EARLY LIFE EXPOSURES AND DEVELOPMENT OF ADHD IN CHILDHOOD
Embargo until
2019-05-01
Date
2018-04-03
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Publisher
Johns Hopkins University
Abstract
Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders that imposes an enormous cost to individual, family and society across lifespan and generations in the U.S. This dissertation sought to systematically examine three potentially important early life factors in relation to ADHD, specifically, maternal cholesterol levels, early childhood lead exposure, and maternal acetaminophen use, using the data of mother-infant pairs already enrolled and followed in the Boston Birth Cohort (BBC), a high risk, predominantly urban low income minority population.
First, I investigated the prospective association of maternal cholesterol levels measured within a few days of delivery with the risk of offspring ADHD diagnosis among 1479 mother-infant pairs of the BBC. A low maternal high-density lipoprotein level (≤60 mg/dL) was associated with an increased risk of ADHD. A “J” shaped relationship was observed between triglycerides and ADHD risk. These associations were more pronounced among boys.
Second, I investigated the prospective associations between early childhood lead exposure and ADHD diagnosis and its potential effect modifiers among 1479 mother-infant pairs in the BBC. I found that the elevated lead levels (5-10µg/dL) in early childhood was associated with a 66% increased risk of ADHD. Boys were more vulnerable than girls at a given lead level. This risk of ADHD was reduced by half if the mother had adequate high-density lipoprotein level or low stress.
Third, I examined the prospective association between maternal plasma biomarkers of acetaminophen intake measured within a few days of delivery and offspring ADHD diagnosis among 1180 mother-infant pairs of the BBC. There were significant dose-response associations between ADHD diagnosis and each maternal acetaminophen biomarker; and such associations were specific to ADHD, rather than other neurodevelopmental disorders.
These findings not only raise a new mechanistic perspective for understanding the origins of ADHD but also shed new light on the sex difference in ADHD and point to opportunities for early risk assessment and primary prevention of ADHD.
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Keywords
ADHD, pregnancy