Department of Psychiatry and Medical Psychology, Faculty of Medicine, University of Granada, Granada, Spain.
Prog Neuropsychopharmacol Biol Psychiatry. 2011 Aug 15;35(7):1780-4. doi: 10.1016/j.pnpbp.2011.07.002. Epub 2011 Jul 19.
Despite the fact that association between winter birth excess and schizophrenia in the northern Hemisphere is well established, possible sex or birth-cohort differences in this winter birth excess remain unclear. We aimed to evaluate sex and birth-cohort differences in the seasonal birth distribution of patients with schizophrenia or non-schizophrenic psychosis.
The sample included 321 ICD-10 schizophrenia and 294 non-schizophrenic psychosis patients consecutively admitted into a psychiatric hospitalization unit in Granada, southern Spain, during a nine-year period (1998-2006). The distribution of births among the general population born over the same period as the patients was calculated.
Among schizophrenia males (n=258), it was possible to demonstrate that the observed proportion of winter birth (December, January or February) was significantly higher than expected. Among schizophrenia females (n=63), although proportions were as in males and the effect size of the difference between observed and expected winter births was not lower than for men, only a statistical trend could be demonstrated. Among patients with non-schizophrenic psychosis, the observed proportion of winter birth was significantly higher than expected in women, but not in men. The sex-adjusted proportion of winter birth among schizophrenia patients born in the 1940's (a time period characterized by poor economy and widespread food restrictions because of the Spanish post-civil-war period) was significantly higher than among those born later; a difference that does not occur among patients with a non-schizophrenic psychosis.
Among schizophrenia patients born in winter there appear to be slight sex-differences and strong birth-cohort differences, possibly due to epidemiological factors such as poverty or maternal nutritional deprivation. Epidemiological findings related to winter birth excess among patients with schizophrenia must be identified in longitudinal studies.
尽管在北半球，冬季出生过剩与精神分裂症之间的关联已得到充分证实，但这种冬季出生过剩在性别或出生队列上的差异尚不清楚。我们旨在评估精神分裂症或非精神分裂性精神病患者季节性出生分布的性别和出生队列差异。
该样本包括在西班牙南部格拉纳达的一家精神病住院病房连续收治的 321 例 ICD-10 精神分裂症患者和 294 例非精神分裂性精神病患者。计算了同期出生于同一时期的一般人群的出生分布情况。
在精神分裂症男性患者（n=258）中，观察到的冬季出生（12 月、1 月或 2 月）比例明显高于预期。在精神分裂症女性患者（n=63）中，虽然比例与男性相同，且观察到的冬季出生与预期的差异效应大小不低于男性，但仅能证明存在统计学趋势。在非精神分裂性精神病患者中，女性的观察到的冬季出生比例明显高于预期，但男性则不然。出生于 20 世纪 40 年代（当时经济状况不佳，由于西班牙内战之后的时期普遍存在食物限制）的精神分裂症患者的性别调整后冬季出生比例明显高于出生较晚的患者；而非精神分裂性精神病患者则没有这种差异。
在冬季出生的精神分裂症患者中，似乎存在轻微的性别差异和强烈的出生队列差异，这可能是由于贫困或孕产妇营养缺乏等流行病学因素所致。必须在纵向研究中确定与精神分裂症患者冬季出生过剩相关的流行病学发现。
