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

Abstract

Activity rhythms disturbances and depression often co-occur among older adults. However, little is known about how activity rhythm disturbances themselves co-occur, or how disturbances to multiple aspects of the activity rhythm relate to depression over time. In the current study, we performed a Latent Class Analysis to derive sub-groups of older men (total n=2933, mean age=76.28, SD=5.48) who shared similar patterns of activity rhythm disturbances (defined as extreme values of modeled activity rhythm parameters). We found eight sub-groups with distinct combinations of activity rhythm disturbances: one had all normative activity rhythm parameters (32.09%), one had only lower activity (10.06%), three had earlier activity (totaling 26.96%), and three had later activity (totaling 30.89%). Groups with similar timing were distinguished depending on whether the relative length of the active period was shorter and/or if the activity rhythm had lesser amplitude/robustness. We next examined whether the derived activity rhythm sub-groups were associated with different rates of change in depression symptom levels over an average of 5.5 (0.52 SD) follow-up years. The sub-group with lower activity only had faster increases in depressive symptoms over time (compared to the group with normative rhythm parameters), but this association was accounted for by adjustments for concurrently assessed health status covariates. Independent of these covariates, we found four activity rhythm disturbance sub-groups that experienced faster depressive symptom increases (compared with the normative sub-group): These included all three sub-groups that had later activity timing, and one sub-group that had earlier activity timing plus a shorter active period and a dampened rhythm. Low activity rhythm height/robustness with normal timing therefore may mark depression risk that is attributable to co-occurring disease processes; in contrast, having late or combined early/compressed/dampened activity rhythms may independently contribute to depression symptom development. Our findings suggest that activity rhythm related depression risk is heterogeneous, and may be detected when multiple aspects of rhythm timing are delayed or when early timing is accompanied by compressed/dampened activity rhythms. Future studies should consider how distinct combinations of altered activity rhythm timing and height/robustness develop and conjointly determine health risks. Future research is also needed to determine whether/how activity rhythms can be modified to improve depression outcomes.

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

“…Initially (7), we only found depression risk associated with a measure of rhythm robustness or regularity (the pseudo F-statistic). But our later work (11) revealed that low pseudo F-statistics tended to only be found when overall activity was also low, and that this occurred in diverse groups – those with earlier, normative, and later timing.…”

“…Only limited research has investigated whether RARs are prospectively associated with the development of depression symptoms (7, 11). Initial findings indicate that different combinations of RAR characteristics (or RAR profiles) may increase depression risk.…”

“…Following-up in the same cohort of older men (11), we next used a data-driven approach to investigate whether RAR disturbances tended to cluster within people. This identified sub-groups who shared similar RAR characteristics.…”

“…These groups experienced faster increases in depression symptoms compared with (A), and this was only attenuated by adjustment for health covariates in the case of group C. MrOS Sleep was supported by R01 HL071194, R01 HL070848, R01 HL070847, R01 HL070842, R01 HL070841, R01 HL070837, R01 HL070838, and R01 HL070839. A version of this figure was previously published in (11). …”

24-h Activity Rhythms and Health in Older Adults

“…A recent UK Biobank study suggested a lower relative amplitude in those with a retrospectively determined lifetime incidence of major depressive disorder, bipolar disorder, and mood instability [21•]. A longitudinal study in elderly men reported that both a late acrophase alone and the combination of an early acrophase with a dampened 24-h activity rhythm amplitude were associated with a faster increase in depressive symptoms over time [56]. Additionally, a genome-wide association study (GWAS) including 71,500 participants reported a possible association between genetic risk of a low relative amplitude and mood disorders [45•].…”