Hyperthyroidism more severe in younger adults with Graves’ disease
Younger adults with Graves’ disease have more severe hyperthyroidism than older adults, and men are less likely to have disease remission compared with women, according to a study published in Thyroid.
“As we found that there are age and gender differences between severity and prognosis of Graves’ disease, we should consider the character of each patient when we choose the treatment method,” Nami Suzuki, MD, of the department of internal medicine at Ito Hospital in Shibuya, Japan, told Healio. “In addition, it was shown in our study that smoking habit was significantly related to low remission rate, so it is important to encourage patients to quit smoking for better prognosis in disease.”
Suzuki and colleagues conducted a retrospective study of 21,633 patients with newly diagnosed Graves’ disease seen at Ito Hospital in Japan from January 2005 to June 2019 (81.7% female). Researchers analyzed seven groups of participants by age: 10 to 19 years, 20 to 29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, 60 to 69 years and 70 to 79 years. Laboratory data were collected through medical records.
Researchers also conducted a prognostic analysis of 2,191 people who had newly diagnosed Graves’ disease in 2009 or 2010, were followed for at least 12 months and were treated with antithyroid drug therapy. Remission of Graves’ disease was defined as remaining euthyroid for 1 year after drug therapy withdrawal, and recurrence of Graves’ disease was defined as a new diagnosis in patients who had previously met remission criteria.
Higher free T3 and free T4 in younger adults
Of the 21,633 participants, 20,816 were positive for thyroid receptor antibodies and the remaining 817 were negative. The largest age group was adults aged 30 to 39 years. There was no significant difference in the prevalence of Graves’ disease between premenopausal and postmenopausal women.
In the study cohort, initial free triiodothyronine and free thyroxine levels declined with age. Median thyroid receptor antibodies also decreased between all groups except for those aged 30 to 39 years and 40 to 49 years, and those aged 60 to 69 years and 70 to 79 years.
For women, median free T3 and free T4 levels declined with older age in all age groups. For men, median free T3 and free T4 also declined with age, but no significant differences were observed between some age groups. Median thyroid receptor antibodies declined with older age for both men and women, although some age groups in both sexes did not have significant differences. Median thyroid volume significantly decreased with older age in men 50 years or older, but not in younger men. Thyroid volume was not significantly different between age groups in women.
Women more likely to have remission
Of the 2,191 people included in the prognostic analysis, 1,391 had Graves’ disease remission. Of those who achieved remission, 262 had a recurrence of Graves’ disease. Median time to remission was shorter among those who had recurrence of Graves’ disease vs. adults without recurrence (28.9 months vs. 32 months; P = .003).
Graves’ disease remission was more likely for women vs. men (adjusted HR = 1.41; 95% CI, 1.21-1.64), for nonsmokers vs. smokers (aHR = 1.58; 95% CI, 1.38-1.81) and for those with lower initial thyroid receptor antibodies vs. higher levels per each 1 U increase. (aHR = 0.98; 95% CI, 0.97-0.98). Each 10-year increase in age was associated with a lower likelihood of recurrence (aHR = 0.86; 95% CI, 0.78-0.94), and lower initial thyroid receptor antibody levels were associated with a high risk for recurrence per each 1 U increase (aHR = 0.97; 95% CI, 0.95-0.98).
“Considering the results, I suggest that definitive therapies — surgery or radioactive iodine therapy — should be considered for young male patients at early stage of the disease,” Suzuki said.
Suzuki said a larger study involving people with other ethnicities is needed. She also said genetic polymorphism should be considered in future research.
For more information:
Nami Suzuki, MD, can be reached at email@example.com.