Persons allocated to the control group will receive no indoor light supplementation and will undergo assessment procedures only. Exposure to the outdoor intervention will be taken into account in the analysis in three ways, (1) by locating the distance between people's home and the modified outdoor light, (2) by a question about the awareness of the change in outdoor light, timing, and duration of exposure and what they think of it, and (3) by recording the amount of light exposure over the 24 hours during two weeks at baseline and after the 1-year light interventions

Change in Interdaily Stability (IS), as derived from wrist actigraph, between the baseline and the end of the light intervention period.

Interdaily Stability (IS) is an index that estimates the stability of the 24-hour rest-activity rhythm across days, quantifying how consistent individual's daily pattern is over time. It ranges from 0 (absence of a stable rhythm) to 1 (perfectly stable rhythm). The hypothesis to be tested is that a participant's IS will increase at the end of the light intervention period compared to baseline; hence, a positive difference between baseline and follow-up indicates an improved rest-activity rhythm.

Change in Intradaily Variability (IV), as derived from wrist actigraphy, between the baseline and the end of the light intervention period.

Intradaily Variability (IV) is an index that reflects fragmentation of the 24-hour rest-activity rhythm within a day, based on the frequency of transitions between rest and activity. It ranges from 0 to 1, with higher values indicating more fragmented rhythms. The hypothesis to be tested is that a participant's IV will decrease at the end of the light intervention period compared to baseline; hence, a negative difference between baseline and follow-up indicates an improved rest-activity rhythm.

Change in Relative amplitude (RA), as derived from wrist actigraphy, between the baseline and the end of the light intervention period.

Relative Amplitude (RA) measures the strength of the 24-hour rhythm: (M10-L5)/(M10+L5). M10 is the mean activity during the 10 most active consecutive hours, and L5 during the 5 least active hours. RA ranges from 0 to 1 and reflects the normalized difference between the most active and least active periods of the day: higher values indicate a well-defined rhythm, lower values a weaker or disrupted rhythm. The hypothesis to be tested is that a participant's RA will increase at the end of the light intervention period compared to baseline; hence, a positive difference between baseline and follow-up indicates an improved rest-activity rhythm.

Persons allocated to the control group will receive no indoor light supplementation and will undergo assessment procedures only. Exposure to the outdoor intervention will be taken into account in the analysis in three ways, (1) by locating the distance between people's home and the modified outdoor light, (2) by a question about the awareness of the change in outdoor light, timing, and duration of exposure and what they think of it, and (3) by recording the amount of light exposure over the 24 hours during two weeks at baseline and after the 1-year light interventions

Total of all reporting groups

2 participants had missing data

Race and Ethnicity were not collected from any participant.

PSQI score ranges from 0 (better) to 21 (worse). A score <= 5 is associated with good sleep quality, while a score > 5 is associated with poor sleep quality.

Perceived quality of life score, ranging from -0.57 (worst perceived quality of life) to 1 (best health state)

7 sequential saliva samples will be collected at baseline in all recruited subjects. The saliva sampling will be performed hourly starting 5 hours prior to each individual's usual sleep onset until 1 hour after usual sleep onset. During sampling, the participant will remain in dim light conditions (< 10 lux) so that melatonin levels are not suppressed. The melatonin profile will allow calculation of the DLMO, a reliable proxy of circadian timing (phase). The reported values reflect clock time of melatonin onset in "hours".

Participants were given an actigraph (ActLumus, Condor Instruments) to be worn on their non-dominant wrist throughout day and night for 14 days during baseline and 14 days during follow-up to evaluate their rest-activity circadian rhythms.

Interdaily Stability (IS) is an index that estimates the stability of the 24-hour rest-activity rhythm across days, quantifying how consistent individual's daily pattern is over time.

It ranges from 0 (absence of a stable rhythm) to 1 (perfectly stable rhythm).

Participants wore an actigraph (ActLumus, Condor Instruments) on the non-dominant wrist for 14 days at baseline and 14 at follow-up to assess rest-activity circadian rhythms. Relative Amplitude (RA) measures the strength of the 24-hour rhythm: (M10-L5)/(M10+L5). M10 is the mean activity during the 10 most active consecutive hours, and L5 during the 5 least active hours. RA ranges from 0 to 1 and reflects the normalized difference between the most active and least active periods of the day: higher values indicate a well-defined rhythm, lower values a weaker or disrupted rhythm.

Participants were given an actigraph (ActLumus, Condor Instruments) to be worn on their non-dominant wrist throughout day and night for 14 days during baseline and 14 days during follow-up to evaluate their rest-activity circadian rhythms.

Intradaily Variability (IV) is an index that reflects fragmentation of the 24-hour rest-activity rhythm within a day, based on the frequency of transitions between rest and activity. It ranges from 0 to 1, with higher values indicating more fragmented rhythms.

Persons allocated to the control group will receive no indoor light supplementation and will undergo assessment procedures only

no indoor light: Persons allocated to the control group will receive no indoor light supplementation and will undergo assessment procedures only. Exposure to the outdoor intervention will be taken into account in the analysis in three ways, (1) by locating the distance between people's home and the modified outdoor light, (2) by a question about the awareness of the change in outdoor light, timing, and duration of exposure and what they think of it, and (3) by recording the amount of light exposure over the 24 hours during two weeks at baseline and after the 1-year light interventions

Change in mental and physical health as measured by Euroqol 5D difference between the baseline and the end of the light intervention period. The Euroqol 5D measures the perceived quality of life and ranges from - 0.57 (worst perceived quality of life) to 1 (best health state). A positive difference from baseline to the end of the follow-up period indicates an improvement in the quality of life.

Change in Interdaily Stability (IS), as derived from wrist actigraph, between the baseline and the end of the light intervention period.

Interdaily Stability (IS) is an index that estimates the stability of the 24-hour rest-activity rhythm across days, quantifying how consistent individual's daily pattern is over time. It ranges from 0 (absence of a stable rhythm) to 1 (perfectly stable rhythm). The hypothesis to be tested is that a participant's IS will increase at the end of the light intervention period compared to baseline; hence, a positive difference between baseline and follow-up indicates an improved rest-activity rhythm.

Change in Intradaily Variability (IV), as derived from wrist actigraphy, between the baseline and the end of the light intervention period.

Intradaily Variability (IV) is an index that reflects fragmentation of the 24-hour rest-activity rhythm within a day, based on the frequency of transitions between rest and activity. It ranges from 0 to 1, with higher values indicating more fragmented rhythms. The hypothesis to be tested is that a participant's IV will decrease at the end of the light intervention period compared to baseline; hence, a negative difference between baseline and follow-up indicates an improved rest-activity rhythm.

Change in Relative amplitude (RA), as derived from wrist actigraphy, between the baseline and the end of the light intervention period.

Relative Amplitude (RA) measures the strength of the 24-hour rhythm: (M10-L5)/(M10+L5). M10 is the mean activity during the 10 most active consecutive hours, and L5 during the 5 least active hours. RA ranges from 0 to 1 and reflects the normalized difference between the most active and least active periods of the day: higher values indicate a well-defined rhythm, lower values a weaker or disrupted rhythm. The hypothesis to be tested is that a participant's RA will increase at the end of the light intervention period compared to baseline; hence, a positive difference between baseline and follow-up indicates an improved rest-activity rhythm.

Persons allocated to the control group will receive no indoor light supplementation and will undergo assessment procedures only. Exposure to the outdoor intervention will be taken into account in the analysis in three ways, (1) by locating the distance between people's home and the modified outdoor light, (2) by a question about the awareness of the change in outdoor light, timing, and duration of exposure and what they think of it, and (3) by recording the amount of light exposure over the 24 hours during two weeks at baseline and after the 1-year light interventions.