Abstract
Objective: The role of smoking in the pathogenesis of thyroid enlargement is currently under debate. The aim of this paper was to investigate the association of smoking with thyroid volume progression and incident goiter for different age-strata in a region with improved iodine supply.
Methods: The population-based Study of Health in Pomerania (SHIP) compromised 3300 subjects with complete 5-year examination follow-up. Data from 2484 participants without known thyroid disorder and thyroid medication were analyzed. Goiter was assessed by thyroid ultrasound. Determinants of thyroid volume progression and incident goiter were analyzed by linear and logistic regression, respectively.
Results: Participants aged 20 to 39 years who were current smokers at baseline and at follow-up had a lower risk of incident goiter (odds ratio: 0.35; 95%; confidence interval: 0.16; 0.76; p=0.008). In this subpopulation age was inversely related to thyroid volume progression. In subjects aged 60 to 79 years smoking at baseline and follow-up was a risk factor for thyroid volume progression (β: 3.40; 95% confidence interval: 0.88; 5.93; p=0.008). After exclusion of individuals who had goiter at baseline this association disappeared.
Conclusion: We conclude that the improvement of iodine supply in this region has led to a decreased impact of smoking on thyroid volume change and incident goiter.