Ângulo de fase: seus preditores e sua relação com a doença cardiovascular no Estudo Pró-Saúde

Abstract

Phase Angle (PhA) is an index of cell membrane integrity and function, and higher values are associated with cellular health. Lower PhA values are related to reduction of cellular integrity and body cell mass. PhA has been considered as an indicator of nutritional status and prognosis in different clinical conditions. Considering inflammation as a determinant of PhA reductions, and that different cardiovascular (CV) risk factors are associated with inflammatory processes, it is possible to suggest that CV risk factors may lead to impairment of cellular integrity, which may result in PhA decreases. Two original manuscripts are presented in this thesis and both are cross-sectional studies conducted with part of a cohort of employees from the State University of Rio de Janeiro, participants of the Pró-Saúde Study. Manuscript 1 investigated the association between PhA and three smoking status in adult men (n=247) and women (n=268), considering information on body composition determined by dual energy X-ray absorptiometry (DXA) and BIA, anthropometry, inflammatory marker and nutrient intake among three smoking categories. Male current smokers had lower PhA values (6.6 ± 0.13 °) than those who have never smoked (7.0±0.06 °) (p=0.038). Lower PhA values in male current smokers indicate a damaged cellular health, which may be a consequence of inflammation caused by smoking per se, and also by the inadequate lifestyle current smokers often adopt. Among women, there were no differences in PhA values between smoking categories (p=0.481). Multiple linear regression showed male smokers had PhA values 0.2° (CI -0.359, -0.046, p=0.012) lower than those who have never smoked. Current smoking status and former smoker status were not predictors of PhA variations among women. In manuscript 2, description and analyses of the association between PhA and prediction models that combine multiple CV risk factors to estimate risk of a first CV event in 10 years were performed. Cardiovascular risk estimation by the Framingham global risk assessment model (FRS-CVD) was performed in 238 men and 251 women. The American College of Cardiology/American Heart Association (ACC/AHA) prediction model estimated the risk of a first atherosclerotic CV event in 222 men and 233 women. Results showed that men and women in high-risk categories, according to both prediction models, presented lower PhA values than those categorized as low-risk (men: ACC/AHA, p <0.001, FRS-CVD, p=0.003 - women: ACC /AHA, p <0.035, FRS-CVD, p = 0.012). Moreover, in logistic and multinomial regression analyses, third PhA tertile (>7.3%) in men was associated with a lower risk of CV event among those categorized as high-risk, according to both prediction models (ACC/AHA OR 0.28, 95% CI 0.14, 0.56) and (FRS-CVD RRR 0.11, 95% CI 0.03, 0.37). It was not observed an association between PhA and risk of a first CV event estimated by ACC/AHA or FRS-CVD among women. Results of both studies show that inflammatory responses associated with current smoking or presence of multiple CV risk factors are associated with PhA decreases