Iodine deficiency disorders in high-risk areas of Hainan province from 2007 to 2009: an analysis of survey results

Objective To know the prevalence of iodine deficiency disorders(IDD) and the implementation of control measures against the disorders in high-risk areas of Hainan province. Methods Typical sampling principle was used. Eight townships with lower coverage rate of iodized salt were chosen in IDD high-risk counties of Hainan. New cretinism cases were screened among children aged 10 years and under. Intelligence quotient (IQ)value, urinary iodine (UI) concentration and thyroid gland size (by palpation and B ultrasonic) were investigated in children aged 8 to 10 years and questionnaire was also carried out among students from grade 5 in elementary school. Edible salt and urine of women of childbearing age were collected to detect iodine levels, respectively,questionnaire was also carried out among the women of childbearing age. The UI was determined by As3-Ce4+ catalytic spectrophotometer, the salt iodine level was determined using self-quantitative kit. IQ values were measured by the Combined Raven Test in China (CRT-C2). Results Seventy-two townships were investigated in three consecutive years, 7937 children aged 8 to 10 years, 1797 women of childbearing age and 4128 students of grade 5 were included in the survey. One child was diagnosed as suspected new cretinism case. The coverage rate of iodized salt was increased from 44.6%(629/1411) in 2007 to 92.1%(1688/1832) in 2009. The goiter rate was dropped from 5.9% (269/4548), 6.0% (274/4548) in 2007 to 1.6% (24/1461), 0.1% (2/1461) in 2009 bypalpation, and by B-ultrasound, respectively, in children aged 8 to 10 years. The median urinary iodine(MUI) was found to be increased from 97.4 μg/L in 2007 to 165.0 μg/L in 2009, and the percentage of UI less than 50.0 μg/L, and 100.0 μg/L were dropped from 21.4%(973/4548), 51.2%(2329/4548) in 2007 to 7.5 %(110/1461), 23.4%(342/1461) in 2009, respectively. The MUI of women of childbearing age was found to be elevated from 73.7 μg/L in 2007 to 126.1 μg/L in 2009, and the value was also increased from 55.7 μg/L to 121.5 μg/L in pregnant women, but these values were still lower than 150.0 μg/L The pass rate of the questionnaire of IDD controlling among the students of grade 5 and the women of childbearing age was raised from 29.8% (446/1495) ,24.1% (179/742) in 2007 to 65.8%(732/1112), 72.1%(264/366) in 2009, respectively. The mean IQ of children was 90.4±16.0, and the percentage of IQ value less than 69 was 12.6% (1000/7937). Conclusions The diseased state of IDD has improved in the high-risk counties of disorders in Hainan province, but the pregnant women are still iodine deficient. Iodine supplimentation should be promoted among pregnant women. Key words: Iodine; Deficiency disorders; Goiter, Endemic; Data collection