Objective: To measure the iodine nutritional status on adult islanders and to evaluate the advantages and disadvantages of iodized salt prophylactic programs.
Methods: A comparative study was carried out in 8 rural townships selected from Dinghai (iodized salt district) and Daishan (non-iodized salt district) of Zhoushan islands by random sampling method. Mann-Whitney test was used to compare the urinary iodine concentration and dietary iodine intake of the two groups. Spearman correlation test was used to look for the correlation of urinary iodine concentration and dietary iodine intake in the two groups respectively.
Results: The amounts of daily iodine intake excluding the iodine intake from iodized salt in the two groups were 128 micro g and 147 micro g respectively but the difference was not statistically significant (u = 1.847, P = 0.065). The urinary iodine concentration of non-iodized salt group was 90 micro g/L, lower than 194 micro g/L in iodized salt group (u = 14.673, P = 0.000). There was no significant correlation between daily iodine intake and urinary iodine concentration (r(s) = 0.052, P = 0.095).
Conclusions: In Zhoushan islands, the daily iodine intake did not meet the daily need (150 micro g/day) suggesting that iodized salt supplement was necessary. However, side effect due to overdose should be brought into attention.