Relationship between abdominal and neck fat with sleep disorders in obese patients

Abstract Introduction Obesity is one of the main public health problem worldwide and it has a negative short- and long-term relationship with women's health. Assessment of this disorder is essential, as is a body composition assessed by dual-energy X-ray absorptiometry (DXA) with the new region of interest as the neck. Objective To verify the association between abdominal and neck fat with sleep quality in obese women. Methods The sample, obtained from a Biomedical Engineering and Health Program database, was characterized by being obese female aged between 20 and 65 years. The tests performed were anthropometric assessment, sleep quality questionnaire, physical activity level, nutritional assessment, and body composition by dual-energy X-ray absorptiometry (DXA). For statistical analysis, the Shapiro-Wilk test, t test for independent samples, Kendall's Tau, linear and multiple regression and ROC curve were used. Results The sample consisted of 15 individuals with a mean age of 45 ± 11.10 years, neck circumference of 41.50 ± 2.61 and abdominal circumference of 128.20 ± 11.62. We found no correlation between the regions of interest and the sleep quality questionnaire. Regression analysis shows non-significant statistical values for abdominal fat. The statistical test proved that the new region of interest in abdominal fat is closer to better sensitivity and has a greater relationship with sleep quality. Conclusion there was no statistically significant correlation between the regions of interest and the sleep quality questionnaire. However, the abdominal fat region of interest was the point that presented the best association with sleep quality assessed by the Pittsburgh questionnaire.


Introduction
Obesity is one of the main public health problems worldwide, considered very important for social, psychological and metabolic reasons, 1 being associated with a high degree of comorbidities and high risk of mortality.2 Among obesity-associated comorbidities are heart diseases, diabetes, some cancer types, arterial hypertension, locomotors disturbance, dyslipidemias, in addition to psychological disorders such as depression and binge eating.3 The sleep apnea is the other respiratory problem caused by obesity, affecting 2% of women and 4% of men worldwide, being characterized by obstruction in airways and respiratory pause.4 In relation to this topic, this phenomenon can cause an increase in intra-abdominal pressure and transfer this pressure to the thoracic region, resulting in changes in pressure/volume curves, decreasing lung volume and making breathing difficult.5 The evaluation of sleep quality and duration is essential to identify causes associated with obesity, including nutritional disturbances and poor physical activity.The recommendation of sleep for adults is seven hours minimum per night and for adolescents, eight hours.6 Some studies show that there is a relationship between dissatisfaction with the quality of sleep and obesity.7 Thus, the duration and quality of sleep are important for controlling the risk of developing obesity and metabolic diseases.Along with a descriptive table we used the t-test for an independent sample to verify the differences between each variable.Significance was established at p < 0.05.

Results
The sample was composed of 15 participants aged median 45.0 years old.The Pittsburgh scale was 6.00 (bad sleep quality), with 75% above 10 points.Table 1 shows  The study included 753 participants aged between 35 and 65, who were assessed using the PSQI.Weight, height and waist circumference were measured and there was a significant association of low quality of sleep with general obesity and high body fat in adults, There was no correlation between Pittsburgh and the regions analyzed, nor a significant difference between the variables (Table 2).The regression analysis presented more influence between Pittsburgh scale and visceral fat, with values above neck fat, but both showed no statistically significant differences ( The study also reports that neck circumference is a useful indicator of metabolic risk, although it is not independent of BMI. 17 The participants were women aged 20 to 65 years, with a body mass index (BMI) classified between overweight and obesity, and weight limit of 150 kg, with sleep disorders.Participants who underwent any radiation examination at least seven days before the DXA analysis and/or missed one of the scheduled examinations were excluded.For the analysis of sleep quality, the Pittsburgh Sleep Quality Index (PSQI) and the excessive sleepiness scale were applied.The Pittsburgh questionnaire has seven components, above five points, and the subject is classified as having poor quality sleep.For the excessive sleepiness scale, the subject who scored above 10 points out of the total was classified as positive.The circumference evaluation of the neck and abdomen was performed with a brand tape measure WISO (WCS®).For the neck circumference was used the above thyroid cartilage and perpendicular along the neck axis.For the abdominal area it was used in the largest abdominal perimeter between the last rib and iliac crest.The body composition was performed by a Hologic model Discovery A densitometer was used.The total body composition and the region of interest for the neck and abdominal area were analyzed and the total fat mass and the fat mass index for each region were measured, as well as lean mass according to International Society for Clinical Densitometry.The statistical analysis was performed by Microsoft version 2015 and software SPSS version 21.0.Shapiro-Wilk test was used for sample characterization, and to correlation test was performed the Kendall's Tau for linear multiple regression analysis.ROC curve was used to obtain the sensitivity and specification between participants with and without sleep disorders.Descriptive analysis was described through the table with median, standard deviation, minimum, maximum and quartile.
In our results the ROC curve analysis showed that abdominal and visceral fat presented values nearest for sensibility and positive outcomes.In a survey of 3,995 participants who were 18 years of age or older and were free from cardiovascular disease, cancer, emphysema, chronic pulmonary disease and depression, sleep disorders were associated with larger body size and higher measurements of body composition assessed by DXA, and this result was largely motivated by sleep apnea.18

Table 1 -
Clinic and body composition characteristics for total sample FISIOTERAPIA EM MOVIMENTO Physical Therapy in Movement Ruthes EMP et al.Fisioter Mov.2023;36:e36108 4

Table 2 -
Correlation between Kendall's Tau and regions of interest and Pittsburgh scale

Table 3 -
Regression analysis for regions of interest withPittsburgh scaleConclusionThe present study concluded that although the statistical data do not indicate a statistical correlation between neck and abdomen measurements analyzed by DXA with sleep quality, these measurements are of great importance as complementary measures for this purpose.The small sample used for the analysis together with the use of only a specific questionnaire without the technological resource of polysomnography for diagnostic definition were the main limitations of this investigation.Therefore, there is still a great need for new researches on the topic and mainly for new resources and diagnostic techniques.