it is known that breast density is a risk factor of breast cancer . a woman who has
more 
 than 75% breast density is 46 times more likely to have breast cancer than a woman who has 
 a breast density of less than 25%1 . 

guidelines for breast cancer screening have been suggested , and women over 50  years old are 
 generally recommended to undergo mammography .
one study even says women in their 40s can 
 also increase their lifespan through mammography , recommending they too should undergo 
 mammography2 , 3 .
not only 
 does higher breast density mean a higher chance of having breast cancer , but breast density 
 can also cause false negatives and increase re - examination rates by lowering mammography s 
 sensitivity4 , 5 .
breast density is affected by race , age , bmi , and the level of 
 female sex hormones .
in particular , body mass index ( bmi ) is a risk factor for breast cancer 
 in women who are in menopause .
it has also been shown in several pilot studies that 
 abdominal obesity and weight increase , even after correcting for bmi , have some connection 
 with the increased rate of breast cancer after menopause6 , 7 . as the amount of body fat 
 grows due to obesity ,
so does the amount of fatty tissue generally , and eventually the 
 density in mammography decreases . as mentioned above ,
some factors related to breast density have been reported , but they are 
 only basic characteristics .
the study subjects were 230 patients who underwent mammography and biochemical marker tests 
 between march 1 and october 1 , 2014 , at soonchunhyang university hospital .
all the subjects 
 signed a written informed consent form approved by the institutional review board of 
 soonchunhyang university hospital .
subjects who may have had abnormal bone density levels , such as diabetic patients , fasting 
 glucose  126  mg / dl ,  7.0  mmol / l , or those who had taken hormone treatment for over a year 
 were excluded , and we chose only post - menopausal women .
six diabetic patients , 14 before 
 menopause , and 10 hormone treatment patients were excluded , leaving 200 subjects whose 
 average age was 48.6410.92 yrs . to perform mammography ,
we used a lorad elite trex mammo 
 ( trex - lorad , usa ) at 26 kvp and 80 mas .
the american college of radiology , breast imaging reporting and data system ( acr bi - rads , 
 usa ) categorizes breast parenchymal pattern density from mammography into four grades : grade 
 1 , almost entire fat ; grade 2 , fibroglandular densities ; grade 3 , heterogeneously dense ; and 
 grade 4 , extremely dense ( fig .
a ) represents almost entirely fat , b ) represents fibroglandular 
 densities , c ) represents heterogeneously dense , and d ) represents extremely dense ) .
height and weight were measured with an automatic height and weight scale , and body 
 mass index ( bmi ) was computed using the formula weight ( kg)/height squared 
 ( m ) . mammography .
a ) represents almost entirely fat , b ) represents fibroglandular 
 densities , c ) represents heterogeneously dense , and d ) represents extremely dense subjects fasted for at least 12  h before blood and urine collections for biochemical marker 
 tests .
fifty items were assayed : erythrocyte sedimentation rate ( esr ) , white blood cell 
 ( wbc ) , red blood cell ( rbc ) , hemoglobin , hematocrit , mean corpuscular volume ( mcv ) , mean 
 corpuscular hemoglobin ( mch ) , mean corpuscular hemoglobin concentration ( mchc ) , platelet 
 count , red cell distribution width ( rdw ) , platelet distribution width ( pdw ) , mean platelet 
 volume ( mpv ) , neutrophil ( % ) , lymphocyte ( % ) , monocytes ( % ) , eosinophil ( % ) , basophil ( % ) , 
 neutrophil , lymphocyte , monocytes , eosinophil , basophil , hba1c , protein , albumin , glucose , 
 total bilirubin , direct bilirubin , aspartate aminotransferase ( ast ) , alanine 
 aminotransferase ( alt ) , alkaline phosphatase ( alp ) , urea nitrogen , creatinine , uric acid , 
 calcium , phosphrus , gamma - glutamyl transferase ( gt ) , lactate dyhydrogenase ( ldh ) , amylase , 
 triglyceride , total cholesterol , high - density lipoprotein ( hdl - cholesterol ) , low - density 
 lipoprotein ( ldl - cholesterol ) , iron ( fe ) , total iron binding capacity ( tibc ) , c - reactive 
 protein ( crp ) , rheumatoid factor ( ra factor ) , hiv combo , hbsag , antihbs , -fetoprotein 
 ( afp ) , carbohydrate antigen 19 - 9 ( ca 19 - 9 ) , cancer antigen 125 ( ca-125 ) , free thyroxine 
 ( free t4 ) , thyroid - stimulating hormone ( tsh ) , anti - hepatitis - c ( anti hcv ) .
simple correlation analysis was performed to investigate correlations among breast density , 
 general characteristic , and biochemical markers .
then , multiple regression analysis was 
 performed to evaluate the factors that showed a significant correlation .
spss software 
 ( ver.18.0 , chicago , usa ) with a significance of 0.05 was used .
the simple correlation analysis of breast density , general characteristics , and biochemical 
 markers before and after menopause is shown in table 
 1table 1.simple correlation analysis of breast density , general characteristics , and 
 biochemical markersvariablebreastdensityvariablebreastdensityvariablebreastdensityvariablebreastdensityage0.55neutrophil % 0.05ast ( got)0.22tibc0.00height0.28lymphocyte % 0.07alt ( gpt)0.27crp0.13weight0.30monocytes % 0.06alp0.28ra factor0.03bmi0.48eosinophil % 0.04urea nitrogen0.07hiv combo0.04esr0.07basophil % 0.03creatinine0.10hbsag0.09wbc0.12neutrophil0.06uric acid0.16antihbs0.06rbc0.01lymphocyte0.04calcium0.09afp0.03hemoglobin0.14monocytes0.05phosphorus0.06ca 19 - 90.02hematocrit0.15eosinophil0.02gt0.18ca 1250.04mcv0.13basophil0.08ldh0.05free t40.11mch0.19hba1c0.10amylase0.03tsh0.05mchc0.05protein0.02triglyceride0.30antihcv0.12platelet count0.04albumin0.04cholesterol , total0.16rdw0.15glucose0.15hdl - cholesterol0.23pdw0.10bilirubin , total0.07ldl - cholesterol0.29mpv0.07bilirubin , direct0.09iron0.00bmi : body mass index , esr : erythrocyte sedimentation rate , wbc : white blood cell , 
 rbc : red blood cell , mcv : mean corpuscular volume , mch : mean corpuscular hemoglobin , 
 mchc : mean corpuscular hemoglobin concentration , rdw : red cell distribution width , 
 pdw : platelet distribution width , mpv : mean platelet volume , ast : aspartate 
 aminotransferase , alt : alanine aminotransferase , alp : alkaline phosphatase , gt : 
 gamma - glutamyl transferase , ldh : lactate dyhydrogenase , hdl - cholesterol : high - density 
 lipoprotein , ldl - cholesterol : low - density lipoprotein , tibc : total iron binding 
 capacity , crp : c - reactive protein , ra factor : rheumatoid factor , afp : -fetoprotein , 
 ca19 - 9 : carbohydrate antigen 19 - 9 , ca-125 : cancer antigen 125 , free t4 : free 
 thyroxine , tsh : thyroid - stimulating hormone , anti hcv : anti - hepatitis - c .
items exhibiting significant correlations with breast density were : age , 
 0.55 ; height , 0.26 ; weight , 0.30 ; bmi , 0.48 ; hematocrit , 0.15 ; mch , 0.19 ; rdw , 0.15 ; 
 glucose , 0.15 ; ast(got ) , 0.22 ; alt(gpt ) , 0.27 ; alp , 0.28 ; uric acid , 0.16 ; gt(ggt ) , 
 0.18 ; triglyceride , 0.30 ; total cholesterol , 0.16 ; hdl - cholesterol , 0.23 ; and 
 ldl - cholesterol , 0.29 ( p < 0.05 ) . the results of multiple regression analysis using 
 breast density - related variables are shown in table 
 2table 2.multiple regression analysis of each variable related to breast densityvariablebseage0.040.00height0.040.01weight0.030.01bmi0.130.02hematocrit0.010.00mch0.060.02rdw0.080.04ast0.010.00alt0.020.00alp0.000.00uric acid0.030.01gt0.010.00triglyceride0.000.00cholesterol , total0.000.00hdl - cholesterol0.020.00ldl - cholesterol0.010.00bmi : body mass index , mch : mean corpuscular hemoglobin , rdw : red cell distribution 
 width , ast : aspartate aminotransferase , alt : alanine aminotransferase , alp : alkaline 
 phosphatase , gt : gamma - glutamyl transferase , hdl - cholesterol : high - density 
 lipoprotein , ldl - cholesterol : low - density lipoprotein .
significant factors were : age , 0.040.00 , height , 0.040.01 ; weight , 
 0.030.01 ; bmi , 0.130.02 ; t - score , 0.130.05 ; hematocrit , 0.010.00 ; mch , 0.060.02 ; 
 rdw , 0.080.04 ; ast(got ) , 0.010.00 ; alt(gpt ) , 0.020.00 ; alp , 0.000.00 ; uric acid , 
 0.030.01 ; gt(gtp ) , 0.010.00 ; triglyceride , 0.000.00 ; total cholesterol , 0.000.00 ; 
 hdl - cholesterol , 0.020.00 ; and ldl - cholesterol , 0.010.00 ( p < 0.05 ) .
bmi : body mass index , esr : erythrocyte sedimentation rate , wbc : white blood cell , 
 rbc : red blood cell , mcv : mean corpuscular volume , mch : mean corpuscular hemoglobin , 
 mchc : mean corpuscular hemoglobin concentration , rdw : red cell distribution width , 
 pdw : platelet distribution width , mpv : mean platelet volume , ast : aspartate 
 aminotransferase , alt : alanine aminotransferase , alp : alkaline phosphatase , gt : 
 gamma - glutamyl transferase , ldh : lactate dyhydrogenase , hdl - cholesterol : high - density 
 lipoprotein , ldl - cholesterol : low - density lipoprotein , tibc : total iron binding 
 capacity , crp : c - reactive protein , ra factor : rheumatoid factor , afp : -fetoprotein , 
 ca19 - 9 : carbohydrate antigen 19 - 9 , ca-125 : cancer antigen 125 , free t4 : free 
 thyroxine , tsh : thyroid - stimulating hormone , anti hcv : anti - hepatitis - c bmi : body mass index , mch : mean corpuscular hemoglobin , rdw : red cell distribution 
 width , ast : aspartate aminotransferase , alt : alanine aminotransferase , alp : alkaline 
 phosphatase , gt : gamma - glutamyl transferase , hdl - cholesterol : high - density 
 lipoprotein , ldl - cholesterol : low - density lipoprotein
of the many risk factors that cause breast cancer , the best known is long - term exposure to 
 female sex hormones8,9,10,11,12 .
it has been reported 
 that as estrogen levels increase , so does the risk of breast cancer13 .
additionally , breast density has a high correlation with 
 breast cancer ; as breast density increases , women are more likely to have breast cancer8 .
factors that affect breast density include 
 race , age , bmi , and levels of female sex hormones6 , 
 7 . in this study ,
the factors related to 
 breast density were age , height , weight , bmi , hematocrit , mch , rdw , ast , alt , alp , uric 
 acid , gt , triglyceride , total cholesterol , hdl - cholesterol , and ldl - cholesterol .
breast tissue 
 degenerates due to the decline in estrogen and progesterone , and breast density starts to 
 decrease due to an increase in fatty tissue14 .
bone density level , breast density , and breast cancer are related . 
 in this study ,
studies of western women 
 reported bmi as one of the major factors that affecting breast density15 , 16 . according to 
 those studies , when bmi was low , even after correcting for age , it indicated high density 
 breasts .
the proportion of dense breast was 60% in low - weight women under age 40 , similar to 
 the results of our present study .
a limitation of this study was that , because there were a 
 small number of subjects , it was difficult to identify correlations between breast density 
 and biochemical markers objectively . thus , an effort is needed to make more precise risk 
 evaluations of breast density by conducting a large - scale prospective study of korean 
 women .
 [ purpose ] the aim of this study was to identify biochemical markers related to breast 
 density . 
 the study was performed with 200 patients who received mammography and 
 biochemical marker testing between march 1 , 2014 to october 1 , 2014 . 
 [ subjects and 
 methods ] following the american college of radiology , breast imaging reporting and data 
 system ( acr bi - rads ) , breast parenchymal pattern density from mammography was categorized 
 into four grades : grade 1 , almost entirely fat ; grade 2 , fibroglandular densities ; grade 
 3 , heterogeneously dense ; and grade 4 , extremely dense . regarding biochemical markers , 
 subjects underwent blood and urine tests after a 12-h fast . 
 we analyzed correlations among 
 breast density , general characteristics , and biochemical markers . 
 [ results ] breast 
 density - related factors were age , height , weight , body mass index ( bmi ) , hematocrit , mch , 
 rdw , ast , alt , alp , uric acid , gt , triglycerides , total cholesterol , hdl - cholesterol , and 
 ldl - cholesterol . [ conclusion ] the results can be used as basic and comparative data for 
 the prevention and early control of breast cancer . 