Anthropometric Factors in the Assessment of Obstructive Sleep Apnea Risk in Patients with Metabolic Syndrome

Cough hypersensitivity in patients with metabolic syndrome: a clinical finding and its possible mechanisms

Purpose

To investigate the changes of cough sensitivity in patients with metabolic syndrome and its possible mechanisms.

Method

A total of 29 metabolic syndrome (MetS) patients with OSAHS (group-1), 22 MetS patients without OSAHS (group-2), and 25 healthy controls (group-3) were included. All participants underwent a routine physical examination and completed the gastroesophageal reflux disease questionnaire (GerdQ), and the inflammatory mediator profile were determined. The cough threshold for capsaicin, induced sputum cell count and cell classification, and inflammatory mediators in induced sputum supernatants were compared. The correlation between capsaicin cough sensitivity and various indicators in the MetS population was analyzed.

Results

The minimum concentration of inhaled capsaicin needed to induce ≥ 5 coughs (C5) was significantly different among three groups (H = 14.393, P = 0.001) and lower for group-1 and group-2 than it for group-3 (P = 0.002, P = 0.005). The percentage of neutrophils in induced sputum and the concentrations of calcitonin gene-related peptide (CGRP), substance P (SP), and interleukin 8 (IL-8) in the sputum supernatant of group-1 and group-2 were significantly higher than those of group-3. Besides, the pepsin concentrations were significantly different among the 3 groups (F = 129.362, P < 0.001), which significantly was highest in group-1 (P < 0.001) and lowest in group-3 (P < 0.001). Triglycerides, AHI, pepsin concentration and BMI were risk factors of increased capsaicin cough sensitivity.

Conclusion

Increased capsaicin cough sensitivity in MetS patients is closely related to sleep apnea and gastroesophageal reflux. For patients in MetS patients without OSAHS, gastroesophageal reflux is an important factor for increased capsaicin cough sensitivity. Airway inflammation, especially airway neurogenic inflammation, may also play a role in the pathogenesis of increased capsaicin cough sensitivity.

Trial registration The protocol was registered in the Chinese Clinical Trials Register (http://www.chictr.org.cn/) (ChiCTR1800014768). Written informed consent was obtained from all participants before enrollment.

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

Background

Anthropometric measurements are simple and reachable tools for self-evaluating and screening patients with a high risk of obstructive sleep apnea (OSA). However, the accumulated relationship of obesity on the anthropometric characteristics of OSA is not well understood. The aim of the study was to show the time-dependent trend of OSA patients and compare overall and regional anthropometric between two ethnicities.

Methods

A cumulative meta-analysis was performed to assess obesity metrics in patients with and without OSA between Asians and Caucasians. We searched PubMed, Web of Science, Embase, and Scopus up to Jun 2020. Included studies used body mass index (BMI), neck circumference (NC), waist circumference (WC) and waist-to-hip ratio (WHR) as measures of anthropometric features in the adult OSA population and controls, utilized in-lab polysomnography or home sleep testing with apnea-hypopnea index (AHI) or respiratory disturbance index (RDI) classification, reported ethnicity/race, and were published in English. Any studies lacking one of these criteria or sufficient data were excluded.

Results

Forty studies with a total of 19,142 subjects were investigated. Comparison of changes between patients with and without OSA showed that OSA patients had a higher BMI [mean difference (MD) 3.12, 95% confidence interval (CI): 2.51–3.73], NC (MD 3.10, 95% CI: 2.70–3.51), WC (MD 9.84, 95% CI: 8.42–11.26) and waist-hip ratio (MD 0.04, 95% CI: 0.03–0.05) than the control subjects. The accumulated time-dependent increase in population with OSA was significantly apparent with all anthropometric features. BMI increased from 2000 (MD 0.50) to 2012 (MD 3.08–3.48) and remained stable afterwards (MD 2.70–3.17), NC increased from 2000 (MD 0.40) to 2013 (MD 3.09) and remained stable afterwards too (MD 3.06–3.21). WC increased from 2000 (MD 2.00) to 2012 (MD 9.37–10.03) and also remained stable afterwards (MD 8.99–9.84). WHR was stable from 2000 to 2004 with an MD of 0.01 and then stable from 2007 onwards with an increased MD of 0.03–0.04. Compared with Caucasian patients, Asian patients had lower obesity relevant variates.

Conclusions

BMI, NC, WC and WHR are associated with OSA in both ethnic groups. Anthropometry for overall and regional obesity could facilitate differentiation of patients with OSA from individuals without OSA by ethnicity.