Environmental (little outdoor light; low indoor lighting) and age-related physiological factors (reduced light transmission through the ocular lens, reduced mobility) contribute to a light-deprived environment for older people living in care homes. This study investigates the effect of increasing indoor light levels with blueenriched white lighting on objective (rest-activity rhythms, performance) and self-reported (mood, sleep, alertness) measures in older people. Eighty residents (69 female), aged 86 ± 8 yrs (mean ± SD), participated (MMSE 19 ± 6). Overhead fluorescent lighting was installed in communal rooms (n=20) of seven care homes.Four weeks of blue-enriched white lighting (17000 K  900 lux) were compared with four weeks of control white lighting (4000 K  200 lux), separated by three weeks wash-out. Participants completed validated mood and sleep questionnaires, psychomotor vigilance task (PVT) and wore activity and light monitors (AWL). Restactivity rhythms were assessed by cosinor, non-parametric circadian rhythm (NPCRA) and actigraphic sleep analysis. Blue-enriched (17000 K) light increased wake time and activity during sleep decreasing actual sleep time, sleep percentage and sleep efficiency (p < 0.05) (actigraphic sleep). Compared to 4000 K lighting, blueenriched 17000 K lighting significantly (p < 0.05) advanced the timing of participants' rest-activity rhythm (cosinor), increased daytime and night-time activity (NPCRA), reduced subjective anxiety (HADA) and sleep quality (PSQI). There was no difference between the two light conditions in daytime alertness and performance (PVT). Blue-enriched lighting produced some positive (increased daytime activity, reduced anxiety) and negative (increased night-time activity, reduced sleep efficiency and quality) effects in older people.Keywords: care home, light therapy; mood; elderly; rest-activity; sleep. 3 Graphical AbstractThe effect of blue-enriched 17000 K lighting (right) on the rest-activity, sleep and mood of older people living in care homes has been investigated compared to control 4000 K lighting (middle) (left, original lighting) 4

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It is unknown whether vitamin D status affects sleep health, but recent studies suggest vitamin D deficiency is associated with shorter sleep duration 1 and lower sleep efficiency 2. This study investigated whether there is a relationship between vitamin D status and sleepwake cycles in UK dwelling South Asian (SA) and Caucasian (C) women, using ambulatory actigraphic data and self-reported sleep quality data from the D-FINES II (Vitamin D, Food Intake, Nutrition and Exposure to Sunlight in Southern England II) study. In June-August 2010, serum 25-hydroxyvitamin D [25(OH)D] and data on self-reported musculoskeletal pain were collected from n = 47 women. In September-October 2010, participants wore Actiwatch-L (AWL, Cambridge Neurotechnology) monitors on their wrists for 24 h/day, over 14 consecutive days to measure sleep-wake activity as well as completing the PSQI (self-reported sleep quality) once. A subset of n = 37 women also wore an AWL on a neckband during the daylight hours to measure environmental light exposure. Each subject's actigraphic data (including light exposure) were eligible to be included in the statistical analysis if they had ⩾ 7 days of valid data and a 25(OH)D measurement. Relationships between 25(OH)D and actigraphic measures were analysed by Pearson's bivariate correlations, as well as by partial correlations to control for potential confounders. PSQI scores are ordinal data so relationships were analysed by Spearman's correlations only. There was a significant negative relationship between 25(OH)D concentration and actigraphic sleep latency in SA (r = −0•562, P = 0•036), and a significant positive relationship between 25(OH)D and both overall PSQI score (r = 0•385 P = 0•047) and PSQI sleep latency subscale (r = 0•439, P = 0•02) in C (see Table). Partial correlations controlling for bone pain (n = 23 C, n = 11 SA) found a statistically significant positive relationship between 25(OH)D and actigraphic sleep latency (r = 0•426, P = 0•048, n = 23) in C only. However, when adjusting for muscle pain (n = 21 C, n = 8 SA), there were no significant associations between 25(OH)D and actigraphic sleep parameters in either ethnic group (P > 0•05). Finally, there were no significant correlations between 25(OH)D and actigraphic sleep parameters when adjusting for outdoor light exposure (mins/d > 1000 lux) (P > 0•05, n = 20 C, n = 8 SA).