Are higher antidepressant plasma concentrations associated with fall risk in older antidepressant users?

PURPOSE

Antidepressants are well-established fall-risk increasing drugs (FRIDs) and therefore falls should be considered an important adverse drug event (ADE) of antidepressants. However, not all antidepressant users experience fall incidents and factors associated with increased fall risk among antidepressant users are incompletely understood. Our objective was to explore whether antidepressant plasma concentrations are associated with falls in older antidepressant users.

METHODS

For this study, we included antidepressant users of the multicenter B-PROOF study. Fall incidents were recorded prospectively using fall calendars. Antidepressant plasma concentrations were analyzed by Liquid chromatography-mass spectrometry (LC-MS) at baseline and at 2 years follow-up. The associations between the observed antidepressant concentration and fall risk were assessed using Cox proportional hazard and logistic regression models and adjusted for potential confounders.

RESULTS

In total 93 selective serotonin reuptake inhibitor (SSRI) and 41 antidepressant (TCA) users were identified. There was a significant association between baseline TCA plasma concentration and fall risk within users (HR 2.50, 95% CI 1.07-5.87, crude model). In the adjusted model, there were no significant associations between concentrations of SSRIs and fall risk.

CONCLUSION

There might be an association between plasma concentrations of TCAs and the risk of falling in older users. However, these results needs to be interpreted with caution considering the small sample size and accompanying limitation of confinement to crude analyses. Therefore, these novel findings need to replicated in a larger cohort, preferably including adjustment for potential confounders and more frequent measures of plasma concentrations is needed.

BMI and Body Fat Mass Is Inversely Associated with Vitamin D Levels in Older Individuals

OBJECTIVE

To assess the association between obesity (measured by Body Mass Index (BMI) and fat percentage) and serum 25(OH)D levels in older persons.

DESIGN

Cross-sectional analysis of data from 'the B-PROOF study' (B-vitamins for the Prevention Of Osteoporotic Fractures).

PARTICIPANTS

2842 participants aged 65 years and older.

MEASUREMENTS

BMI and fat percentage, measured by Dual Energy X-ray, and serum 25(OH)D levels.

RESULTS

Mean age was 74 years (6.5 SD), with 50% women. Mean serum 25(OH)D levels were 55.8 nmol/L (25 SD). BMI and total body fat percentage were significant inversely associated with serum 25(OH)D levels after adjustment for confouders (β-0.93; 95% CI [-1.15; -0.71], p<0.001 and β-0.84; 95% CI [-1.04; -0.64], p<0.001). This association was most prominent in individuals with a BMI in the 'overweight' and 'obesity' range (β -1.25 and -0.96 respectively) and fat percentage in the last two upper quartiles (β-1.86 and -1.37 respectively).

CONCLUSION

In this study, higher BMI and higher body fat percentage were significantly associated with lower serum 25(OH)D levels in older persons. This association was particularly present in individuals with overweight, and higher fat percentages, suggesting that these persons are at increased risk of vitamin D insufficiency.