Adherence to a Mediterranean diet and leisure-time physical activity are associated with reduced initiation of antidepressant, anxiolytic, antipsychotic and antiseizure drug use in older adults: a cohort study

Background: We explored how adherence to the Mediterranean diet (MedDiet) and leisure-time physical activity (LTPA) impact psychoactive medication use in older adults. Methods: We assessed the cumulative MedDiet adherence and LTPA’s impact on mental health medication initiation in older individuals at high risk of chronic disease. Associations between the cumulative average of MedDiet adherence (per one-point increase in the adherence score) and LTPA (per increase in 20 metabolic equivalents of task-minute/day [METs-min/day]) with drug initiation were assessed by multivariable Cox regressions. We explored non-linear exposure-outcome associations using smoothed cubic splines and the multiplicative interaction between MedDiet and LTPA. Results: A total of 5940–6896 participants (mean age 67, 58% women) over 4.2–4.7 years, each point increase in MedDiet adherence decreased the initiation of antidepressants by 23–28% (HR 0.72, 95% CI 0.67–0.77), anxiolytics (HR 0.75, 0.70–0.81), antipsychotics (HR 0.77, 0.65–0.91), and antiseizures (HR 0.77, 0.69–0.85). Associations for anxiolytics and antiseizures were strong at low MedDiet adherence levels. Relationships between LTPA and initiation of antidepressants and anxiolytics were linear in the lowest LTPA values (0–150 METs-min/day); every 20 METs-min/day increases were associated with 20% lower risk of initiating antidepressants (HR 0.80, 0.75–0.86) and 15% less risk in anxiolytics (HR 0.85, 0.79–0.90). Association with antiseizures was linear (+20 METs-min/day: HR 0.96, 0.94–0.99), and no associations were found for antipsychotics. High MedDiet adherence (≥10) and LTPA (≥150 METs-min/day) reduced psychoactive drug initiation by 42%–59%. Combination was additive for antidepressants, antipsychotics and antiseizures and synergistic for anxiolytics. Conclusions: MedDiet and LTPA adherence reduced psychoactive drugs initiation in older adults.