Toddler temperament and prenatal exposure to lead and maternal depression.
Temperament is a psychological construct that reflects both personality and an infant's reaction to social stimuli. It can be assessed early in life and is stable over time Temperament predicts many later life behaviors and illnesses, including impulsivity, emotional regulation and obesity. Early life exposure to neurotoxicants often results in developmental deficits in attention, social function, and IQ, but environmental predictors of infant temperament are largely unknown. We propose that prenatal exposure to both chemical and non-chemical environmental toxicants impacts the development of temperament, which can itself be used as a marker of risk for maladaptive neurobehavior in later life. In this study, we assessed associations among prenatal and early life exposure to lead, mercury, poverty, maternal depression and toddler temperament.



A prospective cohort of women living in the Mexico City area were followed longitudinally beginning in the second trimester of pregnancy. Prenatal exposure to lead (blood, bone), mercury, and maternal depression were assessed repeatedly and the Toddler Temperament Scale (TTS) was completed when the child was 24 months old. The association between each measure of prenatal exposure and performance on individual TTS subscales was evaluated by multivariable linear regression. Latent profile analysis was used to classify subjects by TTS performance. Multinomial regression models were used to estimate the prospective association between prenatal exposures and TTS performance.



500 mother-child pairs completed the TTS and had complete data on exposures and covariates. Three latent profiles were identified and categorized as predominantly difficult, intermediate, or easy temperament. Prenatal exposure to maternal depression predicted increasing probability of difficult toddler temperament. Maternal bone lead, a marker of cumulative exposure, also predicted difficult temperament. Prenatal lead exposure modified this association, suggesting that joint exposure in pregnancy to both was most toxic.



Maternal depression predicts difficult temperament and concurrent prenatal exposure to maternal depression and lead predicts a more difficult temperament phenotype in 2 year olds. The role of temperament as an intermediate variable in the path from prenatal exposures to neurobehavioral deficits and other health effects deserves further study.
Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA. annemarie.stroustrup@mssm.edu.|Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. annemarie.stroustrup@mssm.edu.|Division of Newborn Medicine, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1508, New York, NY, 10029, USA. annemarie.stroustrup@mssm.edu.
Annemarie
A
Stroustrup
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Hsiao-Hsien
HH
Hsu
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Katherine
K
Svensson
Department of Developmental Neurobiology, National Institute of Perinatology, Mexico City, Mexico.
Lourdes
L
Schnaas
Center for Nutrition and Health Research, National Institute of Public Health, Morelos, Mexico.
Alejandra
A
Cantoral
Center for Nutrition and Health Research, National Institute of Public Health, Morelos, Mexico.
Maritsa
M
Solano González
Department of Developmental Neurobiology, National Institute of Perinatology, Mexico City, Mexico.
Mariana
M
Torres-Calapiz
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Chitra
C
Amarasiriwardena
Departments of Neurology and Psychiatry, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.|Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
David C
DC
Bellinger
Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.|Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA.
Brent A
BA
Coull
Center for Nutrition and Health Research, National Institute of Public Health, Morelos, Mexico.
Martha M
MM
Téllez-Rojo
Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.|Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Robert O
RO
Wright
Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.|Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Rosalind J
RJ
Wright
D000328:Adult; D002652:Child Behavior; D002657:Child Development; D002675:Child, Preschool; D003863:Depression / Q000453:epidemiology*; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood*; D018811:Maternal Exposure; D008628:Mercury / Q000032:analysis; D008800:Mexico / Q000453:epidemiology; D009035:Mothers; D009262:Nails / Q000737:chemistry; D010329:Patella / Q000737:chemistry; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D013694:Temperament; D013977:Tibia / Q000737:chemistry; D055815:Young Adult
D004785:Environmental Pollutants; D007854:Lead; D008628:Mercury
Depression in pregnancy; Lead; Neurobehavioral outcomes; Prenatal exposure; Temperament