US trade policy and public health: heterogeneous effects from the North American Free Trade Agreement.

OBJECTIVE

To investigate the causal link between the North American Free Trade Agreement (NAFTA) unrestricted sugar trade agreement signed in 2008 between the USA and Mexico and the diabetes prevalence across all fifty US states.

DESIGN

A quasi-experimental research design to investigate the causal effect of the NAFTA unrestricted sugar trade agreement on diabetes prevalence. Our study utilises a comprehensive panel dataset spanning from 2000 to 2016, comprising 1054 observations. To conduct our analysis, we applied both the difference-in-differences and event-study methodologies.

SETTING

All the states in the USA.

PARTICIPANTS

The fifty states in the USA.

RESULTS

After the enactment of the NAFTA sugar trade agreement between the USA and Mexico in 2008, most states witnessed an increase in diabetes prevalence. The annual impacts displayed significant variation among states, with percentage increases spanning from 0·50 to 2·28 %.

CONCLUSIONS

States with a higher percentage of their population living below the poverty line, a larger Black resident population and a lower proportion of high school graduates had more significant increases in diabetes prevalence attributed to the NAFTA sugar trade agreement.