Iodine nutritional status and prevalence of thyroid nodules among residents using non-iodized salt in Ningbo City, Zhejiang Province / 中华地方病学杂志

ABSTRACT

Objective To investigate the iodine nutritional status,thyroid function and the prevalence of thyroid nodules of residents using non-iodized salt in Ningbo City,Zhejiang Province.Methods In 2011,using typical sampling method,6 villages/communities consumption of non-iodized salt were selected as study fields and residents aged 6-70 were selected as study subjects in Ningbo.Urinary iodine detection,thyroid ultrasound examination and tests of thyroid function [free triiodothyronine (FT3),free thyroxine (FT4),thyroid stimulating hormone (TSH),thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb)] were performed in all participants.Urinary iodine concentration (UIC) was determined by arsenic cerium catalytic spectrophotometry,and thyroid function was monitored by chemiluminescence method.Results A total of 1 177 residents agreed to participate in the study,482 were male,and 695 were female (including 2 pregnant women).The participants' mean age was (48.54 ± 13.98) years.The median UIC in all participants was 90.36 μg/L,and the proportions with a UIC ＜ 100μg/L was 56.07％ (660/1 177).Furthermore,the median UIC in male was 97.05 μg/L and in female was 83.84 μg/L,there was a significant difference in UICs between male and female (Z =-2.99,P ＜ 0.05).Similarly,significant difference in UICs was observed among age groups (x2 =99.34,P ＜ 0.01).Among the participants,19.88％ had thyroid nodules,with standardized prevalence rate of 13.95％.Furthermore,in male,11.83％ had thyroid nodules,with standardized prevalence rate of 8.11％,and in female was 25.47％,with standardized prevalence rate of 19.83％,there was a significant difference in the detection rate of thyroid nodules between male and female (x2 =33.25,P ＜ 0.01).Likewise,significant difference in the detection rate of thyroid nodules was observed among age groups (x2=49.65,P＜ 0.01),and there was a positive and significant correlation between the detection rate of thyroid nodules and increasing age (x2trend =44.22,P ＜ 0.01).Conclusions The residents who using non-iodized salt in Ningbo City are in the status of iodine deficiency.The detection rate of thyroid nodules is higher in female than in male and it has increased with age.