Classificação da aptidão cardiorrespiratória e seu papel mediador na saúde cardiometabólica e respiratória de adultos: resultados transversal do estudo EPIMOV
Data
2019-12-05
Autores
Dourado, Victor Zuniga 
Orientadores
Dourado, Victor Zuniga
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
RESUMO PARTE 1: CLASSIFICAÇÃO DA APTIDÃO CARDIORRESPIRATÓRIA
INTRODUÇÃO: A American Heart Association recomendou em 2016 que a avaliação da aptidão cardiorrespiratória (ACR) seja considerada um sinal vital na prática clínica devido à sua importância na triagem do risco cardiometabólico. Entretanto, a avaliação da ACR ainda não tem sido incorporada como estratégia de rotina. Tabelas de normalidade e equações de predição do consumo máximo de O2 (V ̇O2max), principalmente utilizando testes mais simples como o teste de caminhada de seis minutos (TC6), poderiam facilitar o uso da avaliação da ACR na prática clínica e na saúde pública. OBJETIVOS: Avaliar a ACR e suas alterações relacionadas ao sexo e idade, bem como oferecer tabelas de normalidade para a distância percorrida no TC6 (DTC6) em adultos com base na classificação obtida por avaliação direta da ACR (i.e., V ̇O2max). MÉTODOS: Avaliamos os resultados de 1295 participantes adultos entre 18 e 80 anos (60% mulheres) que realizaram a primeira avaliação no Estudo Epidemiológico do Movimento Humano (EPIMOV). O V ̇O2max foi avaliado diretamente durante teste de exercício cardiorrespiratório máximo realizado em esteira sob protocolo de rampa. O TC6 foi aplicado conforme padronização internacional. Peso, estatura foram mensurados e o índice de massa corporal (IMC) foi calculado. A ACR foi classificada para sexo e faixa etária de acordo com os percentis (p) como se segue: muito fraca (< p5%), fraca (p5% - p25%), regular (p26% - p50%), boa (p51% - p75%), excelente (p76% - p95%) e superior (> p95%), tanto para o V ̇O2max quanto para o TC6. As alterações do V ̇O2max e da DTC6 relacionadas ao sexo e idade foram avaliadas e calculamos o declínio por década (18-29, 30-39, 40-49, 50-59, 60-80 anos). A correlação entre a DTC6 e o V ̇O2max foi inspecionada e uma equação foi desenvolvida para estimativa do V ̇O2max com base na DTC6. De acordo com a classificação do V ̇O2max (i.e., padrão ouro), investigamos a DTC6 em percentual do predito com maior combinação de sensibilidade e especificidade para identificar cada uma das classificações do V ̇O2max utilizando curvas ROC. RESULTADOS: O V ̇O2max declinou em homens e mulheres, ambos em média em 8,7% por década. A DTC6, em média, declinou 9,3% por década nas mulheres e 9,5% por década nos homens. A DTC6 apresentou correlação significativa exponencial com o V ̇O2max (V ̇O2max(mL/min/kg) = 4,910 x exp (0,003 x DTC6(m)); R2 = 0,548). Produzimos tabelas de classificação da ACR nas faixas etárias 18-27, 28-34, 35-42, 43-51, 52-59 e 60-80 anos. Considerando a classificação da ACR obtida por meio do V ̇O2max como critério padrão ouro, a DTC6, em percentual do predito, apresentou excelente capacidade para identificar a ACR muito fraca (DTC6 ≤ 96%; AUC = 0,819). Apresentou boa capacidade para identificar a ACR fraca (DTC6 = 97 – 103%; AUC = 0,735), excelente (DTC6 = 107 – 109%; AUC = 0,715) e superior (DTC6 > 109%; AUC = 0,790). Entretanto, não foi capaz de diferenciar a ACR regular e boa. CONCLUSÕES: A classificação da ACR por meio da DTC6 é válida em comparação à ACR diretamente avaliada pelo V ̇O2max e poderia ser utilizada na prática clínica e na saúde pública para a triagem e monitoramento do risco cardiometabólico e respiratório de adultos da população em geral.
RESUMO PARTE 2: PAPEL MEDIADOR DA APTIDÃO CARDIORRESPIRATÓRIA
INTRODUÇÃO: Estudos de grande dimensão identificaram os baixos níveis de atividade física moderada a vigorosa (AFMV) e aptidão cardiorrespiratória (ACR) como causadores independentes de problemas cardiometabólicos e respiratórios em adultos. Entretanto, a influência combinada desses atributos tem sido investigada inapropriadamente, considerando a ACR como um confundidor. Levantamos a hipótese de que a ACR desempenha papel mediador significativo na relação entre a AFMV e tais desfechos de saúde indesejáveis. OBJETIVO: Investigar o papel mediador da ACR na correlação entre a AFMV e atributos cardiometabólicos e respiratórios em adultos assintomáticos. MÉTODOS: Avaliamos 1295 adultos entre 18 e 80 anos (60% mulheres) que utilizaram um acelerômetro triaxial acima do quadril dominante durante sete dias para avaliação da AFMV. O consumo máximo de O2 (V ̇O2max) foi avaliado diretamente durante teste de exercício cardiorrespiratório realizado em esteira. Fizemos três medidas da pressão arterial sistólica (PAS) e diastólica (PAD) em repouso. A variabilidade da frequência cardíaca (VFC) foi avaliada durante 10 minutos de repouso na posição supina por um monitor de frequ6encia cardíaca. A glicemia, colesterol total e triglicérides foram avaliados em jejum. A composição corporal foi avaliada por impedância bioelétrica tetrapolar. Realizamos espirometria para registrar a capacidade vital forçada (CVF) e o volume expiratório forçado em 1 s (VEF1). O papel mediador do V ̇O2max na relação entre AFMV (variável independente) e as variáveis cardiometabólicas e respiratórias (variáveis dependentes) foi investigado por meio de equações estruturais com cálculo dos efeitos totais (c), indiretos (ab) (i.e., mediados) e diretos (c’). O teste Sobel-Goodman foi utilizado para calcular a proporção de efeitos totais mediados. As análises de mediação foram ajustadas pela idade, sexo e escore de risco cardiovascular e, no caso do VEF1 e CVF, também para a estatura. RESULTADOS: Observamos papel mediador completo da ACR na gordura corporal e na taxa metabólica basal, com 97% e 98% dos efeitos totais mediados, respectivamente. O papel mediador do V ̇O2max foi completo também para a função pulmonar quando considerada a CVF como desfecho, com efeitos totais mediados entre 81% (CVF em L) e 93% (CVF em %pred.). Para as variáveis metabólicas o papel mediador do V ̇O2max foi significativo apenas para os triglicérides, com 77,7% do efeito total mediado. Os efeitos totais mediados pelo V ̇O2max foram significativos para quase todas as variáveis de VFC, com proporções dos efeitos totais mediados entre 36% e 64%. A AFMV não apresentou efeito total significativo na PAS ou na PAD. Diferentemente, o V ̇O2max influenciou significativamente as medidas de pressão arterial. Observamos mediação inconsistente, com a ACR atuando como variável supressora neste caso. CONCLUSÕES: A influência da AFMV na saúde cardiometabólica e respiratória de adultos é amplamente mediada pela ACR, o que demanda o delineamento de estratégias preventivas mais focadas na atividade física com intensidade suficiente para aumentar a ACR. Portanto, o presente estudo reforça as recomendações atuais no sentido de adicionar a avaliação da ACR realmente como um sinal vital na prática clínica e na saúde pública.
ABSTRACT PART 1: CLASSIFICATION OF CARDIORESPIRATORY FITNESS INTRODUCTION: The American Heart Association recommended in 2016 that the assessment of cardiorespiratory fitness (CRF) be considered a vital sign in clinical practice because of its importance in assessing cardiometabolic risk. However, the assessment of CRF has not yet been incorporated as a routine strategy. Tables of norms and prediction equations for maximum O2 uptake (!O2max), especially using simple tests such as the six-minute walk test (6MWT), could facilitate the use of CRF assessment in clinical practice and public health. OBJECTIVE: To assess the CRF and its sex- and age-related changes, as well as to provide tables of norms for the 6MWT distance (6MWD) in adults based on the classification obtained by directly assessed CRF (i.e., !O2max). METHODS: We evaluated the results of 1295 adult participants aged 18 to 80 years (60% women) who performed the first evaluation in the Epidemiology and Human Movement Study (EPIMOV). !O2max was evaluated directly during a maximal cardiopulmonary exercise test performed on a treadmill under ramp protocol. The 6MWT was applied according to international standardization. Weight, height were measured, and body mass index (BMI) was calculated. The CRF was classified for gender and age according to the percentiles (p) as: very weak (< p5%), weak (p5% - p25%), regular (p26% - p50%), good (p51% - p75%), excellent (p76% - p95%) and superior (> p95%) for both !O2max and 6MWT. Sex- and age-related changes in !O2max and 6MWD were assessed, and the decline was calculated by decade (18-29, 30-39, 40-49, 50-59, 60-80 years). The correlation between 6MWD and !O2max was inspected, and an equation was developed to estimate !O2max based on the 6MWD. According to the !O2max classification (i.e., gold standard), we investigated the 6MWD as a percentage of the predicted with the highest combination of sensitivity and specificity to identify each of the classifications using ROC curves. RESULTS: !O2max declined in men and women, both averaging 8.7% per decade. The 6MWD, on average, declined by 9.3% per decade in women and 9.5% per decade in men. The 6MWD showed a significant exponential correlation with !O2max (!O2max(mL/min/kg) = 4.910 x exp (0.003 x DTC6(m); R2 = 0.548). We produced classification tables for CRF stratified as very weak, weak, regular, good, excellent, and superior in the age groups 18-27, 28-34, 35-42, 43-51, 52- 59, and 60-80 years old. Considering the CRF classification obtained by !O2max as the gold standard criterion, the 6MWD, as a percentage of predicted, showed excellent ability to identify very weak CRF (6MWD ≤ 96%; AUC = 0.819). Good ability to identify CRF as weak (6MWD = 97 - 103%; AUC = 0.735), excellent (6MWD = 107 - 109%; AUC = 0.715) and superior (6MWD > 109%; AUC = 0.790). However, it was unable to differentiate between regular and good CRF. CONCLUSIONS: The classification of CRF by 6MWD is valid in comparison with the directly evaluated CRF by CRF and could be useful in clinical practice and public health for screening and monitoring cardiometabolic and respiratory risk management of adults in the general population. ABSTRACT PART 2: MEDIATION ROLE OF CARDIORESPIRATORY FITNESS INTRODUCTION: Extensive studies have identified low levels of moderate to vigorous physical activity (MVPA) and cardiorespiratory fitness (CRF) as independent causes of cardiometabolic and respiratory problems in adults. However, the combined influence of these attributes has been investigated inappropriately, considering CRF as a confounder. We hypothesized that CRF plays a significant mediation role in the relationship between MVPA and such undesirable health outcomes. OBJECTIVE: To investigate the mediation role of CRF in the correlation between MVPA and cardiometabolic and respiratory attributes in asymptomatic adults. METHODS: We evaluated 1295 adults aged 18 to 80 years (60% women) who used a triaxial accelerometer above the dominant hip for seven days to evaluate MVPA. Maximum O2 uptake (!O2max) was evaluated directly during a treadmill cardiopulmonary exercise testing. We obtained three measurements of systolic (SBP) and diastolic (DBP) blood pressure at rest. Heart rate variability (HRV) was assessed for 10 minutes at rest in the supine position by a heart rate monitor. Blood glucose, total cholesterol, and triglycerides were evaluated in fasting. Body composition was assessed by tetrapolar bioelectrical impedance. We performed spirometry to record forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). Structural equations investigated the mediator role of !O2max in the relationship between MVPA (independent variable) and cardiometabolic and respiratory variables (dependent variables) with the calculation of total (c), indirect (ab) (i.e., mediated) and direct (c') effects. The Sobel-Goodman test was used to calculate the proportion of total effects that was mediated. Mediation analyses were adjusted for age, sex, and cardiovascular risk score and, for FEV1 and FVC, also for height. RESULTS: We observed a full mediaton role of CRF in body fat and resting metabolic rate, with 97% and 98% of total effects mediated, respectively. The mediaton role of !O2max was also complete for pulmonary function when considering FVC as the outcome, with total effects mediated between 81% (FVC in L) and 93% (FVC in% pred.). For metabolic variables, the mediaton role of !O2max was observed only for triglycerides, with 77.7% of the total effect mediated. The total effects mediated by !O2max were significant for almost all HRV variables, with proportions of total effects mediated between 36.4% and 64.1%. MVPA had no significant total effect on SBP or DBP. On the other hand, !O2max significantly influenced blood pressure measurements. We observed inconsistent mediation, with CRF acting as a suppressor variable in this case. CONCLUSIONS: The influence of MVPA on cardiometabolic and respiratory health in adults is mostly mediated by CRF, which requires the design of preventive strategies more focused on physical activity with sufficient intensity to increase CRF. Therefore, the present study reinforces current recommendations to add the assessment of CRF really as a vital sign in clinical practice and public health.
ABSTRACT PART 1: CLASSIFICATION OF CARDIORESPIRATORY FITNESS INTRODUCTION: The American Heart Association recommended in 2016 that the assessment of cardiorespiratory fitness (CRF) be considered a vital sign in clinical practice because of its importance in assessing cardiometabolic risk. However, the assessment of CRF has not yet been incorporated as a routine strategy. Tables of norms and prediction equations for maximum O2 uptake (!O2max), especially using simple tests such as the six-minute walk test (6MWT), could facilitate the use of CRF assessment in clinical practice and public health. OBJECTIVE: To assess the CRF and its sex- and age-related changes, as well as to provide tables of norms for the 6MWT distance (6MWD) in adults based on the classification obtained by directly assessed CRF (i.e., !O2max). METHODS: We evaluated the results of 1295 adult participants aged 18 to 80 years (60% women) who performed the first evaluation in the Epidemiology and Human Movement Study (EPIMOV). !O2max was evaluated directly during a maximal cardiopulmonary exercise test performed on a treadmill under ramp protocol. The 6MWT was applied according to international standardization. Weight, height were measured, and body mass index (BMI) was calculated. The CRF was classified for gender and age according to the percentiles (p) as: very weak (< p5%), weak (p5% - p25%), regular (p26% - p50%), good (p51% - p75%), excellent (p76% - p95%) and superior (> p95%) for both !O2max and 6MWT. Sex- and age-related changes in !O2max and 6MWD were assessed, and the decline was calculated by decade (18-29, 30-39, 40-49, 50-59, 60-80 years). The correlation between 6MWD and !O2max was inspected, and an equation was developed to estimate !O2max based on the 6MWD. According to the !O2max classification (i.e., gold standard), we investigated the 6MWD as a percentage of the predicted with the highest combination of sensitivity and specificity to identify each of the classifications using ROC curves. RESULTS: !O2max declined in men and women, both averaging 8.7% per decade. The 6MWD, on average, declined by 9.3% per decade in women and 9.5% per decade in men. The 6MWD showed a significant exponential correlation with !O2max (!O2max(mL/min/kg) = 4.910 x exp (0.003 x DTC6(m); R2 = 0.548). We produced classification tables for CRF stratified as very weak, weak, regular, good, excellent, and superior in the age groups 18-27, 28-34, 35-42, 43-51, 52- 59, and 60-80 years old. Considering the CRF classification obtained by !O2max as the gold standard criterion, the 6MWD, as a percentage of predicted, showed excellent ability to identify very weak CRF (6MWD ≤ 96%; AUC = 0.819). Good ability to identify CRF as weak (6MWD = 97 - 103%; AUC = 0.735), excellent (6MWD = 107 - 109%; AUC = 0.715) and superior (6MWD > 109%; AUC = 0.790). However, it was unable to differentiate between regular and good CRF. CONCLUSIONS: The classification of CRF by 6MWD is valid in comparison with the directly evaluated CRF by CRF and could be useful in clinical practice and public health for screening and monitoring cardiometabolic and respiratory risk management of adults in the general population. ABSTRACT PART 2: MEDIATION ROLE OF CARDIORESPIRATORY FITNESS INTRODUCTION: Extensive studies have identified low levels of moderate to vigorous physical activity (MVPA) and cardiorespiratory fitness (CRF) as independent causes of cardiometabolic and respiratory problems in adults. However, the combined influence of these attributes has been investigated inappropriately, considering CRF as a confounder. We hypothesized that CRF plays a significant mediation role in the relationship between MVPA and such undesirable health outcomes. OBJECTIVE: To investigate the mediation role of CRF in the correlation between MVPA and cardiometabolic and respiratory attributes in asymptomatic adults. METHODS: We evaluated 1295 adults aged 18 to 80 years (60% women) who used a triaxial accelerometer above the dominant hip for seven days to evaluate MVPA. Maximum O2 uptake (!O2max) was evaluated directly during a treadmill cardiopulmonary exercise testing. We obtained three measurements of systolic (SBP) and diastolic (DBP) blood pressure at rest. Heart rate variability (HRV) was assessed for 10 minutes at rest in the supine position by a heart rate monitor. Blood glucose, total cholesterol, and triglycerides were evaluated in fasting. Body composition was assessed by tetrapolar bioelectrical impedance. We performed spirometry to record forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). Structural equations investigated the mediator role of !O2max in the relationship between MVPA (independent variable) and cardiometabolic and respiratory variables (dependent variables) with the calculation of total (c), indirect (ab) (i.e., mediated) and direct (c') effects. The Sobel-Goodman test was used to calculate the proportion of total effects that was mediated. Mediation analyses were adjusted for age, sex, and cardiovascular risk score and, for FEV1 and FVC, also for height. RESULTS: We observed a full mediaton role of CRF in body fat and resting metabolic rate, with 97% and 98% of total effects mediated, respectively. The mediaton role of !O2max was also complete for pulmonary function when considering FVC as the outcome, with total effects mediated between 81% (FVC in L) and 93% (FVC in% pred.). For metabolic variables, the mediaton role of !O2max was observed only for triglycerides, with 77.7% of the total effect mediated. The total effects mediated by !O2max were significant for almost all HRV variables, with proportions of total effects mediated between 36.4% and 64.1%. MVPA had no significant total effect on SBP or DBP. On the other hand, !O2max significantly influenced blood pressure measurements. We observed inconsistent mediation, with CRF acting as a suppressor variable in this case. CONCLUSIONS: The influence of MVPA on cardiometabolic and respiratory health in adults is mostly mediated by CRF, which requires the design of preventive strategies more focused on physical activity with sufficient intensity to increase CRF. Therefore, the present study reinforces current recommendations to add the assessment of CRF really as a vital sign in clinical practice and public health.
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DOURADO, Victor Zuniga, Classificação da aptidão cardiorrespiratória e seu papel mediador na saúde cardiometabólica e respiratória de adultos: resultados transversal do estudo EPIMOV. 2019. 76 f. Tese (Livre-docência) - Instituto de Saúde e Sociedade, Universidade Federal de São Paulo, Santos, 2019.