Batty G D, Shipley M J, Mortensen L H, Boyle S H, Barefoot J, Grønbaek M, Gale C R, Deary I J
MRC Social & Public Health Sciences Unit, University of Glasgow, 4 Lilybank Gardens, Glasgow G12 8RZ, UK.
J Epidemiol Community Health. 2008 Jun;62(6):522-31. doi: 10.1136/jech.2007.064881.
To examine the role of potential mediating factors in explaining the IQ-mortality relation.
DESIGN, SETTING AND PARTICIPANTS: A total of 4316 male former Vietnam-era US army personnel with IQ test results at entry into the service in late adolescence/early adulthood in the 1960/1970s (mean age at entry 20.4 years) participated in a telephone survey and medical examination in middle age (mean age 38.3 years) in 1985-6. They were then followed up for mortality experience for 15 years.
In age-adjusted analyses, higher IQ scores were associated with reduced rates of total mortality (hazard ratio (HR)(per SD increase in IQ) 0.71; 95% CI 0.63 to 0.81). This relation did not appear to be heavily confounded by early socioeconomic position or ethnicity. The impact of adjusting for some potentially mediating risk indices measured in middle age on the IQ-mortality relation (marital status, alcohol consumption, systolic and diastolic blood pressure, pulse rate, blood glucose, body mass index, psychiatric and somatic illness at medical examination) was negligible (<10% attenuation in risk). Controlling for others (cigarette smoking, lung function) had a modest impact (10-17%). Education (0.79; 0.69 to 0.92), occupational prestige (0.77; 0.68 to 0.88) and income (0.86; 0.75 to 0.98) yielded the greatest attenuation in the IQ-mortality gradient (21-52%); after their collective adjustment, the IQ-mortality link was effectively eliminated (0.92; 0.79 to 1.07).
In this cohort, socioeconomic position in middle age might lie on the pathway linking earlier IQ with later mortality risk but might also partly act as a surrogate for cognitive ability.
探讨潜在中介因素在解释智商与死亡率关系中的作用。
设计、背景与参与者：共有4316名曾在越南战争时期服役的美国男性军人，他们于20世纪60/70年代青少年晚期/成年早期入伍时接受了智商测试（入伍时平均年龄20.4岁），并于1985 - 1986年中年时（平均年龄38.3岁）参与了电话调查和医学检查。随后对他们进行了15年的死亡情况随访。
在年龄调整分析中，较高的智商得分与总死亡率降低相关（风险比（HR）（智商每增加1个标准差）为0.71；95%置信区间为0.63至0.81）。这种关系似乎并未受到早期社会经济地位或种族的严重混淆。对中年时测量的一些潜在中介风险指标（婚姻状况、饮酒量、收缩压和舒张压、脉搏率、血糖、体重指数、医学检查时的精神和躯体疾病）进行调整，对智商与死亡率关系的影响可忽略不计（风险降低<10%）。对其他因素（吸烟、肺功能）进行控制有适度影响（10 - 17%）。教育程度（0.79；0.69至0.92）、职业声望（0.77；0.68至0.88）和收入（0.86；0.75至0.98）使智商与死亡率梯度的降低幅度最大（21 - 52%）；在对它们进行综合调整后，智商与死亡率的关联实际上被消除（0.92；0.79至1.07）。
在这个队列中，中年时的社会经济地位可能处于将早期智商与后期死亡风险联系起来的路径上，但也可能部分充当认知能力的替代指标。
