When It Rains It Pours: The Long-Run Economic Impacts of Salt Iodization in the United States

Abstract

In 1924, the Morton Salt Company began nationwide distribution of iodine-fortified salt. Access to iodine, a key determinant of cognitive ability, rose sharply. We compare outcomes for cohorts exposed in utero with those of slightly older, unexposed cohorts, across states with high versus low baseline iodine deficiency. Income increased by 11%, labor force participation rose 0.68 percentage points, and full-time work went up 0.9 percentage points due to increased iodine availability. These impacts were largely driven by changes in the economic outcomes of young women. In later adulthood, both men and women had higher family incomes due to iodization.

Malaria, Race, and Inequality: Evidence from the Early 1900s U.S. South

“…Most of these papers are only able to exploit state-level variation in disease endemicity, and as such, cannot control for broader racial convergence in socioeconomic outcomes between relatively poorer (disease-afflicted) and richer (disease-free) states. Our results may also be distinct from the literature as Black males' labor force participation rates were already high prior to the onset of malaria eradication, thus ruling out labor market entry effects from improved health such as those measured for women (e.g., Adhvaryu et al 2020). Programs specifically targeted towards Blacks during the 1920s were effective in reducing Black-white schooling gaps in the South (Aaronson and Mazumder 2011); however, malaria campaigns were broadly applied and thus were likely unable to produce similar convergence results.…”

“…p(75) -p(25) refers to an increase from the 25th to the 75th percentile. Source: Authors' calculations; Aaronson and Mazumder (2011); Adhvaryu et al (2020); Baker, Blanchette, and Eriksson (2020); Barecca (2010); Bleakley (2007); Niemesh (2015). white-collar, and not in the labor force.…”

Child health as human capital

“…For example, Nilsson (2017) examines a change in alcohol policy that affected binge drinking, Schwandt (2017) examines the impact of contracting influenza during pregnancy (which is preventable by vaccination), and Isen, Rossin-Slater, and Walker (2017) examine the long-term effect of having been exposed to higher levels of particulate air pollution in utero or in early childhood. In a developing country context, several authors have demonstrated the effects of reducing infectious disease (Baird, Hamory Hicks, Kremer, & Miguel, 2016;Beach, Ferrie, Saavedra, & Troesken, 2016;Bhalotra & Venkataramani, 2015) and improving nutrition (Adhvaryu, Bednar, Molina, Nguyen, & Nyshadham, 2016). In an important study, Gertler et al (2014) examined the importance of attending to psychological needs by training mothers to provide psychosocial stimulation.…”

Fetal Iodine Deficiency and Schooling: A Replication of Field, Robles, and Torero (2009)*

“…Murcia et al (2011) find gender differences for children aged 1 in Spain (but the study lacks a clear and credible identification strategy). Both Adhvaryu et al (2018) and Feyrer et al (2017) investigate the effects of salt iodization programs in the United States using fixed-effects methods similar to FRT. The former study finds large effects for women but no effects for men.…”