RESUMO
Perchlorate is known to suppress thyroid function by inhibiting uptake of iodide by the human thyroid at doses of 200 mg/day or greater. A study was conducted to investigate the potential effects of perchlorate in drinking water on thyroid function in newborns and school-age children. A total of 162 school-age children and 9784 newborns were studied in three proximate cities in northern Chile that have different concentrations of perchlorate in drinking water: Taltal (100 to 120 micrograms/L), Chañaral (5 to 7 micrograms/L), and Antofagasta (non-detectable: < 4 micrograms/L). Among schoolchildren, no difference was found in thyroid-stimulating hormone levels or goiter prevalence among lifelong residents of Taltal or Chañaral compared with those of Antofagasta, after adjusting for age, sex, and urinary iodine. No presumptive cases of congenital hypothyroidism were detected in Taltal or Chañaral; seven cases were detected in Antofagasta. Neonatal thyroid-stimulating hormone levels were significantly lower in Taltal compared with Antofagasta; this is opposite to the known pharmacological effect of perchlorate, and the magnitude of difference did not seem to be clinically significant. These findings do not support the hypothesis that perchlorate in drinking water at concentrations as high as 100 to 120 micrograms/L suppresses thyroid function in newborns or school-age children.
Assuntos
Hipotireoidismo/induzido quimicamente , Hipotireoidismo/epidemiologia , Percloratos/efeitos adversos , Compostos de Sódio/efeitos adversos , Poluição da Água/efeitos adversos , Distribuição por Idade , Criança , Pré-Escolar , Chile/epidemiologia , Intervalos de Confiança , Coleta de Dados , Ingestão de Líquidos , Monitoramento Ambiental , Monitoramento Epidemiológico , Estudos de Viabilidade , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Modelos Lineares , Modelos Logísticos , Masculino , Razão de Chances , Percloratos/análise , Fatores de Risco , Distribuição por Sexo , Compostos de Sódio/análise , Testes de Função Tireóidea , Poluição da Água/análiseAssuntos
Ingestão de Líquidos , Fluoretos/análise , Abastecimento de Água/análise , Adolescente , Criança , Humanos , TexasRESUMO
Representative energy data for a human population can be produced by combining randomly sampled time allocation observations with activity-specific energy expenditure measurements. Research to produce representative energy data for adults of a population of Machiguenga Indians has recently been conducted in lowland, southeastern Peru. Marked contrast was found between the sexes for average married adults in energy expended on an average day. Men spent about 3,200 kcals and women, about 1,925; ratio: 1.66 to 1. In general, men tended to work at somewhat more energetic activities and for longer periods than did women. In addition to sex-role-related task differences were contrasts in uses of technological items and in respective work settings. These representative behavior data permit direct estimates of population-level energy requirements for average days, seasons, or for 1 year.