Blood pressure, pulse rate, and skin temperature during hot-water bathing in real-world settings among community-dwelling older adults: the HEIJO-KYO Study.

BACKGROUND: Home hot-tub bathing substantially increases drowning mortality rates among older adults in Japan. Previous laboratory studies on hemodynamic responses during hot-tub bathing have been inconsistent depending on the thermal conditions. Furthermore, real-world hemodynamic changes that occur during bathing remain poorly understood. This study investigated the association between individual thermal states and hemodynamic parameters during hot-tub bathing among community-dwelling older adults. METHODS: In this cross-sectional study conducted between January 2016 and April 2019, which involved 1,479 older adults (median [range] age, 68 [40-90] years), skin temperature on the abdominal surface was measured every minute. Ambulatory blood pressure and pulse rate were recorded at 15-min intervals for 24 h. Participants underwent simultaneous living room temperature measurements in their homes, and the time and methods of bathing were recorded. Associations between skin temperature and hemodynamic parameters during bathing and between the pre-bath living room temperature and in-bath maximum proximal skin temperature were evaluated using mixed-effects and linear regression models, respectively. RESULTS: A 1 °C increase in skin temperature was significantly associated with a 2.41 mmHg (95% confidence interval [CI]: 2.03-2.79) increase in systolic blood pressure and a 2.99 bpm (95% CI: 2.66-3.32) increase in pulse rate, after adjusting for potential confounders, including age, sex, body mass index, antihypertensive medication use, dyslipidemia, diabetes, and living room and outdoor temperatures. Significant interactions were not observed between sex and skin temperature in relation to systolic blood pressure and pulse rate (P = 0.088 and 0.490, respectively). One standard deviation lower living room temperature before bathing was significantly associated with a 0.41 °C (95% CI: 0.35-0.47) higher maximum skin temperature during bathing. CONCLUSIONS: Our findings suggest that pre-bath cold exposure may increase the skin temperature during hot-tub bathing, possibly resulting in excessive hemodynamic changes. This provides a framework for future interventions that utilize pre-bath thermal conditions and bathing environments to prevent bath-related deaths.

Daily light exposure profiles and the association with objective sleep quality in patients with Parkinson's disease: The PHASE study.

STUDY OBJECTIVES: Light information crucially influences the sleep initiation and continuity. The purpose of this study was to compare daily light exposure between patients with Parkinson's disease (PD) and non-PD older adults and evaluate the association of daily light exposure with objective sleep measures in patients with PD. METHODS: In this cross-sectional study of 189 outpatients with PD and 1101 community dwelling older adults (controls), daily light exposure was measured using wrist light meters during the daytime and light meters set in the bedrooms during the nighttime, and objective sleep quality was measured by wrist actigraphy. RESULTS: The median duration of exposure to ≥1000 lux light was significantly shorter in patients with PD than in controls. The median nighttime light intensity was higher in patients with PD than in controls. Among patients with PD, multivariable analysis suggested that the highest quartile of exposure to ≥1000 lux light during the daytime was linked to significantly higher sleep efficiency by 8.0% and shorter wake after sleep onset (WASO) by 36.9 min than the lowest quartile. During the nighttime, the highest quartile of mean light intensity had significantly lower sleep efficiency by 6.8%, longer WASO by 24.1 min, longer sleep onset latency, and higher fragmentation index, than the lowest quartile. Importantly, daytime and nighttime light levels were independently associated with objective sleep measures. CONCLUSION: The present study illustrated that greater daytime light exposure and lower nighttime light exposure are significantly associated with better objective sleep measures in patients with PD.

Effects of a violet-excitation light-emitting diode on melatonin secretion and sleepiness: preliminary findings from a randomized controlled trial.

STUDY OBJECTIVES: A new type of lighting using violet-excitation light-emitting diodes (LEDs) with an action spectrum centered at approximately 405 nm was developed. Although violet-excitation LEDs can reduce melatonin suppression compared with blue-excitation LEDs, no studies have compared the effects of violet-excitation LEDs with those of blue-excitation LEDs on melatonin suppression. This study was designed to compare the effects of violet-excitation LEDs with those of blue-excitation LEDs on melatonin suppression, psychomotor vigilance, and sleepiness. METHODS: Sixteen healthy Japanese males aged 20-39 years were exposed to violet- and blue-excitation LEDs for 3 hours in a crossover randomized manner. The primary outcome was changes in salivary melatonin levels compared with the baseline levels. The secondary outcomes were changes in psychomotor vigilance and the Karolinska Sleepiness Scale. Melatonin suppression was calculated from the difference in the area under the curves between the baseline and intervention. RESULTS: Of the 16 participants, 15 completed the measurements. The baseline characteristics did not differ significantly between the 2 groups. After adjusting for age, a difference of 16.28 pg/mL in mean melatonin suppression was observed between the violet- and blue-excitation LED groups (-2.15 pg/mL vs -18.43 pg/mL; P = .006). The overall melatonin suppression by violet-excitation LEDs was 48.6% smaller than that by blue-excitation LEDs. No significant differences in psychomotor vigilance and sleepiness were observed between the 2 groups. CONCLUSIONS: Melatonin suppression in healthy Japanese males exposed to violet-excitation LEDs was significantly smaller than that in those exposed to blue-excitation LEDs. Our preliminary findings indicate that violet-excitation LEDs may have the potential to reduce the magnitude of blue-excitation LED-induced melatonin suppression. CITATION: Mitsui K, Saeki K, Sun M, Yamagami Y, Tai Y, Obayashi K. Effects of a violet-excitation light-emitting diode on melatonin secretion and sleepiness: preliminary findings from a randomized controlled trial. J Clin Sleep Med. 2024;20(1):101-109.

Association between circadian skin temperature rhythms and actigraphic sleep measures in real-life settings.

STUDY OBJECTIVES: Skin temperature manipulation with little or no change in core body temperature affects sleep-wake states; however, the association of 24-hour skin temperature variation with sleep quality has not been investigated in a large-scale population. We examined the association between the circadian rhythm of distal skin temperature and sleep quality in real-life settings and aimed to provide additional evidence of the link between thermoregulation and sleep-wake states. METHODS: In this cross-sectional study of 2,187 community-dwelling adults, we measured distal skin temperature at the ventral forearm at 3-minute intervals for 7 consecutive days to calculate nonparametric indicators of a circadian skin temperature rhythm, including intradaily variability, interdaily stability, and relative amplitude. Participants underwent simultaneous 7-day wrist actigraphy to objectively measure sleep quality. The association between nonparametric circadian skin temperature rhythm indicators and 7-day sleep measures was evaluated using multivariable linear regression models. RESULTS: Lower intradaily variability and higher interdaily stability and relative amplitude of distal skin temperature were significantly associated with higher sleep efficiency, shorter wake after sleep onset, and longer total sleep time (all P < .001). After adjusting for demographic, clinical, and environmental factors, the coefficients for the linear trend of sleep efficiency were -1.20 (95% confidence interval: -1.53, -0.87), 1.08 (95% confidence interval: 0.80-1.36), and 1.47 (95% confidence interval: 1.04-1.89) per quartile increase in intradaily variability, interdaily stability, and relative amplitude, respectively (all P < .001). CONCLUSIONS: Distal skin temperature with lower fluctuations and higher regularity and rhythm amplitudes was associated with better sleep quality. Our results could be applied in chronobiological interventions to improve sleep quality. CITATION: Tai Y, Obayashi K, Yamagami Y, Saeki K. Association between circadian skin temperature rhythms and actigraphic sleep measures in real-life settings. J Clin Sleep Med. 2023;19(7):1281-1292.

Association between indoor noise level at night and objective/subjective sleep quality in the older population: a cross-sectional study of the HEIJO-KYO cohort.

STUDY OBJECTIVES: Noise exposure could be an important risk factor for low sleep quality; however, evidence on indoor noise in large-scale populations is limited. We evaluate the association between indoor noise at night and objective and subjective sleep quality in the older population. METHODS: In this cross-sectional study of 1076 participants (≥60 years), we measured indoor noise at night (A-weighted equivalent noise from bedtime to rising time [LAeq]) using a portable noise level meter set in bedrooms and sleep quality using actigraphy and a questionnaire for 2 nights. Using multivariable linear regression models, we examined the associations between indoor noise at night and objective and subjective sleep parameters independent of potential confounders such as age, body mass index, and sleep medication. RESULTS: Increased indoor noise at night by 1 dB of LAeq was significantly associated with lower objective sleep quality, such as lower sleep efficiency (regression coefficient [ß], -0.19%; 95% confidence interval [95% CI], -0.26 to -0.12; p < 0.001), longer log-transformed sleep onset latency (ß, 0.02 log min; 95% CI 0.01 to 0.03; p< 0.001) and wake after sleep onset (ß, 0.66 min; 95% CI 0.40 to 0.92; p < 0.001), and higher log-transformed fragmentation index (ß, 0.01; 95% CI 0.008 to 0.017; p < 0.001). These results remained consistent in the analysis using noise-event rate (≥45 dB) as an independent variable. CONCLUSION: This study revealed the quantitative association between indoor noise at night and objective and subjective sleep quality in the older population. Reducing noise and improving sleep quality may prevent fatal diseases.

Breakfast Skipping and Declines in Cognitive Score Among Community-Dwelling Older Adults: A Longitudinal Study of the HEIJO-KYO Cohort.

Previous studies outlined the correlation of adverse effects of breakfast skipping with cognitive function. However, the majority of these studies have focused on the short-term effects; to date, the long-term effect of breakfast skipping on cognitive function among older adults remains unclear. In this prospective cohort study of 712 older adults (mean age, 70.8 years), breakfast skipping was defined as skipping breakfast one or more times per week, and declines in cognitive score was defined as decreases in Mini-Mental State Examination (MMSE) score of two or more in the observed period. During follow-up (median, 31 months), 135 of 712 participants developed declines in cognitive score. Poisson regression models revealed that the incidence rate for declines in cognitive score was significantly higher in breakfast skipper (n = 29) than breakfast eaters (n = 683) [incidence rate ratio (IRR), 2.10; 95% CI, 1.28-3.44]. Additional propensity score adjustments related to breakfast skipping from baseline parameters (age, gender, smoking and drinking status, BMI, household income, educated level, depressive symptoms, hypertension, diabetes, sleep medication, physical activity, caloric intake, and baseline cognition) produced consistent results (IRR, 2.21; 95% CI, 1.33-3.68). Sensitivity analysis, when the cut-off value of decreases in MMSE score was changed to three points, suggested a significant and stronger association (IRR, 3.03; 95% CI, 1.72-5.35). Regarding daily intakes of food groups, breakfast skippers consumed a significantly lower amount of vegetables, fruits, and fish than breakfast eaters. In conclusion, our findings suggest that breakfast skipping is longitudinally associated with declines in cognitive score among older adults.

Association Between Before-bedtime Passive Body Heating and Nocturia During the Cold Season Among Older Adults.

BACKGROUND: Cold exposure induces lower urinary tract symptoms, including nocturia. Cold-induced detrusor overactivity can be alleviated by increasing skin temperature in rats. However, no study has shown an association between passive heating via hot-water bathing and nocturia among humans. METHODS: We included 1,051 Japanese community-dwelling older adults (mean age: 71.7 years) in this cross-sectional study from 2010 to 2014. The number of nocturnal voids was recorded in a self-administered urination diary. Nocturia was defined as ≥2 nocturnal voids. We evaluated bathing conditions in the participants' houses. RESULTS: Hot-water bathing (n = 888) was associated with a lower prevalence of nocturia than no bathing (n = 163), independent of potential confounders, including age, sex, obesity, income, physical activity, diabetes, medication (diuretics, nondiuretic antihypertensives, and hypnotics), depressive symptoms, indoor/outdoor temperature, and day length (odds ratio [OR] 0.68; 95% confidence interval [CI], 0.48-0.97; P = 0.035). Compared with the quartile group with the longest bath-to-bed interval (range: 161-576 min), the second and third quartile groups (range: 61-100 and 101-160 min, respectively) were associated with a lower prevalence of nocturia, after adjusting for water temperature and bathing duration besides the same covariates (OR 0.60; 95% CI, 0.38-0.96; P = 0.031 and OR 0.59; 95% CI, 0.37-0.94; P = 0.025, respectively). CONCLUSION: Hot-water bathing, particularly with a bath-to-bed interval of 61-160 min, was significantly associated with a lower prevalence of nocturia among older adults.

Influence of depression on the association between colder indoor temperature and higher blood pressure.

OBJECTIVES: Cold exposure accounts for more than 7% of all-cause mortality worldwide, and cold-induced blood pressure (BP) elevation and consequent cardiovascular events are partially responsible. For prevention, it is important to identify risk factors for exaggerated temperature-sensitivity of BP but this is not fully understood. This study investigated whether depressive symptoms affect the relationship between indoor temperature and BP. METHODS: We conducted a cross-sectional analysis of 1076 community-based individuals who were at least 60 years of age. Depressive symptoms were assessed using the 15-item Geriatric Depression Scale at a cutoff point of 4/5. We performed ambulatory BP monitoring and indoor temperature measurement on two consecutive days during the cold season in Nara, Japan. RESULTS: When using daytime SBP as a dependent variable, multilevel linear regression analyses showed that lower daytime indoor temperature was significantly associated with higher daytime SBP in the depressive group (n = 216, ß = -0.804, P < 0.001) but not in the nondepressive group (n = 860, ß = -0.173, P = 0.120); moreover, a significant interaction between depression and daytime indoor temperature was observed (P = 0.014). These relationships were independent of potential confounders including age, gender, BMI, medications, and physical activity. Similar results were obtained for morning SBP, nocturnal SBP dipping, and morning BP surge. CONCLUSION: The results suggest that depressive participants are more likely to have cold-induced BP elevation than nondepressive participants. Further longitudinal studies are warranted to determine whether people with depressive symptoms are at a high risk for cold-related cardiovascular events.

Associations between indoor light pollution and unhealthy outcomes in 2,947 adults: Cross-sectional analysis in the HEIJO-KYO cohort.

Nighttime use of artificial light is usual and essential in these modern times. Although light exposure at night (LAN) is reportedly a risk factor of several diseases, epidemiological studies on indoor LAN levels are still limited. Hence, the present study aimed to measure bedroom LAN levels by using light meters in a larger sample than in previous studies, and to evaluate the associations with comprehensive health outcomes. Out of 3012 participants, 2947 (mean age, 69.3 years; female, 60.6%) completed the bedroom LAN intensity measurement. The median bedroom LAN intensity was 1.0 lux (interquartile range, 0.2-4.0 lux). In a multivariable analysis adjusted for potential confounding factors, the highest quartile group of bedroom LAN intensity had significantly higher body weight, body mass index, abdominal circumference, and low-density lipoprotein cholesterol than the lowest quartile group. The group with a median LAN intensity ≥10 lux had significantly higher white blood cell counts and had significantly lower high-density lipoprotein cholesterol levels than the group with a median LAN intensity <10 lux. In addition, the groups with median LAN intensities ≥3 and ≥10 lux had significantly higher odds ratios for sleep disturbances and depressive symptoms than the group with <3 and <10 lux, respectively. Therefore, the present study provided real-world data on bedroom LAN levels as a marker for indoor light pollution in a large sample and suggested that higher bedroom LAN levels are significantly associated with parameters of obesity, dyslipidemia, systemic inflammation, sleep disturbances, and depressive symptoms.

General anesthesia with remimazolam for a pediatric patient with MELAS and recurrent epilepsy: a case report.

BACKGROUND: Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial disease. We report here the safe use of remimazolam in a pediatric MELAS patient. CASE PRESENTATION: A 10-year-old girl (118 cm, 16 kg) was scheduled for an open gastrostomy to improve nutrition and epileptic seizure control. We induced and maintained general anesthesia with remimazolam, remifentanil, fentanyl, and rocuronium. We also performed a bilateral subcostal transversus abdominis plane block before the surgery. The surgery finished uneventfully. After we discontinued remimazolam administration, the patient woke up immediately but calmly without flumazenil. Epileptic seizures did not occur during intra- and early post-operative periods. CONCLUSION: Remimazolam enabled us to provide a pediatric MELAS patient with general anesthesia without causing delayed emergence or epileptic seizures.

Inverse Association of Skin Temperature With Ambulatory Blood Pressure and the Mediation of Skin Temperature in Blood Pressure Responses to Ambient Temperature.

BACKGROUND: The inverse association between ambient temperature and blood pressure (BP) has been investigated in the context of excess cardiovascular mortality in winter. However, the role of skin temperature (ST), which reflects our external and internal thermal environments, in BP regulation remains unclear. Therefore, we examined the association between ST and ambulatory BP and the mediation of ST in BP responses to ambient temperature in real-life settings. METHODS: We conducted a longitudinal analysis using repeated measurements of ambulatory BP and ST for 48 hours (30 711 daytime readings and 17 382 nighttime readings) among 584 older adults between October and March (2012-2014). Linear mixed-effect models were used to examine the association of distal (mean of wrist and ankle) and proximal (abdomen) ST with systolic BP. The mediation of ST in BP responses to ambient temperature was examined using path analysis. RESULTS: Distal and proximal STs were significantly associated with systolic BP during the daytime (regression coefficients: -4.27 mm Hg [95% CI, -4.58 to -3.96] and -2.74 mm Hg [95% CI, -3.14 to -2.56] per SD of ST, respectively), independent of potential confounders. The significant associations also existed during nighttime. The mediation effect of distal ST was 7.1 times higher than that of proximal ST during daytime, while those of distal and proximal STs during nighttime were almost identical. CONCLUSIONS: ST, especially in distal regions, was inversely associated with ambulatory BP. Our results have the potential for application to interventional studies targeting ST regulation to reduce excess cardiovascular deaths in winter.

[Sleep quality and mental well-being of mothers caring for children with disabilities and requiring oxygen therapy and night care at home].

Objectives　This study aimed to 1) determine what kind of care for children with disabilities is related to the mothers' sleep and mental well-being and 2) objectively measure the sleep state of mothers responsible for children with disabilities.Methods　A self-administered questionnaire was distributed to 180 mothers of children enrolled in the Special Needs Education School in prefecture A. Amongst these, nine who provided consent underwent objective sleep measurements using actigraphy. The questionnaire investigated the lifestyle and the type of care needed for children with disabilities and their influence on the mothers. Subjective sleep quality (Pittsburgh Sleep Quality Index) and mental well-being status (General Health Questionnaire) of the mothers were also evaluated. Logistic regression analysis was performed to analyze the background factors affecting sleep quality and mental health.Results　Of the 180 participants, 84 (46.7%) provided valid responses. Fifty-two (64.2%) and 34 (42.0%) individuals subjectively reported poor sleep quality and poor mental well-being, respectively. Mothers having responsibilities of oxygen therapy and night care reported significantly poor sleep quality and mental well-being. Moreover, objective sleep measurements showed that the changes in the child's physical condition, such as ventilator management, epileptic seizures, and fever, resulted in prolonged waking times and affected the sleep efficiency of the mother.Conclusion　Responsibilities toward providing oxygen therapy and night care for their children with disabilities influenced the sleep quality and mental well-being of the mothers. Thus, it is important to provide support to mothers caring such disabled children.

Short-wavelength light exposure at night and sleep disturbances accompanied by decreased melatonin secretion in real-life settings: a cross-sectional study of the HEIJO-KYO cohort.

OBJECTIVES: To determine the association between short-wavelength light exposure at night (LAN) power and sleep quality or melatonin levels in real-life settings. METHODS: In this cross-sectional study of 580 older adults (mean age, 71.0 years), we measured short-wavelength LAN power at cornea level using an originally developed light loggers over two nights. Sleep quality and physiological melatonin levels were measured using the Pittsburgh sleep quality index (PSQI) questionnaire and overnight urinary 6-sulfatoxymelatonin excretion (UME), respectively. RESULTS: The first and second tertile short-wavelength LAN power values obtained were 0.77 × 10-2 µW/cm2 and 7.0 × 10-2 µW/cm2, respectively, and the overall prevalence of sleep disturbances was 34.7%. The mean UME was 1.88 ± 0.70 log µg. The mean global PSQI score and the prevalence of sleep disturbances significantly increased (P = 0.004 and 0.006, respectively) with increasing tertile groups of short-wavelength LAN power. In multivariable analysis adjusted for potential confounders, the odds ratio (OR) for sleep disturbances was significantly higher in the highest tertile group of short-wavelength LAN power compared with that in the lowest tertile group (adjusted OR, 1.90; 95% confidence interval [CI]: 1.20, 3.00; P = 0.006). In addition, UME was significantly lower in the highest tertile group of short-wavelength LAN power than that in the lowest tertile group (adjusted mean difference, -0.14 log µg; 95% CI: -0.28, -0.007; P = 0.039). CONCLUSIONS: Although short-wavelength LAN power measured at cornea level in real-life settings seemed to be significantly low, our findings suggest that short-wavelength LAN power is significantly associated with both melatonin levels and sleep disturbance.

Association Between Passive Body Heating by Hot Water Bathing Before Bedtime and Depressive Symptoms Among Community-Dwelling Older Adults.

OBJECTIVE: Passive body heating can have an antidepressant effect by activating warm-sensitive neural pathways associated with affective functions. Interventional studies showed that patients with depression had reduced depressive symptoms after passive body heating. However, the effect of hot water bathing at home on depressive symptoms in the general population remains unclear. Thus, we evaluated the association between objectively measured hot water bathing and depressive symptoms among older adults. DESIGN: Cross-sectional analysis. SETTING: A baseline survey of community-based cohort study in Japan. PARTICIPANTS: Community-dwelling older volunteers (n = 1,103; mean age: 72.0 years). MEASUREMENTS: The authors evaluated bathing conditions and distal skin temperature for 2 consecutive days. Depressive symptoms were defined as the 15-item Geriatric Depression Scale score of ≥6. RESULTS: Logistic regression showed that the no bathing group (adjusted odds ratio [OR] 2.60, 95% confidence interval [CI] 1.36-4.95, χ² = 8.40, degrees of freedom [df] = 1) and the either-day bathing group (adjusted OR 1.68, 95% CI 1.11-2.56, χ² = 5.89, df = 1) had higher odds of depressive symptoms than the both-day bathing group independent of potential confounders including age, sex, body mass index, alcohol intake, income, living alone, hypnotic use, diabetes, and physical activity. Shorter interval from bathing to bedtime was significantly associated with lower odds of depressive symptoms and higher nighttime distal skin temperature after adjusting for water temperature and duration. CONCLUSION: A higher frequency of hot water bathing and shorter interval from bathing to bedtime were associated with lower odds of depressive symptoms.

Circadian activity rhythm in Parkinson's disease: findings from the PHASE study.

OBJECTIVE: Circadian disruptions in Parkinson's disease (PD) are characterized as amplitude reduction rather than as phase shift; however, large-scale studies evaluating circadian rhythms between PD patients and non-PD older adults have not been performed. The present study aimed to compare the circadian activity rhythm (CAR) between PD patients and non-PD older adults. METHODS: In this cross-sectional study on 157 PD outpatients and 1111 community-dwelling older adults (controls), physical activity was measured using actigraphy at 1-min intervals over 6 days in PD patients and 2 days in non-PD older adults. Data were base-10 log-transformed and regretted to the sigmoidally transformed cosine curve. RESULTS: The mean amplitude (log counts/min) and acrophase were 1.85 (SD, 0.52) and 14:19 (SD, 1:15), respectively, in the controls (n = 1111); 1.42 (0.48) and 14:24 (1:20), respectively, in the early-stage (Hoehn-Yahr I and II) PD patients (n = 95); and 1.23 (0.54) and 13:41 (1:56), respectively, in the late-stage (Hoehn-Yahr III-V) PD patients (n = 62). Multivariable analysis revealed significantly lower amplitude in the early-stage and late-stage PD groups than in the controls. The acrophase significantly advanced in the late-stage PD group than in the controls. With the advancement of PD stage, amplitude and peak significantly decreased; trough increased; acrophase and active offset advanced; and robustness weakened. CONCLUSIONS: Compared with non-PD older adults, PD patients exhibited a phase advance in CAR, along with amplitude reduction. With an advanced stage of PD, a phase advance in CAR also occurred, along with amplitude reduction and weakened robustness.

Hot-water bathing before bedtime and shorter sleep onset latency are accompanied by a higher distal-proximal skin temperature gradient in older adults.

STUDY OBJECTIVES: Passive body heating in controlled settings could shorten sleep onset latency (SOL). The hypothesized mechanism is vasodilation-induced heat loss before bedtime. However, this evidence is based on small sample-sized studies in specific populations. Thus, we analyzed the association of hot-water bathing and its before-bedtime timing with SOL and heat loss in a large study population of older adults. METHODS: We conducted a longitudinal analysis using repeated measurements of hot-water bathing and sleep among 1,094 older adults (mean age, 72.0 years). SOL was recorded using actigraphy and self-reported sleep estimates and was categorized into conditions (intervals of 1-60, 61-120, 121-180, and > 181 minutes between hot bath and bedtime) and compared with the control condition of no bathing. The heat-loss indicator, distal-proximal skin temperature gradient, was examined in the same categorization. RESULTS: Mixed-effects linear regression models suggested that the bathing conditions of 61-120 minutes and 121-180 minutes showed significantly shorter log-transformed actigraphic SOL by 0.23 log-minutes (95% confidence interval (CI), 0.03-0.42) and 0.32 log-minutes (95% CI, 0.09-0.56), shorter self-reported SOL by 0.16 log-minutes (95% CI, 0.02-0.30) and 0.18 log-minutes (95% CI, 0.01-0.35), and higher distal-proximal skin temperature gradient for 30 minutes before bedtime by 0.49°C (95% CI, 0.22-0.75) and 0.51°C (95% CI, 0.20-0.83), respectively, independent of potential confounders. CONCLUSIONS: Hot-water bathing before bedtime is significantly associated with shorter SOL and higher distal-proximal skin temperature gradient among the large-scale older population. This finding could enhance the generalizability of hot-water bathing habits for ameliorating sleep initiation difficulty.

Association between NT-proBNP and nocturia among community-dwelling elderly males and females: A cross-sectional analysis of the HEIJO-KYO study.

AIMS: To investigate the association between B-type natriuretic peptide (BNP) and nocturia among community-dwelling males and females. METHODS: A total of 1096 participants (mean age 71.9 ± 7.1 years, 518 [47.2%] males) were included in the study. The number of nocturnal voids was recorded in a self-reported urination diary, and nocturia was defined as two or more voids per night. Daytime serum concentration of the N-terminal fragment of BNP precursor (NT-proBNP) was measured. Multivariable logistic regression analysis was performed to determine the association between NT-proBNP and nocturia. RESULTS: Nocturia was observed in 23.5% of females and 37.1% of males. Higher NT-proBNP (log pg/ml) was associated with nocturia in both gender groups (females: odds ratio [OR]: 1.67, 95% confidence interval [95% CI], 1.21-2.34, p = .002; males: OR: 1.26, 95% CI, 1.01-1.59, p = .046), independent of confounding variables including night-time blood pressure, mean voided volume, and chronic kidney disease. Although the increase in prevalence of nocturia with higher NT-proBNP was equivalent in both genders, some effect of gender on the relationship between NT-proBNP and nocturia was observed (p = .037). Nocturnal urine volume was also significantly and independently associated with NT-proBNP level (females: ß = 32.9 ml, 95% CI, 5.63-60.2, p = .018; males: ß = 34.6 ml, 95% CI, 9.40-59.9, p = .007). CONCLUSIONS: This study revealed higher serum NT-proBNP is significantly and independently associated with the prevalence of nocturia in both males and females. This is an exploratory cross-sectional study and the analyses are post hoc, so further research works are needed to clarify the causality and clinical value.

Quantitative associations between objective sleep measures and early-morning mobility in Parkinson's disease: cross-sectional analysis of the PHASE study.

STUDY OBJECTIVES: Previous studies have suggested associations between sleep measures and early-morning akinesia; however, objective evidence is limited. The purpose of this study was to evaluate the associations between objective sleep measures and morning mobility among patients with Parkinson's disease (PD). METHODS: In this cross-sectional study, we measured objective sleep parameters and morning mobility in 157 patients with PD (mean age, 71.4 years) for six consecutive days using an actigraph placed on the nondominant wrist. Low morning mobility was defined as less than 100 counts/min within the first 2 hours after rising. RESULTS: The mean duration of low morning mobility was 55.7 minutes (SD, 23.8), and the mean sleep parameters were as follows: sleep efficiency (SE), 72.1% (13.6); wake after sleep onset (WASO), 104.7 minutes (57.9); total sleep time (TST), 343.6 minutes (104.0); and fragmentation index (FI), 3.5 (3.4). Multivariable linear regression analysis adjusted for potential confounders demonstrated significant associations between better objective sleep measures and shorter low morning mobility (SE per %: ß, -0.419; 95% CI = -0.635 to -0.204; p < 0.001; WASO per min: ß, 0.056; 95% CI = 0.003 to 0.109; p = 0.039; and FI per unit; ß, 1.161; 95% CI = 0.300 to 2.023; p = 0.009) but not TST (p = 0.78). These findings were not altered by different cutoff values of mobility (50 counts/min) or duration (1 h after rising). CONCLUSIONS: In patients with PD, better objective sleep measures are significantly associated with shorter low morning mobility. Future studies investigating whether improved sleep reduces symptoms of low morning mobility are required.

Lower Incidence of In-Hospital Falls in Patients Hospitalized in Window Beds Than Nonwindow Beds.

OBJECTIVES: Comparing the incidence rate of in-hospital falls between patients hospitalized in window beds and nonwindow beds. DESIGN: Retrospective cohort study. SETTING: A general hospital in Mie, Japan. PARTICIPANTS: A total of 2767 patients (mean age, 68.4 years) hospitalized in four-bedded rooms between January 2014 and December 2016. MEASURES: We identified patients' bed status (window/nonwindow) and the incidence of in-hospital falls using data on medical records and incidence reports, respectively. RESULTS: During an observation period of 25,450 person-days, 57 patients had in-hospital falls (incidence rate, 2.24/1000 person-days). Incidence rate for in-hospital falls was significantly lower in the window-bed group (n = 1273) than in the nonwindow-bed group (n = 1494) [incidence rate ratio (IRR) 0.49, 95% confidence interval (CI), 0.29, 0.84]. In the multivariable analysis adjusted for age, gender, BMI, smoking and drinking habit, surgical operation during hospitalization, and independence in daily living, the window-bed group exhibited significantly lower incidence rate for in-hospital falls than the nonwindow-bed group (IRR 0.54, 95% CI 0.32, 0.93). Sensitivity analysis excluding patients aged <60 years suggested a consistent result: incidence rate for in-hospital falls was significantly lower in the window-bed group (n = 1123) than in the nonwindow-bed group (n = 925) (IRR 0.55, 95% CI 0.31, 0.95). CONCLUSIONS AND IMPLICATIONS: The incidence rate of in-hospital falls was significantly lower among patients hospitalized in window beds than nonwindow beds. Hospitalization in window beds might be a novel, simple preventive option for in-hospital falls. Further large-scale, prospective, multicenter research is required.

Bedroom lighting environment and incident diabetes mellitus: a longitudinal study of the HEIJO-KYO cohort.

OBJECTIVES: Light information received by the brain influences human circadian timing and metabolism; low-level light at night (LAN) significantly increased body mass and led to prediabetes in mice. We hypothesized that LAN exposure increases the diabetes risk in humans. The aim of the present study was to evaluate a longitudinal association between LAN exposure and the incidence of diabetes in a general population. METHODS: In our prospective cohort study, bedroom light intensity was measured at 1-min intervals in 678 elderly participants without diabetes at baseline. The average light intensity recorded between bedtimes and rise times over two consecutive nights was used in the analysis. RESULTS: During follow-up (median, 42 months), 19 of the 678 participants (mean age, 70.6 years) developed diabetes. Poisson regression models revealed that the incidence rate for diabetes was significantly higher in the LAN group (average ≥ 5 lux, N = 128) than the dark group (average < 5 lux, N = 550) (incidence rate ratio, 3.74; 95% confidence interval (CI), 1.55-9.05; p = 0.003). Further propensity score adjustments in relation to LAN produced consistent results (incidence rate ratio, 3.19; 95% CI, 1.38-7.35; p = 0.007). When the cut-off value of LAN was decreased to 3 lux, the relationship remained significant (incidence rate ratio 2.74; 95% CI, 1.19-6.33; p = 0.018). CONCLUSIONS: Our findings suggest that LAN exposure increases the incidence of diabetes in a general elderly population. Further research involving a large cohort with new-onset diabetes is warranted to elucidate these findings.