Table 2 Risk of dementia according to increasing exposure to outdoor artificial light at night (LAN) using 9-year average 2014–2022 period of VIIRS data, using both linear increase and categories based on median (50th), tertiles, and fixed cutoffs of nighttime luminance exposure (LAN) in nW/cm2/sr, in a multivariable analysis stratified by sex and adjusted by age, and educational attainment. Analysis considering as outcome any dementia, and Alzheimer’s dementia only (with exclusion of other dementia cases ab initio). HR: hazard ratio, CI: confidence interval
2014–2022 |  |  |  | Any dementia |  |  |  |  | AD |  |
|---|---|---|---|---|---|---|---|---|---|---|
LAN (nW/cm2/sr) | 50th | N C+/C- | OR | (95% CI) | P value | 50th | N C+/C- | OR | (95% CI) | P value |
Linear trend (1-unit increase) | - |  | 1.04 | (1.01–1.07) | 0.021 | - |  | 1.01 | (1.00-1.07) | 0.052 |
Linear trend (10-unit increase) | - |  | 1.44 | (1.06–1.97) | 0.021 | - |  | 1.40 | (1.00-1.97) | 0.052 |
LAN-Median | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Below the median | 14.7 | 15/11 | 1.00 | - | Â | 14.1 | 11/11 | 1.00 | - | Â |
Above or equal the median | 33.8 | 19/8 | 1.83 | (0.87–3.84) | 0.109 | 33.8 | 15/8 | 1.90 | (0.82–4.40) | 0.137 |
LAN-Tertiles | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
1st tertile | 9.7 | 8/9 | 1.00 | - | Â | 9.7 | 6/9 | 1.00 | - | Â |
2nd tertile | 26.2 | 13/5 | 2.53 | (0.99–6.50) | 0.053 | 26.3 | 9/5 | 2.16 | (0.72–6.50) | 0.172 |
3rd tertile | 36.4 | 13/5 | 3.61 | (1.34–9.74) | 0.011 | 36.4 | 11/5 | 3.62 | (1.21–10.87) | 0.022 |
LAN - fixed cut-offs | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
< 15 | 9.2 | 7/7 | 1.00 | - |  | 8.8 | 6/7 | 1.00 | - |  |
≥ 15; < 30 | 25.4 | 10/7 | 2.00 | (0.72–5.60) | 0.186 | 25.7 | 6/7 | 1.42 | (0.44–4.56) | 0.558 |
≥ 30 | 35.0 | 17/5 | 3.57 | (1.32–9.70) | 0.013 | 34.4 | 14/5 | 2.88 | (1.02–8.15) | 0.046 |