Relation of Abdominal Obesity to Risk of Atrial Fibrillation (From the Reasons for Geographic and Racial Differences in Stroke [REGARDS] Study)

Visceral and subcutaneous adiposity and cardiovascular disease: Unravelling associations and prognostic value

AIM

The distribution pattern of abdominal adiposity may help determine cardiovascular disease (CVD). Waist circumference (WC) is the most common but imprecise method for measuring abdominal adiposity, as it fails to differentiate between visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT). This study aimed to determine whether elevated VAT or ASAT provides greater prognostic value for CVD events compared to elevated WC in the general population using data from the UK Biobank.

MATERIALS AND METHODS

In this secondary analysis of UK Biobank study, 24 265 participants with available abdominal magnetic resonance imaging data were included. The primary outcome of the study was coronary heart disease (CHD), and secondary outcomes included stroke, heart failure (HF) and atrial fibrillation (AF). Cox regressions for VAT, ASAT and WC were examined in relation to the predefined outcomes on continuous scales using standard deviation (SD) changes and by categories of concordant and discordant values defined by medians.

RESULTS

During a mean follow-up period of 12.9 ± 1.8 years, 2641 participants developed CVD events (1296 CHD, 165 stroke, 286 HF and 894 AF) Each 1 SD increase in VAT yielded a hazard ratio (HR) of 1.15 (95% confidence interval [CI]: 1.09-1.22) for CHD risk, whereas ASAT had a HR of 1.10 (95% CI: 1.04-1.18). Further adjustment for WC eliminated the association between ASAT and CHD risk, in contrast to the association between VAT and CHD risk, which remained almost unaffected. Discordant VAT above the median with WC below presented a HR of 1.43 (95% CI: 1.15-1.78) for CHD, compared with concordant VAT and WC below the median. Similar results were found for discordant WC above the median with VAT below, with a HR of 1.46 (95% CI: 1.18-1.81). In contrast, discordant ASAT above the median with WC below was not associated with an increased risk of CHD. Similarly, discordant ASAT above the median with VAT below was not associated with an increased risk of CHD. Additionally, there was no observed association between VAT or ASAT and the risks of stroke, HF or AF after further adjustment for WC. Additionally, there was no observed association between VAT or ASAT and the risks of stroke, HF or AF after further adjustment for WC.

CONCLUSION

Incorporating VAT measurements alongside WC data improved the ability to identify individuals at high risk for CHD compared to using WC alone. Both VAT and WC proved to be more accurate indicators of CHD risk than ASAT. However, VAT alone did not fully account for the CHD risk associated with elevated WC levels. Neither VAT nor ASAT showed an association with the risk of stroke, HF and AF.

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 < 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.

Bariatric Surgery and Myocardial Mechanics: A Meta-Analysis of Speckle Tracking Echocardiographic Studies

Aim: Current evidence on the effects of bariatric surgery on cardiac mechanics in patients with obesity is based on a few single studies. We investigated this issue through a meta-analysis of speckle tracking echocardiography (STE) studies that reported data on changes in left ventricular (LV) mechanics as assessed by global longitudinal strain (GLS). Methods: The PubMed, OVID-MEDLINE and Cochrane library databases were systematically analysed to search English-language articles published from inception to 31 May 2022. Studies were identified by using Me-SH terms and crossing the following terms: “obesity”, “bariatric surgery”, “left ventricular mechanics”, “left ventricular hypertrophy”, “systolic dysfunction”, “global longitudinal strain”, “echocardiography” and “STE echocardiography”. Results: The meta-analysis, including a total of 512 patients with obesity from 13 studies (follow-up 1−23 months), showed a significant GLS improvement after bariatric procedures, with standard mean difference (SMD) being 0.50 ± 0.08, CI: 0.34/0.65, p < 0.0001. Corresponding SMD value for LV ejection fraction (LVEF) was 0.15 ± 0.09, CI: −0.04/0.34, p = 0.11. A sensitivity analysis restricted to 11 studies with follow-up ≥ 6 months confirmed that GLS (SMD: 0.47 ± 0.08, CI: 0.30/0.63, p < 0.0001) but not LVEF (SMD: 0.14 ± 0.11, CI: −0.08/0.37, p = 0.21) improved after surgery. Conclusions: Our meta-analysis adds a new piece of information on the beneficial effects of bariatric surgery on LV systolic function and, more importantly, suggests that the assessment of myocardial strain should be routinely implemented for a comprehensive evaluation of cardiac functional changes associated with bariatric procedures.