Department of Psychology, Bilkent University, Ankara, Turkey.
Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
Schizophr Bull. 2017 Sep 1;43(5):1056-1063. doi: 10.1093/schbul/sbw147.
Exposure to an urban environment during early life and low IQ are 2 well-established risk factors for schizophrenia. It is not known, however, how these factors might relate to one another. Data were pooled from the North Jutland regional draft board IQ assessments and the Danish Conscription Registry for men born between 1955 and 1993. Excluding those who were followed up for less than 1 year after the assessment yielded a final cohort of 153170 men of whom 578 later developed a schizophrenia spectrum disorder. We found significant effects of having an urban birth, and also experiencing an increase in urbanicity before the age of 10 years, on adult schizophrenia risk. The effect of urban birth was independent of IQ. However, there was a significant interaction between childhood changes in urbanization in the first 10 years and IQ level on the future adult schizophrenia risk. In short, those subjects who moved to more or less urban areas before their 10th birthday lost the protective effect of IQ. When thinking about adult schizophrenia risk, the critical time window of childhood sensitivity to changes in urbanization seems to be linked to IQ. Given the prediction that by 2050, over 80% of the developed world's population will live in an urban environment, this represents a major future public health issue.
在生命早期接触城市环境和智商较低是精神分裂症的两个公认的风险因素。然而，目前尚不清楚这些因素之间可能存在怎样的关系。本研究的数据来自于北日德兰地区兵役委员会的智商评估和丹麦兵役登记处，共纳入了 1955 年至 1993 年期间出生的男性。排除了那些在评估后随访时间少于 1 年的人，最终纳入了 153170 名男性，其中 578 人后来被诊断为精神分裂症谱系障碍。我们发现，在城市出生以及在 10 岁之前经历城市人口密度增加与成年后精神分裂症风险显著相关。城市出生的影响独立于智商。然而，在 10 岁之前儿童时期城市化的变化与智商水平之间存在显著的交互作用，这会影响成年后精神分裂症的风险。简而言之，那些在 10 岁之前搬到更城市化或城市化程度更低地区的人，失去了智商的保护作用。当考虑成年精神分裂症风险时，儿童时期对城市化变化的敏感性的关键时间窗口似乎与智商有关。由于预测到 2050 年，发达国家 80%以上的人口将生活在城市环境中，这将是一个重大的未来公共卫生问题。
