Iodized salt supplementation and its effects on thyroid status amongst Orang Asli in Hulu Selangor, Malaysia.
BACKGROUND
This research was performed to determine the prevalence of iodine deficiency disorder (IDD) and the effects of iodized salt supplementation on thyroid status amongst Orang Asli in Hulu Selangor, Malaysia.


METHODS
Study respondents were from three target groups, i.e. pre-school children (PSC), primary school-going children (SGC) and adult women. Each household was supplied with iodized salt fortified with iodate fortificant for a period of 12 months and the iodine levels in the salt ranged from 20 to 30 μg/L. Samples collected before and after 6 and 12 months of introduction to iodized salt were urine from all groups, as well as serum samples from adult women.


RESULTS
A total of 200 respondents were recruited; 58 (29.0%) PSC, 65 (32.5%) SGC and 77 (38.5%) adult women. The median urine-iodine concentration (mUIC) in all groups were of moderately low before the iodized salt intervention, but increased significantly in all study groups after 6 and 12 months of intervention. However, at the end of the study, there was an increase in severe iodine deficiency (mUIC <20 μg/L) from 7.5% to 12% and about 9% of PSC and SGC respondents had mUIC level of more than 300 μg/L while the adult women showed a significant increase in free triiodothyronine (fT3) levels.


CONCLUSIONS
The study demonstrated that iodized salt supplementation was able to show an improvement in iodine level amongst Orang Asli. However, an increase in severe iodine deficiency and iodine excess indicated that the iodized salt programme needs to be carefully monitored.
Institute for Public Health, Kuala Lumpur, Malaysia. limkk@iku.moh.gov.my
Kuang Kuay
KK
Lim
Ming
M
Wong
Wan Nazaimoon Wan
WN
Mohamud
Nor Azmi
NA
Kamaruddin
D000293:Adolescent; D002648:Child; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy / Q000453:epidemiology* / Q000503:physiopathology; D007455:Iodine / Q000008:administration & dosage* / Q000172:deficiency / Q000652:urine; D008296:Malaysia; D015995:Prevalence; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage* / Q000652:urine; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism; D014284:Triiodothyronine / Q000097:blood
D017673:Sodium Chloride, Dietary; C034024:iodized salt; D014284:Triiodothyronine; D007455:Iodine