Table 1.
Summary statistics for the three cohorts
| Weather station latitude | Time* | Monthly aggregated suicide rate/100 000 people (rescaled to 365 days) |
Mean hours of sunlight/day | Change in mean hours of sunlight/day compared to previous month | R2 (%)† | ||
|---|---|---|---|---|---|---|---|
| Male | Female | ||||||
| Greece (1992–2001) | 37.9778 N (Athens) | Autumn | 5.00 (4.44 to 5.78) | 1.21 (0.68 to 1.61) | 6.85 (4.59 to 8.39) | −2.19 (−3.19 to −1.13) | 87 |
| Winter | 4.82 (3.97 to 5.51) | 1.18 (0.85 to 1.48) | 4.06 (3.05 to 4.66) | 0.33 (−0.88 to 1.15) | |||
| Spring | 6.10 (5.43 to 7.31) | 1.42 (0.87 to 1.77) | 8.00 (7.25 to 9.16) | 1.26 (0.64 to 2.82) | |||
| Summer | 6.56 (5.26 to 7.11) | 1.69 (1.07 to 2.12) | 11.18 (10.17 to 11.78) | −0.22 (−0.86 to 1.11) | |||
| Victoria, Australia (1990–1998) | 37.7833 S (Melbourne) | Autumn | 19.59 (16.96 to 22.58) | 5.54 (4.78 to 6.96) | 5.25 (4.13 to 6.87) | −1.37 (−2.50 to −0.90) | 78 |
| Winter | 20.47 (17.01 to 21.96) | 5.23 (3.64 to 6.48) | 4.45 (3.68 to 5.27) | 0.56 (−0.22 to 1.24) | |||
| Spring | 23.07 (21.47 to 27.28) | 5.92 (4.82 to 6.77) | 6.62 (5.95 to 7.56) | 1.00 (−0.06 to 1.52) | |||
| Summer | 21.54 (17.44 to 25.21) | 6.25 (3.63 to 7.38) | 7.88 (7.47 to 8.55) | −0.03 (−0.75 to 1.28) | |||
| Norway (1969–2009) | 59.9494 N (Oslo) | Autumn | 11.67 (10.00 to 13.95) | 2.95 (1.77 to 4.35) | −1.59 (−2.79 to −0.57) | 79 | |
| Winter | 11.37 (9.91 to 12.85) | 1.56 (1.12 to 2.47) | 0.35 (−0.49 to 1.17) | ||||
| Spring | 12.71 (10.85 to 15.11) | 5.83 (4.50 to 7.15) | 1.50 (0.44 to 3.09) | ||||
| Summer | 12.27 (10.12 to 14.33) | 7.91 (6.20 to 8.82) | −0.36 (−1.96 to 1.29) | ||||
*For Greece and Norway, Autumn=September, October, November; Winter=December, January, February; Spring=March, April, May; Summer=June, July, August. For Victoria, Autumn=March, April, May; Winter=June, July, August; Spring=September, October, November; Summer=December, January, February.
†We performed a linear regression with mean hours of sunlight/day (aggregated at the monthly level) as the outcome, months (as dummy variables) as the exposure, and assessed the percentage of variation explained by this model (R2).