Baseline population characteristics.

**P<0.0001, NS = not significant, GP = general practitioner, CCI = Charlson Comorbidity Index. Data shown are mean (standard deviation) values, except for percentages. Differences in continuous variables between the group with elevated and decreased serum TSH, respectively, and the group with normal TSH values were tested with independent sample t-tests, whereas differences between categorical variables were tested with chi2-tests. Baseline population characteristics.