Study on level of dietary iodine intake and its contribution rate of residents in Zhejiang / 中华预防医学杂志

<p><b>OBJECTIVE</b>To assess the level of dietary iodine intake and its contribution in Zhejiang.</p><p><b>METHODS</b>A total of 9798 subjects were recruited in this survey with multi-stage stratified cluster random sampling method in April, 2010, the 24-hours dietary recall method and the "food composition table" were used to obtain the dietary iodine intake, and edible salt and drinking water samples were collected to detect the content of iodine.</p><p><b>RESULTS</b>A total of 9798 subjects were included in this survey. The mean intake of dietary iodine in Zhejiang residents per standard man-days was (395.13 ± 78.16) µg/d, which in between of Recommended Nutrient Intake (RNI) 150 µg/d and Tolerable Upper Intake Level (UL) 1000 µg/d; the iodine intake of 18.40% (1803/9798) subjects was lower than estimated average requirement of iodine (EAR), 4.68% (459/9798) subjects was higher than the UL. The means of dietary iodine intake in various areas were (498.85 ± 96.77) µg/d, (384.50 ± 88.76) µg/d and (326.33 ± 78.32)µg/d in inland areas, sub-coastal areas and coastal areas, successively (F = 27.17, P < 0.05); the proportions of dietary iodine intake lower than EAR were 34.89% (1239/3551), 10.48% (370/3530) and 7.14% (197/2717) in coastal areas, sub-coastal area and inland areas, successively (χ(2) = 62.87, P < 0.01) , while those higher than UL were 5.10% (180/3530), 4.86% (132/2717) and 4.14% (147/3551) in sub-coastal area, inland areas and coastal areas.In the condition of ignoring cooking loss, the mean contribution of dietary iodine intake in edible salt, all kinds of food and drinking water were 74.92% (296.03/395.13), 23.85% (94.24/395.13) and 1.23% (4.86/395.13), successively; the contributions of edible salt in inland areas, sub-coastal areas and coastal areas were 83.72% (417.64/498.85), 73.05% (280.88/384.50) and 66.83% (280.09/326.33), successively; the contributions of drinking water in sub-coastal areas, coastal areas and inland areas were 1.61% (6.19/384.50) , 1.44% (4.70/326.33) and 0.65% (3.24/498.85) , successively (χ(2) = 7.24, P = 0.032) ; the contribution of laver in coastal areas, sub-coastal areas and inland areas were 22.57% (73.65/326.33), 17.11% (65.79/384.50) and 8.09% (40.36/498.85), successively (χ(2) = 82.17, P < 0.01) ; the contribution of sea fish in coastal areas, sub-coastal areas and inland areas were 2.38% (7.77/326.33), 0.72% (2.77/384.50) and 0.68% (3.39/498.85) (χ(2) = 19.47, P = 0.012).</p><p><b>CONCLUSIONS</b>The dietary iodine intake of Zhejiang residents was at recommended intake levels; the iodized salt turns out to be the main source, the iodine nutrition level was relatively low in coastal areas of Zhejiang, which the coverage of iodized salt should be improved.</p>

Analysis of the prevalence and its influencing factors of diffuse goiter in Zhejiang / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the status of diffuse goiter of population in Zhejiang Province and to analyze the relevant influencing factors.</p><p><b>METHODS</b>A total of 18 188 subjects were recruited in the cross sectional survey, by multistage stratified cluster random sampling method. B ultrasound measurement were carried among the subjects to detect the thyroid volume, and the basic information and life styles were interviewed by questionnaires. Then, we analyzed the distribution and its influencing factors of diffuse goiter.</p><p><b>RESULTS</b>The ratio of diffuse goiter among the surveyed population was 2.2% (403/18 188), the difference showed statistical significance (χ(2) = 267.11, P < 0.05). The ratio among the group aged 6-7 years old and 8-10 years old was comparatively high, separately 10.3% (27/262) and 9.8% (51/519). The ratio among women (2.9%, 305/10 470) was higher than it among men (1.3%, 97/7672) (χ(2) = 55.55, P < 0.05). The residents from inland areas had the highest prevalence (3.2%, 138/4374), followed by residents from sub-coastal areas (2.0%, 131/6411), coastal areas minimum (1.8%, 138/4374) (χ(2) = 24.31, P < 0.05). The content of water iodine and salt iodine among people with symptoms of goiter had statistical difference with it among ordinary population (water iodine:χ(2) = 4.95, P = 0.026; salt iodine: χ(2) = 11.03, P < 0.01). The median(quartile) of water iodine in ordinary population was 2.41 (1.96-6.15) µg/L and among people with symptoms of goiter was 1.88 (1.49-5.15) µg/L. The median(quartile) of salt iodine in ordinary population was 30.18 (24.69-32.65) mg/kg and among people with symptoms of goiter was 29.1 (24.70-31.95) mg/kg. The influential factors of goiter were as follows: the family income, the education degree, the job and profession status, the diet character, the habitual sea food consumption, the alcohol intake status (χ(2) were separately 8.08, 37.85, 98.78, 68.69, 10.91, 12.21, 26.94, P < 0.05). Multi-factor analysis showed the results as follows: female (OR = 0.27 95%CI:0.18-0.39), school students (OR = 8.05, 95%CI:3.87-16.73), vegetarian (OR = 1.60, 95%CI:1.15-2.22) took a higher risk of getting pathogenic goiter; while the group of those who had university degree or above (OR = 0.84, 95%CI: 0.73-0.97), ate sea food frequently (OR = 0.62, 95%CI:0.44-0.88) took a lower risk.</p><p><b>CONCLUSIONS</b>The ratio of diffuse goiter in the group aged among 6-7 years old and 8-10 years old was comparatively high. The ratio was influenced by many factors.</p>

Analysis of urine iodine level and its influencing factors in Zhejiang from 2009 to 2011 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the iodine nutrition level of population in Zhejiang province and to analyze the relevant influencing factors from 2009 to 2011.</p><p><b>METHODS</b>From October 2009 to October 2011, a total of 19 517 subjects were recruited in this cross sectional survey, by multistage stratified cluster random sampling method. The subjects were all living over three years in Zhejiang province. The basic information and life styles were interviewed by questionnaires; and the samples of drinking water, edible salt and urines were separately collected from the subjects to test the content of iodine. In total, 16 228 subjects answered the questionnaire, and 265 samples of drinking water, 7811 samples of edible salt and 19 517 samples of urine were collected. Then, we analyzed the distribution of iodine in water, edible salt and urine samples, as well as the relevance.</p><p><b>RESULTS</b>The median (25% - 75% percentile) of water iodine was 2.42 (1.17 - 6.28) µg/L in drinking water among Zhejiang residents; while separately 2.79 (1.60 - 6.87) µg/L in city and 2.04 (1.03 - 5.29) µg/L in country side (Z = 2.07, P < 0.05). The figures turned out to be 2.17 (1.22 - 5.73) µg/L, 2.77 (1.88 - 6.87) µg/L, and 1.40 (0.77 - 5.65) µg/L, respectively, in coastal areas, coastal periphery areas and inland areas (χ(2) = 11.16, P < 0.05). The median (25% - 75% percentile) of salt iodine was 28.80 (22.93 - 32.40) mg/kg; while separately 29.00 (24.50 - 32.60) mg/kg and 28.50 (13.90 - 32.29) mg/kg in city and country side (Z = 6.32, P < 0.05). The figures turned out to be 25.19 (0.00 - 30.20) mg/kg, 29.00 (26.60 - 31.70) mg/kg and 32.40 (28.94 - 36.30) mg/kg, respectively, in coastal areas, coastal periphery areas and inland areas (χ(2) = 1581.62, P < 0.05). The coverage rate of iodized salt was 79.54% (6213/7811) in all province. The urinary iodine median was 160.74(97.20 - 247.00) µg/L, while the urinary iodine median in pregnant women was 137.99 (82.40 - 215.30) µg/L, lower than the recommended optimal levels, which was 150 - 249 µg/L. The figures turned out to be 153.45(92.00 - 237.50) µg/L in city and 168.00 (102.18 - 257.00) µg/L in country side (Z = -9.25, P < 0.05); while in coastal, coastal periphery place and inland areas, the median were separately 156.00 (94.29 - 242.80) µg/L, 150.14 (94.70 - 227.00) µg/L and 187.70 (109.00 - 276.80) µg/L (χ(2) = 194.12, P < 0.05). The analysis of relevance between urine iodine, water iodine and iodized salt showed that the urine iodine would increase as long as the iodized salt increased; and the difference had statistical significance (χ(2) = 440.88, P < 0.01). And there were no relevance between urine iodine level and the water iodine level (χ(2)cmh = 0.57, P = 0.45). The analysis of the influencing factors showed that education background (χ(2) = 14.17, P < 0.05), different styles of career (χ(2) = 16.15, P < 0.01) and diet habits (χ(2) = 108.63, P < 0.01) could influence the level of urine iodine.</p><p><b>CONCLUSION</b>Iodine was deficient in Zhejiang province. The nutrition level of iodine was fine in Zhejiang in 2009, however, the coverage rate of iodine was commonly low in coastal areas, especially the pregnant women suffered from iodine deficiency. In our study, the factors influencing the urine iodine level included iodized salt, age, education background and diet habits.</p>

A cross-sectional study on iodine nutrition in general population from Zhejiang province,China / 中华流行病学杂志

Objective To understand the current status of iodine nutrition among the community residents to compare the level of iodine nutrition in different areas and groups of populations in Zhejiang province.Methods Stratified cluster sampling method was adopted and residents from twenty-two communities in Zhejiang province were selected.A cross-sectional survey was conducted,using questionnaires,laboratory tests,on urinary iodine,water iodine and the concentration of the iodine in salt,which had played positive roles in the calculation of the level of iodine nutrition.Results Results of the iodine nutrition in this cross-sectional survey were as follows:the median water iodine and salt iodine of Zhejiang were 2.42 μg/L and 28.8 mg/kg,respectively.The coverage of iodized salts was 79.54％,with the ingesting rate of qualified iodized-salt as 76.65％ and the median content of urinary iodine in the population of Zhejiang was 161 μg/L.The average iodine content among pregnant women was 138 μg/L,with the percentage of samples less than 100 μg/L as 25.92％,more than 300 μg/L as 15.30％.The proportions of iodine intake through water,salt and other foods were 1.70％,76.41％ and 21.89％,respectively.Conclusion The status of iodine nutrition in Zhejiang province in general seemed to be appropriate,but the level of iodine nutrition in pregnant women was less than the requirement,which should call for attention.

Dietary iodine intake level of adult population in coastal and inland areas of Zhejiang province / 中国地方病学杂志

Objective To evaluate the dietary iodine intake level of population in coastal and inland areas of Zhejiang province.Methods The cluster sampling method was applied to select Zhoushan,Ningbo and Taizhou cities from Zhejiang province as coastal areas,to select Jinhua,Quzhou and Lishui cities from Zhejiang province as inland areas,and two counties(districts) were randomly selected in each chosen city,three sub-districts(towns) were randomly selected in each chosen counties (districts),then one community (village) was randomly selected in each chosen sub-districts(towns).Adult residents aged greater than 18 were selected as investigation subjects,their dietary iodine intake in the past 24 hours was investigated,and the Food composition table” was inquired to get the data of dietary iodine intake.One hundred copies of residential edible salt samples and drinking water samples in each of the selected community (village) were collected to detect salt iodine and water iodine by direct titrimetric and spectrophotometric method,respectively.Results The mean of adult residents' dietary iodine intake in Zhejiang coastal area was 267.76 μg/d,which was less than that in inland area (429.05 μg/d,t =- 6.90,P ＜0.05),and the means of adult residents' dietary iodine intake from drinking water,laver and fish(5.75,69.72,5.61 μg/d,respectively) in coastal area were higher than those in inland areas(3.25,35.27,3.43 μg/d,respectively,t =21.73,3.92,4.08,all P ＜ 0.05),however,the means of adult residents' dietary iodine intake from salt,kelp and other food (166.81,3.04,16.82 μg/d,respectively) in coastal areas were less than those in inland areas (355.15,6.14,25.81 μg/d,respectively,t =- 8.76,- 5.49,- 18.56,all P ＜ 0.05).In coastal areas,the proportion which was less than estimated average requirement of iodine(EAR,120 μg/d) was 46.48％ (1029/2214),the ratio which was higher than the maximum tolerable intake of iodine(UL,1000 μg/d) was 3.34％ (74/2214),and the average contribution rate of dietary intake of iodine in salt was 62.30％(166.81/267.76).While in inland areas,the corresponding proportions were 7.61％ (171/2246),2.80％ (63/2246) and 82.78％ (355.15/429.05),respectively.Conclusions The dietary iodine intake in Zhejiang inland areas has reached the recommended nutrient intake levels of the Chinese Nutrition Society,but there is a certain degree of insufficient iodine intake in population of the coastal areas.

Surveys on iodine nutritional status of pregnant and lactating women in coastal areas of Zhejiang province / 中国地方病学杂志

Objective To evaluate the nutritional status of iodine of pregnant and lactating women in coastal and inland areas of Zhejiang province,and to provide scientific basis for iodine supplementation.Methods In 2009,five coastal cities,five coastal counties and three inland areas from Zhejiang province were selected by the cluster sampling method,and one sub-district(township) was randomly selected in each city (county),then one community (village) was randomly selected in each sub-district (township).Thirty pregnant women,thirty lactating women and fifty children aged 8 - 10,were randomly selected in each community(village) as the investigation objects to collect instant urine samples to detect urine iodine,and to collect thirty resident edible salt and some water samples to detect salt iodine and water iodine,if the numbers of water source were more than 5 then 1 water sample was collected by their location of east,south,west,north and center in each community(village),otherwise,the numbers of water samples collected were equal to the number of community (village).Results The medians of salt iodine of coastal city,coastal county and inland area were 28.42,25.29,and 33.24 mg/kg,respectively,and the medians of water iodine correspondingly were 5.41,11.52,and 2.80 μg/L,respectively.The medians of urinary iodine of pregnant and lactating women in Zhejiang province were 148.72 and 161.34 μg/L,respectively,which were less than that of children aged 8 - 10(231.02 μg/L,Z =8.57,8.24,all P ＜ 0.017).The medians of urinary iodine in pregnant women from different areas were ranked in order as inland areas(211.42 μg/L),coastal counties (150.51 μg/L) and coastal cities (123.33 μg/L,Z =2.80,5.31,2.42,all P ＜ 0.017),and in lactating women,the medians of urinary iodine in inland areas( 197.43 μg/L) was higher than that in coastal cities( 139.64 μg/L,Z =4.03,P ＜ 0.017).Conclusions The overall levels of iodine nutrition in lactating and pregnant women in Zhejiang province are in the appropriate level,but that of the pregnant women in the coastal cities is inadequate.