Association between Native American-owned casinos and the prevalence of large-forgestational- age births

Abstract

Background: A small number of studies have used a natural experiment approach to examine the health impacts of increased economic resources stemming from Native American-owned casinos.We build on this work by examining whether casinos are associated with obesity-related health in utero. Methods: We examined whether casino openings or expansion (as proxy for increased economic resources) are associated with a decreased likelihood of infants being born large-for-gestational-age (LGA), an important risk factor for childhood overweight/obesity. We used repeated cross-sectional data from California birth records (1987-2011) to assess the prevalence of LGA births among Native Americans (n = 21 011). Using zip code fixedeffect regression models, we compared how prevalence of LGA births changed in association with casino openings or expansions, while controlling for secular trends through the inclusion of a comparison group of Native American newborns in zip codes that were eligible to open or expand casinos, but did not do so. In sensitivity analyses, we evaluated whether there was any change in small-for-gestational-age births (SGA). Results: Average prevalence of LGA births over the period was 11%. Every one slot machine per capita increase was associated with a 0.13 percentage point decrease (95% confidence interval: -0.25, -0.01) in the prevalence of LGA births but was not associated with SGA prevalence. Conclusions: Casino expansion in California is associated with a lower prevalence of LGA births. Interpreted in combination with previous work showing that California casino expansions were associated with a lower body mass index (BMI) among schoolchildren, these results suggest that casinos are associated with improvement in a surrogate marker of excess adiposity. Further studies are needed to elucidate the mechanisms by which casinosmight be associated with obesity-related health outcomes among Native Americans.