Sleep disordered breathing--a new component of syndrome x?

Associations between serum vitamin D status and the cardiometabolic profile of patients with obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) and the metabolic syndrome (MetS) frequently coexist. Low serum vitamin D has been positively associated with OSA presence and severity; however, data on its link to cardiometabolic features in patients with OSA remain scarce. We aimed to assess serum 25-hydroxyvitamin D [25(OH)D] and explore its association with cardiometabolic parameters in OSA.

METHODS

This was a cross-sectional study among 262 patients (49 ± 9 years old, 73% men) with polysomnography-diagnosed OSA. Participants were evaluated in terms of anthropometric indices, lifestyle habits, blood pressure, biochemical, plasma inflammatory and urinary oxidative stress markers, and the presence of MetS. Serum 25(OH)D was assessed by chemiluminescence, and vitamin D deficiency (VDD) was defined as 25(OH)D < 20 ng/mL.

RESULTS

Median (1st, 3rd quartile) serum 25(OH)D levels were 17.7 (13.4, 22.9) ng/mL and 63% of participants had VDD. Serum 25(OH)D correlated negatively with body mass index (BMI), homeostasis model of assessment of insulin resistance (HOMA-IR), total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), and urinary oxidized guanine species (oxG), and positively with high-density lipoprotein cholesterol (all P < 0.050). In logistic regression analysis, serum 25(OH)D was associated with lower odds of MetS [odds ratio (95% confidence interval): 0.94 (0.90-0.98)], after adjustment for age, sex, season of blood sampling, Mediterranean diet score, physical activity, smoking, apnea-hypopnea index, HOMA-IR, hsCRP, and oxG. In the same multivariate model, VDD was associated with ~ twofold greater odds of MetS [2.39 (1.15, 4.97)].

CONCLUSION

VDD is highly prevalent and is associated with a detrimental cardiometabolic profile among patients with OSA.

Cardiometabolic Benefits of a Weight-Loss Mediterranean Diet/Lifestyle Intervention in Patients with Obstructive Sleep Apnea: The "MIMOSA" Randomized Clinical Trial

Although continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA), its cardiometabolic benefits are questionable. Our aim was to explore whether the combination of a weight-loss Mediterranean diet/lifestyle intervention with OSA standard care leads to greater cardiometabolic improvements compared with standard care alone. We randomly assigned 187 adult, overweight, polysomnography-diagnosed moderate-to-severe OSA patients to a standard care group (SCG, n = 65), a Mediterranean diet group (MDG, n = 62) or a Mediterranean lifestyle group (MLG, n = 60). All three groups were prescribed with CPAP. Additionally, the SCG only received brief written healthy lifestyle advice, while intervention arms were subjected to a six-month weight-loss behavioral intervention based on the Mediterranean diet. The MLG also received guidance for improving physical activity and sleep habits. Glucose metabolism indices, blood lipids, liver enzymes and blood pressure improved only in intervention arms, and were significantly lower compared to the SCG post-intervention (all p < 0.05). The age-, sex-, baseline- and CPAP use-adjusted relative risk (95% confidence interval) of metabolic syndrome was 0.58 (0.34–0.99) for the MDG and 0.30 (0.17–0.52) for the MLG compared to the SCG. The MLG additionally presented a lower relative risk of metabolic syndrome compared to the MDG (0.52 (0.30–0.89)). After further adjustment for body-weight change, a lower relative risk of metabolic syndrome was still evident for the MLG compared to the SCG. In conclusion, although standard care alone does not improve OSA patients’ cardiometabolic profile, its combination with a weight-loss Mediterranean diet/lifestyle intervention leads to significant cardiometabolic benefits.

Anthropometric Factors in the Assessment of Obstructive Sleep Apnea Risk in Patients with Metabolic Syndrome

Metabolic syndrome (MetS) and obstructive sleep apnea (OSA) are related to a higher incidence of cardio-vascular diseases and mortality in patients. The aim of the study was to define the potential use of anthropometric factors for the evaluation of OSA risk in patients with diagnosed MetS. The patient group consisted of 50 obese men with MetS (mean age 49 ± 9 years). The following anthropometric indices were assessed: body mass index (BMI), neck circumference (NC), waist circumference (WC), and waist-to-hip ratio (WHR). In addition, blood glucose and lipid profile were investigated. On the basis of polysomnography, clinical symptoms, and Epworth Sleep Scale, patients were stratified into the OSA group accompanied by MetS (n = 31) and the MetS alone group taken as control (n = 19). OSA was evaluated as severe in 26 out of the 31 patients (>30 apneic episodes per hour). We found a significantly larger NC in the OSA with MetS group then that in the MetS alone group. Further, NC associated with the increase in the apnea/hypopnea index. However, the other anthropometric indices investigated failed to differentiate the two groups. We conclude that increased neck circumference in patients suffering from metabolic syndrome is a risk factor for the development of OSA.

Sleep-Disordered Breathing Is Associated with Metabolic Syndrome in Outpatients with Diabetes Mellitus Type 2

BACKGROUND

Metabolic syndrome (MS) and sleep-disordered breathing (SDB) are highly prevalent in patients with diabetes mellitus type 2 (DM2). The present study examined whether there is an independent association between SDB and MS in a sample of outpatients with DM2.

METHODS

MS was determined in 679 patients of the DIACORE-SDB substudy, a study of outpatients with DM2. According to the National Cholesterol Education Program (NCEP) criteria, MS is defined by at least three of the following five criteria: waist circumference of >102 cm (men)/>88 cm (women), blood pressure of ≥130/85 mmHg, a fasting triglyceride level of >150 mg/dl, high-density lipoprotein (HDL) of <40 mg/dl (men)/<50 mg/dl (women), and a fasting glucose level of ≥110 mg/dl. The apnea-hypopnea index (AHI) was assessed with a 2-channel ambulatory monitoring device and used to define the severity of SDB (AHI < 15.0: no/mild SDB; AHI 15.0-29.9: moderate SDB; AHI ≥ 30.0: severe SDB).

RESULTS

228 (34%) of the 679 participants (mean age 66 years, mean body mass index (BMI) 31.2 kg/m², and mean AHI 14/hour) had SDB. MS was significantly more frequent in patients with more severe SDB (no/mild SDB vs. moderate SDB vs. severe SDB: 72% vs. 79% vs. 85%, respectively, p = 0.038). Logistic regression analysis adjusted for sex, age, obesity (BMI ≥ 30 kg/m²), and the HOMA index showed a significant association between the AHI and the presence of MS (OR (95%CI) = 1.039 (1.011; 1.068); p = 0.007). Further, male sex, obesity, and the HOMA index were significantly associated with MS.

CONCLUSION

SDB is significantly and independently associated with MS in outpatients with DM2.

Prevalence and severity of syndrome Z in women with metabolic syndrome on waiting list for bariatric surgery: a cross-sectional study

BACKGROUND

In recent years, obesity has become one of the most important public health problems in the world, with a growing prevalence in both developed and developing countries. Recent studies show that sleep disturbances, especially obstructive sleep apnoea (OSA) may be a manifestation of metabolic syndrome (MetS). Although the association of OSA with the MetS is largely attributed to obesity, the exact pathophysiological mechanisms and their individual characteristics still need to be identified. This study investigated the prevalence and severity of syndrome Z in obese women with MetS on waiting list for bariatric surgery.

METHODS

In this double-center cross-sectional study, female patients aged ≥18 years, stage III severe obesity with MetS, on waiting list for bariatric surgery were recruited. The diagnosis for MetS was made according to the criteria of the national cholesterol education program, adult treatment panel III. Clinical, anthropometric, demographic, biochemistry, and sleep measurements were collected. Correlations between continuous variables with sleep parameters were performed using the Pearson correlation test or Spearman correlation test.

RESULTS

The mean age of 83 patients was 44.8 ± 11.2 years and mean BMI was 42.6 ± 8.1 kg/m². There was a significant correlation between OSA and metabolic score (r = 0.336; P = 0.002), neck circumference (r = 0.218; P = 0.048), basal systolic blood pressure (r = 0.280; P = 0.01), total cholesterol (r = 0.277; P = 0.011) and abdomen circumference (r = 0.284; P = 0.009). The mean values of excessive daytime sleepiness were 10.5 ± 7 demonstrating a value considered normal for its presence. However, a high risk for OSA was observed in practically the entire population. It was observed that the prevalence of Syndrome Z (75.9%) increased significantly according to apnoea hypopnoea index (AHI) (P for trend <0.0000). A prevalence of 27.71% for mild OSA, 20.48% for moderate OSA, and 27.71% for severe OSA was observed. An association of AHI severity with all components of MetS was also observed.

CONCLUSIONS

We can conclude that syndrome Z presents a high prevalence in a female population with MetS and a considerable severity according to the presence of OSA. Therefore, patients with MetS should be investigated for the presence of sleep disorders. Trial registration The study has been registered on ClinicalTrials.gov NCT02409160 and followed the standards of The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies.

Drug treatment of obesity in cardiovascular disease

Obesity is a significant health problem worldwide and is associated with a number of co-morbidities including type 2 diabetes mellitus, hypertension, dyslipidemia, obstructive sleep apnea, and cardiovascular disease. A number of different pathophysiologic mechanisms including increased inflammation, oxidative stress, and insulin resistance have been associated with initiation and progression of atherosclerotic disease in obese individuals. Lifestyle modifications have provided modest results in weight reduction and the focus of interest has now shifted towards drug development to treat severely obese individuals with a body mass index (BMI) >30 kg/m(2) or those with a BMI >27 kg/m(2) who have additional co-morbidities. Different regimens focusing on dietary absorption or acting centrally to control hunger and food intake have been developed. However, their weight loss effect is, in most cases, modest and this effect is lost once the medication is discontinued. In addition, long-term use of these drugs is limited by significant side effects and lack of long-term safety and efficacy data. Orlistat is the only US FDA-approved medication for long-term use. A number of new medications are currently under investigation in phase III trials with promising preliminary results. This review comments on available anti-obesity pharmacologic regimens, their weight-loss benefit, and their impact on cardiovascular risk factors.

Uvulopalatopharyngoplasty with an ultrasound scalpel or laser: is there a difference?

Uvulopalatopharyngoplasty (UPPP) is used for treatment of the obstructive sleep apnoea syndrome, mainly in the lower range of the apnoea-hypopnea index or partial upper airway obstruction. Significant severe pain after UPPP is associated in the area having surgery and therefore less pain causing methods should be investigated. In this study, we compared laser-assisted and ultrasound scalpel-performed UPPP. Sleep apnoea patients (n = 40) recruited to the study were divided into two groups. UPPP was performed with either laser-assisted or an ultrasound scalpel. Perioperative bleeding, operating room time and duration of operation together with histological injury of soft palate were analysed. A postoperative follow-up questionnaire included a self analysis of pain, dietary intake and pain drug consumption. In the same follow-up form, filled in by patients themselves, possible side effects and adequacy of pain medication together with any postoperative haemorrhage events were recorded during 10-day study period after UPPP. The ultrasound scalpel group had significantly fewer haemorrhagic events (P = 0.037) during postoperative follow-up time after UPPP when compared to laser-assisted group. The pain values of all 40 patients were significantly higher in the morning than in the afternoon (P < 0.001) or evening (P < 0.001). Pain increased up to the fifth postoperative day (visual analogue scale, VAS = 46). The significant relief of pain to the mild level (VAS < 30 mm) occurred at ninth and tenth postoperative day. The ultrasound scalpel used as a surgical method in UPPP did not offer significant comprehensive benefits in this study compared to laser-assisted UPPP. Exclusively, postoperative haemorrhage events were minor, paralleling findings of previous studies where ultrasound scalpel had been used for tonsillectomy. We conclude that the ultrasound scalpel is comparable to laser-assisted UPPP.

Is there a clear link between overweight/obesity and sleep disordered breathing in children?

The proportion of children who are overweight or obese has risen steadily in recent decades and approaches a quarter of all children in Western countries. This global epidemic of excess weight and adiposity in humans is associated with increased morbidity and mortality, especially related to diabetes and poor cardiovascular health. It would appear that obesity is also generally accepted to be an important risk factor in the development of sleep disordered breathing (SDB), in children as well as adults. The article, "The prevalence, anatomical correlates and treatment of sleep-disordered breathing in obese children and adolescents", by Verhulst et al., also in this issue, reviews evidence supporting the view that obese children are at higher risk of developing SDB. We believe, however, that the available studies do not support a straightforward association of overweight or obesity with increased prevalence of SDB. Rather, the available data is clearly equivocal mainly due to methodological differences between the previous studies. This review nonetheless examines the factors which may modulate the relationship between overweight or obesity and prevalence of SDB, particularly ethnicity and age.

Chronic intermittent hypoxia sensitizes acute hypothalamic-pituitary-adrenal stress reactivity and Fos induction in the rat locus coeruleus in response to subsequent immobilization stress

Obstructive sleep apnea (OSA) is associated with several pathophysiological conditions, including hypertension, obesity, insulin resistance, hypothalamic-pituitary-adrenal (HPA) dysregulation, and other endocrine and metabolic disturbances comprising the "metabolic syndrome." Repeated episodes of hypoxia in OSA may represent a chronic intermittent stress, leading to HPA dysregulation. Alterations in HPA reactivity could then contribute to or exacerbate other pathophysiological processes. We showed previously that another metabolic stressor, chronic intermittent cold stress, enhanced noradrenergic facilitation of acute HPA stress reactivity. In this study, we investigated whether chronic intermittent hypoxia (CIH), a rat model for the arterial hypoxemia that accompanies OSA, similarly sensitizes the HPA response to novel acute stress. Rats were exposed to CIH (alternating cycles of normoxia [3 min at 21% O(2)] and hypoxia [3 min at 10% O(2)], repeated continuously for 8 h/day during the light portion of the cycle for 7 days). On the day after the final CIH exposure, there were no differences in baseline plasma adrenocorticotropic hormone (ACTH), but the peak ACTH response to 30 min acute immobilization stress was greater in CIH-stressed rats than in controls. Induction of Fos expression by acute immobilization stress was comparable following CIH in several HPA-modulatory brain regions, including the paraventricular nucleus, bed nucleus of the stria terminalis, and amygdala. Fos induction was attenuated in lateral hypothalamus, an HPA-inhibitory region. By contrast, acute Fos induction was enhanced in noradrenergic neurons in the locus coeruleus following CIH exposure. Thus, similar to chronic cold stress, CIH sensitized acute HPA and noradrenergic stress reactivity. Plasticity in the acute stress response is important for long-term adaptation, but may also contribute to pathophysiological conditions associated with states of chronic or repeated stress, such as OSA. Determining the neural mechanisms underlying these adaptations may help us better understand the etiology of such disorders, and inform the development of more effective treatments.

Obesity, metabolic syndrome and sleep apnoea: all pro-inflammatory states

Obesity is associated with significant morbidity and mortality and is increasing in prevalence worldwide. Associated conditions include insulin resistance (IR), diabetes, hypertension and dyslipidaemia; a clustering of these has recently been termed as metabolic syndrome. Weight gain is a major predictor of the metabolic syndrome with waist circumference being a more sensitive indicator than body mass index as it reflects both abdominal subcutaneous adipose tissue and visceral adipose tissue (VAT). VAT has more metabolic activity and secretes a number of hormones and pro-inflammatory cytokines which are linked with the metabolic abnormalities listed above. Central obesity also increases the risk of obstructive sleep apnoea syndrome (OSAS), where the sleep disordered breathing may also independently lead to/or exacerbate IR, diabetes and cardiovascular risk. The contribution of OSAS to the metabolic syndrome has been under-recognized. The putative mechanisms by which OSAS causes or exacerbates these other abnormalities are discussed. We propose that activation of nuclear factor kappa B by stress hypoxia and/or by increased adipokines and free fatty acids released by excess adipose tissue is the final common inflammatory pathway linking obesity, OSAS and the metabolic syndrome both individually and, in many cases, synergistically.

Clinical, anthropometric and upper airway anatomic characteristics of obese patients with obstructive sleep apnea syndrome

BACKGROUND

Obese subjects are at increased risk of developing obstructive sleep apnea syndrome (OSAS). However, the individual role of local (i.e., upper airway-related) and general (clinical and whole-body anthropometric) characteristics in determining OSAS in obese patients is still controversial.

OBJECTIVES

To contrast the clinical, anthropometric and upper airway anatomical features of obese subjects presenting or not presenting with OSAS.

METHODS

Thirty-seven obese (BMI > or =30 kg/m(2)) males with OSAS and 14 age- and gender-matched obese controls underwent clinical and anthropometric (BMI, waist-to-hip ratio and neck circumference) evaluation. In a subgroup of subjects (18 and 11 subjects, respectively), magnetic resonance imaging (MRI) during wakefulness was used to study the upper airway anatomy.

RESULTS

OSAS patients showed significantly higher BMI, waist-to-hip ratio and neck circumference as compared to controls (p < 0.05). They also referred to nonrepairing sleep, impaired attention, and previous car accidents more frequently (p < 0.05). The transversal diameter of the airways (TDAW) at the retroglossal level by MRI was found to be an independent predictor of the presence and severity of OSAS (p < 0.05). Parapharyngeal fat increase, however, was not related to OSAS. A TDAW >12 mm was especially useful to rule out severe OSAS (apnea-hypopnea index >30, negative predictive value = 88.9%, likelihood ratio for a negative test result = 0.19).

CONCLUSIONS

MRI of the upper airway can be used in association with clinical and anthropometric data to identify obese males at increased risk of OSAS.

Diagnosis and management of insomnia in dialysis patients

Sleep-related complaints affect 50-80% of patients on dialysis. Sleep disorders impair quality of life significantly. Increasing evidence suggests that sleep disruption has a profound impact both on an individual and on a societal level. The etiology of sleep disorders is often multifactorial: biologic, social, and psychological factors play a role. This is especially true for insomnia, which is the most common sleep disorder in different populations, including patients on dialysis. Biochemical and metabolic changes, lifestyle factors, depression, anxiety, and other underlying sleep disorders can all have an effect on the development and persistence of sleep disruption, leading to chronic insomnia. Insomnia is defined as difficulty initiating or maintaining sleep, or having nonrestorative sleep. It is also associated with daytime consequences, such as sleepiness and fatigue, and impaired daytime functioning. In most cases, the diagnosis of insomnia is based on the patient's history, but in some patients objective assessment of sleep pattern may be necessary. Optimally the treatment of insomnia involves the combination of both pharmacologic and nonpharmacologic approaches. In some cases acute insomnia resolves spontaneously, but if left untreated, it may lead to chronic sleep problems. The treatment of chronic insomnia is often challenging. There are only a few studies specifically addressing the management of this sleep disorder in patients with chronic renal disease. Considering the polypharmacy and altered metabolism in this patient population, treatment trials are clearly needed. This article reviews the diagnosis of sleep disorders with a focus on insomnia in patients on dialysis.

Prevalence and risk factors of obstructive sleep apnea syndrome in a population of Delhi, India

OBJECTIVE

Obstructive sleep apnea (OSA) has been recognized in the Western world as a public health burden, but there has been no community-based study performed to assess the prevalence of the condition in India. The study was performed to assess the prevalence and risk factors of OSA in a semi-urban Indian population.

DESIGN

A two-stage, cross-sectional, community-based prevalence study.

SETTING

A semi-urban community in Delhi.

DURATION

Two years (2003 to 2005).

PATIENTS AND PARTICIPANTS

All citizens residing in the community who were 30 to 60 years of age. Exclusion criteria included those patients with recent myocardial infarction, upper airway surgery, class III/IV congestive heart failure, pregnancy, hypothyroidism on treatment, acromegaly, chronic renal failure, systemic steroid treatment, and hormone replacement therapy.

INTERVENTION

An OSA assessment was performed in 2,400 subjects who were screened in stage 1 of the study by means of a sleep questionnaire. Subjects were then divided into habitual and nonhabitual snorers. Eighty-three randomly selected habitual snorers and 80 nonhabitual snorers were invited to participate in stage 2 of the study, which consisted of in-hospital polysomnography studies.

OBSERVATIONS AND RESULTS

A total of 2,150 subjects returned questionnaires (response rate, 90%). Of 550 habitual snorers and 1,596 nonhabitual snorers, 77 habitual snorers and 73 nonhabitual snorers underwent polysomnography. A total of 36 habitual snorers (46.75%) and 2 nonhabitual snorers (2.73%) were found to have OSA, giving prevalence rates of 13.74% and 3.57%, respectively, for OSA and OSA syndrome (OSAS) on extrapolation. Multivariate analysis revealed that male gender, age, obesity (defined by a high body mass index), and waist/hip ratio as significant risk factors for OSAS.

CONCLUSIONS

This study demonstrated that the risk factors and prevalence for OSA in India are similar to those in the West, which is contrary to the findings of some previous reports, which had a strong inclusion bias.

Level of proinsulin in association with cardiovascular risk factors and sleep snoring

AIM

To explore the relationship between the level of proinsulin with cardiovascular risk factors and sleep snoring.

METHODS

Based on the random stratified sampling principle, 1 193 Chinese residents in Pizhou City, Jiangsu Province (530 males and 663 females, aged 35-59 years with an average age of 46.69 years) were recruited. Their sleep snoring habits were investigated. Biotin-avidin based double mAbs ELISA was used to detect specific insulin and proinsulin, and a risk factor score was established to evaluate the individuals according to the number of their risk factors.

RESULTS

The results of Spearman correlation analysis and covariate ANOVA analysis after age and sex were controlled, indicated that not only the level of proinsulin (r = 0.156, P = 0.000, F = 5.980 P = 0.000), but also cardiovascular risk factors score (r = 0.194, P = 0.000, F = 11.135, P = 0.000) significantly associated with the frequency of sleep snoring, and the significant relationship between true insulin and frequency of sleep snoring was only shown in the covariate ANOVA analysis (F = 2.868, P = 0.022). The result of multivariate stepwise logistic regression after age, sex, body mass index, waist circumference and true insulin were controlled showed that proinsulin (division by interval of quartile) was an independent risk factor for sleep snoring (OR = 1.220, 95%CI: 1.085-1.373, P = 0.001).

CONCLUSION

The interaction of cardiovascular risk factors clustering, high proinsulin level and sleep breathing disorder may be a syndrome, which has not been recognized in human beings so far.

Alanine aminotransferase elevation not associated with fatty liver is frequently seen in obese Japanese women

OBJECTIVE

To determine the prevalence of fatty liver and alanine aminotransferase (ALT) elevation in obese Japanese women and to clarify the factors contributing to fatty change and ALT elevation in the cohort.

DESIGN

Cross-sectional and population-based study.

SUBJECTS

From 4366 women who received their annual health check-up, 4211 women were selected for analysis. All 4211 women were negative for hepatitis virus markers.

MEASUREMENTS

Peripheral blood cell counts, liver biochemical tests, fasting glucose, cholesterol and triglyceride levels, uric acids, glycosylate hemoglobin A1c, and ultrasound examination.

RESULTS

Ultrasonographic evidence of fatty liver and ALT elevation was seen in 391 (9.3%) and 238 (5.7%), respectively, of the 4211 women. Frequencies of both fatty liver and ALT elevation increased with increase in the degree of obesity. The frequency of ALT elevation was higher in women with fatty liver than in women without fatty liver among the nonobese or mildly obese group. However, the frequency of ALT elevation was not significantly different between women with fatty liver and women without fatty liver among the severely obese group. Multivariate analysis showed that obesity, hemoglobin (> or = 14 g/dl), triglyceride (> or = 150 mg/dl), diabetes mellitus, and fatty liver were significant predictors of ALT elevation. However, only two variables, hemoglobin (> or = 14 g/dl) and presence of diabetes, were significant in the severely obese group.

CONCLUSIONS

ALT elevation not associated with fatty liver was frequently seen in obese women, suggesting that obesity is directly associated with the elevated ALT level in Japanese obese women. In addition, hemoglobin (> or = 14 g/dl) was a strong predictor of ALT elevation in the severely obese group.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

Fructose feeding and intermittent hypoxia affect ventilatory responsiveness to hypoxia and hypercapnia in rats

We hypothesized that, in male rats, 10% fructose in drinking water would depress ventilatory responsiveness to acute hypoxia (10% O2 in N2) and hypercapnia (5% CO2 in O2) that would be depressed further by exposure to intermittent hypoxia. Minute ventilation (V̇e) in air and in response to acute hypoxia and hypercapnia was evaluated in 10 rats before fructose feeding (FF), during 6 wk of FF, and after FF was removed for 2 wk. During FF, five rats were exposed to intermittent air and five to intermittent hypoxia for 13 days. Six rats given tap water acted as control and were exposed to intermittent air and subsequently intermittent hypoxia. In FF rats, plasma insulin levels increased threefold in the rats exposed to intermittent hypoxia and during washout returned to levels observed in rats exposed to intermittent air. During FF, ventilatory responsiveness to acute hypoxia was depressed because of decreased tidal volume (Vt) responsiveness. During washout, V̇e decreased as a result of decreased Vt and frequency of breathing, and the ventilatory responsiveness to hypoxia in intermittent hypoxia rats did not recover. In all rats, the ventilatory responses to hypercapnia were decreased during FF and recovered after washout because of an increased Vt responsiveness. In the control group, hypoxic responsiveness was not depressed after intermittent hypoxia and was augmented after washout. Thus FF attenuated the ventilatory responsiveness of conscious rats to hypoxia and hypercapnia. Intermittent hypoxia interacted with FF to increase insulin levels and depress ventilatory responses to acute hypoxia that remained depressed during washout.

Effects of long-term captopril andl-arginine treatment on ventilation and blood pressure in obese male SHHF rats

We investigated the effects of captopril (Cap) and l-arginine (Arg) on hypertension and cardiopulmonary function. Our hypothesis was that Cap therapy or Arg will improve cardiopulmonary risk factors for hypertension and hypoventilation in the obese spontaneously hypertensive heart failure rat, which is characterized by hypertension, obesity, and disorders of lipid and carbohydrate metabolism. For the first study, one group of rats received Cap in drinking water, and a second group received deionized water (DI). For the second study, rats were further subdivided. Some Cap-treated rats continued on this treatment, and the other half were now given DI to determine whether there would be residual effects of Cap treatment. A subgroup of rats who had received DI was then given Arg, whereas the rest remained on DI. In the first study, Cap-treated rats exhibited decreases in systolic and diastolic blood pressures, frequency of breathing, and minute ventilation, but ventilatory control was maintained. In contrast, blood pressures and relative ventilation to metabolism were higher in the DI-treated group. Removal of Cap increased blood pressure and decreased tidal volume while these rats maintained frequency. Although Arg-treated rats did not exhibit a decrease of blood pressure, ventilation was maintained in this group by preserving tidal volume. Thus Cap and Arg affected ventilation through different mechanisms independent of blood pressure.

Glitazones and the management of insulin resistance: what they do and how might they be used

Thiazolidinediones (glitazones) are the only compounds currently available that specifically target tissue insulin resistance. The two currently available drugs in this class, pioglitazone and rosiglitazone,are approved by the Food and Drug Administration for the treatment of type 2 diabetes mellitus only. The therapeutic potential of the glitazones for other consequences of insulin resistance has stirred considerable interest, especially with regard to their potential beneficial impact on atherosclerotic cardiovascular disease and diabetes prevention. They also have been considered in the management of polycystic ovarian syndrome, nonalcoholic fatty liver disease, and other consequences of insulin resistance. The nonglycemic potential of glitazones is a clinical area in rapid evolution, wherein most data are on the impact of the glitazones onsurrogate markers that are associated with diseases, not on disease outcomes. This article provides insight and guidance to clinicians on the diverse nonglycemic potential of glitazones until conclusive outcome data become available.

Obesity as a disease: no lightweight matter

The epidemic rise in obesity has fuelled the current debate over its classification as a disease. Contrary to just being a medical condition or risk factor for other diseases, obesity is a complex disease of multifaceted aetiology, with its own disabling capacities, pathophysiologies and comorbidities. It meets the medical definition of disease in that it is a physiological dysfunction of the human organism with environmental, genetic and endocrinological aetiologies. It is a response to environmental stimuli, genetic predisposition and abnormalities, and has a characteristic set of signs and symptoms with consistent anatomical alterations. Excess adipose tissue increases the work of the heart and leads to anatomical changes in this organ. It alters pulmonary, endocrine and immunological functions, all with adverse effects on health. Some of the complications of obesity include cardiovascular disease, non-insulin-dependent diabetes mellitus, obstructive pulmonary disease, arthritis and cancer. Given the excess mortality, substantial morbidity and the economic toll of obesity, this is a disease that warrants serious attention by the medical community. Obesity's status and acceptance as a disease is pivotal in determining its treatment, reimbursement for treatment and the development of widespread interventions.

Metabolic syndrome is directly associated with gamma glutamyl transpeptidase elevation in Japanese women

AIM: This study aimed to determine whether metabolic syndrome is directly or indirectly, through fatty liver, associated with elevated gamma-glutamyl transpeptidase (GGT) levels in Japanese women.

METHODS: From 4366 women who received their annual health check-up, 4211 women were selected for analysis. All 4211 women were negative for both hepatitis B surface antigen and antibody to hepatitis C virus. Clinical and biochemical variables were examined by using univariate and multivariate analysis.

RESULTS: A raised GGT level ( > 68 IU/L) was seen in 258 (6.1%) of the 4211 women. In univariate analysis, all variables examined (age, body mass index, blood pressure, hemoglobin concentration, fasting blood glucose, glycosylated hemoglobin A1c, cholesterol, triglyceride, and uric acid) were associated with the elevated GGT level, whereas in multivariate analysis, four variables (age ≧ 50 yr, hemoglobin ≧ 14 g/dL, triglyceride ≧ 150 mg/dL, and presence of diabetes) were significantly and independently associated with raised GGT level. Clinical variables predicting the presence of ultrasonographic evidence of fatty liver were also examined by multivariate analysis; four variables were associated with the presence of fatty liver: BMI ≧ 25 kg/m², hemoglobin ≧ 14 g/dL, triglyceride ≧ 150 mg/dL, and uric acid ≧ 7 mg/dL. There was no significant association between the raised GGT level and the presence of fatty liver. Hypertriglyceridemia was significantly and independently associated with both the raised GGT level and the presence of fatty liver.

CONCLUSION: Metabolic syndrome seemed to be directly, not indirectly through fatty liver, associated with the raised GGT level in Japanese women.

Low sleep quality and daytime sleepiness in obese patients without obstructive sleep apnoea syndrome

OBJECTIVES

To evaluate sleep quality, sleep-related symptoms, and degree of excessive daytime sleepiness (EDS) in severe obesity, independently of obstructive sleep apnoea syndrome (OSAS).

DESIGN

A cross-sectional study.

SETTING

Primary-care setting.

SUBJECTS, MAIN OUTCOME MEASURES

Anthropometric parameters, respiratory function data and sleep related symptoms were evaluated in 78 severely obese patients (aged 16-75 years) without OSAS and in 40 healthy sex- and age-matched normal weight subjects, who underwent a full-night polysomnography.

RESULTS

Obese patients and control subjects had similar sleep latency and rapid eye movement (REM) latency, but they showed lower percentage of REM (P < 0.01) and sleep efficiency (P < 0.05) than controls. All sleep-related symptoms (observed or reported apnoea, awakenings, choking and unrefreshing sleep) were significantly more frequent in obese patients than in control subjects. Loud snoring was present in 46.7% of the obese patients and in 8.1% of the control individuals (P < 0.01). Excess daytime sleepiness was reported by 34.7% of the obese patients and by 2.7% of the normal weight subjects (P < 0.01). The Epworth Sleepiness Scale (ESS) was higher in the obese group than in the control group (P < 0.01), whereas arousals were not different between the two groups.

CONCLUSIONS

This study clearly shows that severe obesity, even in the absence of OSAS, is associated with sleep-related disorders and EDS. All these alterations may be partly responsible for a lower quality of life, a higher prevalence of medical complications, an increased risk of occupational injury, and both social and family problems characterizing obese patients, independently of the presence of OSAS.