Elsevier

The Lancet

Volume 350, Issue 9080, 13 September 1997, Pages 771-773
The Lancet

Articles
Effect on infant mortality of iodination of irrigation water in a severely iodine-deficient area of China

https://doi.org/10.1016/S0140-6736(96)12365-5Get rights and content

Summary

Background

Hotien county in Xinjiang province, China, is an area of severe iodine deficiency and has a high infantmortality rate. We investigated whether iodine replacement through iodination of the irrigation water would decrease infant mortality.

Methods

We added potassium iodate to irrigation water over a 2 to 4 week period beginning in 1992 in certain areas of three townships (Tusala, Long Ru, and Bakechi). Logistic regression analysis was used to compare the odds ratios for infant and neonatal mortality in treated and untreated areas.

Findings

The median urinary iodine concentration significantly increased in women of child-bearing age from <10 μg/L to 55 μg/L. Infant-mortality rates decreased in the treated areas of Long Ru (mean [SD]) 58·2 [4·4] per 1000 births to 28·7 [7·1] per 1000 births), Tusala (47·4 [12·4] per 1000 births to 19·1 [1·5] per 1000 births), and Bakechi (106·2 [9·5] per 1000 births to 57·3 [7·3] per 1000 births). Similar results were also seen for neonatal mortality. On regression analysis iodine treatment and time were significant independent predictors of infant mortality.

Interpretation

Iodine supplementation of irrigation water in areas of severe iodine deficiency decreases neonatal and infant mortality. Iodine replacement has probably been an important factor in the national decrease in infant mortality in China.

Introduction

Hotien county, Xinjiang province, in the Taklamakan Desert of western China, is an area of severe iodine deficiency. Because usual methods of iodine supplementation failed here, in 1992 we began to add potassium iodate to irrigation water. This manouevre had the potential to achieve iodine supplementation in every household, since irrigation water is widely used, and did not require trained health personnel or a change in the preferred use of rock salt. Potassium iodate was added to irrigation water and the iodine concentration was 10–80 μg/L over the 2 to 4 week spring irrigation of wheat. No further iodine supplementation was given but over the next 3 years, iodine concentrations increased five-fold in crops, vegetables, and meat and three-fold in sheep and chicken thyroid glands. In the most iodine-deficient areas, annual sheep production increased by 35–63% during the next 3 years with a subsequent 5% increase in yearly income per person.1

We now report the effect of this single application of potassium iodate to irrigation water on neonatal and infant mortality.

Section snippets

Methods

The method of iodine supplementation by irrigation water has been previously described.2 Briefly, dripping was carried out in three townships. In 1992 30 kg iodine (as potasium iodate) was given to an area of four villages with a total population of 2600 in Long Ru district. The median urinary iodine in women of childbearing age in this area was <10μg/L. In 1993, 80 kg potassium iodate was given to the same Long Ru area and 80 kg to an area of eight villages in Bakechi. The total population was

Results

Urinary iodine concentrations in women of child-bearing age increased from a median of <10 ögo;g/L, the lower limit of the assay, to 55 ögo;g/L. Both infant and neonatal mortality decreased by half in all three treated township areas (table 1). In the treated villages of Long Ru, infant mortality decreased from (mean [SD]) 58·2 (4·4) per 1000 births during the previous 5 years to 28·7 (7·1) per 1000 births. Similar results were found in Tusala, where infant mortality in the treated villages

Discussion

We found a large reduction in both neonatal and infant mortality with iodine treatment of the entire population in a severely iodine-deficient area. The addition of potassium iodate to irrigation water decreased neonatal and infant mortality by about half, compared with untreated adjacent control areas. Despite a small but significant effect of time on infant-mortality rates over the 8 years studied, logistic regression analysis confirmed the effect of iodine. Some of the decrease with time

References (7)

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