Association of Sodium with Obstructive Sleep Apnea. The ELSA-Brasil Study

Sleep irregularity and the association with hypertension and blood pressure levels: the ELSA-Brasil study

OBJECTIVE

To evaluate the associations of sleep irregularity with hypertension (HTN) and blood pressure (BP) levels.

METHODS

Adult participants from the ELSA-Brasil performed a clinical evaluation including objective sleep duration (actigraphy), insomnia, and a sleep study for defining obstructive sleep apnoea (OSA). To quantify sleep irregularity, we used two parameters obtained through actigraphy: 7-day standard deviation (SD) of sleep duration and 7-day SD of sleep-onset timing. A multivariate analysis was used to determine the independent associations of sleep irregularity with HTN and SBP/DBP values.

RESULTS

We studied 1720 participants (age 49 ± 8 years; 43.4% men) and 27% fulfilled the HTN diagnosis. After adjustments for age, gender, race, BMI, excessive alcohol consumption, physical activity intensity, urinary sodium excretion, insomnia, objective sleep duration and OSA (apnoea-hypopnoea index ≥15 events/h), we found that the continuous analysis of 7-day SD of sleep duration was modestly associated with prevalent HTN. However, 7-day SD of sleep duration more than 90 min was independently associated with SBP [ β : 1.55; 95% confidence interval (CI) 0.23-2.88] and DBP ( β : 1.07; 95% CI 0.12-2.01). Stratification analysis excluding participants with OSA revealed that a 7-day SD of sleep duration greater than 90 min was associated with a 48% higher chance of having HTN (OR: 1.48; 95% CI: 1.05-2.07). No significant associations were observed for the SD of sleep-onset timing.

CONCLUSION

Objective measurement of sleep irregularity, evaluated by SD of sleep duration for 1 week, was associated with HTN and higher BP levels, especially in participants without OSA.

Examining the relationship between obstructive sleep apnoea and eating behaviours and attitudes: A systematic review

BACKGROUND

Between 60 and 90% of adults with OSA are reported as overweight. The co-existence of obesity and OSA can greatly increase an individual's risk of type 2 diabetes, metabolic syndrome and cardiovascular disease. To better understand this relationship between OSA and weight, this review aimed to investigate if there is evidence of certain eating behaviours or eating attitudes that might be found in adults living with OSA.

METHODS

We searched four databases (MEDLINE, Embase, PsycInfo and Web of Science) on January 17th, 2022, to identify studies assessing the association between eating patterns and OSA in adults. Twenty-one studies met the inclusion criteria. A narrative synthesis was conducted on the included studies, following the vote-counting method.

RESULTS

There is preliminary evidence that the time of day when calories are consumed is associated with lower OSA severity. No other clear patterns of eating behaviours or attitudes were identified however this may be due to disparity within research studies and their reported results.

CONCLUSION

Further research is needed to examine the relationship between eating times and OSA severity. We recommend standardising the approach to examining the eating patterns of those living with OSA and the relationship that this might have on OSA symptoms as well as looking at attitudes towards food in this population. This may prove helpful in providing a better understanding of the relationship between OSA and persons with overweight and help in future intervention development.

Obstructive sleep apnea, sleep duration and chronic kidney disease in patients with coronary artery disease

BACKGROUND

Limited evidence is available addressing the potential role of sleep disorders on renal function. Here, we aimed to explore the associations of obstructive sleep apnea (OSA) and sleep duration (SD) with renal function in subjects with high cardiovascular risk.

METHODS

Consecutive subjects with coronary artery disease (CAD) underwent clinical evaluation, sleep study to define OSA and one-week wrist actigraphy to objectively measure SD. OSA was defined by an apnea-hypopnea index (AHI) of ≥15 events/hour. The estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI equation. We analyzed the associations of OSA and SD with continuous eGFR values and according to the presence of CKD (eGFR<60 mL/min/1.73 m²) after adjusting for multiple confounding factors.

RESULTS

We studied 242 subjects (62.8% men). The frequency of OSA was 55.4% and the median SD was 412.8 (363.4-457.25) min. There was no difference in the eGFRs between participants with and without OSA (69.3 ± 19.1 vs. 74.6 ± 19.3 mL/min/1.73 m², p = 0.72) and the rate of eGFR <60 mL/min/1.73 m² (34.3% vs. 25.9%; p = 0.21). Similarly, we did not find differences in patients in eGFR for those with SD ≥ 6 h versus SD < 6 h (72.5 ± 20.3 vs. 71.4 ± 19.1 mL/min/1.73 m², p = 0.72). In the linear regression analysis, AHI was independently associated with an eGFR<60 mL/min/1.73 m² in the unadjusted model [-0.15 (-0.27 to -0.04)], (P = 0.01), but not in the adjusted models. Analyses of continuous SD or the stratification in SD ≥ 6 h or <6 h also revealed neutral results on eGFR.

CONCLUSION

OSA severity and SD were not independently associated with CKD in subjects with CAD.