Batty G D, Modig Wennerstad K, Davey Smith G, Gunnell D, Deary I J, Tynelius P, Rasmussen F
MRC Social and Public Health Sciences Unit, University of Glasgow, Glasgow; Department of Psychology, University of Edinburgh, Edinburgh, UK.
Child and Adolescent Public Health Epidemiology Group, Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden.
Ann Oncol. 2007 Jan;18(1):21-28. doi: 10.1093/annonc/mdl473.
While several studies have reported an inverse relation between IQ and total mortality rates, little is known about the association, if any, between IQ and disease-specific outcomes, particularly cancer.
A cohort of 959,540 Swedish men who underwent IQ testing at military conscription at around 19 years of age, and who were followed for incident cancer. Hazards ratios for the relation between IQ and 20 cancer outcomes were computed using Cox regression.
During an average of 19.5 years of follow-up, there were 10 273 new cancer cases. IQ showed few associations with the cancer end points studied. There was a suggestion that IQ was positively associated with lung cancer, and inversely related to stomach, oesophageal and liver malignancies, although effects were modest. The only robust gradient was found for IQ in relation to skin cancer (HRper one standard deviation advantage in IQ; 95% confidence interval 1.18; 1.13, 1.24; P value for trend across categories: <0.01), which was attenuated but retained statistical significance after adjustment for indices of socioeconomic position across the life course.
In this large cohort of Swedish men followed into middle age, IQ was related to very few of the cancer outcomes under investigation. This indicates that the recent observation that low IQ is related to increased mortality rates may not be generated by an IQ-cancer gradient. Given that the present analyses are among the first to examine these associations, replication is required.
虽然多项研究报告了智商与总死亡率之间的负相关关系，但对于智商与特定疾病结局（尤其是癌症）之间的关联（如果存在的话）知之甚少。
对959540名瑞典男性进行队列研究，这些男性在19岁左右征兵时接受了智商测试，并对其新发癌症情况进行随访。使用Cox回归计算智商与20种癌症结局之间关系的风险比。
在平均19.5年的随访期间，有10273例新发癌症病例。智商与所研究的癌症终点之间几乎没有关联。有迹象表明，智商与肺癌呈正相关，与胃癌、食管癌和肝癌呈负相关，尽管影响较小。在智商与皮肤癌的关系中发现了唯一显著的梯度（智商每高出一个标准差的风险比；95%置信区间1.18；1.13，1.24；各分类间趋势的P值：<0.01），在对整个生命过程中的社会经济地位指标进行调整后，这种关联虽有所减弱但仍具有统计学意义。
在这个随访至中年的瑞典男性大队列中，智商与所调查的癌症结局中很少几种相关。这表明最近观察到的低智商与死亡率增加之间的关系可能不是由智商 - 癌症梯度导致的。鉴于目前的分析是首批研究这些关联的分析之一，需要进行重复研究。
