Bioelectrical impedance analysis-derived phase angle is related to risk scores of a first cardiovascular event in adults.

OBJECTIVE: The aim of this study was to investigate the association between phase angle (PhA) and first cardiovascular (CV) event risk. METHODS: This was a cross-sectional study. PhA was determined using a single-frequency bioelectrical impedance analyzer. Scores from the American College of Cardiology/American Heart Association (ACC/AHA; N = 455; 49% men) and the Framingham General Cardiovascular (FRS-CVD; N = 489; 49% men) were used to estimate the risk for a first CV event in adults. Logistic and multinomial regressions were used to evaluate the relationship between ACC/AHA and FRS-CVD risk scores (outcomes) and PhA. Additionally, the consumption of in natura or minimally processed foods was included in the models as an adjustment variable. RESULTS: Men and women, classified according to ACC/AHA (P < 0.001; P = 0.035) and FRS-CVD scores (P = 0.002; P = 0.012) as low risk for first event CV, presented higher PhA values than participants with elevated risk. However, only in men categorized as CV high risk, the third PhA tertile (>7.3°) was associated with a CV lower risk (ACC/AHA, odds ratio, 0.28; 95% confidence interval [CI], 0.14-0.56; FRS-CVD, relative risk ratio, 0.11; 95% CI, 0.03-0.37). The adjustment of all models for consumption of in natura or minimally processed foods did not change the results. CONCLUSION: Higher PhA values were associated with lower risk for a first CV event in men classified in higher-risk categories. In natura or minimally processed food consumption did not influence the relationship between PhA and CV risk. These results may encourage future research about possible applications of PhA as an additional index in primary prevention of CV events.

Smoking status affects bioimpedance-derived phase angle in men but not in women: The Pró-Saúde Study, Brazil.

OBJECTIVE: Phase angle (PhA) is determined by bioelectrical impedance (BIA) and it is interpreted as an index of cell membrane integrity. Smokers are susceptible to systemic oxidative stress and often adopt unhealthy habits, which may contribute to cellular damage. This unfavorable conjuncture may result in lower PhA in smokers. The aim of this study was to investigate the association between PhA and smoking status. METHODS: This cross-sectional study included 247 (48%) adult men. Body composition and PhA were determined using dual-energy x-ray absorptiometry and BIA, respectively. Blood sampling, food habits, and smoking status information were collected. Statistical analyses were performed for each sex separately. Analysis of covariance controlling for body mass index and age compared PhA values across smoking categories. Multiple linear regression determined whether smoking status was a PhA predictor. RESULTS: PhA was lower in male current smokers (6.6 ± 0.13°) compared with never-smokers (7 ± 0.06°; P = 0.038). The ratio of extracellular to intracellular water was higher in current (P = 0.003) and former male smokers (P = 0.006) compared with never-smokers. Body composition did not differ in male and female smoking categories. Male current smokers ingested more calories, protein, carbohydrates, and alcohol than never and former smokers (P < 0.05). Current female smokers had higher alcohol consumption compared with never smokers (P = 0.019). Male current smokers presented lower than never-smokers (unstandardized ß coefficient = -0.202; 95% confidence interval, -0.359 to -0.046). Smoking status was associated with PhA decrease only in men. CONCLUSION: The results from the present study suggest that being a current smoker results in lower PhA in men, even when controlling for other variables.

Bioimpedance parameters in adolescent athletes in relation to bone maturity and biochemical zinc indices.

Phase angle (PA) is derived from resistance and reactance determined by bioimpedance analysis (BIA) and it appears to relate to cellular stability and integrity. Interpretation of PA values could be complemented by bioelectrical impedance vector analysis (BIVA), which relates to body hydration and structure. Body composition, age, sex, and nutrients are known to stabilize cell membranes, such as zinc, have been related to PA although information is scarce in adolescent athletes. The aim of the present study was to assess the association of body composition, skeletal maturity and zinc biochemical indices with phase angle and bioelectrical impedance parameters, in forty male adolescent soccer athletes (13.4±0.6years). BIA was performed with a single-frequency tetrapolar analyzer. PA and BIVA were determined using resistance and reactance BIA data. Plasma and erythrocyte zinc concentrations were measured using inductively coupled plasma-optical emission spectrometry. Body composition was determined by dual-energy X-ray absorptiometry, and bone age by hand X-ray measurements. PA was higher in adolescents classified by bone age as "Early" (6.8±0.9°) compared to "Late" (5.7±0.5°) (p<0.05). PA correlated with bone age (r=0.562), BMI (r=0.382), fat-free mass (r=0.468), and erythrocyte zinc (r=0.379) (p<0.05). BIVA confidence ellipses were sensitive to skeletal maturity status. Phase angle was higher in adolescents with erythrocyte zinc concentration above the median (>0.66µmol.g hemoglobin-1) compared to those below the median. Multiple linear regression analysis showed that bone age (B=0.254, p=0.001) and erythrocyte zinc concentration (B=1.168, p=0.047) were significantly related to PA in this group, and accounted for 34% of its variability. Our results indicate that bone age and zinc erythrocyte contribute to PA values in the young male soccer athletes and that BIVA is influenced by skeletal maturity status in this group.