Childhood intelligence in relation to major causes of death in 68 year follow-up: prospective population study
BMJ 2017; 357 doi: https://doi.org/10.1136/bmj.j2708 (Published 28 June 2017) Cite this as: BMJ 2017;357:j2708All rapid responses
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Catherine M Calvin et. al. did an outstanding study on the impact of intelligence on mortality and longevity (BMJ 28 June 2017).
Their findings reminded me an observation over many years and the perception that the children of doctors and successful professionals can have a higher intelligence than average. I propose then to investigate if these children are in fact more intelligent and if they live longer.
These children have a basic genetic normal or above, are grown in a favorable environment with good conditions for health, learning, nutrition, vaccinations, lifestyle, etc. that allow them to develop the best of their intellectual capacities.
Certainly, intelligence per se is not enough. They also need character, values, personality and emotional intelligence as well as diligence in their professional activities and practices. But if they have this favorable basis it would be a good starting for a long and satisfactory life.
Prof. Enrique Sanchez-Delgado
Internal Medicine- Clinical Pharmacology and Therapeutics
Hospital Vivian Pellas, Managua.
Competing interests: No competing interests
The strong association of early childhood stress with adult disease provides a potential explanation for the association of premature death with lower childhood intelligence. In a large investigation of the Millennium Cohort Study in 2010 and 2011 Goodman and Greaves of the Institute of Fiscal Studies found that the history of parental separation before the age of three years produced a reduction in measured cognitive development of around 1 SD. This finding explained largely why children of married parents had better measured development. If this is a significant confounder for the findings of Calvin et al, the implications are worrying.
Competing interests: No competing interests
Re: Childhood intelligence in relation to major causes of death. Lung cancer highlighted.
To the Editor,
Catherine M. Calvin et al. have posted an intriguing study linking causes of death and childhood intelligence (BMJ 2017;357:j2708). Despite the inherent limitations in defining and quantifying intelligence, the conclusions are based on an impressive number of subjects and rigorously analyzed. The data on lung cancer are particularly compelling – “The strongest association was evident for death
related to lung cancer: the risk in the highest performing 10th of childhood intelligence was reduced by two thirds compared with the lowest performing 10th.”
We investigated the relationship between radon and lung cancer in our community1 and were surprised to find that after adjusting for smoking, income, and both in-home radon and occupational exposure, college-educated study participants had one-third the odds of cancer as compared to those with less than a high school education [AOR (95% CI) = 0.30 (0.13-0.69, p = 0.005]. We cannot know how accurately educational level serves as a surrogate for “intelligence,” but data demonstrating less than one third the risk in the college group seem to support the above work.
While we can offer no explanation with confidence, others,2-4 as well as those referenced by Calvin et al., have concluded similarly. We therefore suggest that any study that includes the epidemiology of lung cancer take educational level into account.
1. Thompson R, Nelson D, Popkin J, Popkin, Z. Case-control study of lung cancer risk from residential radon exposure in Worcester County, Massachusetts. Health Physics 2008:228-241. doi:10.1097/01.HP.0000288561.53790.5f
2. Jemal A, Siegel R, Ward, E et al. Cancer statistics, 2008. CA Cancer J Clin 2008:71–96. doi:10.3322/CA.2007.0010
3. Zhang L, Morgenstern H, Greenland, S, Chang S, Lazarus, P et al. Cannabis smoking and lung cancer risk: Pooled analysis in the International Lung Cancer Consortium. Int J Cancer 2015:894–903. doi: 10.1002/ijc.29036
4. Sommer, I, Griebler U, Mahlknecht P, Thaler K, Bouskill K et al. Socioeconomic inequalities in
non-communicable diseases and their risk factors: an overview of systematic reviews.
BMC Public Health 2015:914. doi 10.1186/s12889-015-2227-y
Competing interests: No competing interests
Joel H. Popkin, MD, FACP
Department of Medicine
St. Vincent Hospital
Worcester, MA 01608 USA
Clinical Professor of Medicine
University of Massachusetts Medical School
joel.popkin@stvincenthospital.com
Donald F Nelson, PhD
Professor of Physics Emeritus
Worcester Polytechnic Institute,
Worcester, MA 01609
dfnelson@charter.net
Richard E. Thompson, PhD
Senior Scientist
Department of Biostatistics
Johns Hopkins Bloomberg School of Public Health
Baltimore, Maryland 21205
rthomps3@jhu.edu
Zenaida Q. Popkin,
Researcher
Shrewsbury, MA, USA
Competing interests: No competing interests