For a study, researchers sought to identify older adult subgroups with comparable 24-hour activity rhythm traits and to describe the depressive symptoms and cognitive function that go along with them.

The National Health and Nutrition Examination and Survey (NHANES) accelerometer research was analyzed cross-sectionally from January to March 2022. Using a multistage probability sample, the NHANES attempted to reflect US noninstitutionalized adults using a multistage probability sample. Participants 65 years of age and older who had accelerometer and depression measurements weighted to approximately 32 million older individuals were included in the main analysis. Using extended-cosine and nonparametric techniques, latent profile analysis discovered groupings with related 24-hour activity pattern features. Covariate-adjusted sample-weighted regressions evaluated the relationships between subgroup membership and depression symptoms, as measured by 9-Item Patient Health Questionnaire (PHQ-9) scores of 10 or higher, and having at least psychometric mild cognitive impairment (p-MCI), as measured by scores that were less than 1 SD below the mean on a composite cognitive performance score.

In fact, there were 1,800 participants in the clustering study (weighted: mean [SD] age, 72.9 [7.3] years; 57% of them were female). Cluster analysis revealed four subgroups: 677 earlier rising/robust (37.6%), 587 shorter active period/less modelable (32.6%), 177 shorter active period/very weak (9.8%), & 359 later settling/very weak (20.0%). There were significant differences in the proportion of groups that had PHQ-9 scores of 10 or above (cluster 1, 3.5%; cluster 2, 4.7%; cluster 3, 7.5%; cluster 4, 9.0%; χ2 P =.004). In addition, different groups had statistically different rates of having at least p-MCI (cluster 1, 7.2%; cluster 2, 12.0%; cluster 3, 21.0%; and cluster 4, 18.0%; χ2 P< .001). Five out of 9 symptoms of depression varied substantially between subgroups.

According to the cross-sectional study results, 1 in 5 older persons living in the US may fall into a grouping with poor activity patterns and later settling, and 1 in 10 may fall into a subgroup with weak patterns and shorter active duration. Future studies were required to examine the biological mechanisms behind these behavioral traits, including the reasons why earlier and more robust activity patterns are protective and if restoring interrupted patterns leads to better results.