Jokela Markus, Elovainio Marko, Singh-Manoux Archana, Kivimäki Mika
Department of Epidemiology and Public Health, University College London, London, UK.
Psychosom Med. 2009 Apr;71(3):322-8. doi: 10.1097/PSY.0b013e31819b69f6. Epub 2009 Feb 27.
To assess whether the association between cognitive ability (IQ) and early mortality is mediated by socioeconomic status (SES) or whether the association between SES and mortality reflects a spurious association caused by IQ.
The participants were from the US National Longitudinal Survey of Youth (n = 11,321). IQ was assessed at age 16 to 23 years and the participants were followed up to 40 to 47 years of age.
Controlling for sex, birth year, race/ethnicity, baseline health, and parental education, higher IQ was associated with lower probability of death (odds ratio (OR) per 1-standard deviation increase in IQ = 0.78, 95% confidence interval (CI) = 0.66, 0.91). This association disappeared (OR = 0.99, 95% CI = 0.81, 1.20) when adjusted for education and household income. Adjustment for IQ had no effect on the association between SES and mortality. These findings were similar in Hispanic, Black, and White/other participants and in women and men. Parental education moderated the IQ-mortality association so that this association was not observed in participants with low parental education.
Low IQ predicts early mortality in the US population and this association is largely explained by SES. The results do not support the alternative hypothesis that the socioeconomic gradient in early mortality would reflect IQ differences.
评估认知能力（智商）与早期死亡率之间的关联是否由社会经济地位（SES）介导，或者SES与死亡率之间的关联是否反映了由智商引起的虚假关联。
参与者来自美国国家青年纵向调查（n = 11321）。在16至23岁时评估智商，并对参与者进行随访至40至47岁。
在控制性别、出生年份、种族/族裔、基线健康状况和父母教育程度后，较高的智商与较低的死亡概率相关（智商每增加1个标准差的优势比（OR）= 0.78，95%置信区间（CI）= 0.66，0.91）。在调整教育程度和家庭收入后，这种关联消失了（OR = 0.99，95% CI = 0.81，1.20）。调整智商对SES与死亡率之间的关联没有影响。这些发现在西班牙裔、黑人以及白人/其他参与者以及女性和男性中相似。父母教育程度调节了智商与死亡率之间的关联，因此在父母教育程度低的参与者中未观察到这种关联。
低智商预示着美国人群的早期死亡率，这种关联在很大程度上由SES解释。结果不支持早期死亡率的社会经济梯度反映智商差异的替代假设。
