Dimitrov B D
Department of Social Medicine, Higher Medical Institute, Plovdiv, Bulgaria.
Cent Eur J Public Health. 2000 May;8(2):114-6.
This is a retrospective study on meningococcal meningitis (MM) in Bulgaria that has, for the first time, reported results on non-linear temporal patterns of incidence and its variations. Methods of descriptive statistics, linear and non-linear modelling as well as periodogram regression analysis have been applied. A non-linear decreasing trend in crude incidence rates per 100 persons over the years 1940-1990 has been described (p < 0.0001) and cyclic variations revealed (periods T = 8.00, 18.75, 24.75 and 33.50 years, p < 0.05-0.01). Above cycles have been detected after the reciprocal trend has been removed (y = 1.04 + 15.78/t). A similar cyclicity (periods T = 8.25 and 27.5 years) in the variations of solar activity (sunspot number Rz) over the same time interval of 51 years has been established after the main cycle of 10.5-13 years has been removed by a two-step procedure. The results from this study have added to our previous findings on cyclic variations in mortality and lethality from meningococcal infections in Bulgaria (1, 2). Above similarity is also in accordance with earlier conclusions on relations of solar activity cycles with epidemics of cerebrospinal meningitis in New York and USA over the years 1800-1935 (3, 4).
这是一项针对保加利亚脑膜炎球菌性脑膜炎（MM）的回顾性研究，首次报告了发病率的非线性时间模式及其变化结果。应用了描述性统计方法、线性和非线性建模以及周期图回归分析。描述了1940年至1990年期间每100人粗发病率的非线性下降趋势（p < 0.0001），并揭示了周期性变化（周期T = 8.00、18.75、24.75和33.50年，p < 0.05 - 0.01）。在去除倒数趋势（y = 1.04 + 15.78/t）后检测到上述周期。在通过两步程序去除10.5 - 13年的主周期后，在相同的51年时间间隔内，太阳活动（太阳黑子数Rz）变化中也建立了类似的周期性（周期T = 8.25和27.5年）。这项研究的结果补充了我们之前关于保加利亚脑膜炎球菌感染死亡率和致死率周期性变化的发现（1, 2）。上述相似性也与早期关于1800年至1935年期间纽约和美国太阳活动周期与脑脊髓膜炎流行关系的结论一致（3, 4）。
