Rest-activity rhythms across the lifespan: cross-sectional findings from the US representative National Health and Nutrition Examination Survey

Association of frailty index with all-cause and cardiovascular mortality with different diabetic status: NHANES 1999-2018

AIMS

The relationship between frailty and mortality among individuals with varying diabetic statuses represents a burgeoning area of concern and scholarly interest within the medical community. However, there are limited studies that explore the relationship between frailty and mortality, as well as cause-specific mortality among individuals with non-diabetes, prediabetes, and diabetes patients. Hence, this study aims to investigate the relationship between the frailty statues and all-cause mortality, as well as cause-specific mortality in individuals with varying diabetic statuses using the data in the NHANES database.

METHODS

The study utilized data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018, incorporating a final sample size of 57, 098 participants. Both univariable and multivariable-adjusted logistic regression analyses, as well as Cox regression analysis were employed to examine the relationship between frailty index (FI) and mortality.

RESULTS

This study, found a significant positive correlation between the frailty and the increased risk of all-cause mortality non-diabetic [OR 4.277, 95%CI (3.982, 4.594), P < 0.001], prediabetic [OR 2.312, 95%CI (2.133, 2.506), P < 0.001], and diabetic patients [OR 3.947, 95%CI (3.378, 4.611), P < 0.001]. This correlation still existed even after adjusting for confounding factors including age, sex, BMI, poverty, fasting insulin, education, smoke, alcohol drink, waist, hypertension, hyperlipidemia, fasting glucose, HbA1c, eGFR, creatinine and total bilirubin. Our result also suggested a significant positive correlation between the frailty index and the increased risk of CVD mortality among non-diabetic [OR 3.095, 95%CI (2.858, 3.352), P < 0.001] and prediabetic [OR 5.985, 95%CI (5.188, 6.904), P < 0.001] individuals. However, in patients with diabetes, the correlation between frailty and CVD mortality lost significance after adjusting for possible confounding factors [OR 1.139, 95%CI (0.794, 1.634), P > 0.05].

CONCLUSION

A nonlinear relationship has been identified between the FI and all-cause mortality, as well as CVD mortality in non-diabetic and pre-diabetic population. In diabetic patients, there was a significant positive correlation between the frailty and the increased risk of all-cause mortality, but not with CVD mortality. Renal function and liver function might potentially acted as an intermediary factor that elevated the risk of CVD mortality in frail patients with diabetes.

Association of triglyceride-glucose index with helicobacter pylori infection and mortality among the US population

BACKGROUND

Limited research has explored the potential association between the Triglyceride-Glucose (TyG) and mortality, especially in individuals with Helicobacter pylori (H. pylori) infection. This study seeks to investigate the correlation between the TyG index and H. pylori infection and investigate whether the associations between the TyG index exposure and all-cause mortality are mediated by H. pylori infection.

METHODS

The study utilized data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018, incorporating a final sample size of 2,187 participants. Both univariable and multivariable-adjusted logistic regression analyses were employed to examine the relationship between H. pylori infection and relevant covariates. To assess the association between TyG index, and all-cause mortality in individuals with or without H. pylori infection, Cox regression analysis, and restricted regression cubic spline analysis were implemented.

RESULTS

A significant positive correlation was observed between the TyG index and an elevated risk of H. pylori infection [OR 1.157, 95% CI (1.383 ~ 1.664)]. This correlation persisted even after adjusting for confounding factors [OR 1.189, 95% CI (1.003, 1.411), P < 0.05]. Furthermore, in patients with positive H. pylori infection, a noteworthy nonlinear correlation between the TyG index and all-cause mortality was identified (P = 0.0361). With an increase in the TyG index, all-cause mortality exhibited a corresponding rise, particularly following adjustment for all potential confounding factors. Conversely, in patients with negative H. pylori infection, no significant association was observed between the TyG index and all-cause mortality after adjusting for potential confounding factors.

CONCLUSION

A higher TyG index was linked to increased H. pylori infection risks. Participants in the higher quantile group of the TyG index are positively associated with higher all-cause mortality compared to the higher quantile group of the TyG index in H. pylori-positive participants instead of H. pylori-negative participants.

Measures of fragmentation of rest activity patterns: mathematical properties and interpretability based on accelerometer real life data

Accelerometers, devices that measure body movements, have become valuable tools for studying the fragmentation of rest-activity patterns, a core circadian rhythm dimension, using metrics such as inter-daily stability (IS), intradaily variability (IV), transition probability (TP), and self-similarity parameter (named α ). However, their use remains mainly empirical. Therefore, we investigated the mathematical properties and interpretability of rest-activity fragmentation metrics by providing mathematical proofs for the ranges of IS and IV, proposing maximum likelihood and Bayesian estimators for TP, introducing the activity balance index (ABI) metric, a transformation of α , and describing distributions of these metrics in real-life setting. Analysis of accelerometer data from 2,859 individuals (age=60-83 years, 21.1% women) from the Whitehall II cohort (UK) shows modest correlations between the metrics, except for ABI and α . Sociodemographic (age, sex, education, employment status) and clinical (body mass index (BMI), and number of morbidities) factors were associated with these metrics, with differences observed according to metrics. For example, a difference of 5 units in BMI was associated with all metrics (differences ranging between -0.261 (95% CI -0.302, -0.220) to 0.228 (0.18, 0.268) for standardised TP rest to activity during the awake period and TP activity to rest during the awake period, respectively). These results reinforce the value of these rest-activity fragmentation metrics in epidemiological and clinical studies to examine their role for health. This paper expands on a set of methods that have previously demonstrated empirical value, improves the theoretical foundation for these methods, and evaluates their empirical use in a large dataset.

Stability and Volatility of Human Rest-Activity Rhythms: Insights from Very Long Actograms (VLAs)

Importance

Wrist-worn activity monitors provide biomarkers of health by non-obtrusively measuring the timing and amount of rest and physical activity (rest-activity rhythms, RARs). The morphology and robustness of RARs vary by age, gender, and sociodemographic factors, and are perturbed in various chronic illnesses. However, these are cross-sectionally derived associations from recordings lasting 4-10 days, providing little insights into how RARs vary with time.

Objective

To describe how RAR parameters can vary or evolve with time (~months).

Design Setting and Participants

48 very long actograms ("VLAs", ≥90 days in duration) were identified from subjects enrolled in the STAGES (Stanford Technology, Analytics and Genomics in Sleep) study, a prospective cross-sectional, multi-site assessment of individuals > 13 years of age that required diagnostic polysomnography to address a sleep complaint. A single 3-year long VLA (author GD) is also described.

Exposures/Intervention

None planned.

Main Outcomes and Measures

For each VLA, we assessed the following parameters in 14-day windows: circadian/ultradian spectrum, pseudo-F statistic ("F"), cosinor amplitude, intradaily variability, interdaily stability, acrophase and estimates of "sleep" and non-wearing.

Results

Included STAGES subjects (n = 48, 30 female) had a median age of 51, BMI of 29.4kg/m2, Epworth Sleepiness Scale score (ESS) of 10/24 and a median recording duration of 120 days. We observed marked within-subject undulations in all six RAR parameters, with many subjects displaying ultradian rhythms of activity that waxed and waned in intensity. When appraised at the group level (nomothetic), averaged RAR parameters remained remarkably stable over a ~4 month recording period. Cohort-level deficits in average RAR robustness associated with unemployment or high BMI (>29.4) also remained stable over time.

Conclusions and Relevance

Through an exemplary set of months-long wrist actigraphy recordings, this study quantitatively depicts the longitudinal stability and dynamic range of human rest-activity rhythms. We propose that continuous and long-term actigraphy may have broad potential as a holistic, transdiagnostic and ecologically valid monitoring biomarker of changes in chronobiological health. Prospective recordings from willing subjects will be necessary to precisely define contexts of use.