Association of Iodine Intake and Iodine-enriched Food with Risk of Thyroid Cancer: A Meta-analysis

Objective To explore the relationship between iodine intake, iodine-enriched food and the risk of thyroid cancer by Meta-analysis.

Methods We made search strategies according to PICOS. Pubmed, Embase, CNKI, Wanfang and CBM databases were searched for case control studies or cohort studies about the relationship between iodine intake, iodine-enriched food and the risk of thyroid cancer by computer from the inception to April, 2015. The reference lists were scanned for relevant studies. The articles were screened according to the inclusion and exclusion criteria by two researchers independently, the data were extracted, the quality was evaluated, and then Meta-analysis was performed using Review Manager 5.2 and Comprehensive Meta-Analysis V2.

Results A total of nine articles involving 5 374 participants were included. The results of Meta-analysis showed that, more than adequate or excess iodine intake(≥300 μg/day) or high consumption of saltwater fish(≥3 times/week or 12 times/month) could decrease the thyroid cancer risk (OR=0.74, 95%CI: 0.60-0.92, P<0.05; OR=0.69, 95%CI: 0.53-0.90, P<0.05). The investigation didn’t show significant relationship between shellfish and thyroid carcinoma risk.

Conclusion Adequately higher intake of dietary iodine (≥300 μg/day) or high consumption of saltwater fish could decrease the thyroid cancer risk and be considered as a protective factor for thyroid cancer.