Effect of low doses of ionising radiation in infancy on cognitive function in adulthood: Swedish population based cohort study.
OBJECTIVE
To determine whether exposure to low doses of ionising radiation in infancy affects cognitive function in adulthood.


METHODS
Population based cohort study.


METHODS
Sweden.


METHODS
3094 men who had received radiation for cutaneous haemangioma before age 18 months during 1930-59.


METHODS
Radiation dose to frontal and posterior parts of the brain, and association between dose and intellectual capacity at age 18 or 19 years based on cognitive tests (learning ability, logical reasoning, spatial recognition) and high school attendance.


RESULTS
The proportion of boys who attended high school decreased with increasing doses of radiation to both the frontal and the posterior parts of the brain from about 32% among those not exposed to around 17% in those who received > 250 mGy. For the frontal dose, the multivariate odds ratio was 0.47 (95% confidence interval 0.26 to 0.85, P for trend 0.0003) and for the posterior dose it was 0.59 (0.23 to 1.47, 0.0005). A negative dose-response relation was also evident for the three cognitive tests for learning ability and logical reasoning but not for the test of spatial recognition.


CONCLUSIONS
Low doses of ionising radiation to the brain in infancy influence cognitive abilities in adulthood.
Hall
Per
P
Department of Medical Epidemiology and Biostatistics, Karolinska Institute, PO Box 281, SE-171 77 Stockholm, Sweden. Per.Hall@mep.ki.se
Adami
Hans-Olov
HO
Trichopoulos
Dimitrios
D
Pedersen
Nancy L
NL
Lagiou
Pagona
P
Ekbom
Anders
A
Ingvar
Martin
M
Lundell
Marie
M
Granath
Fredrik
F
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000528:radiation effects*; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D006391:Hemangioma / Q000453:epidemiology / Q000532:radiotherapy*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007360:Intelligence / Q000528:radiation effects; D008297:Male; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D012044:Regression Analysis; D012878:Skin Neoplasms / Q000453:epidemiology / Q000532:radiotherapy*; D013548:Sweden / Q000453:epidemiology