Time-dependence and comparison of regional and overall anthropometric features between Asian and Caucasian populations with obstructive sleep apnea: a cumulative meta-analysis

Strengths and Limitations of BMI in the Diagnosis of Obesity: What is the Path Forward?

PURPOSE OF REVIEW

This review aims to discuss strengths and limitations of body mass index (BMI) in diagnosing obesity, the use of alternative anthropometric measurements, and potential new technology that may change the future of obesity diagnosis and management.

RECENT FINDINGS

The diagnosis of obesity requires the anthropometric assessment of adiposity. In clinical settings, this should include BMI with confirmation that elevated BMI represents excess adiposity and a measure of fat distribution (i.e., waist circumference (WC), waist to height ratio (WHtR), or WC divided by height0.5 (WHR.5R). Digital anthropometry and bioelectric impedance (BIA) can estimate fat distribution and be feasibly employed in the clinic. In addition, the diagnosis should include a clinical component assessing the presence and severity of weight-related complications. As anthropometric measures used in the diagnosis of obesity, BMI is generally sufficient if confirmed to represent excess adiposity, and there are advantages to the use of WHtR over WC to assess fat distribution. BIA and digital anthropometry have the potential to provide accurate measures of fat mass and distribution in clinical settings. There should also be a clinical evaluation for the presence and severity of obesity complications that can be used to stage the disease.

Association Between Sleep Apnea and Tinnitus: A Meta-Analysis

Objective: It remains unclear whether sleep apnea (SA) is associated with tinnitus in adults. Based on a systematic review and meta-analysis of observational studies, we investigated the association between SA and tinnitus in adult population. Methods: Observational studies relevant to our research were identified by searching PubMed, Embase, Web of Science, Wanfang, and China National Knowledge Infrastructure databases. Random-effects models were used when significant heterogeneity was observed; otherwise, fixed-effects models were used. Results: Eight case-control or cross-sectional studies, including 132,292 adults were included, and 1556 of them had SA. It was shown that SA was related to a higher prevalence of tinnitus (odds ratio [OR]: 1.65, 95% confidence interval: 1.14-2.39, P < .001) with moderate heterogeneity (P for Cochrane Q test = 0.04, I2 = 53%). Seven studies reported the association between obstructive SA and tinnitus, while the other one study reported the association between overall SA and tinnitus. Subgroup analyses showed that the association was not significant for mild (OR: 1.80, P = .17) or moderate (OR: 1.25, P = .53), but significant for severe SA (OR: 2.25, P = .008). In addition, the association between SA and tinnitus seemed to be stronger in studies from Italy or United States as compared to those from China (OR: 2.91 vs 1.35, P for subgroup difference = .02). The association was not significantly affected by study design, mean age, proportion of men, methods for diagnosis of SA, and controlling of age and sex (P for subgroup difference all > .05). Conclusion: Severe SA may be related to tinnitus in adults.

Associations between abdominal obesity and the risk of stroke in Chinese older patients with obstructive sleep apnea: Is there an obesity paradox?

Background and purpose

Abdominal obesity (AO) is a well-known independent risk factor for stroke in the general population although it remains unclear in the case of the elderly, especially in Chinese older patients with obstructive sleep apnea (OSA), considering the obesity paradox. This study aimed to investigate the association between AO and stroke among Chinese older patients with OSA.

Methods

Data were collected from January 2015 to October 2017, and 1,290 older patients (age 60–96 years) with OSA (apnea–hypopnea index ≥ 5 events/h on polysomnography) were consecutively enrolled from sleep centers at six hospitals, evaluated for AO defined as waist circumference (WC) using the standardized criteria for the Chinese population, and followed up prospectively for a median period of 42 months. Logistic regression and Cox regression analyses were used to determine the cross-sectional and longitudinal associations between AO and stroke risk in these participants and different groups of the severity of OSA.

Results

Participants with AO had a higher prevalence of stroke at baseline. A higher incidence of stroke during a median follow-up period of 42 months in participants with AO than in participants without AO (12.4% vs. 6.8% and 8.3% vs. 2.4%, respectively; both P &lt; 0.05) was predicted. Cross-sectional analysis revealed an association between AO and stroke (odds ratio [OR]1.96, 95% confidence interval [CI] 1.31–2.91), which was stronger among participants with moderate OSA only (OR 2.16, 95%CI 1.05–4.43). Cox regression analysis showed that, compared to participants without AO, participants with AO had a higher cumulative incidence of stroke (hazard ratio [HR] 2.16, 95% CI 1.12–4.04) during a median follow-up of 42 months, and this association was observed in patients with severe OSA only (HR 3.67, 95% CI 1.41–9.87) but not for individuals with mild OSA (HR = 1.84, 95% CI 0.43–6.23) and moderate OSA (HR = 1.98, 95% CI 0.73–6.45).

Conclusion

The risk of stroke is associated with AO among Chinese older patients who have OSA, both at baseline and during follow-up, and the strength of the association varied by OSA severity. Active surveillance for early detection of AO could facilitate the implementation of stroke-preventive interventions in the Chinese older OSA population.

Unique clinical phenotypes of patients with obstructive sleep apnea in a Japanese population: a cluster analysis

STUDY OBJECTIVES

In an attempt to better understand the heterogeneity of individuals with obstructive sleep apnea (OSA), unbiased analytic approaches such as cluster analysis have been used worldwide; however, only a few such studies have been conducted for Asian populations alone, despite the potential racial/ethnic differences. We thus applied this approach to a Japanese population with OSA.

METHODS

In this single-center, retrospective, observational study, our nocturnal polysomnography dataset included the findings for 1,020 patients between May 2016 and December 2020. Of these, 712 patients met the study criteria: aged > 20 years, fully completed questionnaire, no missing data on all-night full polysomnography, and confirmed OSA diagnosis with an apnea-hypopnea index (AHI) > 15 events/h. We employed hierarchical cluster analysis using demographic data, self-reported symptoms, and polysomnographic data.

RESULTS

We identified 5 distinct clinical clusters within the OSA patient population, which were labeled as "classic OSA" (20--67 years, obese, high AHI, high Epworth Sleepiness Scale [ESS]), "milder classic OSA" (22--77 years, obese, high AHI, low ESS), "nonobese and minimally symptomatic" (20--88 years, moderate AHI, low ESS), "excessive sleepiness without severe OSA" (26--79 years, moderate AHI, high ESS), and "older adult and severe OSA" 55--92 years, (high AHI, low ESS). Of these, the last 3 clusters were characterized as nonobese. Notably, we identified the cluster with excessive sleepiness despite less severe OSA. We did not identify any clusters with predominant upper-airway obstruction symptoms because the symptoms were prevalent and equally distributed in all clusters.

CONCLUSIONS

We found some unique clinical phenotypes in nonobese patients with OSA in a Japanese population.

CITATION

Ida H, Suga T, Nishimura M, Aoki Y. Unique clinical phenotypes of patients with obstructive sleep apnea in a Japanese population: a cluster analysis. J Clin Sleep Med. 2022;18(3):895-902.

The influence of sex on anthropometric methods and four scales for screening obstructive sleep apnea

OBJECTIVES

Obstructive Sleep Apnea (OSA) is a kind of respiratory disease that occurs apnea repeatedly during sleep. The purpose of this study was to investigate the influence of sex on anthropometric methods and four scales for screening OSA.

METHODS

The basic data and PSG data of 2108 patients who underwent PSG examination at the Sleep Medicine Center of the First Affiliated Hospital of Guangzhou Medical University from July 2017 to December 2020 were continuously included. Then the sensitivity, specificity, positive predictive value, negative predictive value, AUC and DOR of the anthropometric method and the four scales were calculated.

RESULTS

2108 OSA patients were enrolled from the Sleep Medicine Center, including 1644 males (78.0%). The average neck circumference and waist circumference of male and female patients were respectively (39.4±3.4) cm and (96.7±13.8) cm,(34.6±3.5) cm and (90.1±11.6) cm. In female patients. the AUC of NoSAS was the largest. When AHI was 5, 15, and 30 evens/h as the cut-off point, in male patients, the sensitivity of NHR was the highest,in female patients, the sensitivity of WHR was the highest.

CONCLUSIONS

NHR and WHR are good tools for screening OSA in male and female patients respectively. They are worthy of promotion.