TY - JOUR
T1 - Cognitive ability in Swedish conscripts and future risk of venous thromboembolism
T2 - A co-relative prospective national study
AU - Zöller, Bengt
AU - Ohlsson, Henrik
AU - Sundquist, Jan
AU - Sundquist, Kristina
N1 - Publisher Copyright:
© 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - Objective Cognitive ability measured via an IQ-test (intelligence quotient) has been associated with cardiovascular (CVD) incidence. Whether cognitive ability is associated with risk of venous thromboembolism (VTE) is unknown. The present nationwide co-relative study aims to determine whether cognitive ability in male conscripts is a predictor of VTE. Methods A Swedish cohort of male conscripts (n = 940,964) born in 1954-1970 with no history of previous VTE were followed from enlistment (1972-1990) until 2010. Data on cognitive ability, using an IQ-test at conscription, were linked with national hospital register data to calculate future risk of VTE requiring in-patient care. Using the Swedish Multi-Generation Register, we identified all full-siblings, half-siblings and first-cousin pair discordant for IQ. This co-relative design allows for adjustment for unmeasured shared genetic or environmental factors. Results A total of 5110 (0.54%) males were affected by VTE. IQ was associated with risk for VTE (hazard ratio = HR 0.87 95% confidence interval 0.84-0.89 per standard deviation [SD] increment). The association was highly time dependent with attenuation of effect over time and significant interaction between time and IQ. IQ was also associated with VTE in first-cousin pairs (HR = 0.74, 0.69-0.79) but not when examining discordant half-sibling pairs (HR = 0.94, 0.82-1.08), and only weakly in full-sibling pairs (HR = 0.91, 0.84-0.98). Conclusions The present study suggests that familial-shared environmental factors linked to cognitive ability might be involved in the etiology of VTE. However, it is unlikely that IQ by itself causes VTE.
AB - Objective Cognitive ability measured via an IQ-test (intelligence quotient) has been associated with cardiovascular (CVD) incidence. Whether cognitive ability is associated with risk of venous thromboembolism (VTE) is unknown. The present nationwide co-relative study aims to determine whether cognitive ability in male conscripts is a predictor of VTE. Methods A Swedish cohort of male conscripts (n = 940,964) born in 1954-1970 with no history of previous VTE were followed from enlistment (1972-1990) until 2010. Data on cognitive ability, using an IQ-test at conscription, were linked with national hospital register data to calculate future risk of VTE requiring in-patient care. Using the Swedish Multi-Generation Register, we identified all full-siblings, half-siblings and first-cousin pair discordant for IQ. This co-relative design allows for adjustment for unmeasured shared genetic or environmental factors. Results A total of 5110 (0.54%) males were affected by VTE. IQ was associated with risk for VTE (hazard ratio = HR 0.87 95% confidence interval 0.84-0.89 per standard deviation [SD] increment). The association was highly time dependent with attenuation of effect over time and significant interaction between time and IQ. IQ was also associated with VTE in first-cousin pairs (HR = 0.74, 0.69-0.79) but not when examining discordant half-sibling pairs (HR = 0.94, 0.82-1.08), and only weakly in full-sibling pairs (HR = 0.91, 0.84-0.98). Conclusions The present study suggests that familial-shared environmental factors linked to cognitive ability might be involved in the etiology of VTE. However, it is unlikely that IQ by itself causes VTE.
KW - Cognitive ability
KW - Epidemiology
KW - Family study
KW - IQ
KW - Pulmonary embolism
KW - Thrombosis
UR - http://www.scopus.com/inward/record.url?scp=84955612333&partnerID=8YFLogxK
U2 - 10.1016/j.ejim.2016.01.012
DO - 10.1016/j.ejim.2016.01.012
M3 - Article
C2 - 26827099
AN - SCOPUS:84955612333
SN - 0953-6205
VL - 30
SP - 68
EP - 71
JO - European Journal of Internal Medicine
JF - European Journal of Internal Medicine
ER -