[Endemic goiter prevalence survey in Brazilian schoolchildren 6 to 14 years old, 1994-1996].
OBJECTIVE
To determine the national and state-level prevalence of endemic goiter associated with iodine deficiency in schoolchildren between 6 and 14 years of age in Brazil, based on data from a national survey carried out from 1994 to 1996.


METHODS
Thyroid inspection and palpation were performed on 178,774 schoolchildren between 6 and 14 years of age, in all the states of Brazil. A subsample was selected to measure the iodine content in their urine as well as the iodine content of the table salt used for cooking in their homes.


RESULTS
The last survey before this one was carried out in 1975. We found an 86% decrease in the median prevalence of grade 1 and 2 grade 2 goiter, from 12% to 1%. In 21% of the municipalities, the observed prevalence was zero. From the 16,803 urine samples collected for iodine measurement, 7,702 were matched with the corresponding clinical record (a loss of 54%). The median urinary iodine level was 14.0 micrograms/dL, and without a significant correlation with the clinical data on goiter. The median iodine excretion level for the population in the states of Acre, Amapá, and Tocantins was equal to or below 9.0 micrograms/dL. In three municipalities, urinary iodine was below 2.5 micrograms/dL in all the samples: Paranã (in the state of Tocantins), Conceição (Paraíba), and Nova Roma (Goiás). The supplementary iodine found in the salt collected from households (458 samples collected) was below recommended levels, with 50% of them below 20 mg/kg (20 ppm). In 7% of the samples, the level of iodine was below 10 mg/kg of salt, even in salt-producing states such as Rio Grande do Norte.


CONCLUSIONS
There is evidence goiter is expanding to parts of Brazil that more recently have been opened up for agriculture, with children in those areas being exposed to low levels of supplementary iodine in the salt used for cooking. We found an increased risk of goiter in areas with deficient iodine supplementation (< 10 mg/kg) (odds ratio = 1.85; Cornfield 95% confidence interval: 1.68-2.03).
Corrêa Filho
Heleno Rodrigues
HR
Universidade de Campinas (UNICAMP), Faculdade de Ciências Médicas, Departamento de Medicina Preventiva e Social, Laboratório de Aplicação de Epidemiologia, Campinas, SP. helenocf@unicamp.br
Vieira
João Batista Furtado
JB
Silva
Yara Simoni Pereira
YS
Coelho
Giovanini Evelim
GE
Cavalcante
Felicidade dos Anjos Carvalho
Fdos A
Pereira
Maria da Paz Luna
Mda P
D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D003625:Data Collection / Q000379:methods; D006043:Goiter, Endemic / Q000453:epidemiology*; D006801:Humans; D007455:Iodine / Q000008:administration & dosage / Q000172:deficiency / Q000652:urine; D015995:Prevalence; D012574:Schools / Q000706:statistics & numerical data*; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage
D017673:Sodium Chloride, Dietary; C034024:iodized salt; D007455:Iodine