The shrinkage of the Aral Sea has been called the biggest environmental disaster of the 20 th century. The Aral Sea came under the administration of Kazakhstan and Uzbekistan after the collapse of the Union of Soviet Socialist Republics in 1991. People living near the Aral Sea complained of health problems. The aims of this study were to evaluate the potential causes of these problems and how they may be remedied. We conducted a large-scale epidemiological study from the beginning of 1999 in

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... akhstan; the case region was near the Aral Sea and the control region was about 500 km east of the case region. The subjects were 486 randomly selected schoolchildren in each region for a total of 815 children (383 cases and 432 controls were accepted into the study). The study parameters were anthropometric variables, hematological values, respiratory function, and renal function, in addition to a questionnaire on socioeconomic data and food intake. Body mass index was not significantly different between the two regions. The incidence of anemia was high: 62% in the case region and 39% in the control region. With regard to renal function, both urinary N-acetyl-β-D-glucosaminidase and β 2 -microglobulin were significantly higher in the case region than in the control region. Evaluating respiratory function, we found that the prevalence rates of a restrictive pattern were 10.6% and 2.6% in the case and control regions, respectively. The obstructive pattern had a low incidence and did not differ significantly between the two regions. The subjects consumed minerals and vitamins in larger amounts in summer, except for vitamins A and D, which were taken more in winter. Sodium concentrations, determined in drinking water, blood, urine, and hair samples, in the case region were higher than in the control region. Two years after the initial assessment in the same children, anemia and renal function had improved. We considered that the health problems that directly correlated with the shrinkage of the Aral Sea might be respiratory dysfunction, caused by particulates, which was much increased after the shrinkage of the Aral Sea. We planted special local trees, saxaul, in one village in order to reduce particulates.