To investigate the iodine nutrition status of children in water-borne iodine-excess areas in Hebei Province, so as to provide references for scientific prevention and control of water-borne iodine-excess hazards.
From March to September each year during 2018 to 2023, a cross-sectional survey was conducted in 39 water-borne iodine-excess counties (measured in 2017) from 5 cities (Cangzhou, Hengshui, Xingtai, Handan and Langfang) in Hebei Province. The survey included the detection of iodine content in residents' drinking water, the measurement of thyroid volume in children aged 6-12, the detection of salt iodine and urinary iodine. The iodine nutrition status and water iodine distribution of 6-12 year-old children were evaluated from different perspectives such as years, gender, and age. Kruskal-Wallis H test, Mann-Whitney U test and Chi-square test were used for group comparison.
A total of 38 755 children were surveyed from 2018 to 2023, and 1 270 drinking water samples were tested across the province. The mass volume concentration of iodine in water showed a decreasing trend over the years (Z=-30.87, P < 0.01). Among 38 470 salt samples monitored from children 's home, 24 790 were not non-iodized salt, with a non-iodized salt rate of 64.44%. A total of 31 989 urine samples were collected from children aged 8-10 years, with the median urine iodine was 245.94 μg/L. Comparing the results of urinary iodine in children from different years, the median urinary iodine from 2018 to 2023 were 328.0, 339.3, 267.8, 279.1, 291.3, 186.5 μg/L, respectively, with statistically significant differences (H=4 138.40, P < 0.01). Further pairwise comparisons showed that the median urinary iodine of children in 2023 was lower than in all other years (Z=-51.59 to -11.41, all P < 0.01). Among children aged 6-12 years, 1 150 cases of goiter were detected and the rate of goiter was 3.0%; and the goiter rates in boys and girls were 2.8% and 3.1%, with no significant difference between the sexes (χ2=2.76, P>0.05). There were significant differences in the rate of goiter among different years and ages (χ2=324.02, 191.61, both P < 0.05).
With the progress of water reform in water-borne iodine-excess areas of Hebei Province, children's iodine nutrition has reduced from excessive state to suitable state. It is necessary to continue to expand the coverage of water-based iodine reduction projects, and strengthen the monitoring of iodine nutrition status of key populations in water-borne iodine-excess areas.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |