Intelligence in early adulthood and mortality from natural and unnatural causes in middle-aged Danish men
- Rikke Hodal Meincke1,2,
- Erik Lykke Mortensen2,3,4,
- Kirsten Avlund1,2,5,
- Susanne Rosthøj6,
- Holger Jelling Sørensen7,
- Merete Osler2,5,8
- 1Section of Social Medicine, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- 2Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
- 3The Unit of Medical Psychology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- 4Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen, Denmark
- 5Danish Aging Research Center, University of Aarhus, Copenhagen, Denmark
- 6Department of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- 7Mental Health Centre Copenhagen, Bispebjerg Hospital, Copenhagen, The Capital Region of Denmark
- 8Research Centre for Prevention and Health, Copenhagen, The Capital Region of Denmark
- Correspondence to Rikke Hodal Meincke, Center for Healthy Aging, University of Copenhagen, Section of Social Medicine, 5, Øster Farimagsgade, P.O. Box 2099, Copenhagen DK-1014, Denmark;
- Received 15 March 2013
- Revised 30 August 2013
- Accepted 2 September 2013
- Published Online First 23 September 2013
Background High intelligence early in life has consistently been associated with decreased mortality, but the mechanisms are still not fully understood. In this cohort study, we examined the association between intelligence in early adulthood and later mortality from natural and unnatural causes taking birth weight, parental socioeconomic position, participants’ own education and body mass index into account.
Methods 13 536 Danish men born in 1953 and 1959–1961 with data from birth certificates and intelligence test scores from conscription were followed until 2009. Information on vital status was obtained from the Civil Registration System. Mortality risks were analysed by the multiple Cox proportional hazards model.
Results The risk of mortality from natural as well as unnatural causes was more than twice as high among men in the lowest scoring intelligence tertile (HRnatural deaths=2.24; 1.90–2.65 and HRunnatural deaths=2.67; 2.03–3.53). Adjusting for all covariates attenuated the estimates, but the association remained (HRnatural deaths=1.82; 1.48–2.25 and HRunnatural deaths=2.30; 1.63–3.25).
Conclusions In men, intelligence in early adulthood was inversely associated with midlife mortality from natural and unnatural causes. The associations remained after adjustments for a range of covariates.