Plasma lipidome is independently associated with variability in metabolic syndrome in Mexican American families

Plasma lipidome is now increasingly recognized as a potentially important marker of chronic diseases, but the exact extent of its contribution to the interindividual phenotypic variability in family studies is unknown. Here, we used the rich data from the ongoing San Antonio Family Heart Study (SAFHS) and developed a novel statistical approach to quantify the independent and additive value of the plasma lipidome in explaining metabolic syndrome (MS) variability in Mexican American families recruited in the SAFHS. Our analytical approach included two preprocessing steps: principal components analysis of the high-resolution plasma lipidomics data and construction of a subject-subject lipidomic similarity matrix. We then used the Sequential Oligogenic Linkage Analysis Routines software to model the complex family relationships, lipidomic similarities, and other important covariates in a variance components framework. Our results suggested that even after accounting for the shared genetic influences, indicators of lipemic status (total serum cholesterol, TGs, and HDL cholesterol), and obesity, the plasma lipidome independently explained 22% of variability in the homeostatic model of assessment-insulin resistance trait and 16% to 22% variability in glucose, insulin, and waist circumference. Our results demonstrate that plasma lipidomic studies can additively contribute to an understanding of the interindividual variability in MS.     

Correlates of species richness in North American bat families

Aim A near universal truth in North America is that species richness increases from the Arctic Circle to the Central American tropics. Latitude is regarded as a major explanatory variable in species density, although it is only a surrogate for underlying ecological variables. I aimed to elucidate those underlying ecological variables that are associated with variation in bat species richness across the entire North American continent, providing a portrait of the macroecology of the order Chiroptera and its familial components. Methods I determined the number of bat species recorded for every state in Mexico and the United States, every province or territory in Canada, and every country in Central America. For each of these entities (n = 99), I also gathered basic data on mean annual precipitation, variation across the year (July vs. January) in mean temperature, mean January temperature, range in elevation (topographic relief), per cent vegetative cover and median latitude. Using a variety of linear regression and model‐fitting techniques, I analysed the strength and direction of the relationship between species richness and environmental variables for the order Chiroptera as a whole and separately for each of four familial groups: Molossidae (free‐tailed bats), Phyllostomidae (New World leaf‐nosed bats), Vespertilionidae (evening bats), and a set of six families (the Desmodontidae, Emballonuridae, Furipteridae, Natalidae, Noctilionidae, and Thyropteridae) represented in North America relatively poorly. Results and main conclusions Save for the Vespertilionidae, species richness of bats increased towards the Panamanian Isthmus. The Phyllostomidae and the set of miscellaneous families are particularly speciose in tropical Central America, with many fewer species occurring through subtropical Mexico into (in some cases) the southernmost United States. The Molossidae extends farther north, sparingly into the middle of the United States. Species density of the Vespertilionidae peaks in central and western Mexico and the southernmost United States, declining south through tropical southern Mexico and Central America and north through the central United States into Canada. Annual precipitation, January temperature, and topography are good predictors of species richness in the Chiroptera and the Molossidae, precipitation, topography, and temperature range in the Phyllostomidae, January temperature and topography in the Vespertilionidae, and precipitation alone in the collection of families. Vegetative cover explained little variation in the Chiroptera as a whole or in any family. After accounting for the effects of the environmental variables, latitude explained an insignificant amount of the residual variation in species richness. Bat families differ in their ecology, so studies of bat biogeography in North America may be misleading if they are examined only at the ordinal level.     

Increasing trends in waist circumference and abdominal obesity among US adults

Objective: Some studies have shown that abdominal obesity may be a better predictor than overall obesity for disease risks and all‐cause mortality. This study sought to examine the recent trends in waist circumference (WC) among adults in the United States. Research Methods and Procedures: Data from the National Health and Nutrition Examination Survey during 1988–1994, 1999–2000, 2001–2002, and 2003–2004 were analyzed to estimate the trends in the mean WC and the prevalence of abdominal obesity. Pooled t tests were used to test the differences in estimates between two time periods. Results: Between the periods of 1988–1994 and 2003–2004, the age‐adjusted mean WC increased from 96.0 cm to 100.4 cm among men (p < 0.001) and from 89.0 cm to 94.0 cm among women (p < 0.001); the age‐adjusted prevalence of abdominal obesity increased from 29.5% to 42.4% among men (p < 0.001) and from 47.0% to 61.3% among women (p < 0.001). Between the periods of 1999–2000 and 2003–2004, a significant increase occurred in mean WC only among men (from 99.0 cm to 100.4 cm; p = 0.03) and in the prevalence of abdominal obesity among both men (from 37.0% to 42.2%; p = 0.03) and women (from 55.3% to 61.3%; p = 0.04). People with a BMI of 25 to 29 kg/m² had a greater relative increase in abdominal obesity. Discussion: The mean WC and the prevalence of abdominal obesity among U.S. adults have increased continuously during the past 15 years. Over one‐half of U.S. adults had abdominal obesity in the period of 2003–2004.     

Plasma ADMA concentrations associate with aerobic fitness in postmenopausal women

Aims

Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of nitric oxide (NO) synthase, an enzyme responsible for the generation of NO. Plasma concentrations of ADMA increase in the elderly and in postmenopausal women. In fact, an elevated ADMA level is a risk factor of cardiovascular disease. Aerobic exercise has a beneficial effect on cardiovascular disease. However, the relationship between ADMA and aerobic fitness is unknown. The aim of this study was to determine whether plasma ADMA concentrations correlate with aerobic fitness levels in postmenopausal women.

Main methods

Thirty healthy postmenopausal women aged 50–76 years participated in this study. We measured plasma concentrations of ADMA and oxygen consumption at the ventilatory threshold (VO_2VT) as an index of aerobic fitness. Subjects were divided into the low aerobic fitness (Low fitness) and high aerobic fitness (High fitness) groups, and the dividing line was set at the median VO_2VT value.

Key findings

VO_2VT was significantly higher in the High fitness group than in the Low fitness group (P < 0.01). The plasma ADMA concentrations in the High fitness group were significantly lower than those in the Low fitness group (P < 0.05). There was a negative correlation between plasma ADMA concentrations and VO_2VT (r = − 0.532, P < 0.01).

Significance

We found that plasma ADMA concentrations were associated with aerobic fitness in postmenopausal women. The results of this study suggest that habitual aerobic exercise may decrease plasma ADMA concentrations.     

Impact of waist circumference on cardiac phenotype in hypertensives according to gender

Our aim was to assess the differential effect of waist circumference on left-ventricular (LV) structural and functional alterations, in hypertensive males and females. One thousand seven hundred and eighty nine consecutive, nondiabetic, essential hypertensives (aged 55.8 +/- 13.5 years, 966 females), included in the 3H Study, an ongoing registry of hypertension-related-target-organ damage, were classified to obese and nonobese groups according to Adult Treatment Panel III criteria. All participants underwent complete echocardiographic study including LV diastolic function evaluation by means of conventional and tissue Doppler imaging (TDI) methods, averaging early and late diastolic mitral annular peak velocities (Em, Am, Em/Am) from four separate sites of measurement. Hypertensive obese women compared with nonobese exhibited significantly greater LV mass index and prevalence of LV hypertrophy (by 5.5 g/m(2), P = 0.003, and 8.8%, P = 0.005, respectively), while such differences were not present among men. Obese women compared to nonobese ones were accompanied by lower transmitral E/A (by 0.08, P < 0.001), TDI-derived Em/Am (by 0.12, P < 0.001), and higher E/Em ratio (by 0.8, P = 0.016). In contrast, hypertensive obese men compared to nonobese ones exhibited lower E and Em (by 0.04 m/s and 0.6 cm/s, both P < 0.05). A significant interaction between sex and abdominal obesity was observed only regarding TDI-derived Am and Em/Am. Furthermore, waist circumference was a predictor of E/A (beta = -0.097, P = 0.002) and Em/Am (beta = -0.116, P = 0.001), independently of body size, in females but not in males. The adverse effect of abdominal obesity on LV alterations is more pronounced among female hypertensives, suggesting that routine measurement of waist circumference provides additional information on cardiac phenotype especially in women.     

BMI, waist circumference, and incident urinary incontinence in older women

Overall body fat and central adiposity may reflect different mechanisms leading to urinary incontinence (UI). We examined the associations of BMI and waist circumference with incident UI, including the independent associations of BMI and waist circumference with UI type, among women aged 54-79 years in the Nurses' Health Study. Study participants reported their height in 1976 and their weight and waist circumference in 2000. From 2000 to 2002, we identified 6,790 women with incident UI at least monthly among 35,754 women reporting no UI in 2000. Type of incontinence was determined on questionnaires sent to cases with at least weekly incontinence. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated using multiple logistic regression. There were highly significant trends of increasing risk of UI with increasing BMI and waist circumference (P for trend <0.001 for both). Multivariable RRs of developing at least monthly UI were 1.66 (95% CI 1.45-1.91) comparing women with a BMI of > or =35 kg/m(2) to women with BMI 21-22.9 kg/m(2) and 1.72 (95% CI 1.53-1.95) comparing women in extreme quintiles of waist circumference. When BMI and waist circumference were included in models simultaneously, BMI was associated with urge and mixed UI (P for trend 0.003 and 0.03, respectively), but not stress UI (P for trend 0.77). Waist circumference was associated only with stress UI (P for trend <0.001). These results suggest that women who avoid high BMI and waist circumference may have a lower risk of UI development.     

Determining the waist circumference in african americans which best predicts insulin resistance

Total body size and central fat distribution are important determinants of insulin resistance. The BMI and waist circumference (WC) thresholds in African Americans that best predict insulin resistance are unknown. Our goal was to determine the BMI and WC values in African Americans, which optimally predict insulin resistance. The subjects were African Americans (68 men, 63 women), aged 35 +/- 8 years (mean +/- s.d.), with a BMI of 30.9 +/- 7.5, in the range of 18.5-54.7 kg/m(2), and with a WC of 98 +/- 18, in the range of 69-173 cm. Insulin resistance was defined by the lowest tertile of the insulin sensitivity index (S(I)). The Youden index was calculated to determine the WC and BMI thresholds that predict insulin resistance with an optimal combination of sensitivity and specificity. In men the thresholds that optimally predicted insulin resistance were a BMI > or =30 kg/m(2) or a WC > or =102 cm. For women, insulin resistance was best predicted by a BMI > or =32 kg/m(2) or a WC > or =98 cm. In African Americans, insulin resistance (in men) was best predicted by a WC > or =102 cm, and in women by a WC > or =98 cm, or by a BMI value that fell in the obese category (men: > or =30 kg/m(2), women: > or =32 kg/m(2)).     

BMI and waist circumference in predicting cardiovascular risk factor clustering in Chinese adolescents

Objective: To derive the optimal BMI and waist circumference (WC) cut‐off values to predict clustering of cardiovascular risk factors in Hong Kong Chinese adolescents. Research Methods and Procedures: A total of 2102 Hong Kong Chinese 12 to 19 years of age were recruited. Participants were considered to have clustering of risk factors if at least three of the following risk factors were present: 1) high‐density lipoprotein cholesterol (HDL‐C) ≤1.03 mM, 2) low‐density lipoprotein cholesterol (LDL‐C) ≥2.6 mM, 3) triglyceride (TG) ≥1.24 mM, 4) fasting plasma glucose (FPG) ≥6.1 mM, and 5) age‐, sex‐, and height‐adjusted systolic or diastolic blood pressure (BP) ≥ 90th percentile. Receiver operating characteristics (ROC) curves were generated to identify the optimal age‐adjusted BMI and WC cut‐off values to predict clustering of risk factors in boys and girls separately. These age‐adjusted BMI and WC cut‐offs were transformed to percentile values. Cole's lambda‐mu‐sigma (LMS) method was used to obtain smoothed age‐specific BMI and WC at these percentile values. Results: The areas under ROC curves for BMI in girls and boys were 0.85 [95% confidence interval (CI), 0.77 to 0.92] and 0.76 (95% CI, 0.66 to 0.85), respectively. The respective areas under ROC curves for WC in girls and boys were 0.82 (95% CI, 0.74 to 0.91) and 0.78 (95% CI, 0.68 to 0.87). The optimal BMI thresholds were at the 78th percentile for girls and the 72nd percentile for boys. The respective values for WC were at the 77th percentile for girls and the 76th percentile for boys. The sensitivities and specificities of these cut‐off values ranged from 72% to 80%. Discussion: Age‐ and sex‐specific BMI and WC cut‐off values can be used to identify adolescents with clustering of cardiovascular risk factors.     

Low molecular weight adiponectin negatively correlates with the waist circumference and monocytic IL-6 release

Adiponectin circulates as trimer (LMW), hexamer (MMW) and high molecular weight multimer (HMW) but the distribution and effects of these isoforms have not been studied in detail. Monocytes were isolated from normal weight and overweight controls and patients with type 2 diabetes mellitus (T2D) and monocytic release of IL-6 positively correlated with the body mass index (BMI). HMW-adiponectin further enhanced and LMW-adiponectin reduced IL-6 release in monocytes. Systemic total adiponectin, and the HMW isoform were not different in these groups but MMW-adiponectin was lower in T2D, and LMW-adiponectin was reduced in the obese and T2D. Circulating LMW-adiponectin negatively correlated to monocytic IL-6 release. Systemic IL-6 was higher in the obese control group and T2D, respectively, but did not correlate with monocytic IL-6 secretion. Therefore, the current study indicates that HMW-adiponectin exerts pro- and LMW-adiponectin antiinflammatory effects and reduced LMW-adiponectin in obesity may partly contribute to elevated monocytic IL-6 release.     

Trajectories of relative weight and waist circumference among children with and without developmental coordination disorder

Background

Children with developmental coordination disorder have been found to be less likely to participate in physical activities and therefore may be at increased risk of overweight and obesity. We examined the longitudinal course of relative weight and waist circumference among school-aged children with and without possible developmental coordination disorder.

Methods

We received permission from 75 (83%) of 92 schools in southwestern Ontario, Canada, to enrol children in the fourth grade (ages 9 and 10 at baseline). Informed consent from the parents of 2278 (95.8%) of 2378 children in these schools was obtained at baseline. The main outcome measures were body mass index (BMI) and waist circumference. Children were followed up over two years, from the spring of 2005 to the spring of 2007.

Results

Over the course of the study, we identified 111 children (46 boys and 65 girls) who had possible developmental coordination disorder. These children had a higher mean BMI and waist circumference at baseline than did those without the disorder; these differences persisted or increased slightly over time. Children with possible developmental coordination disorder were also at persistently greater risk of overweight (odds ratio [OR] 3.44, 95% confidence interval [CI] 2.34–5.07) and obesity (OR 4.00, 95% CI 2.57–6.21) over the course of the study.

Interpretation

Our findings showed that children with possible developmental coordination disorder were at greater risk of overweight and obesity than children without the disorder. This risk did not diminish over the study period.Developmental coordination disorder is a neuro-developmental condition that affects 5%–6% of school-aged children.¹ Children with the disorder present with a range of coordination difficulties, including fine and gross motor problems,² all of which interfere with normal daily activities, recreational activities and academic performance skills such as handwriting.³ Developmental coordination disorder is diagnosed when existing neurologic and physical problems are ruled out as the cause of motor coordination difficulties and intellectual development has been taken into consideration (Box 1).^1,4 The clinical implications of a diagnosis have been described previously.⁵

Box 1.?Diagnostic criteria for developmental coordination disorder

1. Performance in daily activities that require motor coordination is substantially below that expected given the person’s chronological age and measured intelligence. This may be manifested by marked delays in achieving motor milestones (e.g., walking, crawling, sitting), dropping things, “clumsiness,” poor performance in sports or poor handwriting.
2. The disturbance in criterion A significantly interferes with academic achievement or activities of daily living.
3. The disturbance is not due to a general medical condition (e.g., cerebral palsy, hemiplegia or muscular dystrophy) and does not meet criteria for a pervasive developmental disorder.
4. If mental retardation is present, the motor difficulties are in excess of those usually associated with it.

Reproduced with permission from the Diagnostic and Statistical Manual of Mental Disorders, Text Revision, Fourth Edition.⁴ Copyright © 2000 American Psychiatric Association.Because children with developmental coordination disorder have been found to be less likely to participate in physical activities,⁶ it has been hypothesized that this condition may be a risk factor for obesity.⁷ Only a few studies have examined the association between motor coordination problems and overweight or obesity in children.^7–10 Moreover, the literature in this area is limited in two key respects. First, previous research has relied almost exclusively on body mass index (BMI) as the outcome measure.^8–10 Although important, BMI is not the only indicator of relative weight and has been shown to be weakly correlated with fat mass in young children.^11,12 Waist circumference provides valid estimates of abdominal fat in pediatric populations¹³ and appears to be a stronger predictor of cardiovascular risk among children.^14,15 Second, previous research in this area has been limited to cross-sectional data, with two notable exceptions.^8,9 However, results from these two prospective studies were mixed: one study showed a significant effect of motor coordination on weight,⁸ the other did not.⁹Our objective was to document several measures of adiposity over time in children with and without developmental coordination disorder.     

Changes in waist circumference and the incidence of diabetes in middle-aged men and women

Background

Waist circumference (WC) is positively associated with diabetes, but the association with changes in WC (DWC) is less clear. We investigated the association between DWC and the subsequent risk of diabetes in middle-aged men and women, and evaluated the influence from concurrent changes in body mass index (DBMI).

Methodology/Principal Findings

Data on 15,577 men and 20,066 women from the Danish Diet, Cancer and Health study were analyzed. Anthropometry was assessed in 1993–97 and 1999–02. Information on diabetes was obtained from The Danish National Diabetes Register. Hazard ratios (HR) were calculated from Cox'' proportional hazard models with individuals considered at risk from 1999–02 until December 31 2006. During 5.4 years of follow-up, 1,027 and 876 new cases of diabetes occurred among men and women, respectively. WC was positively associated with diabetes in both sexes also with adjustment for covariates and BMI. DWC was positively associated with diabetes in women, but not in men (HR per 5 cm change = 1.09 (1.04∶1.15) in women, and 1.00 (0.94, 1.07) in men with adjustment for covariates, baseline WC, BMI and DBMI). Associations with DWC were not notably different in sub-groups stratified according to baseline WC or DBMI, or when individuals with diseases or diabetes occurring within the first years of follow-up were excluded.

Conclusions/Significance

While this study confirmed that WC is positively associated with the risk of diabetes in middle-aged men and women, it surprisingly showed that changes in WC were not associated with the subsequent risk of diabetes in men, and only weakly positively associated with the risk of diabetes in women. Accordingly, these findings suggest that a reduction in WC may be a weak or insufficient or target for prevention of diabetes in middle-aged men and women.     

Do Malaysian Myrmarachne associate with particular species of ant?

Ant-mimicry has evolved in numerous families of spiders. Although some mimics resemble ants very precisely in their morphology and behaviour, others have only a superficial resemblance to ants. In the present study, each of at least seven (and probably ten) out of 11 species of Myrmarachne from peninsular Malaysia associates with one particular species or genus of ant that it specifically resembles; these are therefore 'good' or 'specific' mimics. Myrmarachne malayana lives in the foraging ranges of a variety of ants and shows no specific resemblance to any one genus of ant, and it is best considered as a 'poor' or 'general' mimic. A species of Castianeira (Corinnidae) with a much less precise similarity to ants (a 'poor' mimic) was associated with Polyrhachis ants. It had previously been suggested that Orsima ichneumon (Salticidae) is an ant or insect mimic in reverse; in the present study, it was associated with Polyrhachis ants but is not considered to be an ant-mimic. Two recent theoretical models show how a poor ant-mimic may be better protected than a good mimic under certain circumstances. These data provide some support for the multimodel hypothesis, although not for Sherratt's hypothesis. However, a realistic test of these hypotheses requires more information than that provided here on both mimics and models.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 645–653.     

Interrelationship of waist circumference and subcutaneous fat with metabolic and blood pressure measures among Asian Indian men

People of South Asian origin (e.g. Indians) usually have a more centralized distribution of body fat with thick trunk skinfolds and markedly higher mean waist circumference (WC) for a given level of body fat percentage compared to Europeans and are exceedingly susceptible to coronary heart disease (CHD) worldwide. Owing to ethnic heterogeneity, population specific information on the interrelationship of fat topography with metabolic and blood pressure measures in different Indian populations is immediately required. In view of the above consideration the present work was undertaken to study the interrelationship of the WC and the sum of four (biceps, triceps, subscapular, suprailiac) skinfolds (SF4) with metabolic and blood pressure variables among the well-off Bengalee men aged 30 years and above from Calcutta and suburbs. The sample of the present study comprises 212 male railway employees of the Eastern Railway, Government of India. All 212 subjects were residents of Calcutta and its suburbs. Anthropometrics, lipids (total cholesterol, fasting triglyceride, high, low and very low density lipoprotein cholesterol), fasting plasma glucose and blood pressure measures were taken from each participant. Two-sample (unpaired) t-test revealed that centrally obese men (waist circumference=90 cm) had significantly greater means compared to centrally non-obese subjects for metabolic risk factors and blood pressure. Inter-tertile comparison of lipids, lipoproteins and glucose revealed that there existed no significant differences in their distribution according to SF4 tertiles. The results of multiple regression analyses (after controlling for the linear, cubic and quadratic effect of age) using waist circumferences and SF4 as independent variables demonstrated the significant effect of central obesity on metabolic and blood pressure variables in the study population. This finding indicated the clinical and physiological importance of central body fat accumulation particularly in and around the waist line in explaining risk factors for chronic diseases, e.g. CHD.     

A weekly administered sustained-release growth hormone reduces visceral fat and waist circumference in abdominal obesity

Administration of recombinant human growth hormone (rhGH) in obesity has been known to lead to a decrease in visceral adiposity and an increase in lean body mass. Most studies have used supraphysiological doses of rhGH, which were administered daily or every other day. We aimed to evaluate whether weekly administered low dose of sustained-release rhGH (SR-rhGH) could play a therapeutic role in the treatment of abdominal obesity. Prospective, single-arm, open-label, multicenter pilot study was carried out. Participants were 26 adults aged 40-65 years old with abdominal obesity (male: waist circumference >90?cm, female: waist circumference >85?cm). The subjects were given 3?mg of SR-rhGH, administered subcutaneously, weekly for 26 weeks. SR-rhGH treatment for 26 weeks increased the IGF-1 level by 56.53±76.09?μg/l (SDS 0.77±1.12) compared to the baseline (p=0.0022). After 26 weeks, SR-rhGH treatment reduced abdominal visceral adipose tissue (VAT) (140.35±75.97 to 128.43±73.85?cm2, p=0.0038). Average waist circumference decreased from 96.25±6.41 to 91.93±6.13?cm (p<0.0001) after treatment. However, body weight or lean body mass did not show any significant change. In conclusion, SR-rhGH treatment for 26 weeks reduced abdominal visceral fat and waist circumference without severe adverse events. Further studies may be considered on the role of weekly administered SR-rhGH as a treatment for abdominal obesity.