icelandic individuals born preceding the year of 1976 (i.e., 40 years or older) were offered participation in a study screening for monoclonal gammopathy of undetermined significance (MGUS), which is a precursor to multiple myeloma. Individuals that provided informed consent were 78,581 and about half of those individuals completed at least one of the five self-report measures used in the current study. Results: The mean score on the SWLS was relatively high with females scoring slightly higher than males in most age groups. The relationship between satisfaction with life and age followed a nonlinear, slightly U-shaped curve, in which life satisfaction decreased until late middle age and then increased again. The SWLS had good internal consistency and construct validity in the current sample. Conclusions: The results of the current study were in accordance with previous studies into satisfaction with life. On average, the Icelandic population over the age of 40 reported being satisfied with their lives. Additionally, females reported being slightly more satisfied with their lives than males, and the relationship between life satisfaction and age was nonlinear and slightly U-shaped. Results from the current study indicate that the psychometric properties of the Icelandic version of the SWLS are good, and therefore, the Icelandic version of the scale is a reliable and valid measure of life satisfaction