Investigation On The Factors That Influence The Prevalence Of Goiters And Thyroid Nodules In Ten Cities In China

Objective This survey aimed to investigate the prevalence of goiters and thyroid nodules(TNs)in ten cities in China and identify the possible factors that were associated with the prevalence.Methods A grand total of 15008 adults from ten cities in China volunteered to attend this research.All of the subjects received questionnaires,physical examination and thyroid ultrasonography.Urine iodine concentration(UIC),serum thyroid stimulating hormone(TSH),thyroid peroxidase antibodies(TPOAb)and thyroglobulin antibodies(Tg Ab)were also measured in the central laboratory of the project.Multivariate logistic analysis was used to identify independent factors which may be associated with the prevalence of goiters and TNs.Results1.The overall prevalence of goiters and TNs was 2.4%and 15.7%respectively.2.The prevalence of goiters and TNs in females was much higher than in males(P<0.05).The goiters’s and TNs’s prevalence decreased as the urine iodine concentration increased but increased as the body mass index(BMI)increased(P<0.05).Other factors which may influence the goiters included advanced ages,high blood pressure,high waist circumference,family history of thyroid diseases,low TSH,TPOAb positive and Tg Ab positive(P<0.05).However,only advanced ages,high blood pressure,high waist circumference and low TSH were observed in affecting the TNs(P<0.05),family history of thyroid diseases,TPOAb positive and Tg Ab positive didn’t make differences on TNs significantly in this study(P>0.05).The occurrence of goiters and TNs was lower in current smoking subjects(P<0.05).3.Our results showed that when the UIC was more than 300μg/L,it would take protective effect on TNs(OR:0.83;95%CI:0.72,0.96;P for trend 0.013),but not on goiters(OR:1.14;95%CI:0.82,1.58;P for trend 0.463).The associations between UIC and goiters and between UIC and TNs were consistent across different subgroups defined by TPOAb positive,Tg Ab positive,and no significant interaction was observed(P>0.05).4.When BMI was more than 28 kg/m~2,it would become the independent risk factor for goiters(1.61;95%CI:1.14,2.26;P for trend<0.001).Furthermore,when BMI was more than 24 kg/m~2,it would be the independent risk factor for TNs[(1.22;95%CI:1.09,1.36)for BMI 24-27.9 kg/m~2;(1.27;95%CI:1.09,1.49)for BMI≥28 kg/m~2;P for trend<0.001].The positive associations between BMI and goiters and between BMI and TNs were consistent in each autoimmune thyroid antibody group,and no significant interaction was observed(P>0.05).Conclusion The introduction of mandatory universal salt iodization in our country has been scientific and necessary.However,more researches should be carried out to explore the optimal upper limit of high UIC level.Higher BMI level will have adverse impact on goiters and TNs,therefore it will be beneficial for obese patients to lose weight.