Rest-activity rhythms are stronger in Mexican American compared to non-Hispanic White and Black participants: a...

This study aimed to investigate differences in rest-activity rhythms (RAR), key circadian rhythm markers, across race/ethnicity and sex in a diverse community-based cohort of older adults.

We examined RAR (amplitude [strength of activity], mesor [level of activity], acrophase [time of peak activity], and pseudo-F [robustness of activity]) derived from the extended cosinor model based on ≥4 24-hour periods of wrist actigraphy among 756 participants (≥50 years) in the Dormir Study. We conducted linear and multinomial logistic regression models adjusted for socioeconomic status, health conditions, and sleep-related factors.

We studied 218 (28.8%) Black, 221 (29.2%) Mexican American (MA), and 317 (42.0%) non-Hispanic White (NHW) participants, with a mean age of 66.3 ± 8.4 years, and 66.8% women. Compared to NHW adults, MA participants exhibited healthier RAR, with lower odds of being in the lowest tertile for amplitude and mesor, and higher odds of being in the later tertile for acrophase. Black participants had lower odds of being in the earlier tertile for acrophase. Overall, women had better RAR values than men, with lower odds of being in the lowest tertile for amplitude and mesor, and higher odds of being in the later tertile for acrophase. Among subgroups, MA women exhibited the strongest RAR, while NHW men displayed the weakest patterns.

RAR vary by race/ethnicity and sex, with MA participants and women exhibiting stronger rhythms. Further research is needed to understand if these different RAR patterns translate to other health outcomes and the mechanism underlying these differences. Statement of Significance Poor rest-activity rhythms (RAR) are linked to adverse health outcomes. Despite known sociodemographic disparities in many health factors, differences in RAR among diverse populations remain understudied. We investigated RAR pattern differences across race/ethnicity and sex in a diverse community-based cohort of older adults. Mexican American participants and women exhibited stronger rhythms, with notably higher amplitude and mesor values than non-Hispanic White and Black participants and men, independently of socioeconomic, health, and sleep-related factors. Further research is needed to understand if these different RAR patterns translate to other health outcomes and the mechanism underlying these differences.