Study type: Epidemiological study (observational study)

Increasing incidence of thyroid cancer in the Nordic countries with main focus on Swedish data. epidem.

Published in: BMC Cancer 2016; 16: 426

Aim of study (acc. to author)

Time trends of the incidence rates of thyroid cancer were investigated in Sweden and all Nordic countries between 1970 and 2013.

Further details

Thyroid cancer is a relatively rare cancer (about 3 cases per 100,000 persons per year). The only well-established risk factor is ionizing radiation (e.g., radiotherapy, diagnostic X-ray investigation such as computer tomography, radioactive fallout from atomic weapons and nuclear power plant disasters).

Endpoint/type of risk estimation

Type of risk estimation: (standardized incidence rate (SIR))




Statistical analysis method:

Conclusion (acc. to author)

In Sweden, the incidence of thyroid cancer increased during the whole study period 1970 - 2013 in both women and men, although statistically significant only in women. In both genders the incidence significantly increased during the more recent study period, from 2001 in women and from 2005 in men.
In all Nordic countries, a statistically significant increase in the incidence of thyroid cancer was observed during the whole study period 1970 - 2013. The incidence significantly increased from 2006 for both for women and men.
The authors postulate that the whole increase of increase of thyroid cancer cannot be attributed to better diagnostic procedures. Increasing exposure to ionizing radiation (e.g. computed tomography) and to non-ionizing radiofrequency radiation should be further studied.

Limitations (acc. to author)

The study design does not permit conclusions regarding causality.

Study funded by

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