Table 1.
Key characteristics of studies included in the systematic review.
| First Author, Year Reference | Study Design | Country | Sample Size | Age (Years) | Lighting Exposure | Health Domain | Health Outcome | Main Finding | Quality Score |
|---|---|---|---|---|---|---|---|---|---|
| NATURAL LIGHT | |||||||||
| Rahayu, 2015 [28] | Case-control | Indonesia | 212 | Adults | Subjective: Presence of sunlight | PH | OM: Tuberculosis | ↑ Presence of sunlight in the house protective against tuberculosis (OR 0.06, 95% CI 0.00–0.67) * | Fair |
| Kumar, 2001 [29] | Cross-sectional | India | 13,320 | All | Subjective: Insufficient household light exposure | PH | OM: Leprosy | ↑ Persons living in houses with insufficient sunlight exposure observed to be more afflicted by leprosy (OR 1.57, 95% CI 0.84–2.88) | Fair |
| Brown, 2011 [30] | Cross-sectional | Lithuania, Switzerland, Italy, Germany, Portugal, Hungary, Slovakia and France | 6017 | ≥18 | Subjective: Inadequate residential light | PH MH |
SR: Falls and depression | ↑ Participants reporting inadequate natural light in dwelling more likely to report falls (OR 1.5, 95% CI 1.2–1.9) * and depression (OR 1.4, 95% CI 1.2–1.7) * | Fair |
| Ichimori, 2013 [31] | Cross-sectional | Japan | 24 | 76–90 | Objective: Daytime illuminance | PH MH |
SR: Physical health and depression | - No relationship between illuminance and physical health ↑ Time exposed to light over 400 lx and depression scores * |
Fair |
| Youngstedt, 2004 [32] | Cross-sectional | USA | 459 | 50–81 | Objective: Morning illuminance | PH SH |
SR: Mood SR and OM: Sleep |
↑ Morning illumination moderately associated with improved mood * and sleep | Fair |
| ARTIFICIAL LIGHT | |||||||||
| Chen, 2017 [33] | Case-control | Uganda | 934 | NR | Treatment: Solar home lighting system Comparison: Low quality sources |
PH GH |
SR: Burns, cough and personal health | ↑ Burns by lighting source 6.5 p.p. less; cough 9.3 p.p. less; and self-reported health 35.2 p.p. higher among households with solar home lighting system | Fair |
| Brunnstrom, 2004 [34] | Randomised trial | Sweden | 46 | 20–90 | Intervention: Living room adjustment-50 Watts halogen, 12 Volt standard floor lamp | GH | SR: General health and depressed mood | ↑ Improvement in general health p < 0.01 and depressed mood p < 0.04 after the adaptation was found for the intervention group | Fair |
| First Author, Year | Study Design | Country | Sample Size | Age (Years) | Lighting Exposure | Health Domain | Health Outcome | Main Finding | Quality Score |
| Falkenberg, 2019 [35] | Randomised trial | Norway | 60 | 77 | Intervention: Providing lamps to achieve recommended living room lighting levels (200 lux) | GH | SR: Visual health and general health | - Self-reported visual problems and health unchanged in both groups during the intervention | Good |
| Woldesemayat, 2014 [36] | Case-control | Ethiopia | 1154 | Adult | Kerosene lamps, electricity, others | PH | OM: Pulmonary tuberculosis | - Kerosene lamps used for lighting by 73% cases and 71.5% controls, electric lighting used by 24.5% cases and 26.6% controls. The remaining participants used other kerosene-based or other light sources | Fair |
| Savitha, 2007 [37] | Case-control | India | 208 | 0–5 | Kerosene lamps, electricity | PH | OM: Acute lower respiratory infection (ALRI) | ↑ 36.54% of ALRI cases used kerosene lamps for lighting compared to 2.88% of controls, which used electric lighting | Fair |
| Patel, 2019 [27] | Cross-sectional | India | 932,341 | 0–59 months | Electricity and solar, kerosene and other oils, others | PH | SR: Acute respiratory infection (ARI) | ↑ Kerosene and other sources for lighting have higher (OR 1.07, 95% CI 1.05–1.10) * for ARI compared to electric and solar lighting | Fair |
| Mashreky, 2010 [38] | Case–control | Bangladesh | 840 | <10 | Use of traditional kerosene lamp (kupi bati) | PH | OM: Burn | ↑ Using a kupi bati increased risk of burn (OR 3.16, 95% CI 1.58–6.35) * with attributable risk of 68.38% | Fair |
| Camilloni, 2011 [39] | Case-control | Italy | 74 | 65–85 | Subjective: Poor lighting | PH | SR: Home injuries | ↑ Poor household illumination associated with home injuries (OR 3.00, 95% CI 1.41–6.38) * | Fair |
| Shi, 2014 [40] | Cross-sectional | China | 472 | Adults | Subjective: Sufficient lighting for stairway | PH | SR: Falls | ↑ Sufficient lighting for stairway can lower the risk for a single fall (OR 0.45, 95% CI 0.21–0.96) * | Good |
| Isberner, 1998 [41] | Case-control | USA | 90 | ≥60 | Subjective: Poor lighting at stairs | PH | SR: Falls | ↑ Participants with poor lighting at stairs had a higher chance of falling (OR 3.31, 95% CI 0.63–17.36) | Fair |
| First Author, Year | Study Design | Country | Sample Size | Age (Years) | Lighting Exposure | Health Domain | Health Outcome | Main Finding | Quality Score |
| Czepita, 2004 [42] | Cross-sectional | Poland | 3636 | 6–18 | Type of lighting: Fluorescent or incandescent in living room, dining room, child’s room, parent’s room, kitchen and bathroom. | PH | OM: Refractive error: emmetropia, myopia, hyperopia, astigmatism and anisometropia | ↑ Higher prevalence of hyperopia with fluorescent lamp in kitchen (p < 0.01) * - No statistically significant findings for other exposure-outcome combinations |
Fair |
| Hopkins, 2017 [43] | Crossover | UK | 80 | >60 | Blue-enriched white lighting (17,000 K ≃ 900 lux), white lighting (4000 K ≃200 lux) | MH SH |
SR: Mood SR and OM: Sleep |
↑ Blue-enriched lighting reduced anxiety, sleep efficiency and quality * ↑ Blue-enriched light increased night-time activity * |
Fair |
| Kayaba, 2014 [44] | Cross-sectional | Japan | 351 | 20–70 | Light-emitting diode (LED), light bulb, fluorescent light | SH | SR: Sleep quality | Compared with LED lighting: ↑ Light bulbs (OR: 3.7, 95% CI 1.1–12.6) * were risk factors for variable sleep quality - Fluorescent lighting produced no significant results (OR 2.1, 95% CI 0.8–5.7) |
Fair |
| LIGHT AT NIGHT | |||||||||
| Czepita, 2004 [42] | Cross-sectional | Poland | 3636 | 6–18 | Lighting habit: Sleeping in darkness or with the light on | PH | OM: Refractive error (emmetropia, myopia, hyperopia, astigmatism and anisometropia) | - No relationship between prevalence of refractive error and sleeping with the light turned on or off at night | Fair |
| O’Leary, 2006 [45] | Case-control | USA | 1161 | <75 | Lighting habit during sleep hours | PH | OM: Breast cancer | ↑ Increased risk of breast cancer for women who frequently turned on lights at home during sleep hours (OR 1.65, 95% CI 1.02–2.69) * | Fair |
| First Author, Year | Study Design | Country | Sample Size | Age (Years) | Lighting Exposure | Health Domain | Health Outcome | Main Finding | Quality Score |
| Obayashi, 2015 [46] | Cross-sectional | Japan | 700 | ≥60 | Objective: Indoor illumination level | PH | OM: Carotid atherosclerosis | ↑ With each quartile increase in light exposure, mean carotid intima-media thickness increased (ptrend = 0.002) * | Good |
| Obayashi, 2013 [47] | Cross-sectional | Japan | 528 | ≥60 | Objective: Indoor illumination level | PH | SR and OM: Obesity and dyslipidaemia | ↑ Light intensity and Body Mass Index (OR 1.89, 95% CI 1.02–2.57) *; abdominal obesity (OR 1.62, 95% CI 1.02–2.57) *; and dyslipidaemia (OR 1.72, 95% CI 1.11–2.68) * | Good |
| Obayashi, 2014 [48] | Cross-sectional | Japan | 528 | ≥60 | Objective: Indoor illumination level | PH | OM: Night-time blood pressure | ↑ Light intensity (≥5 lux) higher night-time systolic BP (adjusted mean: 120.8 vs. 116.5 mmHg) and diastolic BP (70.1 vs. 67.1 mmHg) compared with group <5lux | Good |
| Obayashi, 2014 [49] | Cross-sectional | Japan | 513 | ≥60 | Objective: Indoor illumination level | PH | OM: Diabetes | ↑ Brighter evening light amounts and increase in diabetes prevalence (OR 1.72, 95% CI 1.12–2.64) * | Good |
| Yamauchi, 2014 [50] | Crossover | Japan | 17 | Adult | Light environment: 1000 lux, Dark: 0 lux |
PH SH |
SR and OM: Sleep (efficacy, latency and apnea) and heart rate variability |
↑ Higher low-frequency power divided by high-frequency ratio power in the analysis of heart rate variability and apnea-hypopnea index in the light environment * - No other differences in sleep in the different light environments |
Fair |
| Obayashi, 2013 [51] | Cross-sectional | Japan | 516 | ≥60 | Objective: Indoor illumination level | MH | SR: Depression | ↑ Higher prevalence of light intensity ≥5lux in the depressed group compared with that in the nondepressed group (OR 1.89, 95% CI 1.10–3.25) * ↑ Light at night 10 lux ≥30 min is a risk for depressive symptoms (OR 1.71, 95% CI 1.01–2.89) * |
Good |
| Obayashi, 2018 [52] | Longitudinal | Japan | 863 | ≥60 | Objective: Indoor illumination level | MH | SR: Depression | ↑ Light intensity (≥5 Lux) and higher depression risk (HR 1.78, 95% CI 1.07–2.96) * | Good |
| Obayashi, 2014 [53] | Cross-sectional | Japan | 857 | ≥60 | Objective: Indoor illumination level | SH | SR and OM: Sleep quality | ↑ Highest quartile of light intensity showed higher odds for insomnia (OR 1.61, 95% CI 1.05–2.45) *; higher OR for insomnia with each quartile increase in light exposure (ptrend = 0.043) * | Good |
| Obayashi, 2014 [54] | Longitudinal | Japan | 192 | ≥60 | Objective: Indoor illumination level | SH | OM: Sleep onset latency | ↑ Brighter evening light amounts and longer sleep onset latency (regression co-efficient 0.133, 95% CI 0.020–0.247) * | Good |
Abbreviations: PH = physical health, MH = mental health, SH = sleep health, GH = general health, OM = objectively measured, SR = self-reported, NR = not reported, OR = odds ratio, HR = hazard ratio, p.p = percentage points, ↑ = expected direction of association, ↓ = unexpected direction of association, - = no association * = statistically significant with p < 0.05.