Antibody responses to BNT162b2 mRNA vaccine: Infection-naïve individuals with abdominal obesity warrant attention.

OBJECTIVE: The excess of visceral adipose tissue might hinder and delay immune response. How people with abdominal obesity (AO) will respond to mRNA vaccines against SARS-CoV-2 is yet to be established. SARS-CoV-2-specific antibody responses were evaluated after the first and second dose of the BNT162b2 mRNA vaccine, comparing the response of individuals with AO with the response of those without, and discerning between individuals with or without prior infection. METHODS: Immunoglobulin G (IgG)-neutralizing antibodies against the Trimeric complex (IgG-TrimericS) were measured at four time points: at baseline, at day 21 after vaccine dose 1, and at 1 and 3 months after dose 2. Nucleocapsid antibodies were assessed to detect prior SARS-CoV-2 infection. Waist circumference was measured to determine AO. RESULTS: Between the first and third month after vaccine dose 2, the drop in IgG-TrimericS levels was more remarkable in individuals with AO compared with those without AO (2.44-fold [95% CI: 2.22-2.63] vs. 1.82-fold [95% CI: 1.69-1.92], respectively, p < 0.001). Multivariable linear regression confirmed this result after inclusion of assessed confounders (p < 0.001). CONCLUSIONS: The waning antibody levels in individuals with AO may further support recent recommendations to offer booster vaccines to adults with high-risk medical conditions, including obesity, and particularly to those with a more prevalent AO phenotype.

Abdominal obesity phenotype is associated with COVID-19 chest X-ray severity score better than BMI-based obesity.

PURPOSE: Chest X-ray (CXR) severity score and BMI-based obesity are predictive risk factors for COVID-19 hospital admission. However, the relationship between abdominal obesity and CXR severity score has not yet been fully explored. METHODS: This retrospective cohort study analyzed the association of different adiposity indexes, including waist circumference and body mass index (BMI), with CXR severity score in 215 hospitalized patients with COVID-19. RESULTS: Patients with abdominal obesity showed significantly higher CXR severity scores and had higher rates of CXR severity scores ≥ 8 compared to those without abdominal obesity (P < 0.001; P = 0.001, respectively). By contrast, patients with normal weight, with overweight and those with BMI-based obesity showed no significant differences in either CXR severity scores or in the rates of CXR severity scores ≥ 8 (P = 0.104; P = 0.271, respectively). Waist circumference and waist-to-height ratio (WHtR) correlated more closely with CXR severity scores than BMI (r = 0.43, P < 0.001; r = 0.41, P < 0.001; r = 0.17, P = 0.012, respectively). The area under the curves (AUCs) for waist circumference and WHtR were significantly higher than that for BMI in identifying a high CXR severity score (≥ 8) (0.68 [0.60-0.75] and 0.67 [0.60-0.74] vs 0.58 [0.51-0.66], P = 0.001). A multivariate analysis indicated abdominal obesity (risk ratio: 1.75, 95% CI: 1.25-2.45, P < 0.001), bronchial asthma (risk ratio: 1.73, 95% CI: 1.07-2.81, P = 0.026) and oxygen saturation at admission (risk ratio: 0.96, 95% CI: 0.94-0.97, P < 0.001) as the only independent factors associated with high CXR severity scores. CONCLUSION: Abdominal obesity phenotype is associated with a high CXR severity score better than BMI-based obesity in hospitalized patients with COVID-19. Therefore, when visiting the patient in a hospital setting, waist circumference should be measured, and patients with abdominal obesity should be monitored closely. Level of evidence Cross-sectional descriptive study, Level V.

Epicardial fat inflammation response to COVID-19 therapies.

OBJECTIVE: Adipose tissue plays a role in the novel coronavirus disease 2019 (COVID-19). Epicardial adipose tissue (EAT), a unique visceral fat, presents with a high degree of inflammation in severe COVID-19. Whether and how adipose tissue may respond to the COVID-19 therapies is unknown. METHODS: The difference in computed tomography-measured EAT and subcutaneous (SAT) attenuation, defined as mean attenuation expressed in Hounsfield units (HU), was retrospectively analyzed in 72 patients (mean [SD] age was 59.6 [12.4] years, 50 patients [69%] were men) at the hospital admission for COVID-19 and 99 days (interquartile range = 71-129) after discharge. RESULTS: At the admission, EAT-HU was significantly correlated with blood glucose levels, interleukin 6, troponin T levels, and waist circumference. EAT-HU decreased from -87.21 (16.18) to -100.0 (11) (p < 0.001), whereas SAT-HU did not change (-110.21 [12.1] to -111.11 [27.82]; p = 0.78) after therapy. Changes in EAT-HU (expressed as ∆) significantly correlated with dexamethasone therapy (r = -0.46, p = 0.006) and when dexamethasone was combined with tocilizumab (r = -0.24, p = 0.04). CONCLUSIONS: Dexamethasone therapy was associated with significant reduction of EAT inflammation in COVID-19 patients, whereas SAT showed no changes. Anti-inflammatory therapies targeting visceral fat may be helpful in COVID-19.

Tri-Ponderal Mass Index vs body Mass Index in discriminating central obesity and hypertension in adolescents with overweight.

BACKGROUND AND AIMS: Recently, it has been hypothesized that Tri-Ponderal Mass Index (TMI) may be a valid alternative to Body Mass Index (BMI) when measuring body fat in adolescents. We aimed to verify whether TMI has better accuracy than BMI in discriminating central obesity and hypertension in adolescents with overweight. METHODS AND RESULTS: This monocentric and retrospective cross-sectional study included 3749 pupils, 1889 males and 1860 females, aged 12-13. BMI (kg/m2) was calculated and expressed as percentiles and as z-scores. TMI (kg/m3) was calculated, and we used pre-defined cut-off previously proposed by Peterson et al.. For central obesity we adopted the Waist-to-Height Ratio (WHtR) discriminatory value of 0.5. Hypertension was defined as blood pressure ≥95th percentile of age- sex-, and height-specific references recommended by NHBPEP Working Group. The discriminant ability of TMI, BMI and BMI z-score, with respect to central obesity and hypertension, was investigated using non-parametric receiver operating characteristic analysis. The overall misclassification rate for central obesity was 8.88% for TMI vs 14.10% for BMI percentiles and vs 14.92% for BMI z-scores (P < 0.001). The overall misclassification rate for hypertension was 7.50% for TMI vs 22.03% for BMI percentiles and vs 25.19% for BMI z-scores (P < 0.001). CONCLUSION: TMI is a superior body fat index and it could discriminate body fat distribution more accurately than BMI. This supports the use of TMI, in association with WHtR, to characterize adolescents with overweight and high cardio-metabolic risk. Our analysis needs to be extended to other ethnic groups and replicated in a wider age range and in longitudinal studies.