Surveillance for urinary iodine concentration of pregnant women in Thailand

Surveillance for urinary iodine concentration of pregnant women in Thailand

Surveillance for urinary iodine concentration of pregnant women in Thailand, ความสัมพันธ์ของเกลือเสริมไอโอดีนในครัวเรือนและความเข้มข้นของไอโอดีนในปัสสาวะหญิงตั้งครรภ์ในประเทศไทย

Rationale: Iodine deficiency disorders (IDD) has been recognized as a serious public health problem in Thailand for over 50 years. Iodine deficiency affects all populations at all stages of life, from the intrauterine stage to elderly group. However, pregnant women, lactating women, women of child-bearing age, and children younger than 3 years of age are considered the most important groups in which to detect and treat iodine deficiency, because iodine deficiency occurring during fetal and neonatal growth and development leads to irreversible damage of the brain and central nervous system and, consequently, to irreversible mental retardation. Ministry of Public Health, by Nutrition Bureau (Nutrition Division), Department of Health has been conducting the surveillance system for urinary iodine concentration (UIC) of pregnant women in Thailand since the year 2000.

Objectives: Surveillance, monitoring and evaluation project for tracking the progression of IDD control in Thailand by prevalence and severity of IDD survey by measuring UIC in pregnant women, including their household coverage of qualified iodized salt.

Methods: UIC in pregnant women who delivered in the hospitals and their household salt samples quality dhecked by I-Kit, as the cyclical monitoring, has been done in 15 provinces annually (5-year clycle) by systematic random sampling, ordered by prevalence of goiter in school children in the year 1999. The data were collected from 300 samples per province, 4,500 samples per year.

Results: Median UIC during 2000-2004 and 2006-2009 are 153, 111.6, 106.8, 114.5, 106.8, 114.5, 101.6, 82.5, 108.2, 125.5 and 117 microgram per litre respectively. Before the year 2007, WHO recommended that the proportion of pregnant women who had urine iodineconcentraion below 100 microgram per litre should not be more than 50%, the proportion in the year 2000-2004 and 2006-2009 are 34.5%, 45.1%, 46.9%, 44.3%, 48.6%, 57.4%, 46.9%, 39.7%, and 43% respectively. By WHO guideline in 2007,the proportion of pregnant women who had urine iodine concentraion below 150 microgram per litre should not be more than 50%, the results are 71.8%, 61.2%, 58.5% and 59% in 2006, 2007, 2008 and 2009 respectively. The percentages of pregnant women's households using qualified iodized salt (>30 ppm.) in 2000-2004 and 2006-2009 are 65.3%, 65.5%, 66.8%, 50.6%, 56.1%, and 54.0%, 49.1%, 80.1%, 79.8% respectively.

Conclusion: Cyclical monitoring in pregnancy is needed to reflect an adequacy of iodine intake. Pregnant women's household coverage of qualified iodized salt is a half to four-fifth of all samples. Quality control of iodized salt production with national regulations reinforcement, throughly distribution to consumers and social campaign for raising public awareness should be done continuously.

Reference: Assessment of iodine deficiency disorders and monitoring their elimination a guide for programme managers. - 3rd ed., World Health Organization, 2007.