Exposure to LAN in an uncontrolled home setting is associated with impaired obese and lipid parameters independent of nocturnal urinary melatonin excretion in elderly individuals. Moreover, LAN exposure is associated with higher ORs for obesity and dyslipidemia independent of demographic and socioeconomic parameters.

Daylight exposure in an uncontrolled daily life setting is positively associated with urinary 6-sulfatoxymelatonin excretion in the elderly.

Indoor temperature showed stronger association than outdoor temperature with BP in colder months.

Epidemiologic data have demonstrated associations of sleep-onset insomnia with a variety of diseases, including depression, dementia, diabetes and cardiovascular diseases. Sleep initiation is controlled by the suprachiasmatic nucleus of the hypothalamus and endogenous melatonin, both of which are influenced by environmental light. Exposure to evening light is hypothesized to cause circadian phase delay and melatonin suppression before bedtime, resulting in circadian misalignment and sleep-onset insomnia; however, whether exposure to evening light disturbs sleep initiation in home settings remains unclear. In this longitudinal analysis of 192 elderly individuals (mean age: 69.9 years), we measured evening light exposure and sleep-onset latency for 4 days using a wrist actigraph incorporating a light meter and an accelerometer. Mixed-effect linear regression analysis for repeated measurements was used to evaluate the effect of evening light exposure on subsequent sleep-onset latency. The median intensity of evening light exposure and the median sleep-onset latency were 27.3 lux (interquartile range, 17.9-43.4) and 17 min (interquartile range, 7-33), respectively. Univariate models showed significant associations between sleep-onset latency and age, gender, daytime physical activity, in-bed time, day length and average intensity of evening and nighttime light exposures. In a multivariate model, log-transformed average intensity of evening light exposure was significantly associated with log-transformed sleep-onset latency independent of the former potential confounding factors (regression coefficient, 0.133; 95% CI, 0.020-0.247; p = 0.021). Day length and nighttime light exposure were also significantly associated with log-transformed sleep-onset latency (p = 0.001 and p < 0.001, respectively). In conclusion, exposure to evening light in home setting prolongs subsequent sleep-onset latency in the elderly.

No abstract

Melatonin secretion is significantly and inversely associated with nocturia in a general elderly population.

Chronic circadian misalignment between the internal and environmental rhythms, which is typically related to night-shift work and clock-gene variants, is associated with disruption of suprachiasmatic nucleus function and increased risk of insomnia. Under controlled laboratory conditions, light at night (LAN) suppresses melatonin secretion, delays the internal biological rhythm, and reduces sleepiness. Therefore, LAN exposure may cause circadian misalignment and insomnia, though it remains unclear in real-life situations whether LAN exposure is associated with insomnia. To evaluate an association between LAN exposure and sleep quality in home settings, we conducted a cross-sectional community-based study in 857 elderly individuals (mean age, 72.2 years). We evaluated bedroom light intensity using a light meter and subjectively and objectively measured sleep quality using the Pittsburgh Sleep Quality Index and an actigraph, respectively, along with urinary 6-sulfatoxymelatonin excretion. Compared with the lowest quartile group of LAN intensity, the highest quartile group revealed a significantly higher odds ratio (OR) for subjective insomnia in a multivariate model adjusted for age, gender, body mass index, daytime physical activity, urinary 6-sulfatoxymelatonin excretion, bedtime, rising time, and day length (adjusted OR, 1.61, 95% confidence interval, 1.05-2.45, p=0.029). In addition, higher OR for subjective insomnia was significantly associated with the increase in quartiles of LAN intensity (ptrend=0.043). Consistently, we observed significant association trends between the increase in quartiles of LAN intensity and poorer actigraphic sleep quality, including decreased sleep efficiency, prolonged sleep-onset latency, increased wake-after-sleep onset, shortened total sleep time, and delayed sleep-mid time in multivariate models adjusted for the covariates mentioned above (all ptrend<0.001). In conclusion, we demonstrated that LAN exposure in home settings is significantly associated with both subjectively and objectively measured sleep quality in a community-based elderly population.

Work-related Aggression and Violence Committed by Patients and Its PsychologicalInfluence on Doctors: Keigo Saeki, et al. Department of Community Health and Epidemiology, Nara Medical University School of Medicine-Objectives: To determine the incidence rate of work-related aggression and violence (WRAV) against doctors and investigate risk factors and psychological influences of WRAV doctors. Methods: We sent a self-administered questionnaire on WRAV committed by patients and their associates to 1,148 doctors in Nara Prefecture, Japan. We calculated the incidence rate of WRAV using the number of incidents encountered during the previous 12 mo and the doctor's average weekly working hours. Risk factors for the incidence WRAV were analyzed by Poisson regression, and the influence of WRAV on the symptoms of post-traumatic stress disorder (PTSD) was evaluated by multiple logistic regression analysis. Results: A total of 758 (66.0%) doctors returned the questionnaire. The incidence rate of WRAV was 0.20 [95% CI: 0.17-0.24]×10 -3 per practice hour. Adjusted incidence rate ratios of WRAV were significantly increased among doctors 1) with a shorter career (11.0; 95% CI: 5.0-24.2), 2) working in a region with the lowest average taxable income (1.6; 1.1-2.4), and 3) whose specialties were dermatology (3.8; 2.3-6.3), psychiatry (2.7; 1.3-5.6) and ophthalmology (1.9; 1.2-3.2). Of 289 subjects who had encountered WRAV at least once during their career, 26 doctors (8.2%) had symptoms suggestive of PTSD due to the most severe incident. Conclusions: Doctors encountered WRAV at an incidence rate of 0.20×10 -3 per practice hour, and some of them might develop PTSD. Countermeasures are required to maintain sound health and safe workplaces for doctors. (J Occup Health 2011; 53: 356-364)