Circadian Rest–Activity Rhythms Predict Future Increases in Depressive Symptoms Among Community-Dwelling Older Men

Abstract

Objectives Circadian rest-activity rhythms (CARs) have been cross-sectionally associated with depressive symptoms, however no longitudinal research has examined whether CARs are a risk factor for developing depressive symptoms. Methods We examined associations of CARs (measured with actigraphy over a mean of 4.8 days) with depressive symptoms (measured with the Geriatric Depression Scale) among 2892 community-dwelling older men (mean age: 76.2 +/− 5.5) from the MrOS Sleep Study who were without cognitive impairment. Among 2124 men with minimal (0–2) symptoms at baseline, we assessed associations between CAR parameters and increases to mild (3–5) or clinically significant (≥6) symptoms after an average of 1.2 (+/− 0.32) years later. Results Cross-sectional associations between rhythm height parameters were independent of chronic diseases, lifestyle, sleep, and self-reported physical activity covariates. For example, men in the lowest mesor quartile had 2 times the adjusted odds (Adjusted Odds Ratio (AOR)=2.04, 95% CI 1.36–3.04, p=0.0005) of having prevalent clinically significant symptoms (compared to minimal). Longitudinally, low CAR robustness (being in the lowest quartile of the pseudo-F statistic) was independently associated with increasing odds of developing symptoms (i.e. AOR for having clinically significant depressive symptoms at follow-up=2.58, 95% CI 1.11–5.99, p=0.03). Conclusion CAR disturbances are indicative of depressive symptomology. Low CAR robustness may independently contribute to the risk of worsening depression symptomology.

Latent activity rhythm disturbance sub-groups and longitudinal change in depression symptoms among older men

“…Note that this finding is consistent with our prior study which found that an association between low rhythm amplitude and future depression was accounted for by concurrent health status covariates (Smagula, Ancoli-Israel et al, 2014b). The present work also found that all three sub-groups with indication of more delayed activity rhythms experienced significantly faster increases in depressive symptoms over time, independent of including chronic diseases, night-time sleep characteristics, and self-reported physical activity; when later activity timing was accompanied by either a compressed active period or low activity levels, depressive symptom increases appeared somewhat faster (compared with having later activity timing alone).…”

“…For timing parameters, the lowest and the highest quartiles were both compared with the others (in a single variable) to represent both phase advances and delays. Using quartiles to represent non-normative or disturbed activity rhythm parameters is consistent with prior work (Paudel, Taylor et al, 2010; Tranah, Blackwell et al, 2010; Tranah, Blackwell et al, 2011; Smagula, Ancoli-Israel et al, 2014b) and, in the context of LCA, is designed to identify subgroups with specific patterns of activity rhythm parameters outside the normative range (disturbances).…”

“…The current study has several key advantages over our prior investigation (Smagula, Ancoli-Israel et al, 2014b), which was limited to a short term follow-up (an average of 1.2 years), and only examined activity rhythm disturbances separately. In our prior investigation, rhythm robustness (measured with the pseudo-F statistics) was the only activity rhythm parameter that independently predicted depressive symptom increases.…”

“…To our knowledge, only one study to date has examined the longitudinal relationship between activity rhythms and future depression risk (Smagula, Ancoli-Israel et al, 2014b). This prior study was limited by a relatively short follow-up period (an average of 1.2 years) and by investigating activity rhythm characteristics separately.…”

Opportunities for clinical applications of rest-activity rhythms in detecting and preventing mood disorders

“…Standardized amplitude and having a later-up mesor were also associated with depression symptoms, but these associations were attenuated by adjustments for covariates. Consistent with these findings, my colleagues and I recently found that community-dwelling older men with low standardized amplitude (indicating a dampened RAR) were more likely to have prevalent depression symptoms, but that this association was completely attenuated after adjusting for concurrent health status measures (7). Later RAR timing (up-mesor and acrophase) was also associated with the presence of depression symptoms, but again, these associations could be explained by adjustments for health status covariates.…”