Genetic Diversity and Virulence Variation of Metarhizium rileyi from Infected Spodoptera frugiperda in Corn Fields.

Metarhizium rileyi is an entomopathogenic fungus that naturally infects the larvae of Spodoptera frugiperda, and has biocontrol potential. To explore more natural entomopathogenic fungi resources, a total of 31 strains were isolated from 13 prefectures in Yunnan Province. All the strains were identified using morphology and molecular biology. The genetic diversity of the 31 isolates of M. rileyi was analyzed using inter-simple sequence repeat (ISSR) techniques. Seven primers with good polymorphism were selected, and fifty-four distinct amplification sites were obtained by polymerase chain reaction amplification. Among them, 50 were polymorphic sites, and the percentage of polymorphic sites was 94.44%. The thirty-one strains were divided into eight subpopulations according to the regions. The Nei's gene diversity was 0.2945, and the Shannon information index was 0.4574, indicating that M. rileyi had rich genetic diversity. The average total genetic diversity of the subpopulations in the different regions was 0.2962, the gene diversity within the populations was 0.1931, the genetic differentiation coefficient was 0.3482 (>0.25), and the gene flow was 0.9360 (<1). The individual cluster analysis showed that there was no obvious correlation between the genetic diversity of the strains and their geographical origin, which also indicated that the virulence of the strains was not related to their phylogeny. Thus, the genetic distance of the different populations of M. rileyi in Yunnan Province was not related to the geographical distance. The virulence of those 32 strains against the 3rd-instar larvae of S. frugiperda were varied with the differences in geographical locations. On the 10th day of inoculation, seventeen strains had an insect mortality rate of 70.0%, and seven strains had an insect mortality rate of 100%. The half-lethal times of the M. rileyi SZCY201010, XSBN200920, and MDXZ200803 strains against the S. frugiperda larvae were less than 4 d. Thus, they have the potential to be developed into fungal insecticidal agents.

Mechanism of the Change in the Intestinal Microbiota of C-Strain Spodoptera frugiperda (Lepidoptera: Noctuidae) after an Interspecific Transference between Rice and Corn.

Spodoptera frugiperda (J.E.Smith) (Lepidoptera: Noctuidae) was first found in 2019 in Yunnan, China, and it was characterized as a corn strain; it was also found on rice strains there, and it damages rice in China, but little is known about the effect of host plant transfer on the intestinal microbiota and the activities of detoxification enzymes in the C-strain (corn strain) S. frugiperda. The intestinal microbiota and the protective enzyme activity of S. frugiperda that were transferred from rice plants were assessed, and the fourth generation of insects transferred from corn were studied; the gene types of S. frugiperda that were transferred from rice plants were tested using mitochondrial Tpi gene sequences. The results showed that the intestinal microbiota in the C-strain S. frugiperda were changed after the host transference, and the diversity and richness of the intestinal bacterial communities of the S. frugiperda feeding on rice were significantly reduced after the transfer of the host from corn. The predominant species of intestinal bacteria of the S. frugiperda on rice transferred from corn were Enterococcus and Enterobacter, with relative abundances of 28.7% and 66.68%; the predominant species of intestinal bacteria of the S. frugiperda that were transferred from rice and feeding on corn were Enterococcus (22.35%) and Erysipelatoclostridium (73.92%); and the predominant species of intestinal bacteria of S. frugiperda feeding on corn was Enterococcus, with a relative abundance of 61.26%. The CAT (catalase) activity of the S. frugiperda transferred from corn onto rice from corn was reduced, the POD (peroxidase) activity was significantly increased after the transfer from corn, and no significant variations were found for the SOD (superoxide dismutase), CarE (carboxylesterase), and GST (glutathione S-transferase) activities of S. frugiperda after the host plant transfer. The results showed that after feeding on rice, the activities of CAT and POD in the in S. frugiperda body changed in order to resist plant secondary metabolites from corn or rice, but there was no significant change in the detoxification enzymes in the body. In summary, switching the host plant between corn and rice induced variations in the intestinal microbiota in C-strain S. frugiperda owing to the strain difference between the C-strain and the R-strain (rice strain), and this was consistent with the results of the activities of detoxification enzymes. The results indicat that changes in intestinal microbiota and physiological enzymes may be important reasons for the adaptive capacity of C-strain S. frugiperda to rice.

Reconstruction of Gut Bacteria in Spodoptera frugiperda Infected by Beauveria bassiana Affects the Survival of Host Pest.

Spodoptera frugiperda (Lepidoptera: Noctuidae) is a migratory agricultural pest that is devastating on a global scale. Beauveria bassiana is a filamentous entomopathogenic fungus that has a strong pathogenic effect on Lepidoptera pests but little is known about the microbial community in the host gut and the dominant populations in fungus-infected insects. B. bassiana AJS91881 was isolated and identified from the infected larvae of Spodoptera litura. The virulence of AJS91881 to the eggs, larvae, pupae and adults of S. frugiperda was measured. Moreover, the gut microbial community diversity of healthy and fungus-infected insects was analyzed. Our results showed that after treatment with B. bassiana AJS91881, the egg hatching rate, larval survival rate and adult lifespan of the insects were significantly reduced, and the pupae rigor rate was significantly increased compared to that of the control group. Additionally, the gut microbial community was reconstructed after B. bassiana infection. At the phylum and genus level, the relative abundance of the Proteobacteria and Serratia increased significantly in the B. bassiana treatment group. The KEGG function prediction results showed that fungal infection affected insect gut metabolism, environmental information processing, genetic information processing, organism systems and cellular processes. Fungal infection was closely related to the metabolism of various substances in the insect gut. Serratia marcescens was the bacterium with the highest relative abundance after infection by B. bassiana; intestinal bacteria S. marcescens inhibited the infection of insect fungi B. bassiana against the S. frugiperda. The presence of gut bacteria also significantly reduced the virulence of the fungi against the insects when compared to the group with the larvae fed antibiotics that were infected with fungal suspension (Germfree, GF) and healthy larvae that were infected with fungal suspension prepared with an antibiotic solution (+antibiotic). In conclusion, the reconstruction of the insect intestinal bacterial community is an indispensable link for understanding the pathogenicity of B. bassiana against S. frugiperda. Most importantly, in the later stage of fungal infection, the increased abundance of S. marcescens in the insect intestine inhibited the virulence of B. bassiana to some extent. The findings aid in understanding changes in the gut microbiota during the early stages of entomopathogenic fungal infection of insects and the involvement of insect gut microbes in host defense mediated by pathogenic fungal infection. This study is also conducive to understanding the interaction between entomopathogenic fungi, hosts and gut microbes, and provides a new idea for the joint use of entomopathogenic fungi and gut bacteria to control pests.

Virulence of Metarhizium rileyi Is Determined by Its Growth and Antioxidant Stress and the Protective and Detoxifying Enzymes of Spodoptera frugiperda.

Spodoptera frugiperda is one of the most destructive crop pests in the world. Metarhizium rileyi is an entomopathogenic fungus specific for noctuid pests and is a very promising prospect in biological control against S. frugiperda. Two M. rileyi strains (XSBN200920 and HNQLZ200714) isolated from infected S. frugiperda were used to evaluate the virulence and biocontrol potential to different stages and instars of S. frugiperda. The results showed that XSBN200920 was significantly more virulent than HNQLZ200714 to eggs, larvae, pupae, and adults of S. frugiperda. In the larvae infected with the two M. rileyi strains, the activity of three protective enzymes (including peroxidase (POD), superoxide dismutase (SOD), catalase (CAT)) and two detoxifying enzymes (including glutathione-S transferase (GST) and carboxylesterase (CarE)) increased firstly and then decreased. The expression levels of protective enzymes and detoxification enzymes in larvae treated with XSBN200920 were greater than with HNQLZ200714. Furthermore, antioxidant stress-related gene (MrSOD and MrCAT family genes) expression in the two strains was measured by RT-qPCR (real-time quantitative PCR). The expression of these genes was significantly higher in the XSBN200920 strain compared to HNQLZ200714. There were also significant differences in the sensitivity of the two strains to the growth of different carbon and nitrogen sources and oxidative stress agents. In addition, the activity expression of antioxidant enzymes on the third day of culturing in XSBN200920 was significantly higher than with HNQLZ200714. In summary, the high virulence of M. rileyi XSBN200920 was not only determined by the expression levels of protective and detoxifying enzymes of the host but also regulated by the growth of entomogenic fungi and the resistance to the oxidative stress against S. frugiperda at different stages and instars. This study provides a theoretical fundament for the systematic control of Spodoptera frugiperda using Metarhizium rileyi.

Mutiple-slice spiral CT diagnosis of atypical intraabdominal hernia / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To discuss the value of multiple-slice spiral CT diagnosis of atypical intraabdominal hernia.</p><p><b>METHODS</b>The clinical and CT findings of 16 cases of atypical intraabdominal hernia confirmed surgically were retrospectively analysed.</p><p><b>RESULTS</b>In all the 16 cases, the contents of hernia were small bowels and the mesentery. Nine cases were caused by the adhesion after abdominal operations or infection, 6 by the mesenteric foramen, and 1 by the gap of pelvic peritoneum. The main CT findings were as follows:(1)the obstructed small bowels gathered abnormally and showed cluster shape(9 cases); the walls of the bowels thickened with edema and showed "target" sign with exudate in the neighboring spaces(5 cases); other part of the abdominal cavity became empty for lack of small bowels(4 cases).(2) Abnormal arrangement of the branches of mesenteric vessel, which appeared gathered or pulled or rigid and displacement of the main branches to left or right(12 cases). Thickened mesenteric vessel (4 cases): torsion of mesentery with "whirlpool" sign (3 cases). (3) With the help of multiplanar reformation, 5 cases showed the evidence of hernia rings. In the ring area, there were gathered or pulled or rigid and radiating mesenteric vessel and the dilated or effusion bowels in cluster arrangement forming "parachute" and "bundle of balloons" sign.</p><p><b>CONCLUSION</b>CT manifestations of atypical intraabdominal hernia has some specific characteristics, which is of important value for clinical diagnosis and treatment.</p>

The value of MRI in diagnosis of ligament injuries of knee joint / 中国骨伤

<p><b>OBJECTIVE</b>To study the performance of MRI and its diagnostic value for ligament injuries of knee joint.</p><p><b>METHODS</b>Form June 2008 to February 2010, the MRI of 74 patients with ligament injuries of knee joint were retrospectively analyzed. There were 47 males and 27 females in the group, which course was from 2 h to 10 d, with an average age of 37.3 years (ranged from 12 to 76). The clinical symptom included knee swelling, pain, joint instability, extension-flexion movement disorder. The physical examination showed valgus test or drawer test positive, and tenderness of medial knee positive.</p><p><b>RESULTS</b>There were ligament injuies in 74 cases, among them, 19 cases were anterior cruciate ligament (25.7%),18 were posterior cruciate ligament (24.3%), 13 were lateral collateral ligament (17.6%), 24 were medial collateral (32.4%), the ligament of 12 cases were completely broken (included 8 cases cruciate ligament and 4 cases collateral ligament presented as discontinued signals of the ligament, and swelling and thickening of the ligament with medium signal in PDWI and high signal intensity in T2WI and in SPIR). The MRI of 62 patients with partial longitudinal tearing ligaments showed continuity, swelling and thickening of the ligaments with medium signal in PDWI and high signal intensity in T2WI and in SPIR. Forty-four cases were examined with surgery and arthroscopy, 41 ligaments were accorded with MRI, diagnosis rate of MRI was 95%.</p><p><b>CONCLUSION</b>MRI can accurately diagnose the ligament injuries of knee joint,which is an ideal technique in the diagnosis of ligament injuries of knee joint, and should be used as a routine examining method.</p>

Effect of iodine intake on serum thyroglobulin——A five-year prospective epidemiological study / 中华内分泌代谢杂志

Objective To clarify the effect of iodine intake on serum thyroglobulin (Tg). Methods A 5-year prospective study was conducted in the 3 different iodine intake areas in China [Panshan (miht deficiency) ,Zhangwu (more than adequate) and Huanghua (excess)]. A total of 3 099 people with normal serum levels of Tg in 1999 were followed and 2 448 of these participants were feasible to be observed in 2004 and included in the present study. The serum levels of Tg, thyraglobulin antibody(TgAb), thyroid peroxidase antibody(TPOAb) and TSH, thyroid volume, family and personal histories of thyroid diseases were measured and inquried. The general linear model (GLM) was used to explore the determinants of Tg. Results Among the study population at baseline, serum Tg were significantly different in three areas [7.5 (4.4-13. 1) μg/L at Panshan, 6.8 (3.6-11.2)μg/L at Huanghua, 5.9 (3.2-10.7) μg/L at Zhangwu, P<0.01]. They were associated with age, sex and the rate of positive TgAb, abnormal thyroid volume, abnormal TSH and positive personal history of thyroid diseases, in order to control the effects of confounding factors, the data from 1856 subjects with thyroid-related indexes all in normal range and without personal history of thyroid diseases were analyzed to clarify the effect of iodine intake on Tg. The serum Tg among three areas were significantly different in both 1999 and 2004, they were all increased in 5 years with significant augment (△ Tg) among the three areas[3.1 (-0.2-8.0) μg/L at Panshan, 3.5 (0.5-9.0)μg/L at Huanghua vs 2. 5(0.3-6.1) μg/L at Zhangwu,P<0.01]. The GLM analysis revealed that age, Tg and TSH levels at baseline were the determinants of △Tg in addition to iodine intake. Conclusion Iodine intake is a dominant determinant of serum Tg. Age and TSH should also be considered while indicating iodine intake by serum Tg.

Prospective study on the effect of different iodine intakes on goiter and thyroid nodules / 中华内分泌代谢杂志

Objective To investigate the epidemiological characteristics of non-toxic goiter and non-toxic thyroid nodules in the regions with different iodine intakes and the factors influencing the occurrence, development and outcome of goiter and thyroid nodules. Methods 3 385 subjects, who had taken part in the previous survey in 1999 with the ultrasonic examination of thyroid, were composed of individuals in Panshan with chronic mild iodine deficiency,in Zhangwu with more than adequate iodine "after iodine supplementation and in Huanghua with excessive iodine. These 3 groups of subjects were followed up in 2004. Results (1) The cumulative incidences of diffuse goiter in Panshan ,Zhangwu and Huanghua were 7.1% ,4.4% and 6.9% ,respectively ,being the lowest in Zhangwu (P<0.01) and those of nodular goiter were 5.0% ,2. 4% and 0.8%, respectively, being the highest in Panshan (P<0.01). (2) The incidences of single nodule were 4.0% ,5.7% and 5.6%, respectively, and those of multiple nodules 0.4%, 1.2% and 1.0%, respectively. (3)The result of logistic analysis showed that iodine deficiency,iodine excess and positive thyroid autoantibodies (TAA) were the independent risk factors for the occurrence of goiter. (4)In Zhangwu ,the incidence of non-toxic goiter in the group with positive TAA was higher than that in the group with negative TAA(P<0.01) ,while there were no such differences in Panshan and Huanghua. (5)In these three regions, the rates of positive TAA in the individuals with diffuse non-toxic goiter were higher than those in the healthy subjects (P<0.05). And in Huanghua,the rate of positive TAA in subjects with non-toxic nodular goiter was also higher than that in the healthy individuals (P<0.05). Conclusion Iodine deficiency and iodine excess may both induce the raising incidence of goiter. Nodular goiter is prevalent in iodine deficient district and diffuse goiter is the predominant form in places with iodine excess. Thyroid autoimmunity is associated with occurrence and maintenance of goiter, and this phenomenon is more obvious in the community with previous iodine deficiency followed then by treatment with more than adequate iodine.

The changes of thyrotropin level in euthyroid population:a 5-year follow-up study in communities with different iodine intakes / 中华内科杂志

Objective To determine the factors that influence the development of abnormal thyrotropin (TSH) level in an euthyroid population.Methods We conducted a follow-up study in 3 communities with different iodine status.Of the 3403 euthyroid subjects at baseline screened in 1999,80.1% ( n = 2727 ) was visited and sampled in 2004 for measuring TSH,thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb).Results Iodine status in the 3 communities were stable.Decreased TSH level( <0.3 mU/L) developed in 2.5% (n =68) of sampled subjects,while raised TSH level( > 4.8 mU/L) in 2.4% (n = 64).A logistic analysis showed that risk factors for developing decreased TSH level included positive conversion of TPOAb (OR = 5.5 ),positive TPOAb both in 1999 and in 2004 ( OR = 4.0),positive TgAb in 2004 ( OR = 3.7) and TSH < 1.0 mU/L in 1999 ( OR = 2.6).Risk factors involved in developing raised TSH level included iodine status of Zhangwu community ( OR = 4.1 ),iodine status of Huanghua community ( OR = 3.9),positive TgAb in 2004 ( OR = 3.7 ),positive TPOAb both in 1999 and 2004 (OR =3.6),positive conversion of TPOAb (OR =2.7) and TSH > 1.9 mU/L in 1999 (OR = 2.6 ).Conclusions Exposure to long-term iodine excess imposes danger of developing hypothyroidism.The risk will be even higher when exposing to iodine adequacy after correction of iodine deficiency.An interval between 1.0 and 1.9 mU/L of TSH level was optimul with the least probability of developing abnormal TSH level.

The relativity between chronic periodontitis and the genetic polymorphisms of vitamin D receptor and estrogen receptor / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between chronic periodontitis and the genetic polymorphisms of vitamin D receptor gene and estrogen receptor gene.</p><p><b>METHODS</b>Clinical parameters including probing depth, clinical attachment loss, sulcus bleeding index and tooth movement were measured by fluoride probe. Genomic DNA from peripheral venous blood was extracted with saturant sodium chloride, and PCR-restriction fragment length polymorphism was applied to examine the Apa I, Bsm I, Taq I polymorphisms of the vitamin D receptor genes and the Xba I and Pvu II polymorphisms of the estrogen receptor genes. The results were analyzed by Z-score test and mean square analysis.</p><p><b>RESULTS</b>Forty-three point four percent of chronic periodontitis patients took vitamin D receptor BB genotype, the rate in healthy controls was 30.0%. 39.6% of chronic periodontitis patients took estrogen receptor XX genotype, the rate in healthy controls was 20.0%. The people who took BBXX genotype had the worst periodontal conditions among all chronic periodontitis patients.</p><p><b>CONCLUSIONS</b>Vitamin D receptor allele B and estrogen receptor allele X are susceptible alleles for chronic periodontitis. The synergistic effects of the two receptor susceptible alleles may promote chronic periodontitis.</p>

Epidemiological study of the effects of smoking cigarette on thyroid gland / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the effect of cigarette smoking on thyroid gland volume, thyroid function and thyroid autoantibodies in the areas with different iodine intakes.</p><p><b>METHODS</b>A cross-sectional epidemiological study in Panshan (mild iodine-deficient area), Zhangwu (more than adequate iodine intake area) and Huanghua (iodine-excessive area) was conducted in 3761 subjects in 1999.80.2 % of them were followed up in 2004. Questionnaires, thyroid function, thyroid autoantibodies, urinary iodine concentration,and thyroid B ultrasound were performed.</p><p><b>RESULTS</b>The prevalence of goiter was higher in smokers than in non-smokers (15.1% vs. 11.5%, P< 0.05). The average thyroid volume was higher in smokers with phenomenon more obvious in Panshan and Huanghua areas. Data from logistic analysis showed that smoking cigarette was an independent risk factor of goiter. There was no difference in serum TSH and Tg level between smokers and non-smokers. The positive rate of TPOAb (>100 IU/ml) was higher in smokers than in non-smokers(10.8% vs. 9.0 % , P <0.05) and was especially obvious in Huanghua area. Smoking was a independent risk factor of increasing positive rate of TPOAb. During the prospective observation,it was found that the incidence of positive TPOAb(>,100 IU/ml) was 7.4% in the subjects that were from non-smokers turning to smokers and 2.9% in those whose smoking behavior did not change. Logistic analysis indicated that the shifting from non-smoking to smoking was independent risk factor for the increase on high incidence of positive TPOAb.</p><p><b>CONCLUSION</b>Smoking cigarette was a independent risk factor of goiter. Smoking was also a risk factor of increasing TPOAb positive rate. Shifting from not smoking to smoking was an independent risk factor of increasing high incidence of positive TPOAb.</p>

Effect of iodine supplement on thyroid of iodine-deficient rats / 中国实用内科杂志

Objective To study the effect of chronic iodine supplement on thyroid of iodine-deficient rats.Methods Iodine-deficient rat models were made by giving 4- week-old rats iodine-deficient fodder for 3 months.These iodine-deficient rats were then supplemented for 8 months 1-,3- and 6- fold iodine which corresponded to the 3 levels of iodine intake found in our epidemiological study in 3 rural communities.Then changes of thyroid after iodine supplement were observed.Results After supplement of 1-,3- and 6- fold iodine to iodine-deficient rats for 8 months,thyroid relative weight did not recover,and iodine accumulated in thyroid.The ultrastructure injuries of swelling mitochondria and dilating endoplasmic reticulum in epithelial cells of iodine-deficient thyroid did not recover,but became worse with iodine supplement increase.Conclusion Iodine supplement alone can not correct the injuries resulting from iodine deficiency;moreover,a sub-pathological state might occur.

The study of thyroid diseases in a community not using iodized salt / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of thyroid diseases in a community which did not use iodized salt.</p><p><b>METHODS</b>The survey was conducted in Panshan, Liaoning Province. 1 103 inhabitants aged 14 years or more attended the examinations, which included questionnaire, physical examination and serum analysis. Iodine in the urine and thyroid B ultrasound examination were also conducted.</p><p><b>RESULTS</b>The prevalence of overt hyperthyroidism and hypothyroidism was 16.3 per thousand and 2.7 per thousand, respectively. Subclinical hyperthyroidism and hypothyroidism were detected in 37.2 per thousand and 9.1 per thousand of the subjects, respectively. Serum autoantibodies to thyroid were detected in 10.9% of the entire population. The prevalence of goiter was 20.7% (diffuse goiter 16.8% and nodular goiter 3.9%).</p><p><b>CONCLUSION</b>In the iodine deficient areas, perhaps autoimmununization is not only related to the development of goiter but is also the main cause of subclinical hyperthyroidism and hypothyroidism.</p>

Impact of iodine intake on thyroid diseases——A five-year prospective epidemiological study / 中华内分泌代谢杂志

Objective To evaluate the relationship between iodine intake level and the occurrence and development of thyroid diseases.Methods During the period of 1999-2004,a cross-sectional survey in 1999 and a 5-year follow-up survey were conducted in the 3 communities with different iodine intake levels in China:Panshan (mild deficiency),Zhangwu (more than adequate) and Huanghua (iodine excess).A total of 3 761 subjects were included in 1999 and 80.24% of them participated in the 5-year follow-up survey in 2004.The levels of serum thyroid hormones and thyroid autoantibodies were measured,and thyroid B ultrasound was performed.Results (1) The prevalence of overt hypothyroidism in 1999 in Zhangwu and Huanghua was 3.5 and 7.3 times,and that of subclinical hypothyroidism was 3.2 and 6.6 times as high as in Panshan,respectively.The 5-year cumulative incidence of subclinical hypothyroidism was 11.3 and 12.6 times as high as in Panshan,but no difference of incidence of overt hypothyroidism was found.(2) The prevalence of autoimmune thyroiditis (AIT) in 1999 in Zhangwu and Huanghua was 3.8 and 6.2 times,and the S-year cumulative incidence of AIT was 4.4 and 5.5 times as high as in Panshan.(3) During the 5-year follow-up period,the incidences of hypothyroidism in subjects with positive thyroid peroxidase antibody and euthyreidism in Zhangwu and Huanghua were 4.2 and 10.3 times as high as in Panshan.(4) No significant differences in both prevalence in 1999 and 5-year cumulative incidence of overt hyperthyroidism were found in the 3 communities.(5) The incidence of thyroid cancer was 19.37/100 000 per year in Huanghua,and all of the cases were papillary thyroid cancer,and no thyroid cancer was found in Zhangwu and Huanghua.Conclusion More than adequate or excessive dietary iodine intake may induce and promote the occurrence and development of hypothyroidism and AIT,therefore,median urinary iodine excretion (MUI)more than 200?g/L in the population appears not safe.The observation that a higher incidence of thyroid cancer occurred in the iodine excessive areas with MUI 600?g/L deserves further investigation.

Thyroid autoantibodies In a five-year follow-up survey of populations with different Iodine intakes / 中华内分泌代谢杂志

Objective To perform a follow-up survey about thyroid disorders in three rural communities with different iodine intakes in China,observe the incidences and natural outcomes of positive thyroid autoantibodies in euthyroid population,and also explore the influence of iodine intakes on these outcomes and autoantibodies.Methods In 1999,a cross-sectional study on thyroid disorders was performed in three rural communities of Pansan ( mild iodine deficient area),Zhangwu ( more than adequate iodine intake area) and Huanghua (excessive iodine intake area) in China.The 5-year follow-up study was performed in 2004.Both in 1999 and 2004,serum levels of TSH,thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) were measured with the same method.Iodine in urine and B ultrasound on thyroid were also examined.Results Among the euthyroid subjects with normal TSH level in 1999,an increased prevalence of positive TPOAb in Zhangwu and an increased prevalence of positive TgAb in Hnanghua were observed in 2004 (both P＜0.05 ).Most of euthyroid subjects with positive TPOAb or positive TgAb in 1999 remained positive thyroid antibodies in 2004. The percentage was even higher in those with high levels of antibodies.Thyroid dysfunction was more frequent in subjects with positive TPOAb and/or TgAh than in those without thyroid antibodies (14.44% vs 3.11%,P＜0.01).For those with positive antibodies in 1999,the incidence of hypothyroidism in 2004 was 1.32%,8.46% and 15.38% in Pansan,Zhangwu and Huanghua,respectively (P＜0.05).The 5-year cumulative incidences of positive TPOAb (≥50 U/ml) and TgAb (≥40 U/ml) were 2.81% and 3.82%,respectively.The incidence of positive TPOAb was the highest in Zhangwu ( 3.84% ).The incidence of positive TgAb was the highest in Huanghua (5.07%),significantly higher than those in other two areas (P＜0.05).Conclusion The incidence of thyroid dysfunction is higher in subjects with positive antibodies than that in those with negative antibodies.The high iodine intake is a risk factor of hypothyroidism in subjects with positive thyroid antibodies.Sustained excessive iodine intake increases the incidence of positive thyroid antibodies.

Incidences of hyperthyroidism in communities with different iodine intake levels:a five-year prospective and comparative epidemiological survey / 中华内分泌代谢杂志

Objective To analyze the relationship between different iodine intakes and epidemiological features of hyperthyroidism in 3 communities with different iodine intake levels,as well as to explore the risk factor for the pathogenesis of hyperthyroidism.Methods A cohort study was performed in 3 Chinese rural communities with long-term stable iodine nutrition status defined as mild deficient (Panshan),more than adequate (Zhangwu, previously mild iodine deficiency and salt iodization lasting 8 years until 2004) and excessive (Huanghua).A total of 3 761 (934 males,2 827 females) inhabitants aged above 13 participated in the original investigation in 1999 and 3 018(709 males,2 309 females) of them received identical examinations after 5 years.Results Median urinary iodine concentration of school-aged children was 87.61zg/L in Panshan,213.9?g/L in Zhangwu and 633.5?/L in Huanghua (P＜0.05) at fallowing up,and no statistic significance was found when comparing the corresponding data from original survey (83.5?g/L,242.9?g/L and 650.9?g/L).The accumulative incidence of hyperthyroidism was 13.6/1 000,9.4/1 000 and 8.1/1 000 (P＞0.05),being 16.4/1 000,11.2/1 000 and 9.1/1 000 (P＞0.05) in female,respectively in Panshan,Zhangwu and Huanghua.In original healthy subjects (without history of thyroid disease and overt thyroid dysfunction) merely with either positive thyroid peroxidase antibody (TPOAb＞50 IU/ml) or thyroglobulin antibody (TgAb＞40 IU/ml),the accumulative incidence of newly diagnosed hyperthyroidism was not significantly different among 3 communities in follow-up survey.TSH＜0.3 mIU/L,positive TPOAb or goiter in original healthy participants were associated with the occurrence of overt hyperthyroidism in 5 years [ Logistic Regression,OR = 5.7 (95% CI 2.1-15 ),OR = 3.8 (95% CI 1.7-8.7 ) and OR = 3.1 (95% CI 1.4-6.8) respectively].Conclusion Iodine supplementation in mild iodine deficient area does not increase the incidence of overt hyperthyroidism ultimately.Long-term excessive iodine intake does not affect the incidence and pattern of hyperthyroidism.TSH＜0.3 mIU/L,positive TPOAb and goiter in healthy individuals are the risk factors for hyperthyroidism.

A five-year follow-up study of hypothyroidism in areas with different iodine intakes / 中华内分泌代谢杂志

Objective To investigate epidemiologieal characteristics of hypothyroidism and factors influencing its outcome in the areas with different iodine intakes.Methods An epidemiologic follow-up study of thyroid diseases was performed in Panshan (iodine deficient),Zhangwu [mild iodine deficiency before universal salt iodination (USI) and more than adequate iodine intakes after USI ] and Huanghua ( iodine excessive) in China.A total of 3 761 subjects were investigated in 1999,and 3 018 (80.2% ) of them were followed up in 2004.FT_4,FT_3,TSH,thyroid autoantibodies and urinary iodine concentration were determined and thyroid B ultrasound was performed in all participants.Results Five-year cumulative incidence of overt hypothyroidism was 0.23%,0.47% and 0.35% in Panshan,Zhangwu and Huanghua,respectively.Twenty patients with autoimmune- induced overt hypothyroidism did not comply with the physician's orders to take thyroxine.Thyroid function spontaneously turned to normal in 55% of them,turned to subclinical hypothyroidism in 20% and maintained overt hypothyroidism in 25%.Five-year cumulative incidence of subclinical hypothyroidism in Zhangwu (2.60%) and Huanghua (2.89%) were significantly higher than that in Panshan(0.23% ) (both P＜0.01 ).One hundred patients with subclinical hypothyroidism were followed up,and 5% of them developed overt hypothyroidism,66% turned to euthyroidism and 29% maintained subclinical hypothyroidism.Raised serum TSH (＞6 mU/L) in the original survey ( OR = 3.4),positive thyroid autoantibodies in the follow-up study ( OR = 5.3 ) and more than adequate iodine supplementation in the mild iodine-deficient population ( OR = 8.0) were risk factors influencing outcome of subclinical hypothyroidism.Conclusion More than adequate iodine supplementation among a population in the mildly iodine-deficient area may increase the incidence of overt and subolinical hypothyroidism, and also influence outcome of subclinical hypothyroidism.