Iodine supply in different geographical areas of Switzerland: comparison between rural and urban populations in the Berne and the Ticino regions.
OBJECTIVE: We studied the question of possible regional differences of iodine intake in the population of rural and urban areas north and south of the Alps. DESIGN: Transversal study. SETTING: Six different regions from northern (Canton Berne) and southern Switzerland (Canton Ticino). SUBJECTS: For each region 30 individuals were studied. RESULTS: While significant differences of urinary iodine between some regions were found (range from 79 microg iodine/g creatinine in Chiasso to 130 microg iodine/g creatinine in the Maggia Valley), no significant differences between rural and urban populations of north and south of Switzerland were observed. Mild iodine deficiency affected 35%, moderate iodine deficiency 12% and severe iodine deficiency 0.6% of the total population investigated. CONCLUSIONS: 49% of this population showed at least mild or moderate iodine deficiency. The mean urinary iodine was just at the lower recommended limits. Significant differences were found between individual regions (such as Chiasso and the Valley of Maggia), but not generally between rural and urban areas in the north and south of the Alps.