Date of Award

January 2024

Document Type


Degree Name

Master of Public Health (MPH)


School of Public Health

First Advisor

Xiaomei Ma

Second Advisor

Rong Wang


Objective: The etiology of hepatoblastoma, the predominant malignant liver tumor in infancy and early childhood, is unclear. We assessed possible associations between birth characteristics, outdoor artificial light at night (ALAN), ambient air pollution (measured by particulate matter PM2.5), and the risk of hepatoblastoma.

Methods: Leveraging a population-based linkage of statewide birth records and cancer registry data in California, we conducted a case-control study that included 356 hepatoblastoma cases diagnosed at the age of 0-6 years during 1988-2015 and 17,800 controls frequency-matched by birth year. Restricted cubic spline transformation was employed to evaluate non-linear associations. Multivariable logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) for the risk of hepatoblastoma overall and in analysis stratified by race and ethnicity.

Results: The spline transformation suggested that both very low and very high birth weights were associated with higher log-odds for hepatoblastoma. In the overall analysis, being male was associated with a higher risk of hepatoblastoma (OR = 1.45; 95% CI: 1.16-1.80). Compared to non-Hispanic White children, children who are Black, Asian/Pacific Islanders, or of other races were less likely to develop hepatoblastoma (OR = 0.68; 95% CI: 0.48-0.95). In addition, children with low birth weight (<2500 g) were 2.95 times more likely to develop hepatoblastoma (OR = 3.95; 95% CI: 2.82-5.53) than those with normal birth weight (2500-3499 g). Preterm birth (<37 weeks) was associated with a 59% increase in the risk of hepatoblastoma (OR = 1.59; 95% CI: 1.15-2.21). Stratified analysis suggested that an intermediate level of outdoor ALAN exposure was associated with an elevated hepatoblastoma risk among non-Hispanic White children (OR = 1.85; 95% CI: 1.15-2.97), but not among Hispanic children (OR = 0.82; 95% CI: 0.54-1.24). Exposure to ambient PM2.5 did not appear to be a predictor of hepatoblastoma risk in the overall or stratified analysis.

Conclusions: Multiple birth characteristics and exposure to outdoor ALAN appeared to play a role in the etiology of hepatoblastoma in young children. Our finding that some of the associations varied across racial and ethnic groups may help inform future investigations.


This thesis is restricted to Yale network users only. It will be made publicly available on 05/07/2026