This paper examines the impact of salt iodization in Switzerland in the 1920s and
1930s on occupational patterns of cohorts born after the intervention. The generalized
use of iodized salt successfully combatted iodine deficiency disorders, which were previously endemic in some areas of Switzerland. The most important effect of universal prophylaxis by means of iodized salt was the eradication of mental retardation inflicted in utero by lack of iodine. This paper looks for evidence of increased cognitive ability
of those treated with iodine in utero by examining the occupational choice and characteristics of occupations chosen by cohorts born after the intervention. By exploiting variation in pre-existing conditions and in the timing of the intervention, I find that cohorts born in previously highly-deficient areas after the introduction of iodized salt
self-selected into higher-paying occupations. I also find that the characteristics of occupations
in those areas changed, and that cohorts born after the intervention engaged
to a higher degree in occupations with higher cognitive demands, whereas they opted
out of physical-labor-intensive occupations
