historically , type 2 diabetes mellitus ( t2 dm ) has been considered an adult disease . however , recent epidemiological studies have reported an increase incidence of t2 dm in 
 children and adolescents in a number of countries1 , 
 2 . data from the 2007 us national 
 diabetes fact sheet indicate that 7.8% of the population and 0.22% of those aged  20  years 
 have diabetes1 . t2 dm has , also been 
 associated with the growing pre valence of childhood obesity2 . in addition , increases in childhood obesity have been accompanied 
 by an increased incidence of type 2 diabetes in youth3 , 4 . in asia the prevalence of 
 t2 dm has increased raidly in recent decades and is characterized by a younger age and lower 
 body mass index ( bmi ) at onset compared with western countries5 . early treatment of t2 dm in children is essential to slow or delay disease progression and 
 prevent complications . lifestyle modifications ( e.g. , dietary adaptations ) are required , and 
 many pediatric patients also require glucose lowering medication to achieve satisfactory 
 glycemic control6 . increased physical 
 activity must be also considered as part of treatment : based on mounting evidence of the 
 benefits of regular exercise on abdominal obesity in adults7 . there is also evidence in children suggesting that engaging in 
 regulatory exercise is associated with a lower waist circumference and reduced visceral 
 fat6 . leptin , visfatin , resistin and retinol binding protein 4 ( rbp4 ) are important adipokines 
 that are involved in inflammation , insulin resistance , obesity and cardiovascular 
 disease8,9,10,11,12 . they may also have a 
 role in the pathogenesis of metabolic syndrome relating to obesity and insulin 
 resistance13 . despite this evidence , diet control and regular exercise this study was designed to examine the effects of a regular exercise program on serum 
 adipokine levels and glycemic control in children who were obese or who had t2 dm . the 1998 children and adolescent physical growth standard proposed by the korean society of 
 pediatrics was used in the assessments of subjects . ten overweight children with bmi > 
 95% or an obesity index > 120% were assigned to the obese group ( ob , meanstandard error 
 age , 16.70.19  years ) , ten children with normal weight were assigned to the healthy control 
 group ( co , 15.00.01  years ) , and ten children were assigned to the t2 dm group 
 ( 16.80.22  years ; metformin therapy : n=6 , repaglinide therapy : n=2 ) the thildren in the t2 dm 
 group were d university hospital inpatients with a 2-h glucose tolerance test  140  mg / dl , 
 blood sugar level  200  mg / dl and no other complicating diseases . the study recruited via 
 poster advertisements and the internet and was approved by the d university hospital 
 institutional review board after medical examination and diagnosis by medical 
 specialists . 6 ) was conducted for 4060 minutes per session four times a week , for 
 12 weeks . 14 , participants engaged in 3040 minutes of aerobic 
 exercise walking / running ) at a school field under the supervision of a professional trainer . participants were monitored using a polar system ( polar electro , kempele , finland ) that 
 calculated heart rate reserve ( hrr ) . in weeks 512 , participants exercised in a similar 
 manner but for 4050 minutes at a hrr equivalent to 60% of vo2max . each session 
 was preceded and followed by a 5-minute warm - up and cool - down6 . body composition testing was performed by measuring height , weight , body fat and bmi with 
 the use of a venus 5.5 impedance analyzer ( jawon medical , seoul , korea ) . an exercise loading 
 test was performed using an inter track 6025 treadmill ( taeha , seoul , korea ) and a quark 
 b2 gas analyzer ( cosmed , rome , italy ) using the lowest grade for physical 
 activity for children in the modified balke treadmill protocols . criteria for determining 
 maximal exercise included : i ) the intensity of exercise was increased when the oxygen intake 
 was < 2.0  ml / kg / min , ii ) heart rate was not increasing , iii ) borg rating of perceived 
 exertion was > 17 , iv ) category ratio scale ( cr10 ) was > 7 , and v ) respiratory 
 exchange rate was > 1.1514 . all blood samples were collected at our laboratory at 08:00 following a 12-hour overnight 
 fast . after a 10-minute rest in a comfortable chair , each blood sample was centrifuged at 3,000 g for 10 
 minutes at 4  c and stored at 70  c until required for analysis . lipid profiles ( tc , tg , hdl - c and ldl - c ) were quantified using commercial , enzyme - based 
 kits ( asan , city , korea ) . plasma ( 2 ul ) and the enzyme solution ( 300 ul ) were rotated and 
 incubated in a water bath at 37  c for 5 minutes for color development . optical density was 
 determined using a uvmini-1240 spectrophotometer ( shimadzu , tokyo , japan ) with the blank as 
 a control . glycemic control in the fasting state was determined by the homeostasis model 
 assessment ( homa - ir ) : [ fasting glucose ( mg / dl )  fasting insulin ( u / ml ) ] / 405 all serum samples were submitted for a solid phase sandwich enzyme - linked immunosorbant 
 assay ( elisa ) measurement of rbp4 ( sino biological company location ) using the standard 
 curve method with a dilution series of a provided human rbp4 . leptin , resistin , visfatin , 
 insulin and glucagon were measured using a bio - plex 200 human serum adipokine ( panel b ) 
 lincoplex kit ( biorad , hercules , ca ) with an accuracy of 93% , inter - assay variation ( % cv ) 
 of < 20% , and intra - assay variation ( % cv ) of 1.47.9% . statistical data were analyzed using spss/+pc windows version 20.0 statistical package ( ibm 
 corp , armonk , ny ) , for which all measurements are expressed as meanstandard error . to 
 examine significant differences between the three groups , a two - way anova ( time ( 2 )  group 
 ( 3 ) ) was used . in addition , if statistically significant differences were detected , post - hoc 
 testing was performed using the duncan s post - hoc test method . descriptive characteristics of the participants are provided in table 1table 1.descriptive characteristics of the study participantsvariablecoobt2dmprepostprepostprepostheight ( cm)162.001.06162.351.08166.351.93167.282.10161.602.25161.652.23weight ( kg)55.742.3355.802.1973.522.6669.162.6463.984.4362.934.19bmi ( kg / m)21.180.7221.130.7026.560.5824.650.6224.281.2723.881.20%fat ( % ) 16.772.1916.852.1730.541.1126.960.8728.971.9027.941.69vo2max ( ml / min / kg)33.171.4133.981.0428.051.1231.161.3630.121.6133.571.31values are mean  se ; p<0.05 vs. co , p<0.05 vs. pre . co : control group ; b : obese group ; t2 dm : type 2 diabetes mellitus group ; bmi : body 
 mass index . at baseline body weight , bmi , and % fat were significantly higher in the ob 
 and t2 dm groups than in the co group ( p<0.05 ) . these parameters were significantly 
 decreased in the ob and t2 dm groups following completion of the 12-week exercise program 
 ( p<0.05 ) . vo2max was significantly increased in the ob and t2 dm groups 
 following the exercise program ( p<0.05 ) . furthermore , significant decreases were evident 
 in the levels of tc , tg , and ldl - c in the ob and t2 dm groups following completion of the 
 exercise program ( p<0.05 ) . in contrast hdl - c levels were significantly increased after 
 the exercise program in the two groups ( p<0.05 ) . however , both pre and post exercise tg 
 and ldl - c levels were significantly higher in the t2 dm group compared with the ob group 
 ( p<0.05 ) ( table 2table 2.blood lipid levels , before and after 12 weeks exercise programvariablecoobt2dmprepostprepostpreposttc ( mg / dl)184.279.50179.716.57219.3910.13191.869.39256.529.73201.529.74tg ( mg / dl)94.507.1092.933.21131.414.96109.684.14147.628.38123.574.42hdl - c ( mg / dl)48.881.3848.191.3550.492.5053.391.7139.761.3242.481.15ldl - c ( mg / dl)116.499.53112.946.15142.6210.37116.538.74187.269.27134.339.30values are mean  se ; p<0.05 vs. co , p<0.05 vs. pre , 
 p<0.05 vs. ob . co : control group ; ob : obese group ; t2 dm : type 2 
 diabetes mellitus group ; tc : total cholesterol ; tg : triglycerol ; hdl - c : high density 
 lipoprotein cholesterol ; ldl - c : low density lipoprotein cholesterol ) . co : control group ; b : obese group ; t2 dm : type 2 diabetes mellitus group ; bmi : body 
 mass index values are mean  se ; p<0.05 vs. co , p<0.05 vs. pre , 
 p<0.05 vs. ob . co : control group ; ob : obese group ; t2 dm : type 2 
 diabetes mellitus group ; tc : total cholesterol ; tg : triglycerol ; hdl - c : high density 
 lipoprotein cholesterol ; ldl - c : low density lipoprotein cholesterol in addition insulin , glucose , homa - ir and c - peptide levels were decreased in the ob and 
 t2 dm groups following the exercise program ( p<0.05 ) ( table 3table 3.glycemic control before and after 12 weeks exercise programvariablecoobt2dmprepostprepostprepostglucagon ( pg / ml)136.056.54125.0612.91116.093.44118.973.09136.614.59140.7211.22insulin ( uu / ml)23.862.8421.201.7745.595.5930.162.7135.292.7327.832.46glucose ( mg / dl)73.091.4275.360.89139.508.8796.365.10203.5014.34140.429.78homa - ir4.290.453.940.2915.351.757.300.8117.831.869.601.02c - peptide ( ng / dl)3.180.362.580.214.180.562.980.415.050.362.530.17values are mean  se ; p<0.05 vs. co , p<0.05 vs. 
 pre , p<0.05 vs. ob . co : control group ; ob : obese group ; t2 dm : type 2 
 diabetes mellitus group ; homa - ir : homoeostasis model assessment - insulin resistance ) . glucose levels were significantly higher in the t2 dm group than the ob group 
 ( p<0.05 ) ( table 3 ) . values are mean  se ; p<0.05 vs. co , p<0.05 vs. 
 pre , p<0.05 vs. ob . co : control group ; ob : obese group ; t2 dm : type 2 
 diabetes mellitus group ; homa - ir : homoeostasis model assessment - insulin resistance leptin , resistin , visfatin , and rbp4 levels were significantly higher in the ob and t2 dm 
 groups compared with the co group prior to the 12-week exercise program ( p<0.05 ) . all of 
 these adipokines were significantly decreased in the ob and t2 dm groups following the 
 exercise program ( p<0.05 ) ( table 4table 4.changes of blood adipokines concentrationvariablecoobt2dmprepostprepostprepostleptin ( ng / ml)1.340.171.200.122.540.241.690.162.930.322.130.24resistin ( ng / ml)6.730.496.670.708.070.476.110.368.400.637.390.61visfatin ( pg / ml)129.7412.16127.666.93247.7214.95184.227.75268.399.62192.888.97rbp4 ( pg / ml)483.404.01479.025.79631.5317.39595.3610.80629.9120.83596.5214.92values are mean  se p<0.05 vs. co , p<0.05 vs. pre . co : 
 control group ; ob : obese group ; t2 dm : type 2 diabetes mellitus group ) . co : 
 control group ; ob : obese group ; t2 dm : type 2 diabetes mellitus group in this study , 12 weeks of exercise produced positive effects on body composition , serum 
 lipid profiles , and adipokines in korean children who were obese or who had t2 dm . these 
 results suggest that regular exercise plays a role in improving body composition control , 
 cardiovascular disease risk factors and glycemic control in these groups . regular exercise and cardiovascular fitness have positive effects on insulin resistance and 
 cardiovascular disease risk factors in children and adolescents15 , 16 . data from the us national health and nutrition examination survey 
 nhanes have implicated vo2max as a risk factor for t2 dm and cardiovascular 
 disease in adolescents18 . kim et al . 
 reported that tc and tg levels were higher and hdl - c levels were lower among participants 
 with low fitness levels than in those with high fitness levels19 . these results suggest that improvements in fitness and 
 reduction of obesity are important factors for the prevention of cardiovascular disease19 . our findings that regular exercise 
 reduces cardiovascular disease risk factors , as well as improving body composition and 
 glycemic control in korean children who are obese or who have t2 dm further strengthens the 
 evidence for the benefits of exercise . in south korea , the average time spent by children physical activity is less than 40 
 minutes each a week . this is due to lack of impetus to improve health despite evidence that , 
 exercise improve insulin sensitivity in children20,21,22 . in a study by nassis et al . overweight adolescent girls were 
 assigned to a 12-week aerobic exercise program consisting of 40-minute exercise sessions 
 three days per week21 . insulin levels 
 were reduced significantly by the end of the study21 . reduction in insulin levels are not always accompanied by a 
 reduction in % fat suggesting that physical activity has a positive effect on insulin 
 sensitivity independent of body mass23 . interestingly , in the diabetes prevention program , those who met the physical activity goal 
 and not the weight loss goal had a 44% decrease in diabetes incidence24 , furthermore , in the finnish diabetes trial , achieving 
 4-hours of physical activity per week led to a reduction in diabetes risk in subjects who 
 did not lose weight25 . aerobic and 
 resistance exercises have important implications and provide therapeutic strategies for the 
 treatment of childhood obesity and the reduction of insulin resistance26 . six months of lifestyle modification , through a 
 combination of improved diet and physical exercise , significantly reduced body weight , 
 adiposity , waist circumference , blood pressure , fasting glucose , and insulin , and improved 
 insulin resistance and lipid profiles in obese children27 . a recent meta - analysis reported that aerobic exercise performed 
 for 60 minutes three times a week lowers ldl - c and tg levels in obese children , and combined 
 exercise increases the level of hdl - c28 . reductions in adipokine levels and cardiometabolic risk factors 
 have been associated with weight loss . elevated circulating levels of adipokines are 
 independently associated with a higher risk for cardiovascular disease31 . showed that only baseline bmi 
 was associated with higher tg , higher insulin levels , and reduced hdl - c levels . especially , 
 baseline leptin has been associated with higher levels of tg and insulin levels11 . the benefits of regular exercise on 
 adipokine levels are not permanent : discontinuation of exercise can lead to negative effects 
 on lipid profiles and leptin levels in overweight children32 . increases in serum rbp4 concentration have been observed in obese adults with 
 insulin - resistant t2 dm , whereas reductions in circulating concentrations are associated with 
 improved insulin action33 , 34 . in addition , increased rbp4 concentrations have been 
 observed in lean individuals with insulin resistance33 , 35 , and regulatory single 
 nucleotide polymorphisms of the rbp4 gene have recently been described in patients with 
 t2dm36 . rbp4 levels could be linked to 
 obesity and insulin resistance , although it must be emphasized that a positive association 
 has not always been demonstrated37 . most 
 studies report increased rbp4 levels with increasing levels of obesity , and high rbp4 levels 
 have been demonstrated in obese children10 , 38,39,40 . resistin is expressed in adipose tissue 
 and has roles in glucose homeostasis , lipid metabolism and insulin action41 , 42 . it might be a weak biochemical marker of metabolic dysfunction , but 
 it does not predict insulin resistance in chinese children43 . . showed that an intensive short - term diet and 
 exercise intervention decreased resistin ( control 40% , obese 35.1% ) and leptin ( control 
 69.3% , obese 44.1% ) levels in children6 . 
 in the current study , baseline adipokines levels were higher in children who were obese or 
 who had t2 dm . thus regular exercise from childhood is believed to be necessary to 
 control body weight and metabolic syndrome . regular aerobic exercise in korean children with obesity or t2 dm improved body composition 
 and vo2max , ameliorated lipid profiles and glycemic control , and decreased 
 adipokines levels . these results suggest that weight loss associated with regular exercise 
 reduces the risks associated with obesity and t2 dm in children . thus , regular exercise is 
 beneficial for glycemic control in korean children with obesity or t2 dm .
[ purpose ] the aim of the study was to clarify the effects of regular exercise on lipid 
 profiles and serum adipokines in korean children . [ subjects and methods ] subjects were 
 divided into controls ( n=10 ) , children who were obese ( n=10 ) , and children with type 2 
 diabetes mellitus ( n=10 ) . 
 maximal oxygen uptake ( vo2max ) , body composition , 
 lipid profiles , glucagon , insulin and adipokines ( leptin , resistin , visfatin and retinol 
 binding protein 4 ) were measured before to and after a 12-week exercise 
 program . [ results ] body weight , body mass index , and percentage body fat were 
 significantly higher in the obese and diabetes groups compared with the control group . 
 total cholesterol , triglycerides , low - density lipoprotein cholesterol and glycemic control 
 levels were significantly decreased after the exercise program in the obese and diabetes 
 groups , while high - density lipoprotein cholesterol levels were significantly increased . 
 adipokines were higher in the obese and diabetes groups compared with the control group 
 prior to the exercise program , and were significantly lower following completion . 
 [ conclusion ] these results suggest that regular exercise has positive effects on obesity 
 and type 2 diabetes mellitus in korean children by improving glycemic control and reducing 
 body weight , thereby lowering cardiovascular risk factors and adipokine levels .