Studies on Feeding Effect of Different Levels of Iodine in Salts at Consumption Level

Abstract

A prospective cohort study was undertaken to determine the optimum level of iodine in
salts at household level which is best suitable to fulfill daily requirements and not excrete
too much iodine in urine. A total number of 99 households of 3'“* categories and 4'*’
categories employees of Dhaka University, Bangladesh, living in university campus,
were randomly divided into 3 groups. A total 778 causal urine samples from 351
individuals of the total households were collected and urinary iodine was estimated by
the wet digestion method adapted by Gutekunst et.al. to determine the feeding effect of
different levels of iodine in salts. The overall median urinary iodine were 202.7, 196.9
and 238.0 ng/1 during baseline study and baseline consumption pattern showed that mean
iodine content of salts were 41.6, 34.1 and 36.9 ppm in group-1, group-2 and group-3
respectively. The first follow-up results showed that the overall median urinary iodine
were 92.9, 165.2 and 265.6 ^lg/l and at that time their average iodine content of the
experimental salts were 17.5, 27.5 and 45 ppm in group-1, group-2 and group-3
respectively. During first follow-up the majority (72.7%) of the selected population were
biochemically iodine deficient in group-1 whereas, almost all (99.1%) were normal in
group-2 and a remarkable fraction of the population {21.9%) excreted excessive urinary
iodine in group-3. The second follow-up findings indicates the overall median urinary
iodine were 156.5, 169.3 and 180.3 fig/l in group-1, group-2 and group-3 respectively
and at that time their experimental salt contained same amount of iodine (25-30 ppm).
Iodine nutriture status of the study subjects during second follow-up revealed that almost
all subjects (97.3%) were normal in group-1, on the other hand, biochemically deficient
or excessive excretion of urinary iodine was not observed in group-2 and group-3 i.e. all
of the subjects were within the normal range (UI 100-299.99 jxg/l) of urinary iodine
excretion.