Association between Iodized Salt Intake and Cognitive Function in Older Adults in China.

OBJECTIVES: To investigate the association between iodized salt intake and cognitive function in older adults. DESIGN: A cross-sectional study. SETTINGS: Individuals from the Zhejiang Major Public Health Surveillance Program (ZPHS). PARTICIPANTS: Data of 10,217 participants (including 4,680 coastal residents and 5,537 inland residents) aged ≥ 60 years were analyzed. MEASUREMENTS: Salt intake was evaluated using a questionnaire, and participants were stratified into the following three groups: iodized salt, non-iodized salt, and mixed salt. Cognitive function was assessed through the Mini-Mental State Examination and defined using education-specific cut-off points. Logistic regression models controlling for an extensive range of potential confounders were generated to examine the association between salt intake and cognitive function among all participants. RESULTS: Data from 10,217 participants with a 16.1% prevalence of cognitive impairment were analyzed. Compared with non-iodized salt intake, consumption of iodized salt was inversely associated with cognitive impairment (odds ratio [OR], 0.410; 95% confidence interval [CI], 0.351-0.480; P < 0.001) in all participants after multivariable adjustment. An association between iodized salt intake and cognitive impairment was observed in coastal (OR, 0.441; 95% CI, 0.340-0.572; P < 0.001) and inland residents (OR, 0.569; 95% CI, 0.439-0.738; P < 0.001). Despite the insufficient sample size, the results for individuals consuming mixed salt suggested an inverse association between mixed salt intake and cognitive impairment among coastal residents (OR, 0.598; 95% CI, 0.405-0.885; P = 0.010) after multivariable adjustment. CONCLUSION: Our results indicate that iodized salt intake may reduce the risk of cognitive impairment in older adults living in coastal or inland areas, and the protective effect of iodized salt intake is greater in coastal areas than in inland areas.

Changes of Iodine Nutritional Status in the Elderly after Replacing Iodized Salt with Non-Iodized Salt for Half a Year.

China has issued the "Reform Plan of the Salt Industry System" in 2016 and it is necessary to attach the importance to the changes of iodine nutritional status of those people who might consume non-iodized salt for a long time. Forty-six elderly subjects were recruited and replaced iodized salt with non-iodized salt for 6 months. Urine iodine concentration (UIC), dietary iodine intake, thyroid function, thyroid B-ultrasound, and plasma iodine were monitored during the follow-up period. The median dietary iodine intakes of the baseline, the 1st, 2nd,3rd, 4th, and 6th month were 255.3 µg/d, 183.6 µg/d, 164.6 µg/d, 179.2 µg/d, 139.4 µg/d, and 146.9 µg/d, respectively. The median UIC of baseline and follow-up was 155.7 (111.0-263.1) µg/L and 69.7(36.7-119.8) µg/L, respectively. The proportion of urinary iodine less than 50 g/L at the baseline and follow-up was 3.0 (0 ~ 8.9)% and 36.0 (33.1 ~ 38.9)%, respectively. Dietary iodine intake had a significant correlation with urine iodine. Six subjects (15.4%) had abnormal thyroid function. Three subjects (7.7%) had first-onset new nodules or enlarged solid nodules and the median UIC of these three subjects during the follow-up period was 39.8 µg/L, which was significantly lower than that of other subject (74.0 µg/L). T4 and T3 had a significant correlation with plasma iodine. The importance of monitoring and evaluating iodine nutrition of people consuming non-iodized salt should be stressed to prevent the potential poor iodine nutrition and iodine deficiency diseases.

Non-iodized salt consumption among women of reproductive age in sub-Saharan Africa: a population-based study.

OBJECTIVE: To identify countries in sub-Saharan Africa (SSA) that have not yet achieved at least 90 % universal salt iodization and factors associated with the consumption of non-iodized salt among women of reproductive age. DESIGN: A cross-sectional study using data from Demographic and Health Surveys (DHS). The presence of iodine in household salt (iodized or non-iodized), which was tested during the survey process, was the study outcome. Multivariable logistic regression models were used to determine independent factors associated with the consumption of non-iodized salt among women of reproductive age. SETTING: There were eleven countries in SSA that participated in the DHS since 2015 and measured the presence of iodine in household salt. PARTICIPANTS: Women (n 108 318) aged 15-49 years. RESULTS: Countries with the highest rate of non-iodized salt were Senegal (29·5 %) followed by Tanzania (21·3 %), Ethiopia (14·0 %), Malawi (11·6 %) and Angola (10·8 %). The rate of non-iodized salt was less than 1 % in Rwanda (0·3 %), Uganda (0·5 %) and Burundi (0·8 %). Stepwise multivariable logistic regression showed that women were more likely to be using non-iodized salt (adjusted OR; 95 % CI) if they were poor (1·62; 1·48, 1·78), pregnant (1·16; 1·04, 1·29), aged 15-24 years (v. older: 1·14; 1·04, 1·24) and were not literate (1·14; 1·06, 1·23). CONCLUSIONS: The use of non-iodized salt varies among SSA countries. The higher level of use of non-iodized salt among poor, young women and pregnant women is particularly concerning.

Should both iodised and non-iodised salt be made available in Chinese cities? A cross-sectional survey.

OBJECTIVE: To contribute evidence relevant to the policy of supplying iodised salt (IS), non-iodised salt (NIS) or both in Chinese cities. DESIGN: Subnational telephone interview survey. SETTING: China. PARTICIPANTS: Totally, 24 557 telephone numbers were dialled and 4833 citizens accepted the telephone interview. The telephone numbers were randomly selected by random digit dialling and a Mitofsky-Waksberg two-stage sampling method in 17 capital cities and 6 coastal cities from 17 iodine deficiency disorder (IDD)-eliminated provinces (municipalities). RESULTS: The 4833 citizens finished the telephone interview. Among them, 3738 (77.3%) citizens chose IS, 481 (10%) citizens chose NIS, and the others chose both IS and NIS. The citizens' awareness rates of IDD and IDD preventive measures were 68.7% and 62.5%, respectively. CONCLUSIONS: It is not a suitable time to supply IS and NIS simultaneously in the developed cities of China, but a pilot project may be conducted in the cities where IDD has been sustainably eliminated, there is strong awareness of IDD and the population can make informed decisions regarding IS. IDD health education should be further strengthened, especially regarding the potential for IQ damage.