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.

OBJECTIVETo investigate the prevalence of thyroid diseases in a community which did not use iodized salt.

METHODSThe 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.

RESULTSThe 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%).

CONCLUSIONIn 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.

Adolescent ; Adult ; Aged ; Autoantibodies ; analysis ; China ; epidemiology ; Female ; Goiter ; epidemiology ; Health Surveys ; Humans ; Hyperthyroidism ; epidemiology ; Hypothyroidism ; epidemiology ; Iodine ; deficiency ; urine ; Male ; Middle Aged ; Prevalence ; Residence Characteristics ; Sodium Chloride, Dietary ; Thyroid Diseases ; epidemiology ; immunology ; metabolism ; Thyroid Nodule ; epidemiology

OBJECTIVETo investigate the effect of cigarette smoking on thyroid gland volume, thyroid function and thyroid autoantibodies in the areas with different iodine intakes.

METHODSA 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.

RESULTSThe 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.

CONCLUSIONSmoking 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.

Autoantibodies ; blood ; Cross-Sectional Studies ; Female ; Goiter ; blood ; epidemiology ; immunology ; physiopathology ; Humans ; Incidence ; Male ; Smoking ; adverse effects ; Thyroid Function Tests ; Thyroid Gland ; physiopathology ; Thyroid Hormones ; blood

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.

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.

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.

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.

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.

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.

OBJECTIVE: To establish the fixation model of anterior cervical transpedicular system (ACTPS) after subtotal resection of two segments of lower cervical spine(C₃-C₇) in order to provide a finite element modeling method for anterior cervical reconstruction. METHODS: The CT data of the cervical segment (C₁-T₁) of a 30-year-old adult healthy male volunteer was collected. Used Mimics 10.0, Rapidform XOR3, HyperMesh 10.0, CATIA5V19 and ANSYS 14.0 to establish the three-dimensional nonlinear complete model of lower cervical spine(C₃-C₇) as the intact group. The number of units and nodes of the complete model were recorded. After the effectiveness of the complete model was verified, the C₅ and C₆ vertebral subtotal resection was performed, and the ACTPS model was established as the ACTPS group. The axial force of 75 N and moment couple of 1N·m was loaded on the upper surface of C₃ in intact group and ACTPS group, the range of motion(ROM)and stress distribution in states of flexion extension, lateral flexion, rotation was compared between two groups. RESULTS: There were 85 832 elements and 23 612 nodes in the complete model of lower cervical spine(C₃-C₇) which was established in this experiment. The stress distribution of ACTPS internal fixation model was relatively uniform. Comparing with the intact group, the overall range of motion in ACTPS group was decreased in flexion extension, lateral flexion and rotation directions, and the corresponding compensation of adjacent C_3,4 segment was increased slightly. CONCLUSION The stress distribution of ACTPS fixation system is uniform, there is no stress concentration area at the joint of screw and titanium plate, and the fracture risk of internal fixation is low. It is suitable for stability reconstruction after anterior decompression of two or more cervical segments.
Adult ; Biomechanical Phenomena ; Bone Screws ; Cervical Vertebrae/surgery* ; Finite Element Analysis ; Humans ; Male ; Range of Motion, Articular ; Spinal Fusion