the metabolic syndrome ( mes ) is defined as a cluster of interrelated metabolic abnormalities that doubles the risk of type 2 diabetes mellitus and cardiovascular disease ( cvd ) .
the major features of mes are insulin resistance , central obesity , hypertension , and dyslipidaemia .
this condition is often associated with suppression of adiponectin and elevation of leptin and various inflammatory markers ( e.g. , interleukin-6 [ il-6 ] , monocyte chemoattractant protein-1 [ mcp-1 ] , c - reactive protein [ crp ] , and regulated on activation , normal t cell expressed and secreted [ rantes ] ) [ 2 , 3 ] that may play a causal role in insulin resistance .
also , insufficient physical activity accompanied with increased or inappropriate fat accumulation [ 4 , 5 ] may potentially increase the risk of cvd .
the prevalence of mes in gulf cooperation council ( gcc ) countries is ranked amongst the highest in the world .
furthermore , the risk of mes is higher amongst arab women ( 1355% ) compared to arab men ; it is 18% higher in women in oman [ 8 , 9 ] , 55% in qatar , 22% in united arab emirates , and 13% in saudi arabia . on the other hand , data from caucasian populations either point to men and women being equally at risk of developing mes [ 1315 ] or to men being more predisposed to developing mes than women [ 1621 ]
this difference in mes risk is thought to be , at least partly , explained by men having a greater propensity for abdominal obesity compared to premenopausal women .
it is unclear as to what factors confer the reported higher risk of developing mes in arab women compared to men .
gender differences in fat accumulation and/or the secretory function of adipose tissue may explain some of this disparity .
poor aerobic fitness , in addition to low grade inflammation , contributes to the development of insulin resistance   and is often a better predictor for cvd risk factors than self - reported physical activity .
furthermore , muscular strength and aerobic fitness combined or independently are inversely related to mes .
therefore , this study investigated gender differences in body composition , systemic levels of adipokines and inflammatory markers , and aerobic fitness in a cohort of healthy qatari adults matched for age and body mass index ( bmi ) .
a matched case - control study was conducted at aspetar , qatar orthopaedic and sports medicine hospital between february 2009 and december 2009 .
this study was approved by the institutional research ethics committee and all subjects provided written consent prior to participation .
healthy qatari men ( n = 29 ) and women ( n = 29 ) were matched for age and bmi .
subjects with diabetes mellitus , those who were pregnant or postmenopausal , or receiving medical treatment for any chronic disease were excluded from the study .
after a 10-hour overnight fast , subjects underwent a detailed clinical assessment , including body composition , fat distribution , anthropometry measurements , and blood pressure .
subjects also underwent a series of tests for aerobic fitness and indices of muscular strength .
height was measured to the nearest 0.1  cm ( seca 242 , germany ) , and weight was measured to the nearest 0.1  kg using a portable stadiometer ( detecto , usa ) . both height and weight measurements
waist circumference was measured to the nearest 0.1  cm at the smallest girth horizontally around the trunk underneath the subject 's clothing .
central obesity was defined as > 80  cm for women and > 90  cm for men .
two blood pressure readings were taken 5 minutes apart with the subject at rest in a relaxed sitting position . the average systolic and diastolic blood pressures were calculated and used in subsequent analyses .
dxa ( ge medical system lunar , madison , wisconsin , usa ) using the encore software ( version 12.10 ) was used to quantify fat mass ( g ) , tissue ( g ) , lean mass ( g ) and percentage of body fat .
ct scans were performed to obtain 5 axial images of each of the following regions : heart , liver , abdomen , and midthigh . for the abdominal region ,
omental adipose tissue was differentiated from subcutaneous adipose tissue by manual drawing , and subcutaneous adipose tissue was further classified as superficial and deep .
two cross - sectional axial images of the left and right thigh at the femoral midpoint region were obtained .
intramuscular adipose tissue and subcutaneous adipose tissue in the thigh were distinguished by manual drawing using the right thigh image .
an upper limit of 30 hounsfield units ( hu ) and a lower limit of 190  hu were used to differentiate adipose tissue from other tissue types on the ct images .
all volumetric analyses were performed by an experienced radiologist using the somaris/5 syngo ct2006a system ( siemens , germany ) .
a complete blood count was performed , and serum levels of iron , ferritin , iron - binding capacity , transferrin , and lipids , including high - density lipoprotein ( hdl ) , low - density lipoprotein ( ldl ) , total cholesterol , and triglycerides , determined by the pathology laboratory at aspetar .
fasting plasma glucose ( beckman , ca , usa ) insulin ( mercodia , uppsala , sweden ) was also assessed , and the homa - ir ( homeostasis model of assessment - insulin resistance ) was calculated using the following formula : ( fasting insulin in miu / l  fasting glucose in mmol / l)/22.5 . fasting serum levels of crp , adiponectin , leptin , rantes , mcp-1 , and il-6 were measured using human 2-site elisas ( r&d systems , oxon , uk ) .
il-6 concentrations were assayed with the high sensitivity elisa with a limit of detection of 0.09  pg / ml . all inter- and intraassay cvs were less than 10% .
starting speed was set to 2.74  km / hr , and the intensity ( speed and incline ) was increased by 2% every 3 minutes until volitional exhaustion .
peak heart rate ( hr ) , percentage of predicted maximal hr , test duration , and peak oxygen uptake were measured .
the hand grip strength was measured with the lode dynamometer ( lode bv , groningen , the netherlands ) .
leg strength was assessed by recording isokinetic knee flexion and extension concentrically ( at 30/second and 120/second ) and isometric extension at 90 on the dominant leg ( biodex 3.0 system , version 3.4 , shirley ,
data were analysed using the spss ( statistical package for the social sciences , version 15.0 ) software .
descriptive statistics included mean  sd for normally distributed data and median ( interquartile range , iqr ) for skewed data .
an independent sample t - test was used to compare continuous data between two groups and the nonparametric equivalent mann - whitney u test was used when appropriate .
log transformations were applied to normalize the distribution of adipokines and cytokines before computing spearman 's correlation coefficients against metabolic markers .
data from this study population was compared to the published age- and gender - specific percentiles for aerobic fitness from the aerobic center longitudinal study ( acls ) .
a total of 29 men and 29 women matched for age and bmi were included in the study , with a mean age of 33.4  10.3 years ( table 1 ) . despite the similarity in bmi and waist circumference ,
body fat percentage was higher in women ( women : 43.4  6.3% versus men : 32.7  8.8% , p < 0.01 ) .
women had significantly lower levels of triglycerides ( p < 0.01 ) and ldl ( p = 0.05 ) and higher levels of hdl ( p < 0.01 ) , compared to men .
women had lower values for various iron indices compared with men : serum iron ( p = 0.05 ) , serum ferritin ( p < 0.01 ) , and haemoglobin level ( p < 0.01 ) .
indices of insulin sensitivity and glucose handling ( insulin , homa - ir , fasting glucose , and hba1c levels ) were similar in men and women .
total fat in the abdominal region was higher in women compared to men , especially in the deep subcutaneous abdominal region ( table 2 ) .
adiposity was also significantly higher in women than men in the heart intra- ( p = 0.04 ) and overall heart ( p < 0.01 ) regions , as well as in the thigh region ( p < 0.01 ) .
gender differences in the correlations between serum metabolic markers , adipokines / cytokines , and vo2  max were investigated ( table 3 ) . in men , adiponectin and rantes
were not associated with any of the metabolic markers studied , whereas in women , adiponectin was negatively correlated with triglycerides ( r = 0.45 , p = 0.02 ) and insulin ( r = 0.39 , p = 0.05 ) . in both men and women ,
crp was negatively correlated with aerobic fitness ( r = 0.43 , p = 0.05 and r = 0.54 , p < 0.01 resp . ) .
il-6 , leptin , and crp were strongly correlated with waist circumference and systolic bp only in men ( table 3 ) .
serum adiponectin and leptin levels were significantly higher in women than men , whereas rantes , crp , mcp-1 , and il-6 were not different ( figure 1 ) .
tests of aerobic fitness showed that both men and women reached at least 95% of their age - predicted maximum hr ( table 4 ) . on average , women ran on the treadmill for almost 7 minutes , whereas men completed 9.5 minutes ( p < 0.01 ) . calculated aerobic fitness ( vo2  max ) was markedly higher in men than women ( p < 0.01 ) as were all indices of leg and hand grip strength ( p < 0.01 ) . using multiple regression analysis , we found that gender was the strongest determinant for poor aerobic fitness ( 7.5 , 95% ci : 10.3 to 4.8 ) followed by waist circumference ( 0.22 , 95% ci : 0.34 to 0.11 ) , after adjusting for bp .
reports suggest that prevalence of coronary heart disease is higher in men and postmenopausal women .
[ 17 , 28 , 29 ] . however , in the arab population , coronary heart disease - associated risk of morbidity and mortality are elevated even in younger women compared to other ethnic groups [ 30 , 31 ] .
this study sought to clarify the gender differences in fat distribution , serum markers of metabolism and inflammation , and measures of aerobic fitness in an age- and bmi - matched population of healthy qatari men and women .
the relatively young premenopausal women in this study had significantly greater fat content in the heart , abdominal , and thigh regions compared with age - matched men ( table 2 ) .
however , this fat distribution pattern was also accompanied by a favourable lipid profile ( high hdl and low ldl ) and elevated adiponectin and leptin in women , compared with men .
subcutaneous fat alone is responsible for 80% of leptin production in the body , and thus leptin levels appear to be a good marker for this type of fat deposition in women .
the positive correlation of femoral fat with adiponectin ( r = 0.44 , p = 0.01 ) in the present study ( table 3 ) is consistent with previous findings that gluteofemoral deposition of fat is cardioprotective .
adiponectin was negatively correlated with homa - ir ( r = 0.38 , p = 0.056 ) and serum triglycerides ( r = 0.46 , p = 0.02 ) in women , but these relationships were surprisingly absent in men ( homa - ir ; r = 0.08 , p = 0.72 and tg ; r = 0.04 , p = 0.84 ) .
adiponectin acts as an endogenous insulin sensitizer , both directly on muscle cells and indirectly through insulin , and circulating concentrations of this adipokine are strongly and positively correlated with hdl concentration and negatively correlated with triglyceride levels .
while adiponectin may be related to the favourable lipid profile seen in the women in this study , it does not appear to be anti - inflammatory , as both women and men had comparable levels of il-6 , mcp-1 , crp , and rantes ( figure 1 ) .
the comparable levels of circulating adipokines / cytokines may reflect similar levels of omental adipose tissue amongst the study subjects .
adipose tissue - derived il-6 and mcp-1 account for approximately 15%30% of systemic levels of these cytokines in obese individuals .
crp plays a role in inflammation and insulin resistance [ 3 , 36 ] and may be derived from adipose tissue or elevated as a consequence of higher il-6 and mcp-1 levels .
adipose tissue also releases rantes , another putative mediator of impaired glucose tolerance and type 2 diabetes . among patients with elevated risk of type 2 diabetes ,
both men and women in the present study had extremely low levels of aerobic fitness .
vo2  max for half of the men ( 44.8% ) and the majority of women ( 87.5% ) was below the 20th percentile reported by acls for a caucasian population   ( figure 2 ) .
however , for measures of muscular strength , approximately 87.0% of men and 75.9% of women were above the 75th percentile of values reported by acls .
despite higher levels of abdominal body fat compared with arab men , premenopausal arab women have elevated serum adiponectin that may maintain normolipidemia and insulin sensitivity .
the accumulation of omental adipose tissue , combined with extremely low aerobic fitness , in arab women may abrogate the protective effect of adiponectin , leading to a greater risk of developing mes .
further research is needed to understand the gender - specific causal factors that increase the risk of mes among arab women .
 recent studies from the gulf region suggest that compared to men , women have a greater risk of developing metabolic syndrome ( mes ) . objective . to investigate gender differences in body composition , adipokines , inflammatory markers , and aerobic fitness in a cohort of healthy qatari adults . 
 participants . 
 healthy qatari ( n = 58 ) were matched for age , gender , and body mass index . 
 methods . body composition and regional fat distribution were determined by dual - energy x - ray absorptiometry and computerized tomography . 
 laboratory assessments included serum levels of fasting glucose , insulin , lipid profile analysis , adipokines , and inflammatory markers . 
 subjects were also evaluated for aerobic fitness . 
 results . 
 women had more adipose tissue in the total abdominal ( p = 0.04 ) and abdominal subcutaneous ( p = 0.07 ) regions compared to men . waist circumference and indices of insulin sensitivity were similar ; however , women had a more favourable lipid profile than men . 
 serum adiponectin and leptin levels were significantly higher in women , whereas inflammatory profiles were not different between men and women . 
 aerobic fitness was lower in women and was associated with abdominal fat accumulation . conclusion . 
 in premenopausal women , higher levels of adiponectin may support maintenance of insulin sensitivity and normolipidemia despite greater adiposity . 
 however , poor aerobic fitness combined with abdominal fat accumulation may explain their greater future risk of mes compared with men . 