Selected antidepressants may be bad for bones in older women

Use of antidepressants in older women has been linked to cortical bone and physical function deterioration, effects that are specific to selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs), a study has found.

Researchers compared the musculoskeletal health in current female antidepressant users and nonusers from a population-based multi-ethnic (35.6 percent black, 22.3 percent white, and 42.1 percent mixed) cohort study of 195 older adults (mean age, 76.3 years).

Among antidepressant users, 35.7 percent were on SSRIs, 17.9 percent were on SNRIs, and 46.4 percent were taking other drugs of other classes. Compared with nonusers, users were more likely to be white than nonwhite (odds ratio [OR], 1.9, 95 percent confidence interval [CI], 1.2–2.9). There were no differences seen in age, weight, body mass index, physical activity, calcium/vitamin D intake, falls, and self-rated health.

Pelvic fractures were more prevalent among users (7.1 percent vs 0 percent; p=0.04), although they were limited to the SSRI and SNRI groups (p=0.06). Age- and weight-adjusted T-score by dual x-ray absorptiometry (DXA) was lower in users at the 1/3-radius (mean, −1.6 vs −1.0; p=0.04) site only. No differences were observed in trabecular bone score, vertebral fractures, and fat/lean mass.

Compared with nonusers, users had 13.3-percent lower grip strength (p=0.04) and 4.8-percent lower cortical volumetric bone mass density at the 4-percent radius site (p=0.007). A similar cortical pattern was seen at the proximal (30 percent) tibia.

When assessed by antidepressant class, deteriorated cortical microstructure was present at the radius only among SSRI users and at the proximal tibia only among SNRI users.

The findings offer insight into the mechanism by which antidepressants may contribute to the increased fracture risk in older women, the researchers said.