This report combines three epidemiologic studies previously
undertaken by the authors in three different places in southern
Spain. The Axarquía study (1997e1998) was carried out with 757
schoolchildren (4e16 years) in order to determine the prevalence of
goiter in the province of Malaga.14 The Jaen study (2001e2002)
involved 1205 schoolchildren (4e16 years) from the province of
Jaen, again to determine the prevalence of goiter.1 The Pizarra study
(1996e1998) was done in 1051 adults (18e64 years) from
a different part of the province of Malaga and was designed to
examine the “nature-nurture” relation to explain the metabolic and
cardiovascular risk factors of this population.15 All three studies
involved a standardized food frequency questionnaire to determine
the consumption of iodized salt and other sources of iodine, such as
the consumption of milk and other dairy products, fish or eggs.
The food surveys were based on questionnaires validated by the
authors in previous studies16 and were carried out by certified
dieticians. These surveys also included measurements of urinary
iodine concentrations in a casual urine sample from the whole
study population.