Intelligence in early adulthood appears to be a more telling risk factor for early death, offering better predictions of premature mortality than blood pressure, elevated blood cholesterol and body mass index, according to Duke University researchers.
Aging is a phenomenon that enhances your risk of multiple age-related diseases simultaneously. Despite the fact that life expectancy is increasing, and continues to do so, what we now have is an elderly society living with disability longer than they were two decades ago.¹ With this, pinpointing risk factors that promote accelerated aging has become a significant public health interest. Luckily, scientific investigations are beginning to shed some light.
Research findings, presented in the most recent issue of The Proceedings of the National Academy of Sciences, have been looking at the biological age of middle-aged individuals in relation to their childhood intelligence. The study is based on a group of 954 people born in New Zealand in 1972 or 1973.
“We set out to measure aging in these relatively young people,” Dan Belsky, an assistant professor of geriatrics at Duke University’s Center for Aging and one of the study’s authors, said in a press release. “Most studies of aging look at seniors, but if we want to be able to prevent age-related disease, we’re going to have to start studying aging in young people.”
Researchers tested the hypthotesis that low intelligence predisposes to accelerated aging using four measures of biological age: perceived facial age, a 10-biomarker algorithm, an estimate of cardiovascular disease (CVD) risk, and leukocyte telomere length (LTL). Intelligence was primarily measured at age 3, followed by assessments of middle age at 38, prior to the onset of most age-related disease.
Their results suggest that lower early-life intelligence can actually accelerate the aging process, with evidence assessing this occurrence being evident even before the onset of most age related disease. Thus, this finding implies that accelerated aging could be one of the mechanisms linking low early-life intelligence to an array of negative, age-related health outcomes.
The association between intelligence and aging has previously been noted: a meta-analysis of 16 independent studies found that a single standard deviation advantage in intelligence test scores, taken within the first two decades of life, generated a 24% lower risk of death over a continual period of 17-69 years.²
Consistent findings suggest that intelligence correlates with premature death, and a whole range of health conditions across one’s lifespan: all the way from obesity and metabolic syndrome in the first half of life, subsequently to type 2 diabetes and heart disease in later life, and dementia in old age. ³
This association may arise because intelligent people typically gain access to better health care, which can retard aging. Moreover, intelligent individuals may work in safer occupational environments, reducing exposure to aging conditions such as chronic stress, dangerous working conditions, environmental toxins and/or interpersonal violence. ² Higher intelligence may enhance healthy behaviours, such as sleep, physical activity and dietary habits. Moreover, previous research showed that genes account for only about 20 percent of aging, leaving the rest up to health behaviors and the environment.
“That gives us some hope that medicine might be able to slow aging and give people more healthy active years,” said senior author Terrie Moffitt, a professor of psychology and neuroscience at Duke University.
Moffitt’s novel study supports the notion that cognitive enhancement interventions in the formative years could help to decrease or delay age-related morbidity. Previously, early-life educational interventions have been noted for their effects on later health.4 Counting up risk considerations, it would appear that intelligence affects more than one organ.
1. Murray, C. J. L., Vos, T., Lozano, R., Naghavi, M., Flaxman, A. D., Michaud, C., … Grant, B. (2012). Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990–2010: A systematic analysis for the Global Burden of Disease Study 2010. The Lancet, 380, 2197–223.
2. Terrie E. Moffitt et al. Early-Life Intelligence Predicts Midlife Biological Age. Journals of Gerontology, Series B: Psychological Sciences and Social Sciences, 2015, Vol. 00, No. 00
3. Arden, R., Gottfredson, L. S., & Miller, G. (2009). Does a fitness factor con- tribute to the association between intelligence and health outcomes? Evidence from medical abnormality counts among 3654 US Veterans. Intel- ligence, 37, 581–591. doi:10.1016/j.intell.2009.03.008
4. Campbell, F., Conti, G., Heckman, J. J., Moon, S. H., Pinto, R., Pungello, E., & Pan, Y. (2014). Early childhood investments substantially boost adult health. Science, 343, 1478–1485. doi:10.1126/science.1248429