Discussion
napping, non-PCOS, sleep behavior, PCOS, co-morbidity, psychiatric
OBSTRUCTIVE SLEEP APNEA, INCREASED SLEEP
To our knowledge, this is the first study investigating objectively measured sleep health variables in overweight women with PCOS both compared to controls, as well as after lifestyle intervention. We found that women with PCOS had poorer sleep efficiency and longer wakefulness after sleep onset than controls. Furthermore, there was a non-significant reduction in total sleep time over 24 hours, as well as in total daytime sleep following behavioral modification intervention, although this was significant when compared to the minimal intervention group. There was no reduction in the total sleep time at night, suggesting less daytime napping after behavioral modification intervention.In adults, the recommended sleep duration is between 6h to 8h per night, where sleep over 9h could be used to detect co-morbidity (An increased sleep duration could have been an artefact of a wider sleep window. The data for the control group was partly recorded during the beginning of the COVID-19 pandemic, when working from home was recommended, which could have permitted a larger night time sleep window for this group as well as opportunities for daytime napping. In addition, the proportion of women with children was lower among the controls, and fewer were in a stable relationship. However, there was no difference in the proportion of students between the groups and no-one was unemployed, factors that could otherwise have permitted a wider sleep window and provided an explanation for the longer sleep times in the control group. When controlling for the potential covariates of being in a relationship, having children, BMI and waist circumference, the difference between groups in daytime sleep and time of rising disappeared, leading us to believe that being in a relationship and having children affected these variables. However, this does not alter the fact that sleep quality, in terms of sleep efficiency, was considerably higher in the control group even after adjusting for covariates.Our findings are in agreement with two other studies that have found lower actigraphy recorded sleep efficiency in women with PCOS compared to controls; Shreeve et al. (In terms of psychiatric well-being, we found a positive correlation between self-control and sleep efficiency and a negative correlation between self-control and wakefulness after sleep onset which is reasonable since the latter contributes largely to the sleep efficiency measure. A recent study by Yang et al. (In addition to comparing the objectively measured sleep variables in women with POCS with controls, we have also for the first time investigated the effects of lifestyle intervention on sleep variables in women with PCOS. We found that following behavioral modification intervention the overweight/obese women with PCOS displayed a non-significant reduction in the total sleep time over 24 hours and in daytime sleep, compared to the minimal intervention group where the total sleep time over 24 hours and daytime sleep increased, and the difference in these changes following intervention between groups was significant. As no such significant difference between groups was seen for the total sleep time at night, the reduction of total sleep time over 24hours is explained by less daytime napping following behavioral modification intervention. A meta-analysis based on a non-PCOS population by Zhong et al. (A strength of the study is the use of actigraphy for objectively measured sleep variables compared to the majority of studies on similar populations using subjective reporting of sleep quality. Actigraphy also allows for a non-invasive method of assessing sleep for a long period of time in a patient’s normal environment. However, actigraphy cannot be used for the assessment of obstructive sleep apnea. One limitation of his study is that the collection of sleep data for the control group partly was completed during the COVID-19 pandemic, when working from home was recommended by the authorities, enabling a wider window of sleep. In addition, there were differences in the proportion of women with children, as well as those in a stable relationship between the groups, however these differences were adjusted for in the statistical analyses.In conclusion, we found that women with PCOS had shorter sleep duration, although within the normal range, but poorer sleep-efficiency and longer periods of wakefulness after sleep onset compared to controls. In terms of sleep quality after lifestyle intervention in the women with PCOS, there was a non-significant reduction in the total sleep time over 24 hours, as well as total daytime sleep following behavioral modification intervention, which was significant when compared to the minimal intervention group. Behavioral modification intervention seems to reduce the amount of daytime sleep, suggesting improved sleep behavior.