What is the clinical evidence from this study?

Study design: Cohort. Population: Thyroid cancer (n=99742). Intervention: Sustained smoking vs. Consistent non-smoking. Primary outcome: Incident cardiovascular disease (myocardial infarction or stroke) (HR 1.90, 95% CI 1.42-2.54, p=<0.05).

What question did this study set out to answer?

This study aims to understand how health behaviors influence cardiovascular risk among thyroid cancer survivors with different metastatic statuses.

June 18, 2026Open Access

Impact of Health Behaviors on Cardiovascular Risk in Thyroid Cancer Survivors according to Metastasis: A Nationwide Cohort Study

Q: What are the key findings of this study?

Sustained smoking significantly increased the risk of cardiovascular disease (HR 1.90) compared to consistent non-smoking among thyroid cancer survivors.

Q: What question did this study set out to answer?

This study aims to understand how health behaviors influence cardiovascular risk among thyroid cancer survivors with different metastatic statuses.

JLJeongmin LeeKyungpook National University JLJaekyung LeeSeoul St. Mary's Hospital JPJoonseon ParkSeoul St. Mary's Hospital

Key Result

Sustained smoking significantly increased the risk of cardiovascular disease (HR 1.90) compared to consistent non-smoking among thyroid cancer survivors.

Key Points

This study aims to understand how health behaviors influence cardiovascular risk among thyroid cancer survivors with different metastatic statuses.
Nationwide cohort study using data from Korean National Health Insurance Service claims and Cancer Clinical Library Database.
Analyzed 99,742 thyroid cancer survivors over a mean follow-up of 5.7 years.
Examined associations between lifestyle changes (smoking, activity) and cardiovascular disease risk by metastasis status.
Current smoking increased cardiovascular disease risk in no metastasis (HR, 1.77; 95% CI, 1.33 to 2.35) and local metastasis groups (HR, 1.30; 95% CI, 1.00 to 1.68).
Regular physical activity reduced cardiovascular disease risk in the no metastasis group (HR, 0.84; 95% CI, 0.79 to 0.96).
Sustained smoking heightened cardiovascular disease risk in no metastasis (HR, 1.95; 95% CI, 1.31 to 2.90) and local metastasis groups (HR, 1.88; 95% CI, 1.28 to 2.77).

Study Design

Type

Cohort (n=99,742)

Multicenter

Yes

Structured PICO

Do health behaviors such as smoking and physical activity affect cardiovascular disease risk in thyroid cancer survivors according to metastasis status?

Population

99,742 adult thyroid cancer survivors aged 30 years or older, free of prior cardiovascular disease, followed for a mean of 5.7 years.

Exposure

Health behaviors (smoking, physical activity, alcohol consumption)

Comparator

Absence of these behaviors (e.g., non-smoking, physical inactivity)

Outcome

Cardiovascular disease (CVD) risk over a mean follow-up of 5.7 yearscomposite

In thyroid cancer survivors, sustained smoking increases and regular physical activity decreases cardiovascular disease risk, particularly in those without distant metastasis.

Main Result

Hazard Ratio: 1.9 (95% CI 1.42–2.54)

p-value: p=<0.05

Limitations

Observational design cannot establish causality and reverse causality is possible.
Self-reported questionnaires for lifestyle behaviors may introduce recall bias or misclassification.
Dynamic behavior changes were assessed using only two or three time points, limiting granularity.
Potential residual confounding from unmeasured variables such as dietary patterns, psychosocial stress, or genetic predispositions.
Lack of dose-response data for radioactive iodine therapy and levothyroxine use.
Analyses were restricted to a thyroid cancer survivorship cohort without a direct comparison to the general population.

Abstract

Background: Patients with thyroid cancer receive thyroid-stimulating hormone suppressive therapy and radioactive iodine therapy, which can alter metabolism and affect the association between lifestyle factors and cardiovascular disease (CVD) outcomes. However, it remains unclear how changes in lifestyle relate to CVD risk, particularly according to metastatic status. We investigated the impact of baseline and changing lifestyle behaviors on CVD risk among thyroid cancer patients by metastasis status. Methods: This study was a nationwide cohort study using data from the Korean National Health Insurance Service claims database with the Cancer Clinical Library Database from the Korea Clinical Data Utilization Network for Research Excellence project. Over a mean follow-up of 5.7 years, 99,742 thyroid cancer patients were analyzed. Results: Current smoking increased CVD risk in both no metastasis (NM) group (hazard ratio HR, 1.77; 95% confidence interval CI, 1.33 to 2.35) and the local metastasis (LM) group (HR, 1.30; 95% CI, 1.00 to 1.68), but not in those with distant metastasis. Regular activity reduced the risk in the NM group (HR, 0.84; 95% CI, 0.79 to 0.96). Alcohol consumption was not significantly associated with the CVD risk. Sustained smoking showed an increased CVD risk in both NM (HR, 1.95; 95% CI, 1.31 to 2.90) and LM (HR, 1.88; 95% CI, 1.28 to 2.77). Sustained regular physical activity was associated with a lower risk of CVD only in NM (HR, 0.68; 95% CI, 0.53 to 0.87). Conclusion: Sustained smoking increased CVD risk, while regular physical activity was associated with a lower risk of CVD, particularly in those without distant metastasis.

KI fragen

Bookmark

View Full Paper