Silent iodine prophylaxis in Western Europe only partly corrects iodine deficiency; the case of Belgium

Objective: Belgium is one of the Western European countries in which no pro gram of iodine-deficiency correction using iodized salt has been implemente d, in spite of well-documented mild iodine deficiency. In 1995, the median urinary iodine concentration was 55 rho g/l (normal: 100-200) and the preva lence of goiter was 11% (normal: below 5%) in representative samples of sch oolchildren aged 6-12 years. Based on these results, the authors of the pre sent study and others had emphasized to health professionals and to the pub lic the necessity for iodine supplementation. The objective of this study w as to evaluate as to whether these efforts had resulted in an improvement i n the status of iodine nutrition. Design: We performed a national survey of the status of iodine nutrition in Belgium based on the determination of thyroid volume, obtained by ultrason ography and urinary iodine concentrations in schoolchildren. Methods: A mobile van equipped with an ultrasound instrument, a computer an d a deep-freeze visited 23 schools selected from across the country. The sa mple included 2855 schoolchildren (13 65 boys and 1490 girls) aged 6-12 yea rs. Results: The results show a homogeneous situation in the whole country, wit h a median urinary iodine concentration of 80 mu g/l and a goiter prevalenc e of 5.7%. Urinary iodine slightly decreases with age in girls and reaches a critical value of 59 mu g/l at the age of 12 years, together with a goite r prevalence of 18.4%. Conclusion: Iodine nutrition has improved slightly in Belgium but mild iodi ne deficiency continues, with public-health consequences. The improvement i ndicates silent iodine prophylaxis, as no official salt-iodization measures have been taken, Silent iodine prophylaxis only partly corrects iodine def iciency in Western Europe. Active measures, including the implementation of a program of salt iodization, are urgently required.