Over the past several decades abdominal obesity and physical inactivity have increased at an alarming pace. Since both are related to adverse health risk it is important to determine their independent influence. It is well established that cardiorespiratory fitness (CRF, the ability to perform physical activity) and physical activity (PA) are negatively associated with cardiometabolic risk factors (commonly obtained risk factors for disease, e.g: TG, HDL, etc.). In other words, the higher a person’s levels of PA and fitness, the lower that person’s likelihood of developing cardiometabolic risk factors. Abdominal obesity is positively associated with cardiometabolic risk factors which means the more abdominally obese a person is, the more prone that person is to develop cardiometabolic risk factors. However, it is unknown whether PA influences cardiometabolic risk factors independent of fitness level and/or abdominal obesity. My study objective was to examine whether PA is associated with cardiometabolic risk factors independent of cardiorespiratory fitness and/or abdominal obesity in inactive abdominally obese women. The study enrolled 141 inactive abdominally obese women. PA, cardiorespiratory fitness, and cardiometabolic risk profile were measured in all participants. A novel feature of this study was the use of the accelerometer to objectively measure PA and to divide exercise into different levels of intensity, such as: low PA, moderate to vigorous PA (MVPA), etc. My findings revealed that abdominal obesity was positively associated with cardiometabolic risk independent of PA or CRF. I also observed that CRF was inversely related to cardiometabolic risk independent of PA or abdominal obesity. MVPA explained cardiometabolic risk factors by itself, but with insulin resistance measurements (2-hour glucose, and homeostasis model of assessment) this relationship was abolished when abdominal obesity and CRF were also taken into consideration. The findings of this study provide further support for the recommendation that waist circumference and CRF be included as routine measures screening for cardiometabolic risk factors in inactive obese women. Our findings also support the suggestion that even modest amounts of daily MVPA that are below the recommended threshold of 30 minutes/day convey health benefit. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2013-07-23 13:46:57.088

Image-based quantifications of visceral adipose tissue (VAT) volumes from segmented VAT areas are increasingly considered for risk assessment in obese patients. The goal of this study was to determine the power of partial VAT areas to predict total VAT volume in morbidly obese patients (BMI > 40 kg/m2) as a function of gender, age and anatomical landmarks. 130 morbidly obese patients (mean BMI 46.5 kg/m2; 94 females) underwent IRB-approved MRI. Total VAT volumes were predicted from segmented VAT areas (of single or five adjacent slices) at common axial landmark levels and compared with the measured ones (VVAT-T, about 40 slices between diaphragm and pelvic floor). Standard deviations σ1 and σ5 of the respective VAT volume differences served as measures of agreement. Mean VVAT-T was 4.9 L for females and 8.1 L for males. Best predictions were found at intervertebral spaces L3-L4 for females (σ5 = 688 ml, σ1 = 832 ml) and L1-L2 for males (σ5 = 846 ml, σ1 = 992 ml), irrespective of age. In conclusion, VAT volumes in morbidly obese patients can be reliably predicted by multiplying the segmented VAT area at a gender-specific lumbar reference level with a fixed scaling factor and effective slice thickness.

Weight loss has been shown to significantly improve Adipose tissue (AT) function, however changes in AT gene expression profiles particularly in visceral AT (VAT) have not been systematically studied. Here, we tested the hypothesis that extensive weight loss in response to bariatric surgery (BS) causes AT gene expression changes, which may affect energy and lipid metabolism, inflammation and secretory function of AT. We assessed gene expression changes by whole genome expression chips in AT samples obtained from six morbidly obese individuals, who underwent a two step BS strategy with sleeve gastrectomy as initial and a Roux-en-Y gastric bypass as second step surgery after 12 ± 2 months. Global gene expression differences in VAT and subcutaneous (S)AT were analyzed through the use of genome-scale metabolic model (GEM) for adipocytes. Significantly altered gene expressions were PCR-validated in 16 individuals, which also underwent a two-step surgery intervention. We found increased expression of cell death-inducing DFFA-like effector a (CIDEA), involved in formation of lipid droplets in both fat depots in response to significant weight loss. We observed that expression of the genes associated with metabolic reactions involved in NAD+, glutathione and branched chain amino acid metabolism are significantly increased in AT depots after surgery-induced weight loss.

The increasing prevalence of abdominal obesity worldwide poses a serious public health problem and hence, presents a target for research designed to improve the assessment or treatment of abdominal obesity. Specifically, the first study in this thesis investigated the influence of age and gender on visceral (VAT) and abdominal subcutaneous adipose tissue (ASAT) for a given waist circumference (WC) in 481 men and women varying widely in age and BMI. Significant gender differences in VAT and ASAT for a given WC were observed, however, only the relationship between WC and VAT was substantially influenced by age. The second study examined whether the associations between VAT, ASAT and the metabolic syndrome (MetS) were altered depending on measurement methodology used to assess VAT and ASAT. The odds ratio (OR) for MetS was higher for total VAT volume (OR=7.26) and the partial volumes at T12-L1 (OR=7.46) and L1-L2 (OR=8.77) compared to the classic L4-L5 (OR=3.94) measurement. The OR for MetS was not substantially different among the ASAT measures (OR~2.6). Measurement site for VAT, but not ASAT, has a substantial influence on the magnitude of the association with MetS. The third study examined the independent associations between VAT, ASAT, liver fat and all-cause mortality in 291 men (97 decedents and 194 controls, mortality follow-up of 2.2±1.3 years). In a model including VAT, ASAT, liver fat, age, and length of follow-up, only VAT (1.93 [1.15-3.23]) remained a significant predictor of mortality. We concluded that VAT is a strong, independent predictor of all-cause mortality in men. The purpose of the final study was to determine the effect of aerobic exercise dose (energy expenditure) on WC in sedentary, overweight/obese postmenopausal women (n=424). The women were randomly assigned to a control group or one of three aerobic exercise groups that exercised at energy expenditures of 4-, 8-, or 12-kcal/kg body weight/week. By comparison to control, there were significant reductions in WC in the exercise groups (~3 cm, P <0.05), which were independent of weight loss. However, the amount of exercise performed was not associated with reductions in WC in a dose dependent manner. / Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2007-05-17 19:24:06.777

Os níveis de obesidade vêm aumentando, no Brasil e no mundo, de maneira exponencial. A condição de excesso de tecido adiposo pode gerar um prejuízo funcional, bem como alterações em uma série de parâmetros de saúde cardiovascular. A quantidade e qualidade muscular apresentada por um indivíduo obeso podem ser determinantes na maneira como o organismo lida com esses desafios. Dessa forma, o objetivo do presente estudo foi verificar a existência de associação entre variáveis de força, qualidade e quantidade muscular, funcionalidade, saúde vascular e adiposidade em indivíduos obesos. Para isso, trinta e quatro indivíduos obesos, com idade entre 20-60 anos, sedentários, não fumantes e não diabéticos, se voluntariaram a participar do estudo. Após prévia familiarização, foram realizados testes de força nos extensores de joelho (contração isométrica voluntária máxima - CIVM ; 1 repetição máxima - 1RM; potência média) e funcionalidade (teste de caminhada de 6 minutos - TC6M; sentar e levantar em 30 segundos - SL30; get up and go). A massa muscular (EMQUA) e echo intensity do quadríceps femoral (EIQUA) foram medidas por ultrassonografia, bem como diferentes parâmetros de adiposidade e função endotelial (avaliada por dilatação mediada por fluxo - DMF). Foram verificados os coeficientes de correlação de pearson entre as variáveis acima citadas e adotou-se um p<0.05 para associação significativa. Foi encontrada uma associação negativa significativa entre a EIQUA e todos os testes de força analisados, bem como com os testes funcionais. A EMQUA também apresentou correlação significativa, porém positiva, com os testes de força e funcionalidade. A EIQUA apresentou uma associação significativa com a gordura visceral, bem como com a gordura subcutânea da coxa. Além disso, a gordura subcutânea abdominal apresentou associação significativa com a DMF. Os dados do presente estudo mostraram haver uma associação significativa entre a quantidade e qualidade muscular e o desempenho em testes de força e funcionais em indivíduos obesos. Ainda, importantes parâmetros de adiposidade se correlacionaram com a EIQUA e com a DMF, um importante marcador de saúde endotelial. Dessa forma, estartégias de intervenção (por exemplo, treinamento de força), que sejam capazes de modificar os parâmetros acima descritos, devem ser priorizadas quando o objetivo for uma melhora na qualidade de vida de indivíduos obesos. / Obesity levels are increasing in Brazil and all over the world in an exponential way. The adipose tissue excess may affect functionality, as well as another health parameters. The skeletal muscle quantity and quality in obese individual may be determinant in how that the organism deals with theses problems. Thus, the objective of the present study was to verify the association between strength, muscle quantity and quality, functionality, vascular health and adiposity in obese subjects. Thirty four obese subjects, aged 20-60 years, sedentary, non-smokers and non-diabetic, volunteered to participate in the study. After a familiartization session, the knee extensors strength (isometric maximal volunatry contraction - IMVC; on repetition maximum - 1RM ; average power) and functional (6 minutes walk test - TC6M; sit to stand up test - 30SL; get up and go) tests were performed. The quadriceps femoris muscle thickness (EMQUA) and echo intensity (EIQUA) were evaluated by ultrasonography, as well as different adiposty parameters and vascular function. The pearson correlation coefficent were verified between all variables cited above and a P<0.05 were adopted. There was found a negative significant association between the EIQUA and all the strength tests performed, as well as all functional tests. The EMQUA presented significant positive association with all strength and functional tests. Additionally, the EIQUA presented a significant negative association with the visceral adipose tissue, as well as the thigh subcutaneous adipose tissue. Besides that, the abdominal subcutaneous adipose tissue was associated positively with the vascular function. The data presented here have shown a significant association between the muscle quantity and quality and the performance in functional and strength tests in obese subjects. In addition, important adiposity parameters correlated with the EIQUA and vascular function. Thus, intervention strategies (such as strength training), that are capable of modifying these parameters, should be prioritized when the objective is to enhance the quality of life in an obese person.

Objetivo: Verificar o efeito em longo prazo do tratamento da apneia do sono com CPAP na circunferência da cintura em pacientes com apneia do sono. Métodos: Foram incluídos indivíduos com apneia do sono de ambos os sexos, idade superior a 18 anos, com indicação de uso de CPAP que aderiram ou não ao tratamento. Todos foram submetidos à polissonografia de noite inteira pelo método convencional em laboratório do sono afiliado a universidade entre 01/01/2007 e 01/06/2012. O grupo com CPAP realizou pelo menos três polissonografias. O grupo controle foi composto por pacientes que repetiram a polissonografia após pelo menos seis meses, que relataram não receber qualquer tipo de tratamento e que mantinham o IAH na segunda polissonografia. Resultados: No grupo CPAP foram incluídos 77 pacientes e no grupo controle, 43 pacientes. O tempo de acompanhamento foi respectivamente de 2,5 e 2,3 anos. Foi observada uma redução significativa na circunferência abdominal no grupo CPAP, comparando com controles através do teste t de Student (P= 0,024). O modelo logístico binário para prever redução da circunferência abdominal após o período de acompanhamento foi significativo (P <0,001), utilizando-se como regressores: uso do CPAP, sexo, idade> 45 anos, IMC≥ 30 kg/m2 e IAH≥ 30. O R2 de Nagelkerke foi de 0,36, indicando que essas variáveis explicam 36% da variação da redução da circunferência abdominal. Conclusão: O uso de CPAP se associa à redução da circunferência abdominal, independentemente de sexo, idade e índice de apneia-hipopneia basais, bem como da diferença de índice de massa corporal. Este achado justifica pesquisas futura sobre o papel da apneia do sono no volume de gordura visceral. / Objective: Verify the long term effect of sleep apnea treatment with CPAP on waist circumference in patients with sleep apnea. Methods: Individuals of both genders, older than 18 years that adhered to CPAP use or not were included. All underwent a full-night polysomnography by the conventional method in a university-affiliated sleep laboratory between 01/01/2007 to 01/06/2012. The group using CPAP underwent at least three polysomnographies. The control group consisted of patients with moderate to severe OSA who repeated a polysomnography after at least six months. Only individuals who reported not receiving any treatment and in which the AHI continued in the same OSA categories at the second polysomnography were included. Results: The CPAP group included 77 and the control group, 43 patients. Follow up time was, respectively, 2.5 and 2.3 years. A significant reduction in waist circumference was observed in the CPAP group, comparing with controls by Student’s t test (P= 0.024). The binary logistic model to predict decreased waist circumference after follow up period was significant (P<0.001), using as regressors: CPAP use, gender, age>45 years, BMI≥30 Kg/m2, and AHI≥30. The Nagelkerke R Square was 0.36, indicating that these variable explain 36% of the variance of waist circumference reduction. Conclusion: Long-term CPAP therapy is associated with a reduction in waist circumference, regardless of sex, age and basal apnea-hypopnea as well as the difference in body mass index.

Os níveis de obesidade vêm aumentando, no Brasil e no mundo, de maneira exponencial. A condição de excesso de tecido adiposo pode gerar um prejuízo funcional, bem como alterações em uma série de parâmetros de saúde cardiovascular. A quantidade e qualidade muscular apresentada por um indivíduo obeso podem ser determinantes na maneira como o organismo lida com esses desafios. Dessa forma, o objetivo do presente estudo foi verificar a existência de associação entre variáveis de força, qualidade e quantidade muscular, funcionalidade, saúde vascular e adiposidade em indivíduos obesos. Para isso, trinta e quatro indivíduos obesos, com idade entre 20-60 anos, sedentários, não fumantes e não diabéticos, se voluntariaram a participar do estudo. Após prévia familiarização, foram realizados testes de força nos extensores de joelho (contração isométrica voluntária máxima - CIVM ; 1 repetição máxima - 1RM; potência média) e funcionalidade (teste de caminhada de 6 minutos - TC6M; sentar e levantar em 30 segundos - SL30; get up and go). A massa muscular (EMQUA) e echo intensity do quadríceps femoral (EIQUA) foram medidas por ultrassonografia, bem como diferentes parâmetros de adiposidade e função endotelial (avaliada por dilatação mediada por fluxo - DMF). Foram verificados os coeficientes de correlação de pearson entre as variáveis acima citadas e adotou-se um p<0.05 para associação significativa. Foi encontrada uma associação negativa significativa entre a EIQUA e todos os testes de força analisados, bem como com os testes funcionais. A EMQUA também apresentou correlação significativa, porém positiva, com os testes de força e funcionalidade. A EIQUA apresentou uma associação significativa com a gordura visceral, bem como com a gordura subcutânea da coxa. Além disso, a gordura subcutânea abdominal apresentou associação significativa com a DMF. Os dados do presente estudo mostraram haver uma associação significativa entre a quantidade e qualidade muscular e o desempenho em testes de força e funcionais em indivíduos obesos. Ainda, importantes parâmetros de adiposidade se correlacionaram com a EIQUA e com a DMF, um importante marcador de saúde endotelial. Dessa forma, estartégias de intervenção (por exemplo, treinamento de força), que sejam capazes de modificar os parâmetros acima descritos, devem ser priorizadas quando o objetivo for uma melhora na qualidade de vida de indivíduos obesos. / Obesity levels are increasing in Brazil and all over the world in an exponential way. The adipose tissue excess may affect functionality, as well as another health parameters. The skeletal muscle quantity and quality in obese individual may be determinant in how that the organism deals with theses problems. Thus, the objective of the present study was to verify the association between strength, muscle quantity and quality, functionality, vascular health and adiposity in obese subjects. Thirty four obese subjects, aged 20-60 years, sedentary, non-smokers and non-diabetic, volunteered to participate in the study. After a familiartization session, the knee extensors strength (isometric maximal volunatry contraction - IMVC; on repetition maximum - 1RM ; average power) and functional (6 minutes walk test - TC6M; sit to stand up test - 30SL; get up and go) tests were performed. The quadriceps femoris muscle thickness (EMQUA) and echo intensity (EIQUA) were evaluated by ultrasonography, as well as different adiposty parameters and vascular function. The pearson correlation coefficent were verified between all variables cited above and a P<0.05 were adopted. There was found a negative significant association between the EIQUA and all the strength tests performed, as well as all functional tests. The EMQUA presented significant positive association with all strength and functional tests. Additionally, the EIQUA presented a significant negative association with the visceral adipose tissue, as well as the thigh subcutaneous adipose tissue. Besides that, the abdominal subcutaneous adipose tissue was associated positively with the vascular function. The data presented here have shown a significant association between the muscle quantity and quality and the performance in functional and strength tests in obese subjects. In addition, important adiposity parameters correlated with the EIQUA and vascular function. Thus, intervention strategies (such as strength training), that are capable of modifying these parameters, should be prioritized when the objective is to enhance the quality of life in an obese person.

Objetivo: Verificar o efeito em longo prazo do tratamento da apneia do sono com CPAP na circunferência da cintura em pacientes com apneia do sono. Métodos: Foram incluídos indivíduos com apneia do sono de ambos os sexos, idade superior a 18 anos, com indicação de uso de CPAP que aderiram ou não ao tratamento. Todos foram submetidos à polissonografia de noite inteira pelo método convencional em laboratório do sono afiliado a universidade entre 01/01/2007 e 01/06/2012. O grupo com CPAP realizou pelo menos três polissonografias. O grupo controle foi composto por pacientes que repetiram a polissonografia após pelo menos seis meses, que relataram não receber qualquer tipo de tratamento e que mantinham o IAH na segunda polissonografia. Resultados: No grupo CPAP foram incluídos 77 pacientes e no grupo controle, 43 pacientes. O tempo de acompanhamento foi respectivamente de 2,5 e 2,3 anos. Foi observada uma redução significativa na circunferência abdominal no grupo CPAP, comparando com controles através do teste t de Student (P= 0,024). O modelo logístico binário para prever redução da circunferência abdominal após o período de acompanhamento foi significativo (P <0,001), utilizando-se como regressores: uso do CPAP, sexo, idade> 45 anos, IMC≥ 30 kg/m2 e IAH≥ 30. O R2 de Nagelkerke foi de 0,36, indicando que essas variáveis explicam 36% da variação da redução da circunferência abdominal. Conclusão: O uso de CPAP se associa à redução da circunferência abdominal, independentemente de sexo, idade e índice de apneia-hipopneia basais, bem como da diferença de índice de massa corporal. Este achado justifica pesquisas futura sobre o papel da apneia do sono no volume de gordura visceral. / Objective: Verify the long term effect of sleep apnea treatment with CPAP on waist circumference in patients with sleep apnea. Methods: Individuals of both genders, older than 18 years that adhered to CPAP use or not were included. All underwent a full-night polysomnography by the conventional method in a university-affiliated sleep laboratory between 01/01/2007 to 01/06/2012. The group using CPAP underwent at least three polysomnographies. The control group consisted of patients with moderate to severe OSA who repeated a polysomnography after at least six months. Only individuals who reported not receiving any treatment and in which the AHI continued in the same OSA categories at the second polysomnography were included. Results: The CPAP group included 77 and the control group, 43 patients. Follow up time was, respectively, 2.5 and 2.3 years. A significant reduction in waist circumference was observed in the CPAP group, comparing with controls by Student’s t test (P= 0.024). The binary logistic model to predict decreased waist circumference after follow up period was significant (P<0.001), using as regressors: CPAP use, gender, age>45 years, BMI≥30 Kg/m2, and AHI≥30. The Nagelkerke R Square was 0.36, indicating that these variable explain 36% of the variance of waist circumference reduction. Conclusion: Long-term CPAP therapy is associated with a reduction in waist circumference, regardless of sex, age and basal apnea-hypopnea as well as the difference in body mass index.

Os níveis de obesidade vêm aumentando, no Brasil e no mundo, de maneira exponencial. A condição de excesso de tecido adiposo pode gerar um prejuízo funcional, bem como alterações em uma série de parâmetros de saúde cardiovascular. A quantidade e qualidade muscular apresentada por um indivíduo obeso podem ser determinantes na maneira como o organismo lida com esses desafios. Dessa forma, o objetivo do presente estudo foi verificar a existência de associação entre variáveis de força, qualidade e quantidade muscular, funcionalidade, saúde vascular e adiposidade em indivíduos obesos. Para isso, trinta e quatro indivíduos obesos, com idade entre 20-60 anos, sedentários, não fumantes e não diabéticos, se voluntariaram a participar do estudo. Após prévia familiarização, foram realizados testes de força nos extensores de joelho (contração isométrica voluntária máxima - CIVM ; 1 repetição máxima - 1RM; potência média) e funcionalidade (teste de caminhada de 6 minutos - TC6M; sentar e levantar em 30 segundos - SL30; get up and go). A massa muscular (EMQUA) e echo intensity do quadríceps femoral (EIQUA) foram medidas por ultrassonografia, bem como diferentes parâmetros de adiposidade e função endotelial (avaliada por dilatação mediada por fluxo - DMF). Foram verificados os coeficientes de correlação de pearson entre as variáveis acima citadas e adotou-se um p<0.05 para associação significativa. Foi encontrada uma associação negativa significativa entre a EIQUA e todos os testes de força analisados, bem como com os testes funcionais. A EMQUA também apresentou correlação significativa, porém positiva, com os testes de força e funcionalidade. A EIQUA apresentou uma associação significativa com a gordura visceral, bem como com a gordura subcutânea da coxa. Além disso, a gordura subcutânea abdominal apresentou associação significativa com a DMF. Os dados do presente estudo mostraram haver uma associação significativa entre a quantidade e qualidade muscular e o desempenho em testes de força e funcionais em indivíduos obesos. Ainda, importantes parâmetros de adiposidade se correlacionaram com a EIQUA e com a DMF, um importante marcador de saúde endotelial. Dessa forma, estartégias de intervenção (por exemplo, treinamento de força), que sejam capazes de modificar os parâmetros acima descritos, devem ser priorizadas quando o objetivo for uma melhora na qualidade de vida de indivíduos obesos. / Obesity levels are increasing in Brazil and all over the world in an exponential way. The adipose tissue excess may affect functionality, as well as another health parameters. The skeletal muscle quantity and quality in obese individual may be determinant in how that the organism deals with theses problems. Thus, the objective of the present study was to verify the association between strength, muscle quantity and quality, functionality, vascular health and adiposity in obese subjects. Thirty four obese subjects, aged 20-60 years, sedentary, non-smokers and non-diabetic, volunteered to participate in the study. After a familiartization session, the knee extensors strength (isometric maximal volunatry contraction - IMVC; on repetition maximum - 1RM ; average power) and functional (6 minutes walk test - TC6M; sit to stand up test - 30SL; get up and go) tests were performed. The quadriceps femoris muscle thickness (EMQUA) and echo intensity (EIQUA) were evaluated by ultrasonography, as well as different adiposty parameters and vascular function. The pearson correlation coefficent were verified between all variables cited above and a P<0.05 were adopted. There was found a negative significant association between the EIQUA and all the strength tests performed, as well as all functional tests. The EMQUA presented significant positive association with all strength and functional tests. Additionally, the EIQUA presented a significant negative association with the visceral adipose tissue, as well as the thigh subcutaneous adipose tissue. Besides that, the abdominal subcutaneous adipose tissue was associated positively with the vascular function. The data presented here have shown a significant association between the muscle quantity and quality and the performance in functional and strength tests in obese subjects. In addition, important adiposity parameters correlated with the EIQUA and vascular function. Thus, intervention strategies (such as strength training), that are capable of modifying these parameters, should be prioritized when the objective is to enhance the quality of life in an obese person.

Objetivo: Verificar o efeito em longo prazo do tratamento da apneia do sono com CPAP na circunferência da cintura em pacientes com apneia do sono. Métodos: Foram incluídos indivíduos com apneia do sono de ambos os sexos, idade superior a 18 anos, com indicação de uso de CPAP que aderiram ou não ao tratamento. Todos foram submetidos à polissonografia de noite inteira pelo método convencional em laboratório do sono afiliado a universidade entre 01/01/2007 e 01/06/2012. O grupo com CPAP realizou pelo menos três polissonografias. O grupo controle foi composto por pacientes que repetiram a polissonografia após pelo menos seis meses, que relataram não receber qualquer tipo de tratamento e que mantinham o IAH na segunda polissonografia. Resultados: No grupo CPAP foram incluídos 77 pacientes e no grupo controle, 43 pacientes. O tempo de acompanhamento foi respectivamente de 2,5 e 2,3 anos. Foi observada uma redução significativa na circunferência abdominal no grupo CPAP, comparando com controles através do teste t de Student (P= 0,024). O modelo logístico binário para prever redução da circunferência abdominal após o período de acompanhamento foi significativo (P <0,001), utilizando-se como regressores: uso do CPAP, sexo, idade> 45 anos, IMC≥ 30 kg/m2 e IAH≥ 30. O R2 de Nagelkerke foi de 0,36, indicando que essas variáveis explicam 36% da variação da redução da circunferência abdominal. Conclusão: O uso de CPAP se associa à redução da circunferência abdominal, independentemente de sexo, idade e índice de apneia-hipopneia basais, bem como da diferença de índice de massa corporal. Este achado justifica pesquisas futura sobre o papel da apneia do sono no volume de gordura visceral. / Objective: Verify the long term effect of sleep apnea treatment with CPAP on waist circumference in patients with sleep apnea. Methods: Individuals of both genders, older than 18 years that adhered to CPAP use or not were included. All underwent a full-night polysomnography by the conventional method in a university-affiliated sleep laboratory between 01/01/2007 to 01/06/2012. The group using CPAP underwent at least three polysomnographies. The control group consisted of patients with moderate to severe OSA who repeated a polysomnography after at least six months. Only individuals who reported not receiving any treatment and in which the AHI continued in the same OSA categories at the second polysomnography were included. Results: The CPAP group included 77 and the control group, 43 patients. Follow up time was, respectively, 2.5 and 2.3 years. A significant reduction in waist circumference was observed in the CPAP group, comparing with controls by Student’s t test (P= 0.024). The binary logistic model to predict decreased waist circumference after follow up period was significant (P<0.001), using as regressors: CPAP use, gender, age>45 years, BMI≥30 Kg/m2, and AHI≥30. The Nagelkerke R Square was 0.36, indicating that these variable explain 36% of the variance of waist circumference reduction. Conclusion: Long-term CPAP therapy is associated with a reduction in waist circumference, regardless of sex, age and basal apnea-hypopnea as well as the difference in body mass index.