Relationships Between Changes in Body Composition and Changes in Cardiovascular Risk Factors: The SOS Intervention Study

SJÖSTRÖM, C DAVID, LAUREN LISSNER, LARS SJÖSTROM. Relationships between changes in body composition and changes in cardiovascular risk factors: The SOS Intervention Study. Relationships between 2-year changes in body composition (estimated from computed tomography-validated anthropometry based on sagittal trunk diameter, weight, and height), adipose tissue (AT) distribution, and cardiovascular risk factors (blood pressure, lipids, glucose, insulin, uric acid) were examined in 842 treated adults with severe obesity with weight changes from ?95. 5 to +30. 6 kg. Although the change (Δ) of visceral AT mass (expressed in % total AT) for a given change in body mass index (ΔBMI) was 6-fold larger in men than in women, Δwaist and Δwaist/hip were similar in both sexes. In men, risk factor changes were similarly related to Awaist, Abodyweight, and ΔBMI, whereas in women, Δbodyweight seemed to be the single independent variable with the highest explanatory power. In multivariate regressions adjusted for ΔBMI and baseline conditions, Δvisceral AT mass was more strongly associated with risk factor changes than were Δwaist and ?waist/hip. When using a three-compartment model (lean body mass, subcutaneous and visceral AT masses) plus neck and thigh girths (indicators of subcutaneous AT distribution), risk factor changes were related both to ?subcutaneous and ?visceral AT masses but not to Δlean body mass. In agreement with cross-sectional findings, Δneck was positively and Δthigh was negatively related to some risk factor changes. Thus, the use of waist as a single risk factor indicator seems less effective for epidemiological studies than the simple anthropometric measures presented here, which are able to separate the effects of visceral AT mass, subcutaneous AT mass, and subcutaneous AT distribution on metabolic parameters under both cross-sectional and longitudinal conditions.     

Regional muscle and adipose tissue amino acid metabolism in lean and obese women

The effect of obesity on regional skeletal muscle and adipose tissue amino acid metabolism is not known. We evaluated systemic and regional (forearm and abdominal subcutaneous adipose tissue) amino acid metabolism, by use of a combination of stable isotope tracer and arteriovenous balance methods, in five lean women [body mass index (BMI) <25 kg/m(2)] and five women with abdominal obesity (BMI 35.0-39.9 kg/m(2); waist circumference >100 cm) who were matched on fat-free mass (FFM). All subjects were studied at 22 h of fasting to ensure that the subjects were in net protein breakdown during this early phase of starvation. Leucine rate of appearance in plasma (an index of whole body proteolysis), expressed per unit of FFM, was not significantly different between lean and obese groups (2.05 +/- 0.18 and 2.34 +/- 0.04 micromol x kg FFM(-1) x min(-1), respectively). However, the rate of leucine release from forearm and adipose tissues in obese women (24.0 +/- 4.8 and 16.6 +/- 6.5 nmol x 100 g(-1) x min(-1), respectively) was lower than in lean women (66.8 +/- 10.6 and 38.6 +/- 7.0 nmol x 100 g(-1) x min(-1), respectively; P < 0.05). Approximately 5-10% of total whole body leucine release into plasma was derived from adipose tissue in lean and obese women. The results of this study demonstrate that the rate of release of amino acids per unit of forearm and adipose tissue at 22 h of fasting is lower in women with abdominal obesity than in lean women, which may help obese women decrease body protein losses during fasting. In addition, adipose tissue is a quantitatively important site for proteolysis in both lean and obese subjects.     

Methods of Estimation of Visceral Fat: Advantages of Ultrasonography

Objective: To compare methods for the assessment of visceral fat with computed tomography (CT) and establish cutoffs to define visceral obesity based on such alternative methods. Research Methods and Procedures: One hundred women (50.4 ± 7.7 years; BMI 39.2 ± 5.4 kg/m²) underwent anthropometric evaluation, bioelectrical impedance, DXA, abdominal ultrasonography (US), and CT scan. Results: Waist circumference, waist‐to‐hip ratio (WHR), and US‐determined visceral fat values showed the best correlation coefficients with visceral fat determined by CT (r = 0.55, 0.54, and 0.71, respectively; p < 0.01). Fat mass determined by DXA was inversely correlated with visceral‐to‐subcutaneous‐fat ratio (r = ?0.47, p < 0.01). Bioimpedance‐determined fat mass and skinfolds were correlated with only subcutaneous abdominal fat quantified by CT. Linear regression indicated US visceral‐fat distance and WHR as the main predictors of CT‐determined visceral fat (adjusted r² = 0.51, p < 0.01). A waist measurement of 107 cm (82.7% specificity, 60.6% sensitivity) and WHR of 0.97 (78.8% specificity, 63.8% sensitivity) were chosen as discriminator values corresponding with visceral obesity diagnosed by CT. A value of 6.90 cm for visceral fat US‐determined diagnosed visceral obesity with a specificity of 82.8%, a sensitivity of 69.2%, and a diagnostic concordance of 74% with CT. Discussion: US seemed to be the best alternative method for the assessment of intra‐abdominal fat in obese women. Its diagnostic value could be optimized by an anthropometric measurement. Prospective studies are needed to establish CT and US cutoffs for defining visceral‐fat levels related to elevated cardiovascular risk.     

Incidental physical activity and sedentary behavior are not associated with abdominal adipose tissue in inactive adults

The aim was to determine the association between objectively measured incidental physical activity (IPA) (i.e.,nonpurposeful activity accrued through activities of daily living) and sedentary behavior (SED) with abdominal obesity in a sample of inactive men and women. Participants were inactive, abdominally obese men (n = 42; waist circumference (WC) ≥102 cm) and women (n = 84; WC ≥88 cm) recruited from Kingston, Canada. Physical activity and SED were determined by accelerometry over 7 days and summarized as IPA (accelerometer counts per min (cpm) >100), light physical activity (LPA; cpm 100-1951), sporadic moderate-to-vigorous physical activity (MVPA; cpm ≥1,952, accumulated in bouts <10 consecutive minutes) and SED (cpm <100). Magnetic resonance imaging was used to acquire measures of abdominal obesity, visceral adipose tissue (VAT), and subcutaneous adipose tissue (ASAT). Participants spent on average 310.2 ± 102.6 min/d in IPA and 627.8 ± 86.9 min/d in SED. Neither IPA nor SED was associated with any measure of abdominal obesity (P > 0.1). Similarly, LPA was not a significant predictor of abdominal obesity whereas sporadic MVPA was negatively associated with VAT (P < 0.05) after control for age and sex. In this study, neither IPA nor SED was associated with abdominal obesity among inactive men and women.     

Conflicting effects of BMI and waist circumference on iron status

The association between obesity and iron status has a long history and is still receiving attention. However comparative analysis of the association between general obesity (BMI) and visceral obesity (waist circumference) with iron status has not been extensively researched. The aim of the present study is thus to determine if body mass index and waist circumference have the same correlation with iron status. One thousand one hundred and thirty people (225 men and 905 women) aged 30 years and above participated in this study. Anthropometric parameters, haemoglobin, iron and total iron binding capacity concentrations were measured using standard methods. Percentage transferrin saturation was calculated and ferritin concentrations were measured using an enzyme linked immunosorbent assay. Obese or overweight women had significantly lower iron and transferrin saturation concentration when compared to non-obese women. In contrast, women with high waist circumference had comparable plasma iron and transferrin saturation to women with normal waist circumference. Partial correlation analysis and linear regression analysis showed that BMI is negatively and significantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration, whilst waist circumference is positively but insignificantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration. Binary regression analysis showed that obese or overweight people are more likely to have iron deficiency, whilst those with raised waist circumference are more likely to have iron overload. Multivariate analysis showed that body mass index is negatively and significantly associated with low iron status, while waist circumference is positively and insignificantly associated with iron status. This is supported by a comparison of plasma iron, transferrin saturation and ferritin concentrations in participants with high body mass index and normal waist circumference and participants with normal body mass index and high waist circumference to those participants having normal body mass index and normal waist circumference. The present study suggests that in women body mass index is associated with low plasma iron, transferrin saturation and ferritin concentrations, while waist circumference is associated with high plasma iron, transferrin saturation and ferritin concentrations.     

Diabetes in Urban African Americans. XII. Anthropometry for Assessing Municipal Hospital Outpatients Recently Diagnosed with Type 2 Diabetes

Objective : Abdominal obesity is associated with insulin resistance and cardiovascular risk factors, but there has been little information published to advance the use of abdominal anthropometry in the care of diabetic patients. Research Methods and Procedures : A cross-sectional survey of municipal hospital outpatients recently diagnosed with type 2 diabetes (73 men and 142 women of whom 89% were African Americans). Age-adjusted linear regression was used to compare the supine sagittal abdominal diameter (SAD), supine waist circumference, four anthropometric ratios, and the body mass index (kg/m²) for their ability to predict serum fasting C-peptide and lipid levels. Results : The best predictor of log-transformed C-peptide was SAD/height (p<0.0001 for men; p = 0.0003 for women). SAD/thigh circumference was the best predictor of log-transformed triglycerides for men (p = 0.002) and of total cholesterol/HDL cholesterol for women (p = 0.043). The body mass index was less able to predict C-peptide, HDL cholesterol and total cholesterol/HDL cholesterol than was SAD/height or SAD/thigh circumference or waist circumference/height. Discussion : Anthropometric indices of abdominal obesity appear to be correlated with insulin production and lipid risk factors among municipal-hospital, type 2 diabetic patients much as they are in other studied populations. Since anthropometric data are inexpensively obtained and immediately available to the practitioner, their utility for preliminary clinical assessment deserves to be tested in prospective outcome studies.     

Short-term effects of resistance training frequency on body composition and strength in middle-aged women

Although a dose-response relationship between resistance training frequency and strength has been identified, there is limited research regarding the association between frequency and body composition. This study evaluated the effects of 3 vs. 4 d·wk(-1) of resistance training on body composition and strength in middle-aged women. Twenty-one untrained women (age 47.6 ± 1.2 years) completed 8 weeks of resistance training either 3 nonconsecutive days of the week using a traditional total-body protocol (RT3) or 4 consecutive days of the week using an alternating split-training protocol (RT4). The RT3 completed 3 sets of 8 exercises, whereas RT4 completed 3 sets of 6 upper body exercises or 6 sets of 3 lower body exercises. Both groups completed 72 sets per week of 8-12 repetitions at 50-80% 1 repetition maximum. Weekly training volume load was calculated as the total number of repetitions × load (kg) completed per week. Body composition was measured using air displacement plethysmography. At baseline and after 8 weeks of resistance training, there were no significant between-group differences. Both protocols resulted in significant increases in absolute lean mass (1.1 ± 0.3 kg; p = 0.001), body weight (1.02 ± 0.3 kg; p = 0.005), body mass index (0.3 ± 0.1 kg·m(-2); p = 0.006), strength (p < 0.001), and weekly training volume load (p < 0.001). Correlation analysis revealed that weekly training volume load was strongly and positively related to gains in lean mass (r = 0.56, p = 0.05) and strength (r = 0.60, p = 0.006). In these untrained, middle-aged women, initial short-term gains in lean mass and strength were not influenced by training frequency when the number of training sets per week was equated.     

Body Compartment and Subcutaneous Adipose Tissue Distribution - Risk Factor Patterns in Obese Subjects

The purpose of this study was to investigate whether upper body obesity and/or visceral obesity are related to cardiovascular risk factors among severely obese subjects, phenomena that have previously been reported in more heterogeneous body weight distri -buttons. 2450 severely obese men and women aged 37 to 59 years, with a body mass index of 39 ± 4.5 kg/m² (mean ± SD) were examined cross-sectionally. Eight cardiovascular risk factors were studied in relation. to the following body composition indicators: four trunk and three limb circumferences, along with weight, height and sagittal trunk diameter. From the latter three measurements lean body mass (LBM, i.e., the non-adipose tissue mass) and the masses of subcutaneous and visceral adipose tissue were estimated by using sex-specific prediction equations previously calibrated by computed tomography. Two risk factor patterns could be distinguished: 1. One body compartment- risk factor pattern in which the subcutaneous adipose tissue (AT) mass and, in particular, the visceral AT mass were positively related to most risk factors while the lean body mass was negatively related to some risk factors. 2. One subcutaneous adipose tissue distribution- risk factor pattern in which the neck circumference was positively and the thigh circumference negatively related to several risk factors. It is concluded that lean body mass (LBM), visceral and subcutaneous adipose tissue masses as well as neck and thigh circumferences, used as indices of subcutaneous adipose tissue distribution, are independently related to cardiovascular risk factors in severely obese men and women.     

Impact of body mass index on the predictive ability of body fat distribution for Type 2 diabetes risk in Koreans

Aims The optimal anthropometric measure of obesity or body fat distribution that best predicts the risk of Type 2 diabetes in Asians is unclear. Moreover, it has not been determined whether BMI modifies the effect of body fat distribution on diabetes risk in Asians. Methods We analysed the anthropometric and laboratory data of 7658 non-diabetic Korean adults (5061 men and 2597 women, aged 20-79?years) who underwent routine medical check-ups at 5-year intervals. BMI, waist circumference, waist-to-height ratio, and bioelectrical impedance (to calculate fat mass and per cent body fat) were measured at baseline. Results Of the 7658 participants, 278 subjects (3.6%) developed diabetes over 5?years. Each of the anthropometric measures of general obesity (BMI, fat mass, per cent body fat) and central body fat distribution (waist circumference and waist-to-height ratio) was a good predictor of Type 2 diabetes. However, when the areas under the receiver-operating characteristic curves were compared, BMI (0.697; 95% CI, 0.669-0.725), waist circumference (0.709, 0.682-0.736) and waist-to-height ratio (0.718, 0.692-0.743) were better predictors of diabetes risk than fat mass (0.672, 0.643-0.700) or per cent body fat (0.657, 0.628-0.686). In the low- (相似文献   

Body adiposity and type 2 diabetes: increased risk with a high body fat percentage even having a normal BMI

Obesity is the major risk factor for the development of prediabetes and type 2 diabetes. BMI is widely used as a surrogate measure of obesity, but underestimates the prevalence of obesity, defined as an excess of body fat. We assessed the presence of impaired glucose tolerance or impaired fasting glucose (both considered together as prediabetes) or type 2 diabetes in relation to the criteria used for the diagnosis of obesity using BMI as compared to body fat percentage (BF%). We performed a cross-sectional study including 4,828 (587 lean, 1,320 overweight, and 2,921 obese classified according to BMI) white subjects (66% females), aged 18-80 years. BMI, BF% determined by air-displacement plethysmography (ADP) and conventional blood markers of glucose metabolism and lipid profile were measured. We found a higher than expected number of subjects with prediabetes or type 2 diabetes in the obese category according to BF% when the sample was globally analyzed (P < 0.0001) and in the lean BMI-classified subjects (P < 0.0001), but not in the overweight or obese-classified individuals. Importantly, BF% was significantly higher in lean (by BMI) women with prediabetes or type 2 diabetes as compared to those with normoglycemia (NG) (35.5 ± 7.0 vs. 30.3 ± 7.7%, P < 0.0001), whereas no differences were observed for BMI. Similarly, increased BF% was found in lean BMI-classified men with prediabetes or type 2 diabetes (25.2 ± 9.0 vs. 19.9 ± 8.0%, P = 0.008), exhibiting no differences in BMI or waist circumference. In conclusion, assessing BF% may help to diagnose disturbed glucose tolerance beyond information provided by BMI and waist circumference in particular in male subjects with BMI <25 kg/m(2) and over the age of 40.     

The Associations between Anthropometric Indices and Obstructive Sleep Apnea in a Korean Population

Background

Obesity is a major risk factor for the development of obstructive sleep apnea (OSA). Although clinical and epidemiological studies have shown that OSA and obesity are strongly associated, few Asian studies have examined the associations between anthropometric obesity indices and OSA, especially in the Korean population. The purpose of this study was to evaluate the influence of anthropometric obesity indices on OSA in a Korean population.

Methods

Anthropometric indices, including neck circumference, waist circumference, and body mass index, were assessed in 383 consecutive subjects with suspected OSA.

Results

Of the 383 subjects assessed, 316 (82.5%) were diagnosed with OSA. Neck circumference (r = 0.518), waist circumference (r = 0.570), and body mass index (r = 0.512) were correlated with the apnea-hypopnea index (p<0.001, for all). After adjusting for age, sex, alcohol consumption, and smoking, a logistic regression model showed that neck circumference [odds ratio (OR), 1.414; p<0.001)], waist circumference (OR, 1.114; p<0.001), and body mass index (OR, 1.364; p<0.001) were associated with OSA. The linear regression model showed that neck circumference (β = 3.748, p<0.001), waist circumference (β = 1.272, p<0.001), and body mass index (β = 3.082, p<0.001) were associated with apnea-hypopnea index. The cut-off values for predicting OSA were determined as 34.5 cm for neck circumference, 76.5 cm for waist circumference, and 23.05 kg/m² for body mass index for females, and 38.75 cm for neck circumference, 88.5 cm for waist circumference, and 24.95 kg/m² for body mass index for males.

Conclusion

Increased anthropometric indices were significantly associated with the presence and severity of OSA in a Korean population. In addition, this study demonstrated the cut-off values for body mass index, waist circumference, and neck circumference for increased OSA risk.     

Obesity,Metabolic Syndrome and Risk of Atrial Fibrillation: A Swedish,Prospective Cohort Study

AimWe aimed to investigate whether different measures of obesity could similarly predict atrial fibrillation, and whether the atrial fibrillation risk associated with obesity is dependent on presence of metabolic syndrome.ResultsDuring a mean follow-up of 13.6 years, 285 incident atrial fibrillation cases were recorded. One standard deviation increment of each obesity measure was associated with increased atrial fibrillation risk as: body mass index 1.25 (1.12 – 1.40), waist circumference 1.35 (1.19 – 1.54) and sagittal abdominal diameter 1.28 (1.14 – 1.44). Compared to normal weight subjects without metabolic syndrome, increased atrial fibrillation risk was noted for overweight subjects with metabolic syndrome, 1.67 (1.16 – 2.41), obese subjects without metabolic syndrome, 1.75 (1.11 – 2.74) and obese subjects with metabolic syndrome, 1.92 (1.34 – 2.74). Compared to subjects with normal waist circumference without metabolic syndrome, subjects with elevated waist circumference and metabolic syndrome suffered increased atrial fibrillation risk, 2.03 (1.44 – 2.87).ConclusionsBody mass index, waist circumference and sagittal abdominal diameter could similarly predict atrial fibrillation. Obesity was associated with an increased atrial fibrillation risk regardless of metabolic syndrome, whereas overweight and elevated waist circumference was associated with increased atrial fibrillation risk only if metabolic syndrome was present.     

Impact of nightshift work on overweight and abdominal obesity among workers of a poultry processing plant in southern Brazil

The authors examined the associations of shiftwork with overweight and abdominal obesity through a cross-sectional study of 1206 employees 18 to 50 yrs of age who were working on a production line in a poultry processing plant. Night-shift workers (n = 800) were considered exposed, whereas day shiftworkers (n = 406) were considered nonexposed. Overweight was defined as a body mass index ≥ 25 kg/m(2) and abdominal obesity as a waist circumference ≥ 88 cm in women and ≥ 102 cm in men. The mean age of the workers was 30.5 yrs (standard deviation = 8.7 yrs), and 65.2% were women. Nightshift workers compared to dayshift workers showed higher prevalences of overweight (42.2% vs. 34.3%; p=?.020) and abdominal obesity (24.9% vs. 19.5%; p =?.037). After adjusting for sociodemographics, parental overweight status, behavioral characteristics, and sleep characteristics, including hours of sleep, the prevalence ratios for overweight and abdominal obesity were 1.27 (95% confidence interval [ CI]: 1.00-1.61) and 1.45 (95% CI: 1.10-1.92), respectively, for the nightshift workers compared to the dayshift workers. A consistent finding in our study was the independent contribution of night shiftwork to overweight and abdominal obesity among Brazilian workers. Further studies are needed to understand the biological mechanisms involved and the complex behavioral and social adaptations experienced by night-shift workers.     

Prevalence and five-year cumulative incidence of abdominal obesity in Croatian women of childbearing age: the CroHort study

Generalised obesity is increasing in prevalence globally, however trends in abdominal obesity are less well known. In 2003, 1,999 women of childbearing age participated in the Croatian Adult Health Survey, of whom 598 (29.9%) participated in the second cycle in 2008. For 2008, the prevalence of abdominal obesity using the International Diabetes Federation (IDF) criterion (waist circumference > or = 80 cm) was estimated at 70.3% (95% CI 61.8% to 75.7%), whereas the prevalence of abdominal obesity using the National Cholesterol Education Program, Adult Treatment Panel III (NCEP ATP III) criterion (waist circumference > or = 88 cm) was estimated at 48.6% (42.6% to 54.7%). The preceding five-year cumulative incidence was 54.3% (44.5% to 64.2%) and 35.2% (28.0% to 42.4%) using the IDF and NCEP ATP III criteria, respectively. The burden of abdominal obesity is high and rapidly increasing in Croatian women of childbearing age, the key population subgroup for obesity control.     

Body fat distribution has no effect on serum visfatin levels in healthy female subjects

Obesity is the presence of either abnormal absolute amount or relative proportion of body fat. Contrary to gluteal obesity, visceral obesity is associated with different metabolic alterations including insulin resistance (IR). A relatively new adipocytokine visfatin is shown to be expressed predominantly in visceral fat and exhibit insulin-mimicking effects in rodents. It is still unclear whether serum visfatin levels are associated with increased total or visceral fat mass in humans. The aim of our study was to investigate the relation between visfatin and obesity parameters namely body mass index (BMI) and waist circumference (WaC) and IR in healthy female subjects. Eighty one female subjects ?20 years of age, having no diagnosis of glucose intolerance or diabetes, hypertension and dyslipidemia were chosen. The patients were divided into four groups according to their BMI and WaC values. Serum visfatin and HOMA-IR levels did not differ among groups. No correlation was detected between serum visfatin levels and obesity and metabolic parameters. In conclusion, we demonstrated that body fat distribution did not affect serum visfatin levels in healthy female subjects. Further studies are needed to clarify the exact factors influencing and determining serum visfatin levels and its clinical reflections.     

Cigarette Smoking Increases Abdominal and Visceral Obesity but Not Overall Fatness: An Observational Study

Background

Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity.

Methodology/Principal Findings

Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size.

Conclusions/Significance

Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications.     

Impact of Nightshift Work on Overweight and Abdominal Obesity Among Workers of a Poultry Processing Plant in Southern Brazil

The authors examined the associations of shiftwork with overweight and abdominal obesity through a cross-sectional study of 1206 employees 18 to 50 yrs of age who were working on a production line in a poultry processing plant. Night-shift workers (n?=?800) were considered exposed, whereas day shiftworkers (n?=?406) were considered nonexposed. Overweight was defined as a body mass index ≥25?kg/m² and abdominal obesity as a waist circumference ≥88?cm in women and ≥102?cm in men. The mean age of the workers was 30.5 yrs (standard deviation?=?8.7 yrs), and 65.2% were women. Nightshift workers compared to dayshift workers showed higher prevalences of overweight (42.2% vs. 34.3%; p?=?.020) and abdominal obesity (24.9% vs. 19.5%; p?=?.037). After adjusting for sociodemographics, parental overweight status, behavioral characteristics, and sleep characteristics, including hours of sleep, the prevalence ratios for overweight and abdominal obesity were 1.27 (95% confidence interval [ CI]: 1.00–1.61) and 1.45 (95% CI: 1.10–1.92), respectively, for the nightshift workers compared to the dayshift workers. A consistent finding in our study was the independent contribution of night shiftwork to overweight and abdominal obesity among Brazilian workers. Further studies are needed to understand the biological mechanisms involved and the complex behavioral and social adaptations experienced by night-shift workers. (Author correspondence: mtolinto@gmail.com)     

Homocysteine Levels in Patients with Schizophrenia on Clozapine Monotherapy

We tested the hypothesis that homocysteine levels are higher in blood of schizophrenic subjects on clozapine monotherapy than in healthy controls and they correlate with anthropometric measurements, laboratory tests and results of bioimpedance analysis of body composition. Data for 24 subjects with schizophrenia treated with clozapine and 24 age- and sex-matched healthy volunteers was analyzed. Regarding the whole group, homocysteine levels were significantly higher in men (17.0 ± 3.4 vs. 12.1 ± 4.0 μmol/L, p = 0.009). Homocysteine levels correlated with waist circumference (R = 0.58, p = 0.003), waist-to-hip ratio (R = 0.57, p = 0.003), basal metabolic rate (R = 0.48, p = 0.01), lean body mass [kg] (R = 0.53, p = 0.008), body water [L] (R = 0.53, p = 0.008) and triglycerides (R = 0.57, p = 0.003). There were no significant differences of homocysteine levels for impaired fasting glucose, abdominal obesity, obesity/overweight, and dyslipidemia. Homocysteine levels did not correlate with age, treatment duration, clozapine dose, weight, body mass index, abdominal circumference, blood pressure, total body fat, cholesterol, high density lipoproteins, low density lipoproteins, uric acid, calcium, glucose, insulin, homoeostasis model assessment of insulin resistance 1, and homoeostasis model assessment of insulin resistance 2. We did not find significant differences in blood homocysteine levels between subjects with schizophrenia and controls. Association with waist circumference may support homocysteine role as an important cardiovascular risk factor. Association with lean weight may explain why men have higher levels of homocysteine than women.