Insufficient iodine nutrition may affect the thyroid cancer incidence in China.

Epidemiological studies have focused on the effects of iodine intake on the risk of thyroid cancer. However, their relationship is still obscure. The objective of the present study was to examine the association in the Chinese population. A new ecological study which combined the Data of Annual Report of Cancer, the Survey of Iodine Deficiency Disorders (IDD) surveillance and the Water Iodine Survey was conducted to analyse the relationship between iodine intake and the thyroid cancer incidence in China. In total, 281 counties were included. Thyroid cancer incidence was negatively correlated with the consumption rate of qualified iodised salt (CRQIS) and positively correlated with goiter prevalence (GP) of children aged 8-10 years, residents' annual income and coastal status. Areas with a low CRQIS and areas with a high GP had a relatively high incidence of thyroid cancer. Regression models showed that a low CRQIS and a high GP in children aged 8-10 years (both reflecting iodine deficiency status) play a substantial role in thyroid cancer incidence in both males and females. Additionally, living in coastal areas and having a high annual income may also increase the risk of thyroid cancer. These findings suggest that mild iodine deficiency may contribute to the exceptionally high incidence of thyroid cancer in some areas in China. Maintaining appropriate iodine nutrition not only helps to eliminate IDD but also may help to reduce the occurrence of thyroid cancer.

Factors affecting sustainable iodine deficiency elimination in Pakistan: A global perspective.

Iodine deficiency remains a considerable challenge worldwide, even after decades of efforts to address the problem. The aim of this review is to present the current situation in historically iodine-deficient Pakistan regarding iodine nutritional status and place it in a global perspective. We collected relevant articles from online bibliographic databases and websites of concerned organizations that addressed prevalence of goiter/iodine deficiency and barriers to sustainable control. We divided the studies into pre- and post-1994, a landmark year when Pakistan formally adopted the universal salt iodization (USI) programme. Overall, 56 studies reported goiter/iodine deficiency prevalence in Pakistan. Before 1994, six studies (30%) reported a goiter prevalence ≥70%, while nine studies (45%) reported a goiter prevalence between 30% and 70%. Only five studies (25%) found a goiter prevalence less than 30%, of which only two studies reported prevalence <10%. From 1994 onwards, 15 studies (41.7%) reported a goiter/iodine deficiency (ID) prevalence ≥50%, of which seven studies reported prevalence ≥70%, while three studies (8.3%) found a goiter prevalence of 30%-49%, nine studies (25%) found a goiter prevalence of 10%-29%, and five studies (13.9%) reported prevalence of <10%. Four studies (11.1%) reported lower goiter prevalence but higher prevalence of iodine deficiency. The efforts in the past two decades resulted in up to a 50% decline in iodine deficiency disorders (IDD). Variable remaining factors and the recent results, however, indicate that this decline may be non-uniform and even over-estimated. Coordinated and regionally adopted efforts for eradication of IDD from all stakeholders should be pursued. Policy makers should take steps to protect future generations and alert concerned organizations about the importance of careful assessments and estimates of iodine nutritional status.

The prevalence of goiter and hypothyroidism among school children 6 years after introduction of a mandatory salt iodination program in a severely iodine-deficient area of the West Black Sea region of Turkey.

The objective of the current study was to determine the prevalence and the degree of iodine deficiency after mandatory salt iodization in Yigilca's school-aged children. A total of 806 school children aged 6-19 years were evaluated. The prevalence of goiter in children aged 6-12 and 13-19 years was 20.3 and 23.8%, respectively. The prevalence of hypothyroidism in children aged 6-12 and 13-19 years was 10.4 and 18.9%, respectively. The median serum free tetraiodothyronine (fT4) levels in children aged 6-12 and 13-19-years were 1.16 ng/dL and 0.91 ng/dL, respectively. The median urinary iodine concentration levels in children aged 6-12 and 13-19 years were 83 µg/l and 78 µg/l, respectively. The frequency of autoimmune thyroid disease was 2.1% in Yigilca's SAC. Goiter and iodine deficiency problems remain in rural areas of the West Black Sea Region of Turkey.

Assessment of Sustainable Elimination Criteria for Iodine Deficiency Disorders Recommended by International Organizations.

Enormous efforts have been made to evaluate the worldwide prevention and control of iodine deficiency disorders (IDDs). This study evaluated China's achievements in IDD prevention and control against WHO criteria for sustainable elimination of IDD. The study sample consisted of 556,390 school-aged children and 271,935 pregnant women enrolled in the 2018 China National IDD Surveillance. As a result, at the national level, median urine iodine concentration (MUIC) was 206.1 and 163.5 µg/l in children and in pregnant women, respectively. The proportion of households consuming adequate iodized salt (PHCAIS) was 90.2%. The prevalence rates of goiter in children and thyroid disease in pregnant women were 2.0 and 0.8%, respectively. MUIC showed significant non-linear increasing trends with increasing PHCAIS in both children and pregnant women. The prevalence of thyroid disease in pregnant women had a sharp decreasing trend with increasing PHCAIS. Of note, the prevalence of goiter in children and thyroid disease in pregnant women against MUIC both presented as significant U-shaped curves, with the lowest prevalence at 100-300 µg/l of MUIC in children and 150-250 µg/l in pregnant women. PHCAIS, MUIC, and the programmatic indicators at the national level were all above their cut-offs proposed in the 2007 Criteria. Evaluation by adding the prevalence of goiter (<5%) yielded the different results at the county level. Sustainable elimination of IDD has been achieved nationally. 2018 Chinese surveillance data support the expansion of global cut-offs for optimal iodine status in school-age children from 100-199 to 100-299 µg/l as recommended by others and the lower limit of MUIC (150 µg/l) in pregnant women also seems justified. Inclusion of goiter prevalence <5% in our analysis reduced the number of municipalities and counties which had achieved sustainable elimination of IDD.

Regional Influences on Nutritional Iodine Status of Pregnant Women in Pakistan.

BACKGROUND: Pregnant women are particularly vulnerable to iodine deficiency. Considering the rural-urban disparities in nutritional status in Pakistan, this study aimed to assess regional influences on nutritional iodine status of pregnant women in Pakistan. METHODS: Data were collected from 1246 pregnant women in all trimesters of pregnancy who visited antenatal clinics for routine checkups in five Khyber Pakhtunkhwa province districts. Information concerning iodized salt intake and knowledge of iodine deficiency disorders (IDD) was obtained through an interview questionnaire. Goiter and urinary iodine concentration (UIC) levels were assessed by the palpation method and Sandell-Kolthoff reaction, respectively. Logistic regression analysis was used to quantify associations between residence (rural-urban), pregnancy trimester, and previous pregnancy outcomes with knowledge about IDD, iodized salt intake, presence of goiter, and UIC <150 µg/L. RESULTS: Among study participants, 87.7% had no knowledge about IDD, and only 21.0% were consuming iodized salt. Goiter was present in 25.5% of the women. The median UIC level was 131 µg/L, and 41.3% of study participants had a UIC ≥150 µg/L. There were no significant differences between pregnant women from rural and urban settings in regions with a solid socioeconomic status with respect to knowledge about IDD, iodized salt intake, iodine deficiency, and goiter prevalence. Urban-rural differences were observed only in socioeconomically disadvantaged districts. Only pregnant women living in the Lakki Marwat district had higher odds of having knowledge of IDD and iodized salt intake than those from rural regions. Trimesters of pregnancy and previous pregnancy outcomes had no significant effect on the outcome measures. CONCLUSIONS: Relative to a national nutrition survey conducted in Pakistan in 2011, the results from this study indicate that UIC levels remained stable with mild iodine deficiency, whereas rates of goiter and iodized salt intake remained high and low, respectively, especially in rural areas. Rural-urban disparities were observed only in socioeconomically disadvantaged districts, and these disparities limit the effectiveness of the IDD prevention program in rural areas in Pakistan. Thus, implementation of mandatory salt iodization requires improvement, and program effectiveness should be continuously monitored to prevent adverse health effects of iodine deficiency during pregnancy.