"We see a lot of patients who have depression and are on antidepressants," explains Maria Lapid, M.D., a Mayo Clinic geriatric psychiatrist. "Often they undergo pharmacogenetic testing to guide selection of medications."
One part of pharmacogenetic testing looks at the serotonin transporter gene, which has long and short versions. The long version is considered normal. The short version is linked with depression and anxiety. The researchers combined this test result for the long/short version of the gene with data on bone mineral density. This information, in the form of a DEXA scan, is collected if there are concerns about a patient's bone health in general.
The authors wondered if patients with the short version would report lower bone density scores. What they found was a bit more complex.
"It was actually the group of women less than 50 years of age who had lower bone mineral density," said Dr. Lapid.
The result was surprising, say the authors, because bone loss tends to be a problem among older women, after menopause, and not in younger women.
“This study adds to the pool of research examining long-term effects of depression and antidepressants,” says Sundeep Khosla, M.D., director of Mayo Clinic's Center for Clinical and Translational Science, which provided support for the study. “Dr. Lapid and colleagues are developing new approaches to potentially better identify patients with depression at risk for osteoporosis and, in the future, perhaps help minimize the adverse effects of anti-depressant drugs on bone.”
The study included 3016 patients who had undergone pharmacogenetics testing between 2003 and 2013. Of those, 239 had at least one bone mineral density assessment (either for hip or spine). The subjects were primarily white, female and 52 years of age on average. Among the group, 51 percent had one long (normal) and one short version, 34 percent had two long versions, and 15 percent had two short versions. The findings, Dr. Lapid explains, point to the complexity of the systems that affect bone mineral density.
"Antidepressants, especially if used long-term, are linked with bone loss, but depression by itself is too," says Dr. Lapid. "This research suggests that it's not enough to just focus on mental health. It is also important to physicians to pay attention to general bone health."