Publications

We tested the effect of daytime indoor light exposure with varying melanopic strength on cognitive performance in college-aged students who maintained an enforced nightly sleep opportunity of 7 h (i.e., nightly sleep duration no longer than 7 h) for 1 week immediately preceding the day of light exposure. Participants (n = 39; mean age ± SD = 24.5 ± 3.2 years; 21 F) were randomized to an 8 h daytime exposure to one of four white light conditions of equal photopic illuminance ( 50 lux at eye level in the vertical plane) but different melanopic illuminance [24-45 melanopic-EDI lux (melEDI)] generated by varying correlated color temperatures [3000K (low-melEDI) or 5000K (high-melEDI)] and spectra [conventional or daylight-like]. Accuracy on a 2-min addition task was 5% better in the daylight-like high-melEDI condition (highest melEDI) compared to the conventional low-melEDI condition (lowest melEDI; p < 0.01). Performance speed on the motor sequence learning task was 3.2 times faster (p < 0.05) during the daylight-like high-melEDI condition compared to the conventional low-melEDI. Subjective sleepiness was 1.5 times lower in the conventional high-melEDI condition compared to the conventional low-melEDI condition, but levels were similar between conventional low- and daylight-like high-melEDI conditions. These results demonstrate that exposure to high-melanopic (short wavelength-enriched) white light improves processing speed, working memory, and procedural learning on a motor sequence task in modestly sleep restricted young adults, and have important implications for optimizing lighting conditions in schools, colleges, and other built environments.

OBJECTIVES: Extended-duration work rosters (EDWRs) with shifts of 24+ hours impair performance compared with rapid cycling work rosters (RCWRs) that limit shifts to 16 hours in postgraduate year (PGY) 1 resident-physicians. We examined the impact of a RCWR on PGY 2 and PGY 3 resident-physicians.

METHODS: Data from 294 resident-physicians were analyzed from a multicenter clinical trial of 6 US PICUs. Resident-physicians worked 4-week EDWRs with shifts of 24+ hours every third or fourth shift, or an RCWR in which most shifts were ≤16 consecutive hours. Participants completed a daily sleep and work log and the 10-minute Psychomotor Vigilance Task and Karolinska Sleepiness Scale 2 to 5 times per shift approximately once per week as operational demands allowed.

RESULTS: Overall, the mean (± SE) number of attentional failures was significantly higher (P =.01) on the EDWR (6.8 ± 1.0) compared with RCWR (2.9 ± 0.7). Reaction time and subjective alertness were also significantly higher, by ∼18% and ∼9%, respectively (both P <.0001). These differences were sustained across the 4-week rotation. Moreover, attentional failures were associated with resident-physician-related serious medical errors (SMEs) (P =.04). Although a higher rate of SMEs was observed under the RCWR, after adjusting for workload, RCWR had a protective effect on the rate of SMEs (rate ratio 0.48 [95% confidence interval: 0.30-0.77]).

CONCLUSIONS: Performance impairment due to EDWR is improved by limiting shift duration. These data and their correlation with SME rates highlight the impairment of neurobehavioral performance due to extended-duration shifts and have important implications for patient safety.

CONTEXT: Dyslipidemia and cardiovascular disease are common in shift workers and eating at night may contribute to this pathophysiology.

OBJECTIVE: To examine the effects of eating at different times of day on lipid profiles.

DESIGN: Two 24-hour baseline days with 8 hours of sleep, 3 meals (breakfast, lunch, dinner) and a snack, followed by a 40-hour constant routine (CR) with hourly isocaloric meals.

SETTING: Intensive Physiological Monitoring Unit, Brigham and Women's Hospital.

PARTICIPANTS: Twenty-one healthy adults [23.4 ± 2.7 years, 5F].

INTERVENTION: Forty-hour CR.

MAIN OUTCOME MEASURES: A standard clinical lipid panel, consisting of total cholesterol, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), was assayed in blood samples collected 4-hourly across  4 days.

RESULTS: When participants ate at night, levels of TG were similar to eating during the day, however, these levels at night were reached with consuming approximately half the calories. Additionally, 24-hour levels of TG were 10% higher when meals were consumed hourly across 24 hours compared to consuming a typical 3-meal schedule while awake during the day and sleeping at night. The endogenous circadian rhythms of TG, which peaked at night, were shifted earlier by  10 hours under baseline conditions, whereas the rhythms in total cholesterol, HDL-C, and LDL-C remained unchanged and peaked in the afternoon.

CONCLUSIONS: The time-of-day dependency on postprandial lipid metabolism, which leads to hypersensitivity in TG responses when eating at night, may underlie the dyslipidemia and elevated cardiovascular disease risk observed in shift workers.

OBJECTIVE: Vasomotor symptoms (VMS) (hot flashes and night sweats) affect most women over the menopause transition. Comparing the safety and effectiveness of treatments for vasomotor symptoms is limited by the use of inconsistent outcome measures, and uncertainty as to which outcomes are most important to symptomatic women. To address this, we have developed a Core Outcome Set (COS) for use in clinical trials of treatments for VMS.

METHODS: We systematically reviewed the primary outcomes measured in randomized controlled trials of treatments for VMS. These were refined and entered into a two-round modified Delphi survey completed by clinicians, researchers, and postmenopausal women between November 2019 and March 2020. Outcomes were scored on a nine-point scale from "not important" to "critically important." Two international consensus meetings were held to finalize the COS.

RESULTS: Based on the systematic review, 13 separate outcomes were included in the Delphi process. This was completed by 227 participants of whom 58% were postmenopausal women, 34% clinicians, and 8% researchers. Predefined thresholds were applied to categorize importance scores obtained during Round 2 of the Delphi survey. These informed discussions at the consensus meetings which were attended by 56 participants from 28 countries. The final COS includes six outcomes: 1) frequency of VMS, 2) severity of VMS, 3) distress, bother or interference caused by VMS, 4) impact on sleep, 5) satisfaction with treatment, and 6) side-effects of treatment.

CONCLUSION: Implementation of this COS will: better enable research studies to accurately reflect the joint priorities of postmenopausal women, clinicians and researchers, standardize outcome reporting, and facilitate combining and comparing results from different studies, and ultimately improve outcomes for women with bothersome VMS.

OBJECTIVE: Irritability is a highly burdensome complaint, commonly, but not universally, linked with depressive symptoms. While increased variability in estradiol has been associated with depressive symptoms during perimenopause, more insight is needed into reproductive hormone dynamics and other factors that predispose perimenopausal women to irritable mood.

METHODS: Among 50 mildly depressed perimenopausal women (mean (SD) age 48.4 (3.9) years), severity of irritability symptoms (on Symptom Questionnaire Hostility subscale, range 0-23) was assessed weekly for eight weeks, concurrent with potential predictors. Associations between these were examined using generalized estimating equating models.

RESULTS: Most women (82.0%) reported having moderate to severe irritability at least once. However, the severity of irritability was highly variable from week-to-week (between-subject mean coefficient of variation [CV] 72.9% and within-subject mean CV 63.7%). In multivariate analyses, less variable serum estradiol levels (standardized β within-person CV -0.23 95%CI [-0.32, -0.14], p < 0.001), greater depression severity (0.45 [0.35, 0.56], p < 0.001), younger age (-0.23, [-0.28, -0.09], p < 0.001), and more frequent vasomotor symptoms (0.14 [0.05, 0.23], p = 0.002) were associated with more irritability. Depression severity explained the largest portion of the variance in irritability, but still not more than 20.3%. Neither crude values, weekly change in, or variability of progesterone or FSH levels were associated with irritability.

CONCLUSIONS: Irritability was highly prevalent among mildly depressed perimenopausal women. In contrast to depressive symptoms, decreased rather than increased variability in estradiol levels was associated with more irritability. This highlights that irritable mood can be disentangled from depressive symptoms in perimenopausal women and might be linked with different estradiol dynamics.

OBJECTIVE: To examine the effects of prescription sleep medications on patient-reported sleep disturbances.

DESIGN: Retrospective cohort.

SETTING: Longitudinal cohort of community-dwelling women in the USA.

PARTICIPANTS: Racially and ethnically diverse middle-aged women who reported a sleep disturbance.

INTERVENTIONS: New users of prescription sleep medications propensity score matched to women not starting sleep medications.

MAIN OUTCOMES AND MEASURES: Self-reported sleep disturbance during the previous 2 weeks-difficulty initiating sleep, waking frequently and early morning awakening-using a 5-point Likert scale, ranging from no difficulty on any night (rating 1) to difficulty on 5 or more nights a week (rating 5). Sleep disturbances were compared at 1 year (primary outcome) and 2 years of follow-up.

RESULTS: 238 women who started sleep medications were matched with 447 non-users. Participants had a mean age of 49.5 years and approximately half were white. At baseline, sleep disturbance ratings were similar: medication users had a mean score for difficulty initiating sleep of 2.7 (95% CI 2.5 to 2.9), waking frequently 3.8 (95% CI 3.6 to 3.9) and early morning awakening 2.8 (95% CI 2.6 to 3.0); non-users ratings were 2.6 (95% CI 2.5 to 2.7), 3.7 (95% CI 3.6 to 3.9) and 2.7 (95% CI 2.6 to 2.8), respectively. After 1 year, ratings for medication users were 2.6 (95% CI 2.4 to 2.8) for initiating sleep, 3.6 (95% CI 3.4 to 3.8) for waking frequently and 2.8 (95% CI 2.6 to 3.0) for early morning awakening; for non-users, the mean ratings were 2.3 (95% CI 2.2 to 2.5), 3.5 (95% CI 3.3 to 3.6) and 2.5 (95% CI 2.3 to 2.6), respectively. None of the 1 year changes were statistically significant nor were they different between medication users and non-users. Two-year follow-up results were consistent, without statistically significant reductions in sleep disturbance in medication users compared with non-users.

CONCLUSIONS: These analyses suggest that women who initiated sleep medications rated their sleep disturbances similar after 1 and 2 years. The effectiveness of long-term sleep medication use should be re-examined.

OBJECTIVE: The menopausal transition is characterized by progressive changes in ovarian function and increasing circulating levels of gonadotropins, with some women having irregular menstrual cycles well before their final menstrual period. These observations indicate a progressive breakdown of the hypothalamic-pituitary-ovarian axis often associated with an increase in menopausal symptoms. Relationships between vasomotor symptoms (VMS) and depressed mood and sleep as well as a bidirectional association between VMS and depressed mood in mid-life women have been reported, but the endocrine foundations and hormone profiles associated with these symptoms have not been well described. Our objective was to determine the relationship between daily urinary hormone profiles and daily logs of affect and VMS during the early perimenopausal transition.

STUDY DESIGN: SWAN, the Study of Women's Health Across the Nation, is a large, mutli-ethnic, multisite cohort study of 3302 women aged 42-52 at baseline, designed to examine predictors of health and disease in women as they traversed the menopause. Inclusion criteria were: an intact uterus and at least one ovary present, at least one menstrual period in the previous three months, no use of sex steroid hormones in the previous three months, and not pregnant or lactating. A subset (n = 849) of women aged 43-53 years from all study sites in the first Daily Hormone Study collection were evaluated for this substudy.

OUTCOME MEASURES: We measured daily VMS, and urinary hormones: follicle stimulating hormone (FSH), luteinizing hormone (LH), pregnanediol glucuronide (PdG) and estradiol (estrone conjugate, E1C).

RESULTS: A variable pattern of LH and negative LH feedback were the hormone patterns most strongly associated with increased VMS. In contrast, no hormone pattern was significantly related to negative mood.

CONCLUSION: Fluctuations of LH associated with low progesterone production were associated with VMS but not negative mood, suggesting different endocrine patterns may be related to increased negative mood than to the occurrence of VMS.

OBJECTIVE: Risk-reducing bilateral salpingo-oophorectomy (RRBSO) substantially reduces ovarian cancer risk in women with pathogenic gene variants and is generally recommended by age 34-45 years. Natural menopause is a vulnerable period for mood disturbance, but the risk of depression and anxiety in the first 12 months after RRBSO and potential modifying effect of hormone therapy are uncertain.

METHODS: Prospective controlled observational study of 95 premenopausal women planning RRBSO and a Comparison group of 99 premenopausal women who retained their ovaries,- 95% of whom were at population level risk of ovarian cancer. Clinically significant symptoms of depression and anxiety were measured using standardised instruments at baseline, 3, 6 and 12 months. Chi-square tests and adjusted logistic regression models compared differences between groups.

RESULTS: Baseline symptoms and previous depression or anxiety did not differ between groups. At 3 months after RRBSO clinically significant depressive symptoms were doubled (14.5% vs 27.1%, p = 0.010), which persisted at 12 months. Depressive symptoms were stable in comparisons. At 3 months after RRBSO, clinically significant anxiety symptoms almost trebled (6.1% vs 17.7%, p = 0.014) before plateauing at 6 months and returning to baseline at 12 months. Compared to comparisons, RRBSO participants were at 3.0-fold increased risk of chronic depressive symptoms (Wald 95% CI 1.27-7.26), 2.3-fold increased risk of incident depression (95% Wald CI 1.08-5.13) and 2.0-fold increase of incident anxiety (Wald 95% CI 0.78-5.00). Depression and anxiety were slightly more common in Hormone Therapy users after RRBSO vs non-users.

CONCLUSIONS: RRBSO leads to a rapid increase in clinically significant depressive and anxiety symptoms despite Hormone Therapy use.

This White Paper presents the results from a workshop cosponsored by the Sleep Research Society (SRS) and the Society for Research on Biological Rhythms (SRBR) whose goals were to bring together sleep clinicians and sleep and circadian rhythm researchers to identify existing gaps in diagnosis and treatment and areas of high-priority research in circadian rhythm sleep-wake disorders (CRSWD). CRSWD are a distinct class of sleep disorders caused by alterations of the circadian time-keeping system, its entrainment mechanisms, or a misalignment of the endogenous circadian rhythm and the external environment. In these disorders, the timing of the primary sleep episode is either earlier or later than desired, irregular from day-to-day, and/or sleep occurs at the wrong circadian time. While there are incomplete and insufficient prevalence data, CRSWD likely affect at least 800,000 and perhaps as many as 3 million individuals in the United States, and if Shift Work Disorder and Jet Lag are included, then many millions more are impacted. The SRS Advocacy Taskforce has identified CRSWD as a class of sleep disorders for which additional high-quality research could have a significant impact to improve patient care. Participants were selected for their expertise and were assigned to one of three working groups: Phase Disorders, Entrainment Disorders, and Other. Each working group presented a summary of the current state of the science for their specific CRSWD area, followed by discussion from all participants. The outcome of those presentations and discussions are presented here.