Behavioral-social rhythms and cardiovascular disease risk in retired night shift workers and retired day workers

OBJECTIVE

Stability in the timing of key daily routine behaviors such as working/doing housework, sleeping, eating, and engaging in social interactions (i.e., behavioral-social rhythms) contributes to health. This study examined whether behavioral-social rhythms were associated with CVD risk factors in retired night shift workers and retired day workers and explored whether past night shift work exposure moderated this association.

METHODS

154 retired older adults participated in this study. Multiple logistic regression models were used to examine associations between behavioral-social rhythms and CVD risk factors. Independent variables included Social Rhythm Metric (SRM)-5 score and actigraphy rest-activity rhythm intra-daily variability (IV) and inter-daily stability (IS). Dependent variables were metabolic syndrome prevalence and its five individual components.

RESULTS

More regular behavioral-social rhythms were associated with lower odds of prevalent metabolic syndrome (SRM: OR = 0.57, 95% CI [0.35, 0.88]; IV: OR = 4.00, 95% CI [1.86, 8.58]; IS: OR = 0.42, 95% CI [0.24, 0.73]) and two of its individual components: body mass index (SRM: OR = 0.56, 95% CI [0.37, 0.85]; IV: OR = 2.84, 95% CI [1.59, 5.07]; IS: OR = 0.42, 95% CI [0.26, 0.68]) and high-density lipoprotein cholesterol (SRM: OR = 0.49, 95% CI [0.30, 0.80]; IV: OR = 2.49, 95% CI [1.25, 4.96]; IS: OR = 0.35, 95% CI [0.19, 0.66]). Past shift work history did not moderate the association between behavioral-social rhythms and metabolic syndrome.

CONCLUSIONS

Behavioral-social rhythms were related to CVD risk factors in retired adults regardless of prior night shift work exposure. Older retired workers may benefit from education and interventions aiming to increase behavioral-social rhythm regularity.

Co-sleeping with pets, stress, and sleep in a nationally-representative sample of United States adults

This cross-sectional study tested the direct and stress-buffering effects of co-sleeping with pets on human sleep characteristics in a nationally-representative sample of United States adults. Participants completed questionnaires assessing their sleep characteristics, including perceived sleep quality, perceived sleep efficiency, insomnia severity, and multidimensional sleep health. We evaluated whether co-sleeping with pets was associated with sleep characteristics and whether co-sleeping with pets moderated the association of stress and sleep characteristics. Exploratory analyses examined whether sleep characteristics were impacted by number of pets, pet type, and bondedness to pets. Our final sample of 1591 participants (Mage = 46.4 years, SD = 17.5; 56% female; 76% White) included 758 participants who reported co-sleeping with pets (47.6%). Co-sleeping with pets was associated with poorer sleep characteristics-specifically, poorer perceived sleep quality and greater insomnia severity. Although higher levels of stress were associated with poorer sleep, we did not observe evidence for a stress-buffering effect of co-sleeping with pets. Exploratory analyses indicated that the negative impact of co-sleeping with pets on human sleep was associated with dog ownership but not cat ownership, more pronounced when individuals own a greater number of pets, and not impacted by bondedness to pets. Our findings contribute to emerging evidence for the impact of co-sleeping with pets on human sleep. Study was pre-registered at: https://aspredicted.org/3VN_WF6 .

Mechanisms Linking Attachment Orientation to Sleep Quality in Married Couples

There is emerging evidence for links between relationship factors and sleep quality. Existing research linking attachment orientation to sleep quality has yielded inconsistent effects, has focused on younger samples, and has not considered underlying mechanisms of action. This research addressed these gaps in two studies that investigated the links between attachment orientation and sleep quality in both younger/middle-aged (Study 1) and older (Study 2) adult couples using Actor-Partner Interdependence Models. We also tested mediating effects of relationship-specific security and negative affect. In both studies, participants completed surveys assessing their attachment orientation, sleep quality, and the proposed mediators. Both studies revealed that relationship-specific security and negative affect mediated the negative association between insecure attachment and one's own sleep quality. This research enhances our understanding of how attachment orientation affects sleep quality, provides a foundation for future research on relationship influences on sleep, and suggests avenues for improving sleep quality.

Attachment Orientation and Preferences for Partners' Emotional Responses in Stressful and Positive Situations

Attachment theory proposes that close relationships help us to regulate our emotions in stressful and positive situations. However, no previous studies have examined preferences for a partner's emotional response to one's own stressful and positive situations or tested whether these preferences differ based on attachment orientation. This study examines the association of attachment orientation and preferences for partners' emotional responses relative to one's own emotional responses in stressful and positive contexts among 425 United States adults who were currently in a committed relationship of ≥6 months. Data were collected in 2020. Overall, participants preferred their partners to feel and express less distress, less worry, more calm, and more hope than themselves during stressful situations and for their partners to feel and express more excitement, pride, and hope than themselves during positive situations. Higher attachment anxiety predicted preferences for partners to feel and express more distress/worry in stressful situations, whereas higher attachment avoidance predicted preferences for partners to feel and express less hope in stressful situations. Statistical interactions of attachment anxiety × attachment avoidance indicated that the combination of low attachment anxiety and high attachment avoidance (dismissing avoidance) was associated with preferences for partners to feel and express less positive emotions in positive situations, whereas the combination of high attachment anxiety and high attachment avoidance (fearful avoidance) was associated with preferences for partners to feel and express more negative emotions in stressful situations and less positive emotions in positive situations. This investigation provides novel evidence for links between attachment orientation and preferences for partners' emotional responses in two theoretically important contexts, which has implications for the nature and function of emotion regulation in close relationships. Future research is needed to determine the generalizability of these findings to more collectivist cultural contexts.

Heart rate and heart rate variability following sleep deprivation in retired night shift workers and retired day workers

Shift workers experience poor sleep and dysregulated cardiac autonomic function during sleep. However, it is unknown if this dysregulation persists into retirement, potentially accelerating the age-associated risk for adverse cardiovascular outcomes. Using sleep deprivation as a physiological challenge to cardiovascular autonomic function, we compared heart rate (HR) and high-frequency heart rate variability (HF-HRV) during baseline and recovery sleep following sleep deprivation between retired night shift and day workers. Participants were retired night shift (N = 33) and day workers (N = 37) equated on age (mean [standard deviation] = 68.0 [5.6] years), sex (47% female), race/ethnicity (86% White), and body mass index. Participants completed a 60-h lab protocol including one night of baseline polysomnography-monitored sleep, followed by 36 h of sleep deprivation and one night of recovery sleep. Continuously recorded HR was used to calculate HF-HRV. Linear mixed models compared HR and HF-HRV during non-rapid eye movement (NREM) and REM sleep between groups during baseline and recovery nights. Groups did not differ on HR or HF-HRV during NREM or REM sleep (ps > .05) and did not show differential responses to sleep deprivation. In the full sample, HR increased and HF-HRV decreased from baseline to recovery during NREM (ps < .05) and REM (ps < .01). Both groups exhibited cardiovascular autonomic changes during recovery sleep following 36 h of sleep deprivation. Sleep deprivation appears to induce cardiovascular autonomic changes that persist into recovery sleep in older adults, regardless of shift work history.

Pet ownership and mental health in United States adults during COVID-19

The COVID-19 pandemic was associated with declines in mental health and increased interest in pet ownership. We aimed to extend past theories and research linking pet ownership and mental health by investigating whether pet ownership was associated with mental health during the initial phases of the COVID-19 pandemic in a sample of American adults. We also tested whether the association of pet ownership and mental health was moderated by relationship status. Participants were 2,906 American adults who were recruited for an online survey study between May 2020 and May 2021. Pet ownership was assessed via dichotomous self-report (yes/no) and mental health was assessed using a 13-item questionnaire. The sample was 69.2% female with an average age of 46.0 years. 36.1% of the sample owned a pet and 68.5% of the sample was currently partnered. There was no overall association of pet ownership and mental health during the COVID-19 pandemic (estimated mean difference (EMD) = 0.35, 95CI = -0.10, 0.80, p = 0.12). However, we found evidence for an association that was moderated by relationship status. Pet ownership was associated with better mental health among partnered individuals (EMD = 0.76, 95CI = 0.21, 1.30, p = 0.006). There was no association of pet ownership and mental health among unpartnered individuals (EMD = -0.41, 95CI = -1.20, 0.37, p = 0.30). Our findings suggest that relationship status may represent a critical moderator of the link between pet ownership and mental health. Future studies are needed to identify specific mechanisms of pet ownership that could explain its varied impact on the mental health of partnered and unpartnered individuals.

Longitudinal associations of social support, everyday social interactions, and mental health during the COVID-19 pandemic

Main effect models contend that perceived social support benefits mental health in the presence and the absence of stressful events, whereas stress-buffering models contend that perceived social support benefits mental health especially when individuals are facing stressful events. We tested these models of how perceived social support impacts mental health during the COVID-19 pandemic and evaluated whether characteristics of everyday social interactions statistically mediated this association - namely, (a) received support, the visible and deliberate assistance provided by others, and (b) pleasantness, the extent to which an interaction is positive, flows easily, and leads individuals to feel understood and validated. 591 United States adults completed a 3-week ecological momentary assessment protocol sampling characteristics of their everyday social interactions that was used to evaluate between-person average values and within-person daily fluctuations in everyday social interaction characteristics. Global measures of perceived social support and pandemic-related stressors were assessed at baseline. Psychiatric symptoms of depression and anxiety were assessed at baseline, at the end of each day of ecological momentary assessment, and at 3-week follow-up. Consistent with a main effect model, higher baseline perceived social support predicted decreases in psychiatric symptoms at 3-week follow-up (β = -.09, p = .001). Contrary to a stress-buffering model, we did not find an interaction of pandemic-stressors × perceived social support. The main effect of perceived social support on mental health was mediated by the pleasantness of everyday social interactions, but not by received support in everyday social interactions. We found evidence for both main effects and stress-buffering effects of within-person fluctuations in interaction pleasantness on daily changes in mental health. Results suggest the importance of everyday social interaction characteristics, especially their pleasantness, in linking perceived social support and mental health.

Cardiometabolic function in retired night shift workers and retired day workers

Night shift work is associated with poor cardiometabolic outcomes, even post-retirement. However, the characteristics of cardiometabolic function in retired night shift workers (RNSW) compared to retired day workers (RDW) are not well-understood. Rigorous characterization of cardiometabolic dysfunction in RNSW and RDW will inform targeted risk stratification for RNSW. This observational study evaluated whether RNSW (n = 71) had poorer cardiometabolic function than RDW (n = 83). We conducted a multimodal assessment of cardiometabolic function including metabolic syndrome prevalence, brachial artery flow-mediated dilation, and carotid intima-media thickness. Main analyses tested overall group differences. Sex-stratified follow-up analyses tested group differences separately in men and women. RNSW had 2.6-times higher odds of metabolic syndrome prevalence than RDW in unadjusted analyses (95% CI  [1.1,6.3]); this association was not significant when adjusting for age, race and education. RNSW and RDW (Mage = 68.4; 55% female) did not differ in percent flow-mediated dilation or carotid intima-media thickness. In sex-stratified analyses, women RNSW had 3.3-times higher odds of having high body mass index than women RDW (95% CI  [1.2,10.4]). Men RNSW had 3.9-times higher odds of having high triglycerides than men RDW (95% CI [1.1,14.2]). No other group differences were observed. We found mixed evidence that night shift work exposure was associated with cardiometabolic dysfunction in retirement, possibly in a sex-specific manner.

Social Integration and Sleep Quality during the COVID-19 Pandemic: Prospective Evidence from a Study of Retired Older Adults

BACKGROUND

Growing evidence has documented the adverse impact of the global COVID-19 pandemic on sleep quality among older adults. Given the negative consequences of poor sleep, it is critical to identify factors that provide older adults with resilience against worsening sleep quality. Social integration may represent one such resilience factor.

PURPOSE

This study evaluated the association of social integration and sleep quality during the COVID-19 pandemic.

METHODS

113 retired older adults completed assessments of their social integration after the onset of the COVID-19 pandemic, and of their sleep quality before and after the onset of the COVID-19 pandemic.

RESULTS

Higher levels of social integration were associated with better sleep quality during the COVID-19 pandemic, even when statistically controlling for pre-pandemic sleep quality. Sex-stratified analyses showed that this association was driven by women in our sample.

CONCLUSIONS

Social integration may confer resilience against poor sleep quality, especially in older adult women. Additional research is warranted to assess candidate mechanisms and moderators of the link between social integration and sleep quality.

Sleep and Daily Social Experiences as Potential Mechanisms Linking Social Integration to Nocturnal Blood Pressure Dipping

OBJECTIVE

Socially integrated individuals are at lower risk of cardiovascular disease morbidity and mortality compared with their more isolated counterparts. This association may be due, in part, to the effect of social integration on nocturnal blood pressure (BP) decline or "dipping," a physiological process associated with decreased disease risk. However, the pathways linking social integration with nocturnal BP dipping are unknown. We sought to replicate the association between social integration and BP dipping, and to test whether sleep characteristics (duration, regularity, continuity) and/or daily social interactions (frequency, valence) helped to explain the association.

METHODS

A total of 391 healthy midlife adults completed an actigraphy assessment protocol that measured sleep. During four actigraphy assessment days, participants also completed ambulatory BP monitoring and ecological momentary assessment protocols that measured BP and social interactions at regular intervals throughout the day. Social integration was assessed via a questionnaire.

RESULTS

Linear regression controlling for age, sex, race, education, and body mass index indicated that higher levels of social integration were associated with greater nocturnal BP dipping, as indicated by a smaller ratio of night/day mean arterial pressure (β = -0.11, p = .031). Analyses of indirect effects suggested that this association was explained, in part, by greater sleep regularity among more integrated individuals. We did not find evidence for other hypothesized indirect effects.

CONCLUSIONS

This was the first study to investigate sleep and social mechanisms underlying the link between social integration and nocturnal BP dipping. Because sleep regularity is modifiable, this pathway represents a potential intervention target to promote nocturnal BP dipping.