Changing Iodine Status and the Incidence of Thyroid Disease in Mainland China: A Prospective 20-Year Follow-Up Study
Authors' conclusion
The incidence of thyroid disorders (except for thyroid nodules) stabilized or decreased among adults in the three communities from year 5 to year 15 of follow-up.
Study context
- Population
- Adults in three regions of north China, followed in a cohort started in 1999; questionnaires, thyroid US, UIC, serum thyroid hormones and thyroid antibodiescohort started 1999
- Participants
- 3,761 adults
- Exposure
- Regions with shifts in iodine status: Panshan and Huanghua vs Zhangwu
- Outcome
- Incidence of thyroid disorders after shifts in iodine status
- Follow-up
- Up to another 15 years after initial 5 years
Methodological details20-year follow-up, cluster sampling, three regions in north China
- 20-year follow-up
- Cluster sampling
- Three regions in north China
Main finding
As reported in the abstract
Incidence density of thyroid disorders
- Panshan (insufficient to adequate): incidence density of subclinical hyperthyroidism, positive TPOAb, positive thyroglobulin antibody (TgAb) and goiter decreased significantly
- p < 0.05 for all
- Huanghua (excessive to more than adequate): significant decrease in incidence density of subclinical hyperthyroidism, positive thyroid antibodies, positive TgAb and goiter
- p < 0.05 for all
- Huanghua: increase in thyroid nodule incidence density
- 17.26 vs. 28.25 per 1000 person-years, p < 0.001
Observational data: associations, not effects.
Further findings
| Outcome | Panshan | Zhangwu | P value |
|---|---|---|---|
| Cumulative incidence of SCHPanshan vs Zhangwu · significantly lower with Panshan | 1.9% | 6.0% | P < 0.001 |
Original publication
Changing Iodine Status and the Incidence of Thyroid Disease in Mainland China: A Prospective 20-Year Follow-Up Study. Thyroid. Published 26 May 2023. doi:10.
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