Table 1.
Chronobiologic analysis of seasonal distribution of multiple sclerosis relapses, and meteorological data
| N | Period (hours) | PR (%) | MESOR ± SE | Amplitude | Acrophase | p | |
|---|---|---|---|---|---|---|---|
| Total relapses | 164 | 8766.00 | 10.7 | N.S. | |||
| 4383.00 | 64.0 | 0.012 | |||||
| Overall | 74.7 | 13.69 ± 0.83 | 6.42 | -142° (May) | 0.030 | ||
| Females | 108 | 8766.00 | 12.1 | N.S. | |||
| 4383.00 | 29.6 | N.S. | |||||
| Overall | 41.7 | 9.01 ± 0.95 | 3.62 | -139° | N.S. | ||
| Males | 56 | 8766.00 | 2.3 | N.S. | |||
| 4383.00 | 35.1 | N.S. | |||||
| Overall | 37.4 | 4.68 ± 0.87 | 2.81 | -144° | N.S. | ||
| < 40 yrs | 115 | 8766.00 | 2.7 | N.S. | |||
| 4383.00 | 64.9 | 0.021 | |||||
| Overall | 67.6 | 9.60 ± 0.72 | 4.37 | -142° (May) | 0.065 | ||
| ≥40 yrs | 49 | 8766.00 | 41.0 | 0.031 | |||
| 4383.00 | 34.9 | 0.043 | |||||
| Overall | 75.8 | 4.09 ± 0.26 | 2.11 | -141° (May) | 0.025 | ||
| Temperature (°C) | 8766.00 | 97.4 | 15.4 ± 0.39 | 10.05 | -188.8 ± 3. 2 (July) | < 0.001 | |
| Humidity (%) | 8766.00 | 81.2 | 61.0 ± 1.65 | 14.57 | -3.3 ± 9.2 (January) | < 0.001 | |
| Wind speed (m/sec) | 8766.00 | 63.1 | 2.20 ± 0.11 | 0.63 | -164.7 ± 14.6 (June) | 0.011 | |
| Rain precipitation (mm) | 8766.00 | 0.7 | 1.81 ± 0.47 | 0.17 | -20.8 ± 227.1 | N.S. |
Abbreviations (see text for details) derived by Cosinor analysis of the time series data: PR : percentage of rhythm - MESOR: midline estimated statistic of rhythm (the rhythm-adjusted mean over the time period analyzed, i.e., the monthly mean for a cycle of one year) - Amplitude: one-half the difference between the absolute maximum and minimum of the fitted curve - Acrophase: the absolute time of the peak expressed in degrees, with 360° = 12 months or 1 day = 0.9863, as a negative value (i.e., a delay) in reference to midnight December 31. P value derived by the F-test statistic of the null hypothesis that the amplitude of the fitted cosine approximation of a given period = 07