People who have hyperthyroidism are more likely to take sick leave for extended periods than their healthy colleagues, particularly in the first year after diagnosis, according to a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
Hyperthyroidism occurs when the thyroid gland is overactive. The thyroid, which is located in the front of the neck, secretes hormones that regulate how the body uses energy, consumes oxygen and produces heat.
The most common cause of hyperthyroidism is Graves' disease, an autoimmune condition where the immune system produces antibodies that attack the thyroid gland. Graves' disease can be accompanied by eye complications or swelling of the thyroid gland known as a goiter.
"When we examined sick leave records, our research found patients with hyperthyroidism faced a significantly higher risk of missing work for three weeks or longer due to illness compared to healthy controls," said one of the study's authors, Mette Andersen Nexø, MA, of the National Research Centre for the Working Environment and the University of Copenhagen in Copenhagen, Denmark. "People who experienced eye complications from Graves' disease were the most likely to require extended sick leave. This same population also was the most likely to leave the workforce altogether and retire on a disability pension."
The longitudinal register study is the largest systematic assessment of the effect of thyroid conditions on the workplace conducted to date, Nexø said. Researchers analyzed sick leave and disability pension claims among 862 Danes who were treated in one of two university outpatient clinics in 2007 for a thyroid condition. The study authors then compared claim rates in this population to a group of 7,043 controls using national and municipal records from 1994 to 2011. In Denmark, people who miss work for more than three weeks due to illness are compensated by local municipalities, so the researchers were able to track when subjects missed work for an extended period due to illness.
The analysis revealed that Graves' disease patients with eye complications were seven times more likely than healthy peers to have an extended sick leave from work within a year of diagnosis. In subsequent years, the risk diminished but remained twice as high compared to healthy peers. This population was more than four times as likely to retire on a disability pension compared to healthy controls.
People with hyperthyroidism without eye complications also faced a heightened risk of taking an extended sick leave. They were twice as likely as peers to miss weeks of work due to illness within a year of diagnosis.
The study also examined records for people with hypothyroidism, or an underactive thyroid. While the risk of taking sick leave was not significantly affected, people with hypothyroidism faced longer recovery than healthy peers if they had to take sick leave in the first year after diagnosis. In subsequent years, the researchers did not find significant indication that the hypothyroidism affected workplace absenteeism.
"The findings demonstrate the potential socioeconomic effects thyroid conditions can have, but also indicate that socioeconomic effects diminish once the disorders are treated," Nexø said. "It's important not only for patients, but for employers and society as a whole, to ensure that people who have thyroid conditions receive the medical care they need."