A comparison of body mass index and percent body fat as predictors of cardiovascular risk factors

The relationship between cardiorespiratory fitness and blood pressure among airline pilots: a mediation analysis of body composition

OBJECTIVE

Blood pressure (BP), cardiorespiratory fitness (CRF), and body composition are independently associated with health outcomes, yet the relationship between these variables has not been explored among airline pilots. The aim of this study was to evaluate the relationship between CRF and BP, and further examine whether the relationship is mediated by body composition.

METHODS

A cross-sectional study was conducted among 356 airline pilots in New Zealand. We measured height, body mass, BP, waist circumference, skinfolds, and CRF (via a WattBike cycle ergometer submaximal VO 2max test). Partial correlation coefficients were estimated to examine the relationships between all variables while controlling for age and sex. Haye's PROCESS macro and the Sobel test were utilized for the mediation analysis.

RESULTS

All body composition variables (body mass index, waist circumference and body fat percentage) were positively correlated with all BP variables (systolic pressure, diastolic pressure and mean arterial pressure) ( P  < 0.001). CRF was negatively correlated with all body composition and BP variables ( P  < 0.001). The Sobel test and indirect effect were significant ( P  < 0.001), confirming that all body composition variables partially mediate the relationship between CRF and all blood pressure variables.

CONCLUSION

Lower CRF is associated with higher blood pressure, and body composition partially mediates the relationship between these health risk factors. These findings highlight the importance of physical fitness and healthy body composition in the management of blood pressure among this occupational group.

Body composition predicts hypertension using machine learning methods: a cohort study

We used machine learning methods to investigate if body composition indices predict hypertension. Data from a cohort study was used, and 4663 records were included (2156 were male, 1099 with hypertension, with the age range of 35-70 years old). Body composition analysis was done using bioelectrical impedance analysis (BIA); weight, basal metabolic rate, total and regional fat percentage (FATP), and total and regional fat-free mass (FFM) were measured. We used machine learning methods such as Support Vector Classifier, Decision Tree, Stochastic Gradient Descend Classifier, Logistic Regression, Gaussian Naïve Bayes, K-Nearest Neighbor, Multi-Layer Perceptron, Random Forest, Gradient Boosting, Histogram-based Gradient Boosting, Bagging, Extra Tree, Ada Boost, Voting, and Stacking to classify the investigated cases and find the most relevant features to hypertension. FATP, AFFM, BMR, FFM, TRFFM, AFATP, LFATP, and older age were the top features in hypertension prediction. Arm FFM, basal metabolic rate, total FFM, Trunk FFM, leg FFM, and male gender were inversely associated with hypertension, but total FATP, arm FATP, leg FATP, older age, trunk FATP, and female gender were directly associated with hypertension. AutoMLP, stacking and voting methods had the best performance for hypertension prediction achieving an accuracy rate of 90%, 84% and 83%, respectively. By using machine learning methods, we found that BIA-derived body composition indices predict hypertension with acceptable accuracy.

Cardiometabolic risk factors in adults with normal weight obesity: A systematic review and meta-analysis

Normal weight obesity (NWO) is a new emerging phenotype of obesity, defined as a normal body mass index with a high body fat percentage. While several studies have described the impact of NWO on cardiometabolic risk factors, the association between them remains uncertain. This meta-analysis systematically evaluated cardiometabolic risk factors in adults with NWO compared to adults with normal weight lean (NWL). A systematic literature search was performed from the inception until September 21, 2021 in order to comprehensively search for all observational studies that had three important variables, including adults (age ≥18 years old), NWO and cardiometabolic risk factors including metabolic syndrome, hypertension, diabetes mellitus, dyslipidaemia or all laboratory findings related to cardiometabolic risk factors. Twenty-four cross-sectional studies with a total of 75 201 subjects are included in the qualitative and quantitative analysis. Overall, older age and female sex are more likely in NWO population. Compared to NWL, NWO is significantly associated with cardiometabolic risk factors, including metabolic syndrome (OR = 2.24 [1.74, 2.89]; p < .001; I²  = 76%, P_{heterogeneity}  < 0.001), hypertension (OR = 1.60[1.36, 1.89]; p < .001; I²  = 76%, P_{heterogeneity}  < 0.001), diabetes mellitus (OR = 1.72[1.54, 1.92]; p < .001; I²  = 47%, P_{heterogeneity}  < 0.001), dyslipidaemia (OR = 1.50 [1.03, 2.18]; p = .03; I²  = 94%, P_{heterogeneity}  < 0.001) and other laboratory findings, except for C-reactive protein in both sexes group; and adiponectin levels in female group. Our meta-analysis showed that NWO was associated with cardiometabolic risk factors. Thus, the traditional definition of obesity using the BMI criteria should be challenged, as those with NWO might still be exposed to a heightened risk of cardiometabolic disorders. Nonetheless, further prospective cohort studies are needed better to understand this syndrome.

Impact of bariatric surgery on cardiovascular outcomes and mortality: a population-based cohort study

Background

Cohort studies have shown that bariatric surgery may reduce the incidence of and mortality from cardiovascular disease (CVD), but studies using real-world data are limited. This study examined the impact of bariatric surgery on incident CVD, hypertension and atrial fibrillation, and all-cause mortality.

Methods

A retrospective, matched, controlled cohort study of The Health Improvement Network primary care database (from 1 January 1990 to 31 January 2018) was performed (approximately 6 per cent of the UK population). Adults with a BMI of 30 kg/m2 or above who did not have gastric cancer were included as the exposed group. Each exposed patient, who had undergone bariatric surgery, was matched for age, sex, BMI and presence of type 2 diabetes mellitus (T2DM) with two controls who had not had bariatric surgery.

Results

A total of 5170 exposed and 9995 control participants were included; their mean(s.d.) age was 45·3(10·5) years and 21·5 per cent (3265 of 15 165 participants) had T2DM. Median follow-up was 3·9 (i.q.r. 1·8– 6·4) years. Mean(s.d.) percentage weight loss was 20·0(13·2) and 0·8(9·5) per cent in exposed and control groups respectively. Overall, bariatric surgery was not associated with a significantly lower CVD risk (adjusted hazard ratio (HR) 0·80; 95 per cent c.i. 0·62 to 1·02; P = 0·074). Only in the gastric bypass group was a significant impact on CVD observed (HR 0·53, 0·34 to 0·81; P = 0·003). Bariatric surgery was associated with significant reduction in all-cause mortality (adjusted HR 0·70, 0·55 to 0·89; P = 0·004), hypertension (adjusted HR 0·41, 0·34 to 0·50; P &lt; 0·001) and heart failure (adjusted HR 0·57, 0·34 to 0·96; P = 0·033). Outcomes were similar in patients with and those without T2DM (exposed versus controls), except for incident atrial fibrillation, which was reduced in the T2DM group.

Conclusion

Bariatric surgery is associated with a reduced risk of hypertension, heart failure and mortality, compared with routine care. Gastric bypass was associated with reduced risk of CVD compared to routine care.