Title: 1282 - Early-life Events are Risk Factors for Hypomineralised Second Primary Molars


Mihiri Silva (Presenter)
Murdoch Childrens Research Institute

Nicky Kilpatrick, Murdoch Childrens Research Institute
David Burgner, Murdoch Childrens Research Institute
Jeff Craig, Deakin University
David Manton, University of Melbourne
Katrina Scurrah, Murdoch Childrens Research Institute


Objectives: The objective of this study was to investigate in a longitudinal twin cohort the relative contribution of genes and environment to the aetiology of Hypomineralised Second Primary Molars (HSPM) and to identify potential environmental risk factors.

Methods: Children from twin pregnancies (N=250) were recruited antenatally from three hospitals in Melbourne, Australia between 2007 and 2009. Detailed demographic, health and phenotypic data were collected at recruitment, 24 and 36-weeks’ gestation and from the twin offspring at birth and 18 months-of-age. 25-Hydroxyvitamin D was quantified in mothers at 28-weeks’ gestation and in infants at birth. Dental examinations were conducted on the twins at six years of age to determine the presence, severity and extent of HSPM, using standardized criteria. Twin-twin concordance for monozygotic (MZ) and dizygotic (DZ) pairs was calculated. To investigate associations between environmental risk factors and HSPM, multiple logistic regression models were fitted using generalised estimating equations to adjust for twin correlation.

Results: Three hundred and forty-four twins underwent the 6-year-old dental assessment; HSPM was present in 68 (19.8%). Overall concordance in twin pairs for HSPM was 0.46 (95% CI 031-0.61) and we found weak evidence of higher concordance in MZ twins (0.59, 95% CI 0.31-0.86) than in DZ twins (0.42, 95% CI 0.24–0.59). After adjusting for potential confounders, infantile eczema, maternal smoking in pregnancy, in vitro fertilization and socio-economic status had the strongest evidence of association with HSPM. There was no evidence of an association between HSPM and factors previously implicated in retrospective studies, such as low birth weight and childhood infection.

Conclusions: These findings suggest that shared genetic and environmental factors, (such as maternal smoking in pregnancy) and unshared early life factors (such as eczema) may be important in the aetiology of HSPM.

Student Presenter

This abstract is based on research that was funded entirely or partially by an outside source:
NIH (R01DE019665), Australian NHMRC (437015 and 607358), the Bonnie Babes Foundation (grant number BBF20704), the Financial Markets Foundation for Children (032-2007), Victorian Government’s Operational Infrastructure Support Program

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE