Association between erythrocyte sedimentation rate and IQ in Swedish males aged 18-20.

OBJECTIVE To investigate if signs of inflammation are associated with performance on a contemporaneous IQ-test in males aged 18-20. DESIGN Cohort study using data from the conscript register on performance on an IQ-test and on erythrocyte sedimentation rates (ESR) measured in 1969/70. Data on cardiovascular risk factors measured at conscription and national register data on childhood circumstances at age 10 were considered as potential sources of confounding. Data from national registers was linked to the cohort in order to explore long term associations between ESR at age 18-20 and mortality between the years 1971-2006. SETTING 49,321 Swedish males aged 18-20, screened for general health and for mental and physical capacity at compulsory conscription examination before military service. RESULTS We found an inverse correlation between ESR and performance on an IQ-test. While an association was observed across IQ bands and ESR ranges, independent of cardiovascular risk factors or childhood circumstances, the association was slightly attenuated by adjustment for childhood socioeconomic position (SEP). An association between childhood SEP and ESR was detected that remained after adjusting for IQ. The ESR was also associated with future mortality following adjustment for childhood SEP. CONCLUSIONS Low-grade inflammation, as indicated by the ESR, is associated with reduced cognitive abilities already at age 18-20.