Beneficial Effect Of Weight Loss Research Articles

Baseline phenotypes with preserved β-cell function and high insulin concentrations have the best improvements in glucose tolerance after weight loss: results from the prospective DEXLIFE and EGIR-RISC studies

BackgroundWeight loss and lifestyle intervention improve glucose tolerance delaying the onset of type 2 diabetes (T2D), but individual responses are highly variable. Determining the predictive factors linked to the beneficial effects of weight loss on glucose tolerance could provide tools for individualized prevention plans. Thus, the aim was to investigate the relationship between pre-intervention values of insulin sensitivity and secretion and the improvement in glucose metabolism after weight loss. MethodsIn the DEXLIFE cohort (373 individuals at high risk of T2D, assigned 3:1 to a 12-week lifestyle intervention or a control arm, Trial Registration: ISRCTN66987085), K-means clustering and logistic regression analysis were performed based on pre-intervention indices of insulin sensitivity, insulin secretion (AUC-I), and glucose-stimulated insulin response (ratio of incremental areas of insulin and glucose, iAUC I/G). The response to the intervention was evaluated in terms of reduction of OGTT-glucose concentration. Clusters' validation was done in the prospective EGIR-RISC cohort (n = 1538). ResultsFour replicable clusters with different glycemic and metabolomic profiles were identified. Individuals had similar weight loss, but improvement in glycemic profile and β-cell function was different among clusters, highly depending on pre-intervention insulin response to OGTT. Pre-intervention high insulin response was associated with the best improvement in AUC-G, while clusters with low AUC-I and iAUC I/G showed no beneficial effect of weight loss on glucose control, as also confirmed by the logistic regression model. ConclusionsIndividuals with preserved β-cell function and high insulin concentrations at baseline have the best improvement in glucose tolerance after weight loss.

Weight loss affects disease activity and treatment response in inflammatory rheumatic diseases

The quantity and quality of the adipose tissue is altered in obesity: hypertrophy of adipocytes, decrease in expandability, fibrosis, production of pro-inflammatory cytokines and adipokines, inflammatory infiltration by pro-inflammatory M1 macrophages and T lymphocytes. Excess adipose tissue and obesity are associated with low-grade inflammation that can aggravate chronic inflammatory diseases, decrease treatment efficacy, contribute to the development of comorbidities, and of the disease in its preclinical phase. Obesity increases the incidence of rheumatoid arthritis (RA), psoriasis, psoriatic arthritis with a weight-dose effect. It is also a predictor of worse response to treatment, in particular TNF inhibitors. Weight loss induced by bariatric surgery decreases the risk of psoriasis and psoriatic arthritis and improves disease activity and remission in RA. A 5% weight loss through a low-calorie diet improves the response to TNF inhibitors in psoriatic arthritis, losing even more weight improves the response even more. In RA, the beneficial effect of weight loss from a low-calorie diet on disease activity has been reported in a few observational studies but has not been demonstrated in a randomized controlled trial. Screening and management of obesity are part of the dietary recommendations of the French Society for Rheumatology in patients with chronic inflammatory rheumatic diseases. Of course, this should be combined with other lifestyle modifications such as smoking cessation, higher food quality, increased physical activity and reduced sedentary behavior.

Supplementation with calcium + vitamin D enhances the beneficial effect of weight loss on plasma lipid and lipoprotein concentrations

Background: Adequate calcium intake can have a favorable effect on some metabolic variables.Objective: The objective of the study was to determine the effects of daily calcium intake and of supplementation with calcium and vitamin D (calcium+D) during a weight-loss intervention on blood pressures, plasma lipid and lipoprotein concentrations, and glucose and insulin concentrations in low calcium consumers.Design: Healthy, overweight or obese women (n = 63) with a daily calcium intake of <800 mg/d were randomly assigned in a double-blind manner to 1 of 2 groups: the group consuming 2 tablets/d of a calcium + vitamin D supplement (600 mg elemental calcium and 200 IU vitamin D/tablet) or the group consuming placebo; both groups observed a 700 kcal/d energy restriction. These 63 women then completed a 15-wk weight-loss intervention.Results: Initial daily calcium intake was significantly correlated with plasma HDL cholesterol (r = 0.41, P < 0.001) and with 2-h postload glycemia (r = −0.29, P < 0.05) during an oral-glucose-tolerance test, independent of fat mass and waist circumference. After the 15-wk intervention, significantly greater decreases in total:LDL and LDL:HDL (P < 0.01 for both) and of LDL cholesterol (P < 0.05) were observed in the calcium+D group than in the placebo group. The differences in total:HDL and LDL:HDL were independent of changes in fat mass and in waist circumference. A tendency for more beneficial changes in HDL cholesterol, triacylglycerol, and total cholesterol was also observed in the calcium+D group (P = 0.08).Conclusion: Consumption of calcium+D during a weight-loss intervention enhanced the beneficial effect of body weight loss on the lipid and lipoprotein profile in overweight or obese women with usual low daily calcium intake.

Potential for optimizing management of obesity in the secondary prevention of coronary heart disease.

Prevention guidelines have identified the management of obese patients as an important priority to reduce the burden of incident and recurrent cardiovascular disease. Still, studies have demonstrated that over 80% of patients with coronary heart disease (CHD) fail to achieve their weight target. Here, we describe advice received and actions reported by overweight CHD patients since being discharged from hospital and how weight changes relate to their risk profile. Based on data from 10 507 CHD patients participating in the EUROASPIRE IV and V studies, we analysed weight changes from hospital admission to the time of a study visit ≥6 and <24 months later. At hospitalization, 34.9% were obese and another 46.0% were overweight. Obesity was more frequent in women and associated with more comorbidities. By the time of the study visit, 19.5% of obese patients had lost ≥5% of weight. However, in 16.4% weight had increased ≥5%. Weight gain in those overweight was associated with physical inactivity, non-adherence to dietary recommendations, smoking cessation, raised blood pressure, dyslipidaemia, dysglycaemia, and lower levels of quality of life. Less than half of obese patients was considering weight loss in the coming month. The management of obesity remains a challenge in the secondary prevention of CHD despite a beneficial effect of weight loss on risk factor prevalences and quality of life. Cardiac rehabilitation programmes should include weight loss interventions as a specific component and the incremental value of telehealth intervention as well as recently described pharmacological interventions need full consideration.

Low-fat hypocaloric diet reduces neprilysin in overweight and obese human subjects.

AimsNeprilysin (NEP), a zinc metallopeptidase, degrades a variety of bioactive peptides including natriuretic peptides terminating their biological action on arterial blood pressure and natriuresis. Pharmacological inhibition of NEP reduces mortality in patients with heart failure with reduced ejection fraction. Physiological interventions reducing NEP levels are unknown in humans. Because obesity leads to increased NEP levels and increases the risk for heart failure, we hypothesized that weight loss reduces NEP concentrations in plasma and tissue.Methods and resultsWe randomized overweight to obese human subjects to a low‐fat or low‐carbohydrate hypocaloric 6 month weight loss intervention. Soluble NEP was determined in plasma, and NEP mRNA was analysed from subcutaneous adipose tissue before and after diet. Low‐fat diet‐induced weight loss reduced soluble NEP levels from 0.83 ± 0.18 to 0.72 ± 0.18 μg/L (P = 0.038), while subcutaneous adipose tissue NEP mRNA expression was reduced by both dietary interventions [21% (P = 0.0057) by low‐fat diet and 16% (P = 0.048) by low‐carbohydrate diet]. We also analysed the polymorphisms of the gene coding for NEP, rs9827586 and rs701109, known to be associated with plasma NEP levels. For both single‐nucleotide polymorphisms, minor allele carriers (A/A) had higher baseline plasma NEP levels (rs9827586: β = 0.53 ± 0.23, P < 0.0001; rs701109: β = 0.43 ± 0.22, P = 0.0016), and minor allele carriers of rs9827586 responded to weight loss with a larger NEP reduction (rs9827586: P = 0.0048).ConclusionsOur study identifies weight loss via a hypocaloric low‐fat diet as the first physiological intervention in humans to reduce NEP in plasma and adipose tissue. Specific single‐nucleotide polymorphisms further contribute to the decrease. Our findings may help to explain the beneficial effect of weight loss on cardiac function in patients with heart failure.

The impact of a significant weight loss on inflammation assessed on DCE-MRI and static MRI in knee osteoarthritis: a prospective cohort study

To study the impact of weight loss on inflammation in individuals with overweight and knee osteoarthritis (OA) using both static- and dynamic contrast-enhanced (DCE)-MRI and assess the association of these changes to pain. Individuals with overweight (BMI>27) and knee OA were examined before and after a >5% weight loss over 8 weeks (ClinicalTrials.gov NCT02905864). Using 3-T MRI, inflammation was quantified from non-contrast enhanced static-MRI according to MOAKS and contrast enhanced static MRI according to BLOKS and 11-point whole-knee synovitis score. DCE-MRI was used to assess the inflammation in the infra patellar fat pad (IPFP). Pain was assessed using KOOS. Complete data were available in 117 participants with a mean age of 60 years, BMI of 35kg/m2 and KOOS pain score of 64. Mean weight loss was 12kg and KOOS pain was improved by 13 points at follow-up. Change in inflammation was not associated with weight loss in static MRI. None of the MRI variables correlated with the change in KOOS pain. Weight loss did not induce a significant change in inflammation in individuals with overweight and OA. The significant clinical beneficial effect of weight loss on knee pain in individuals with overweight and knee OA seems uncoupled to changes in imaging markers of synovitis.

SUN-225 CHANGES IN BODY MASS INDEX AND INCIDENT CHRONIC KIDNEY DISEASE GENERAL POPULATION: A COMMUNITY-BASED COHORT STUDY

Obesity increases cardio-metabolic risk and has emerged as an important determinant for chronic kidney disease (CKD) in the general population. However, it is uncertain whether weight reduction can prevent the development of CKD. We studied the association between weight loss and development of CKD in healthy individuals using database from a large-scale prospective cohort of the Korean Genome and Epidemiology Study. Among 10,030 participants aged 40-69 years who were recruited between 2001 and 2002, 6,497 healthy subjects without comorbidities were included in the analysis. These subjects were categorized into five group based on quintiles of % changes in body mass index (BMI). The primary outcome of interest was incident CKD, which was defined as an eGFR of < 60 mL/min per 1.73 m2 for two consecutive measurements. During a mean follow-up duration of 9.5 (3.4) years, incident CKD occurred in 455 (7.0%) participants; 4.8, 8.2, 9.0, 8.0, and 6.8 per 1000 patients-years across the quintiles, respectively (P = .01). The lowest quintile group with the largest reduction in BMI was associated with a 42 % decreased risk of incident CKD in multivariable Cox model after adjustment of confounding factors compared to the 3rd quintile group with the smallest change in BMI (hazard ratio [HR], 0.579; 95% CI, 0.408-0.820; P < .001). The beneficial effect of weight loss was consisted in 2nd lowest quintile group (HR, 0.712; 95% CI, 0.215-0.989; P = .04). This association was observed in overweight and obese groups, while the significance was lost in underweight or normal weight group. Interestingly, weight loss in obese participants was associated with a significantly decreased risk of incident CKD compared to those without weight loss and conferred a comparable risk to non-obese counterpart. This favorable effect of weight loss was partly attributed to improvements in blood pressure and metabolic profiles. Changes in BMI positively correlated with changes in blood pressure, insulin resistance, and triglyceride, but negatively correlated with changes in HDL-C and eGFR. Weight loss was associated with decreased risk of developing CKD in healthy individuals without comorbid diseases.

The Health Risks of Obesity Have Been Exaggerated.

The Health Risks of Obesity Have Been Exaggerated.

Pregnancy and bariatric surgery.

A large number of women experience pregnancy after bariatric surgery. The purpose of this review was to understand the evidence base in this area to come up with practical, evidence-based recommendations. We examined PubMed for all published articles on pregnancy in patients who have previously undergone a bariatric surgery. There is an increasing body of evidence pointing towards a beneficial effect of weight loss induced by bariatric surgery on female and male fertility prompting calls for recognition of infertility as a qualifying co-morbidity for patients between the Body Mass Index of 35.0 kg/m2 and 40.0 kg/m2. Women in childbearing age group should be routinely offered contraceptive advice after bariatric surgery and advised to avoid pregnancy until their weight has stabilized. Until more focused studies are available, the advice to wait for 12 months or 2 months after the weight loss has stabilized, whichever is latter, seems reasonable. Patients should be advised to seek clearance from their bariatric teams prior to conception and looked after by a multi-disciplinary team of women health professionals, bariatric surgeons, and dietitians during pregnancy. The main objective of care is to ensure adequate nutritional state to allow for a satisfactory weight gain and fetal growth. There is a relative lack of studies and complete lack of Level 1 evidence to inform practice in this area. This review summarizes current literature and makes a number of practical suggestions for routine care of these women while we develop evidence to better inform future practice.

The Effects of Weight Loss on Blood Rheology in Obese Patients

capillaries. This blood flow structure is the result of a specifically ordered disposition of the RBCs surrounded by plasma in the microvessel lumen during flow in the capillaries and in the adjacent arterioles and venules up to approximately 15-20 μm wide [12]. The blood flow structure disturbances produce disordered blood fluidity during microcirculation because of increased blood flow resistance under conditions of constant, or even increased, pressure gradient. Based on perennial studies of blood flow disturbances inside the capillary microvessels, several primary factors that produce increased blood flow resistance in the narrowest blood vessels are as follows: enhancement of the RBC aggregation, lowered RBC deformability, increased local hematocrit and increased local blood plasma viscosity. The impact of a hypocaloric diet on the hemorheology of obese patients has been reported in numerous studies [2,13-17]. Several studies concerned with the influence of a hypocaloric diet on RBC aggregation in obese patients reported that weight loss after dieting in obese patients normalized the aggregation of the RBCs, affecting a corresponding improvement in the erythrocyte aggregation index [13-15]. Other authors have showed the absence of improvement in rheological parameters, including RBC aggregation, after weight loss associated with a low-calorie diet [2,16]. Sola et al. (2004) showed that a very low-calorie diet of 458 kcal/day reduced erythrocyte aggregation in one month; however, a prolonged lowcalorie diet (1500 kcal/day) did not provide additional benefit for red cell aggregation, which returned to its basal value after 3 months of follow-up [17]. The impact of a hypocaloric diet on the obese patients’ blood and plasma viscosities are also not conclusive. According to Poggi et al. [14], after three months of a 500-kcal/day diet, there was a reduction in blood viscosity at low shear rates by significant decreases in RBC aggregation and hematocrit levels. Fanari et al. (1993) also demonstrated that weight loss after dieting in obese patients contributed to improving plasma and blood viscosity [13]. Other studies have shown an absence of improvement in blood and plasma viscosity after weight loss associated with a low-calorie diet [14,15]. The results of research on the impact of diet on hemorheology indicated that a beneficial effect of weight loss on rheological profiles depends on the amount of weight lost and its long-term maintenance. Bariatric surgery is recognized to substantially improve body weight, obesity-associated co-morbidities and long-term survival. The influence of weight loss surgery on hemorheological parameters has been investigated in several publications. In our first papers, verticalbanded gastroplasty was shown to induce several beneficial changes Abstract

Weight loss and coronary heart disease

Evidence for the effect of weight loss on coronary heart disease (CHD) or mortality has been mixed. The effect estimates can be confounded due to undiagnosed diseases that may affect weight loss. We used data from the Nurses' Health Study to estimate the 26-year risk of CHD under several hypothetical weight loss strategies. We applied the parametric g-formula and implemented a novel sensitivity analysis for unmeasured confounding due to undiagnosed disease by imposing a lag time for the effect of weight loss on chronic disease. Several sensitivity analyses were conducted. The estimated 26-year risk of CHD did not change under weight loss strategies using lag times from 0 to 18 years. For a 6-year lag time, the risk ratios of CHD for weight loss compared with no weight loss ranged from 1.00 (0.99, 1.02) to 1.02 (0.99, 1.05) for different degrees of weight loss with and without restricting the weight loss strategy to participants with no major chronic disease. Similarly, no protective effect of weight loss was estimated for mortality risk. In contrast, we estimated a protective effect of weight loss on risk of type 2 diabetes. We estimated that maintaining or losing weight after becoming overweight or obese does not reduce the risk of CHD or death in this cohort of middle-age US women. Unmeasured confounding, measurement error, and model misspecification are possible explanations but these did not prevent us from estimating a beneficial effect of weight loss on diabetes.

Risk factors for obstructive sleep apnea in non-obese Korean patients: Significance of body weight

The aim of this study is to evaluate if there is an association between body weight and obstructive sleep apnea even in patients who are not obese. From our hospital database, we identified 139 patients who underwent an overnight polysomnography. The inclusion criteria were patients (i) who visited our hospital with a chief complaint of snoring or apnea that was witnessed by a sleep partner, and (ii) with a body mass index <25 kg/m2. We compared the clinical variables, polysomnographic variables, and Epworth Sleepiness Scale scores in subjects with and without obstructive sleep apnea. Additionally, correlation analysis was performed between apnea-hypopnea index and age, body weight, and neck circumference. Of the 139 patients, 62 patients met the inclusion criteria for this study. Forty-two of the 62 patients were diagnosed with obstructive sleep apnea. Patients with obstructive sleep apnea were older, had higher body weight, larger neck circumference, and greater apnea-hypopnea index, longer time of pulse oxygen saturation <90%, and lower minimum pulse oxygen saturation compared to those without obstructive sleep apnea. In addition, apnea-hypopnea index was found to be positively correlated with age, body weight, and neck circumference. Multiple logistic regression analysis showed that old age, high body weight, and large neck circumference were independently associated with obstructive sleep apnea. We demonstrated that there was a significant association between body weight and obstructive sleep apnea in non-obese patients, and further prospective study is needed to evaluate the beneficial effect of weight loss on obstructive sleep apnea in non-obese patients.

Obesity Alters Balance and Movement Control

Epidemic excess of weight is considered as a critical and common health problem. It is associated with many physiological and psychological disorders. Other than metabolic problems, obesity also affects the efficient execution of daily living activities such as the simple act of standing, walking or grabbing an object while standing. This article aims at presenting a state of knowledge of recent studies illustrating the detrimental effect of obesity and the beneficial effect of weight loss on postural stability and on the speed and accuracy of upper-limb goal-directed movements performed from a standing posture. Evidence supporting the suggestion that greater strength and training, at least for standing conditions, do not overcome the functional limitations imposed by obesity are presented. It is suggested that obese individuals may suffer from a reduced plantar sole sensitivity. As a conclusion to this work, we confirm the deleterious effect of overweight on motor control as weight loss translates into an improved balance control and upper limb speed-accuracy performance when standing.

THU0504 The Relationship Between Weight Loss and Reduced Cartilage Loss in the Medial Knee Joint is Non-Linear in Obese People

BackgroundObesity is the strongest modifiable risk factor for development and progression of knee osteoarthritis (OA). There is emerging evidence for a beneficial effect of weight loss on knee structure. The...

Sleep apnea modifies the long‐term impact of surgically induced weight loss on cardiac function and inflammation

Obesity is frequently associated with obstructive sleep apnea (OSA). Both conditions are proinflammatory and proposed to deteriorate cardiac function. We used a nested cohort study design to evaluate the long-term impact of bariatric surgery on OSA and how weight loss and OSA relate to inflammation and cardiac performance. At 10-year follow-up in the Swedish Obese Subjects (SOS) study, we identified 19 obese subjects (BMI 31.2 ± 5.3 kg m(-2) ), who following bariatric surgery at SOS-baseline had displayed sustained weight losses (surgery group), and 20 obese controls (BMI 42.0 ± 6.2 kg m(-2) ), who during the same time-period had maintained stable weight (control group). All study participants underwent overnight polysomnography examination, echocardiography and analysis of inflammatory markers. The surgery group displayed a lower apnea hypopnea index (AHI) (19.9 ± 21.5 vs. 37.8 ± 27.7 n/h, P = 0.013), lower inflammatory activity (hsCRP 2.3 ± 3.0 vs. 7.2 ± 5.0 mg L(-1) , P < 0.001), reduced left ventricular mass (165 ± 22 vs. 207 ± 22 g, P < 0.001) and superior left ventricular diastolic function (E/A ratio 1.24 ± 1.10 vs. 1.05 ± 0.20, P = 0.006) as compared with weight stable obese controls. In multiple regression analyses including all subjects (n = 39) and controlling for BMI, the AHI remained independently associated with hsCRP (β = 0.09, P < 0.001), TNF-α (β = 0.03, P = 0.031), IL-6 (β = 0.01, P = 0.007), IL 10 (β = -0.06; P = 0.018), left ventricular mass (β = 0.64, P < 0.001), left atrial area (β = 0.08, P = 0.002), pulmonary artery pressure (β = 0.08, P = 0.011) and E/Ea ratio (β = 0.04, P = 0.021). Patients with sustained weight loss after bariatric surgery display less severe sleep apnea, reduced inflammatory activity, and enhanced cardiac function. Persisting sleep apnea appears to limit the beneficial effect of weight loss on inflammation and cardiac performance.

The ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) K121Q polymorphism modulates the beneficial effect of weight loss on fasting glucose in non-diabetic individuals

Background and aimsSeveral studies have reported that the ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) K121Q polymorphism (rs1044498) interacts with increased adiposity in affecting glucose homeostasis and insulin sensitivity. Conversely, one would expect that the amelioration of glucose homeostasis observed after weight loss is modulated by the ENPP1 K121Q polymorphism. The aim of our study was to test such hypothesis, in non-diabetic overweight-obese individuals. Methods and resultsTwo hundred eleven non-diabetic overweight-obese individuals were studied. Body mass index (BMI), fasting glucose, homeostasis model assessment of insulin resistance (HOMA-IR index) and lipid levels were obtained before and after 6-week lifestyle intervention (LI; diet and exercise) and their changes calculated as baseline minus 6-week values.LI decreased BMI, glucose, HOMA-IR and triglyceride levels (p < 0.001 for all). No difference across genotype groups (160 KK and 51 KQ or QQ – named as XQ – individuals) was observed in these changes. In a multivariate model, BMI changes predicted fasting glucose changes (β = 0.139 mmol/L (2.50 mg/dl) for 1 unit BMI change, p = 0.005). This correlation was not significant among KK individuals (β = 0.082; p = 0.15), while much steeper and highly significant among XQ individuals (β = 0.336; p = 0.00008) (p-value for Q121-by-weight loss interaction = 0.047). ConclusionIndividuals carrying the ENPP1 Q121 variant are highly responsive to the effect of weight loss on fasting glucose. This reinforces the previously suggested hypothesis that the Q121 variant interacts with adiposity in modulating glucose homeostasis.

Impaired nasal breathing may prevent the beneficial effect of weight loss in the treatment of OSA

Weight loss is considered an effective treatment for obstructive sleep apnoea (OSA) in overweight patients. Some patients, however, do not benefit from weight loss. It has been postulated that nasal obstruction may act as an independent risk factor for OSA. The aim of our study was to evaluate whether impaired nasal airflow might explain the missing effect of weight reduction on OSA. Fifty-two overweight adult patients with mild OSA were recruited. After the 12-month lifestyle intervention, all patients who achieved more than 5% weight loss were divided into two groups based on whether they still had OSA or not. Change in nasal resistance measured by rhinomanometer and AHI were the main outcome variables. A total of 26/52 patients achieved 5% weight reduction. Of those 26 patients, 16 were objectively cured from OSA and 10 patients did not benefit from weight loss. Nasal resistance reduced significantly more in patients who had been cured from OSA. Smoking had a negative impact on both nasal resistance and improvement of AHI. Impaired nasal breathing and smoking may prevent the beneficial effects of weight reduction in the treatment of OSA.

Impaired nasal breathing may prevent the beneficial effect of weight loss in the treatment of OSA

Background: Weight loss is considered an effective treatment for obstructive sleep apnoea (OSA) in overweight patients. Some patients, however, do not benefit from weight loss. It has been postulated that nasal obstruction may act as an independent risk factor for OSA. Objective: The aim of our study was to evaluate whether impaired nasal airflow might explain the missing effect of weight reduction on OSA. Methodology: Fifty-two overweight adult patients with mild OSA were recruited. After the 12-month lifestyle intervention, all patients who achieved more than 5% weight loss were divided into two groups based on whether they still had OSA or not. Change in nasal resistance measured by rhinomanometer and AHI were the main outcome variables. Results: A total of 26/52 patients achieved 5% weight reduction. Of those 26 patients, 16 were objectively cured from OSA and 10 patients did not benefit from weight loss. Nasal resistance reduced significantly more in patients who had been cured from OSA. Smoking had a negative impact on both nasal resistance and improvement of AHI. Conclusions: Impaired nasal breathing and smoking may prevent the beneficial effects of weight reduction in the treatment of OSA.

Impaired nasal breathing may prevent the beneficial effect of weight loss in the treatment of OSA

Background: Weight loss is considered an effective treatment for obstructive sleep apnoea (OSA) in overweight patients. Some patients, however, do not benefit from weight loss. It has been postulated that nasal obstruction may act as an independent risk factor for OSA. Objective: The aim of our study was to evaluate whether impaired nasal airflow might explain the missing effect of weight reduction on OSA. Methodology: Fifty-two overweight adult patients with mild OSA were recruited. After the 12-month lifestyle intervention, all patients who achieved more than 5% weight loss were divided into two groups based on whether they still had OSA or not. Change in nasal resistance measured by rhinomanometer and AHI were the main outcome variables. Results: A total of 26/52 patients achieved 5% weight reduction. Of those 26 patients, 16 were objectively cured from OSA and 10 patients did not benefit from weight loss. Nasal resistance reduced significantly more in patients who had been cured from OSA. Smoking had a negative impact on both nasal resistance and improvement of AHI. Conclusions: Impaired nasal breathing and smoking may prevent the beneficial effects of weight reduction in the treatment of OSA.

Does medically induced weight loss improve obstructive sleep apnoea in the obese: review of randomized trials.

Obstructive sleep apnoea is characterized by repeated periods of breathing cessation during sleep. Obstructive sleep apnoea is both common and underdiagnosed in the obese. A recent study found that as many as 86% of older obese type 2 diabetics had obstructive sleep apnoea. Obesity is independently associated with developing obstructive sleep apnoea, and the reverse may also occur. The prevalence of obstructive sleep apnoea is therefore expected to rise in the wake of the obesity epidemic. The number of partial (hypopnoea) or complete (apnoea) airway obstructions per hour (apnoea-hypopnoea index) is used to classify obstructive sleep apnoea as mild (5-14 events per hour), moderate (15-30) or severe (>30). Severe obstructive sleep apnoea is associated with a two to sixfold increase in all-cause mortality; the impact of mild and moderate obstructive sleep apnoea is less clear. Until recently, the evidence supporting a beneficial effect of weight loss on obstructive sleep apnoea has been limited by a lack of randomized trials. In 2009, at least three randomized controlled trials evaluated whether medically induced weight loss improves obstructive sleep apnoea. The treatment effect ranged from 42% to 62% improvement, although the highest estimate was seen in a very short duration study (9 weeks). Patients who either lost 10-15 kg or more, or had severe obstructive sleep apnoea at baseline, benefited most from treatment.