From trenches to technology: a narrative review of sleep medicine in the military.

Diagnoses of military-relevant sleep disorders have increased substantially since the terrorist attacks of 9-11. The cause of this increase appears to be complicated and multifactorial, with military and civilian populations clearly differing with respect to both the nature and distribution of sleep disorders diagnoses. In part, these differences may be attributable to the fact that a majority of service members (SMs) are chronically sleep restricted - an unavoidable consequence of continuous and sustained military operations that 'set the stage' for development of specific sleep disorders. The purpose of this narrative review is to describe the military relevance of several common sleep disorders, assess the extent to which these disorders currently constitute a burden on the military healthcare system, and suggest strategies to alleviate that burden. The military healthcare system does not have enough sleep providers to address the immediate and long-term consequences of sleep disorders in military personnel. Digital technologies and education packages can be leveraged to improve access to care.

Using Mixture Modeling to Construct Subgroups of Cognitive Aging in the Wisconsin Longitudinal Study.

OBJECTIVES: Longitudinal surveys of older adults increasingly incorporate assessments of cognitive performance. However, very few studies have used mixture modeling techniques to describe cognitive aging, identifying subgroups of people who display similar patterns of performance across discrete cognitive functions. We employ this approach to advance empirical evidence concerning interindividual variability and intraindividual change in patterns of cognitive aging. METHOD: We drew upon data from 3,713 participants in the Wisconsin Longitudinal Study (WLS). We used latent class analysis to generate subgroups of cognitive aging based on assessments of verbal fluency and episodic memory at ages 65 and 72. We also employed latent transition analysis to identify how individual participants moved between subgroups over the 7-year period. RESULTS: There were 4 subgroups at each point in time. Approximately 3 quarters of the sample demonstrated continuity in the qualitative type of profile between ages 65 and 72, with 17.9% of the sample in a profile with sustained overall low performance at both ages 65 and 72. An additional 18.7% of participants made subgroup transitions indicating marked decline in episodic memory. DISCUSSION: Results demonstrate the utility of using mixture modeling to identify qualitatively and quantitatively distinct subgroups of cognitive aging among older adults. We discuss the implications of these results for the continued use of population health data to advance research on cognitive aging.

A cohort longitudinal study of individual level social capital and depressive symptoms in the Wisconsin Longitudinal Study.

This study examined the association between two dimensions of social capital, structural and cognitive, and depression, as well as investigating their within- and between-effects. Using the Wisconsin Longitudinal Study, I applied a multi-level 2-wave longitudinal analysis, over a 7-year period, to examine these two dimensions of social capital influence on individual's depressive symptoms at both the between- and within-person levels. Results suggest both dimensions of social capital are negatively related with levels of depressive symptoms. The within-person changes for both self-efficacy and sense of belonging were larger than the estimates of between-effects, while trust and structural social capital effects were equal. These findings add to the growing body of literature examining depressive symptoms in late life, while also providing evidence for policymakers to hone in on key areas that can address depressive symptoms with social capital interventions.

Self-selected fluid volume and flavor strength does not alter fluid intake, body mass loss, or physiological strain during moderate-intensity exercise in the heat.

INTRODUCTION: The purpose of this study was to determine the effects of ad libitum flavor and fluid intake on changes in body mass (BM) and physiological strain during moderate intensity exercise in the heat. METHODS: Ten subjects (24±3yrs, 7M/3F) performed 60 min of treadmill walking at 1.3 m/s and 7% grade in an environmental chamber set to 33 °C and 10% relative humidity while carrying a 22.7 kg pack on two different occasions. Subjects consumed either plain water or water plus flavor (Infuze), ad libitum, at each visit. Pre and post exercise, fluid consumption (change in fluid reservoir weight) and BM (nude) were measured. During exercise, heart rate (HR), systolic blood pressure (SBP), rate of perceived exertion (RPE), oxygen consumption (VO2), respiratory exchange ratio (RER), core temperature (TC), and physiological strain index (PSI) were recorded every 15 min during exercise. RESULTS: No significant differences were observed for fluid consumption between fluid conditions (512 ± 97.2 mL water vs. 414.3 ± 62.5 mL Infuze). Despite a significant decrease from baseline, there were no significant differences in overall change of BM (Δ -1.18 vs. -0.64 Kg) or percent body weight loss for water and Infuze conditions, respectively (1.58 ± 0.6 and 0.79 ± 0.2%). Furthermore, there were no significant differences in HR (144 ± 6 vs. 143 ± 8 bpm), SBP (157 ± 5 vs. 155 ± 5 mmHg), RPE, VO2 (27.4 ± 0.9 vs. 28.1 ± 1.2 ml/Kg/min), RER, TC (38.1 ± 0.1 vs. 37.0 ± 0.1 °C), and peak PSI (5.4 ± 0.4 vs. 5.7 ± 0.8) between conditions. CONCLUSIONS: Offering individuals the choice to actively manipulate flavor strength did not significantly influence ad libitum fluid consumption, fluid loss, or physiological strain during 60 min of moderate intensity exercise in the heat.

Childhood socioeconomic status and genetic risk for poorer cognition in later life.

The ε4 allele of the APOE gene is associated with poorer cognition in later life. This study aimed to advance understanding of how environments potentially moderate this genetic risk by focusing on childhood socioeconomic status (SES). Previous research across diverse national contexts has found that older adults from higher-SES families in childhood demonstrate better cognitive functioning than their lower-SES counterparts. Nevertheless, few studies have examined whether higher childhood SES might also promote later life cognition by mitigating the effects of ε4 carrier status. To address this gap, we used data from 3017 participants in the Wisconsin Longitudinal Study, which has followed a random sample of people who graduated from Wisconsin high schools in 1957. Childhood SES included parents' educational attainment, father's occupational status, and household income in adolescence. We constructed measures of memory and of language/executive functioning using scores from neurocognitive tests administered when participants were approximately ages 65 and 72. APOE ε4 status was measured through saliva samples. Results from cross-controlled multilevel models indicated that APOE ε4 status-and not childhood SES-independently predicted memory, whereas childhood SES-and not APOE ε4 status-independently predicted language/executive functioning. Moreover, a statistical interaction between APOE ε4 status and childhood SES for memory indicated that at baseline, higher childhood SES protected against the risk of APOE ε4 status, whereas lower childhood SES exacerbated the risk of APOE ε4 status. However, by follow-up, these moderating effects dissipated, and APOE ε4 status alone was associated with memory. We interpret these results in light of theorizing on differential susceptibility for poorer cognition across the life course.