coronary artery disease ( cad ) is the leading cause of morbidity and mortality throughout the world [ 1 , 2 ] .
male pattern baldness , also called androgenetic alopecia , is responsible for the majority of hair loss in male individuals [ 35 ] .
it generally starts at the second or third decade and is characterised by varying degrees of thinning / hair loss primarily at the frontal area and vertex of the scalp .
several epidemiological studies have shown an association between androgenetic alopecia and cad [ 610 ] . among these ,
the framingham heart study revealed an association between progression of hair loss during adulthood and cad in male individuals , although there was no relationship with the extent of baldness . in a case - control study ,
lesko et al .   reported that vertex baldness was associated with threefold higher risk of myocardial infarction among men younger than 55 years .
several other studies reported the presence of an association between androgenetic alopecia and cad [ 1113 ] .
however , results of several other studies argue against this relationship [ 14 , 15 ] .
clarifying the potential relationship between androgenetic alopecia and cad might help to better understand the pathophysiology of coronary heart disease .
although several epidemiological studies have shown an association between male pattern baldness and atherosclerosis , it has never been studied by investigating angiographic presence and severity of cad .
we therefore aimed to shed light on this issue by investigating whether there is an association between male pattern baldness and angiographic cad severity and collateral development .
the study was approved by the local ethics committee , and all participants gave written informed consent before participating .
patients scheduled for an elective coronary arteriogram in the cardiology department of gaziantep university hospital were invited to participate .
demographic data on the study population including age , sex , height , weight , history of diabetes mellitus , hypertension , smoking status , family history of cad , lipid parameters and creatinine levels were recorded . before coronary arteriogram ,
the presence and severity of hair loss was recorded according to the criteria mentioned later in the text .
severity of cad was determined according to the gensini score and collateral flow was graded according to the rentrop score .
exclusion criteria were female sex , history of coronary artery bypass surgery , history of acute coronary syndrome in the past 4 weeks , other types of alopecia and patients with known hormonal problems .
coronary arteriogram was performed via the femoral , radial or brachial artery using judkins technique ( integris h 5000 , philips medical systems , the netherlands ) .
coronary artery stenosis severity ( gensini and rentrop scores ) was estimated visually by two independent observers who were blinded to clinical information on the patients .
coronary arteries were considered to be normal ( 0 : no stenosis ) , obstructed ( 25 , 50 , 75 , 90 or 99  % stenosis ) or 100  % occluded , according to the maximum obstruction that was observed in any projection .
the severity of coronary atherosclerosis was classified according to the gensini score , which grades narrowing of the lumen as 1 for 125  % stenosis , 2 for 2650  % , 4 for 5175  % , 8 for 7690  % , 16 for 9199  % and 32 for total occlusion .
this score was multiplied by a factor that accounted for the importance of a lesion s position in the coronary arterial tree : 5 for the left main coronary artery ; 2.5 for the proximal left anterior descending coronary artery or proximal circumflex artery ; 1.5 for the mid left anterior descending coronary artery ; 1 for the proximal right coronary artery , distal left anterior descending coronary artery , obtuse marginal artery or posterior lateral artery ; and 0.5 for other stenoses .
the severity of disease was expressed as the sum of the scores for the individual lesions . by definition ,
collateral vessels were graded according to the rentrop classification : 0 : no filling of any collateral vessels , 1 : filling of side branches of the artery to be perfused by collateral vessels without visualisation of the epicardial segment ; 2 : partial filling of the epicardial artery by collateral vessels ; and 3 : complete filling of the epicardial artery by collateral vessels . by definition
, a rentrop score of 2 or more was accepted as well - developed collaterals .
we used the modified hamilton grading system , as it was used by the majority of the studies : grade 1 : no hair loss ; grade 2 : frontal baldness only ; grade 3 : mild vertex baldness ; grade 4 : moderate vertex baldness and grade 5 : severe vertex baldness as previously described [ 12 , 18 ] .
each investigator had a chart illustrating these five different hair types , as depicted by lotufo et al .   and decided to which grade the individual patient s hair status fits best .
additionally , investigators asked each participant which category best describes his hair status when he was 35 years old . according to the power calculation , to provide 95  % power at 5  % significance to detect a 4  % mean absolute difference in baldness and gensini score ,
306 subjects were necessary . to provide 80  % power at 5  % significance to detect a 4  % mean absolute difference in baldness and rentrop score , 149 subjects were necessary .
continuous data were expressed as mean    standard deviation , while categorical data were presented as number or percentage of patients .
chi - square test was used for comparison of categorical variables , while the mann 
multivariate logistic regression analysis ( backward ) was performed to determine the independent predictors of a high gensini score .
all analyses were carried out with spss version 15.0 software for windows ( spss inc . ,
the study was approved by the local ethics committee , and all participants gave written informed consent before participating .
patients scheduled for an elective coronary arteriogram in the cardiology department of gaziantep university hospital were invited to participate .
demographic data on the study population including age , sex , height , weight , history of diabetes mellitus , hypertension , smoking status , family history of cad , lipid parameters and creatinine levels were recorded . before coronary arteriogram ,
the presence and severity of hair loss was recorded according to the criteria mentioned later in the text .
severity of cad was determined according to the gensini score and collateral flow was graded according to the rentrop score .
exclusion criteria were female sex , history of coronary artery bypass surgery , history of acute coronary syndrome in the past 4 weeks , other types of alopecia and patients with known hormonal problems .
coronary arteriogram was performed via the femoral , radial or brachial artery using judkins technique ( integris h 5000 , philips medical systems , the netherlands ) .
coronary artery stenosis severity ( gensini and rentrop scores ) was estimated visually by two independent observers who were blinded to clinical information on the patients .
coronary arteries were considered to be normal ( 0 : no stenosis ) , obstructed ( 25 , 50 , 75 , 90 or 99  % stenosis ) or 100  % occluded , according to the maximum obstruction that was observed in any projection . the severity of coronary atherosclerosis was classified according to the gensini score , which grades narrowing of the lumen as 1 for 125  % stenosis , 2 for 2650  % , 4 for 5175  % , 8 for 7690  % , 16 for 9199  % and 32 for total occlusion .
this score was multiplied by a factor that accounted for the importance of a lesion s position in the coronary arterial tree : 5 for the left main coronary artery ; 2.5 for the proximal left anterior descending coronary artery or proximal circumflex artery ; 1.5 for the mid left anterior descending coronary artery ; 1 for the proximal right coronary artery , distal left anterior descending coronary artery , obtuse marginal artery or posterior lateral artery ; and 0.5 for other stenoses .
the severity of disease was expressed as the sum of the scores for the individual lesions . by definition ,
collateral vessels were graded according to the rentrop classification : 0 : no filling of any collateral vessels , 1 : filling of side branches of the artery to be perfused by collateral vessels without visualisation of the epicardial segment ; 2 : partial filling of the epicardial artery by collateral vessels ; and 3 : complete filling of the epicardial artery by collateral vessels . by definition
, a rentrop score of 2 or more was accepted as well - developed collaterals .
we used the modified hamilton grading system , as it was used by the majority of the studies : grade 1 : no hair loss ; grade 2 : frontal baldness only ; grade 3 : mild vertex baldness ; grade 4 : moderate vertex baldness and grade 5 : severe vertex baldness as previously described [ 12 , 18 ] .
each investigator had a chart illustrating these five different hair types , as depicted by lotufo et al .   and decided to which grade the individual patient s hair status fits best .
additionally , investigators asked each participant which category best describes his hair status when he was 35 years old .
according to the power calculation , to provide 95  % power at 5  % significance to detect a 4  % mean absolute difference in baldness and gensini score , 306 subjects were necessary . to provide 80  % power at 5  % significance to detect a 4  % mean absolute difference in baldness and rentrop score , 149 subjects were necessary .
continuous data were expressed as mean    standard deviation , while categorical data were presented as number or percentage of patients .
chi - square test was used for comparison of categorical variables , while the mann 
multivariate logistic regression analysis ( backward ) was performed to determine the independent predictors of a high gensini score .
all analyses were carried out with spss version 15.0 software for windows ( spss inc . ,
a total of 511 male patients ( mean age : 58.6 ; range : 3384 ) were included in the study .
gensini score was available in 511 patients , whereas the rentrop score was available in 136 patients .
table  1 presents the characteristics of the study population.table 1characteristics of the study population 
 n 
 age51158.6    12.0hypertension ( % ) 511182 ( 35.7)diabetes ( % ) 511106 ( 20.9)smoking ( % ) 511330 ( 64.6)family history ( % ) 511190 ( 37.2)baldness
scale5112.84    1.54gensini score51141.3    40.3rentrop score1361.84    1.09body mass index ( kg / m 
 50927.1    4.4creatinine ( mg / dl)4781.02    0.94low - density lipoprotein ( mg / dl)419111.2    33.5high - density lipoprotein ( mg / dl)41935.5    15.9total cholesterol ( mg / dl)419176.0    42.0triglyceride ( mg / dl)419173.3    128.0data are expressed as mean  standard deviation or percentages characteristics of the study population data are expressed as mean  standard deviation or percentages comparison of demographic , clinical and laboratory characteristics of the subjects according to gensini score is expressed in table  2 .
those with a higher gensini score (   20 ) were older , had a higher level of triglycerides and androgenetic alopecia was more common among them .
the hair status at the age of 35 was similar between the groups with high and low gensini scores .
additionally , the rest of the laboratory results and demographic characteristics were similar between the groups with high and low gensini scores . when we compared bald ( modified hamilton score   2 ) and non - bald ( modified hamilton score =  1 ) subjects , bald patients had a higher gensini score ( 44.2    42.1 vs. 33.0    35.3 ; p  =  0.003 ) .
smoking rate was higher in the group with higher gensini scores ( p  =  0.002 ) .
there were no differences in terms of presence of diabetes , hypertension and family history of cad between the groups with high and low gensini scores.table 2comparison of demographic , clinical and laboratory characteristics of the subjects according to gensini scoreparameter 
 n 
 gensini score <  20 
 n 
 gensini score   20 
 p valueage19656.3    12.231560.1    11.7 
 0.001 
 baldness scale1962.63    1.53142.97    1.5 
 0.016 
 baldness scale at age 351701.58    0.92931.52    0.90.4creatinine , mg / dl1791.03    1.172951.01    0.780.8triglycerides ,
mg / dl161154.5    81263185.5    149 
 0.006 
 hdl , mg / dl15236.7    9.926334.7    18.50.1ldl , mg / dl158112    30.8264110.7    35.10.7total cholesterol , mg / dl158175.8    37.6264176.2    44.70.6bmi , kg / m 
 19527    4.231027.4    4.30.2data are expressed as mean  standard deviation or as number of patients 
 hdl high - density lipoprotein , ldl low - density lipoprotein , bmi body mass index comparison of demographic , clinical and laboratory characteristics of the subjects according to gensini score data are expressed as mean  standard deviation or as number of patients 
 hdl high - density lipoprotein , ldl low - density lipoprotein , bmi body mass index comparison of demographic , clinical and laboratory characteristics of the subjects according to the rentrop score is expressed in table  3 .
there were no differences in terms of presence and severity of baldness , hair status at the age of 35 , demographic characteristics and laboratory findings in subjects with ( rentrop score   2 ) and without ( rentrop score 0 or 1 ) adequate collateral development . additionally , the rate of smoking , presence of diabetes , hypertension and family history of cad were similar in subjects with and without adequate collateral development.table 3comparison of demographic , clinical and laboratory characteristics of the subjects according to rentrop scoreparameter 
 n 
 rentrop <  2 
 n 
 rentrop   2 
 p valueage4258.2    12.69460.6    12.10.3baldness scale423    1.4942.9    1.40.7baldness scale at age 35421.67    1941.55    10.5creatinine , mg / dl420.98    0.38850.97    0.280.8triglycerides , mg / dl35195.5    142.477194.5    158.30.9hdl , mg / dl3541.5    45.57732.5    9.20.2ldl , mg / dl35111.1    33.978110.7    41.60.9total cholesterol , mg / dl35176.3   
31.977174.2    55.20.8bmi , kg / m 
 4226.9    4.29027.4    3.70.5data are expressed as mean  standard deviation or as number of patients 
 hdl high - density lipoprotein , ldl low - density lipoprotein , bmi body mass index comparison of demographic , clinical and laboratory characteristics of the subjects according to rentrop score data are expressed as mean  standard deviation or as number of patients 
 hdl high - density lipoprotein , ldl low - density lipoprotein , bmi body mass index of 511 patients , 59 had normal coronary arteries ( zero - vessel disease ) , 171 had one - vessel disease , 176 had two - vessel disease and 105 had triple - vessel disease .
the mean number of diseased vessels was higher in bald subjects when compared with their non - bald counterparts ( 1.71    0.9 vs. 1.44    0.9 ; p  =  0.004 ) . the number of diseased vessels correlated with the severity of baldness ( r  =  0.125 ; p  =  0.005 ) .
the mean number of diseased vessels was lower in the group with adequate collateral development when compared with those without adequate collateral development ( 2.47    0.5 vs. 2.69    0.4 ; p  =  0.028 ) .
the number of diseased vessels was inversely correlated with rentrop score ( r  =    0.226 ; p  =  0.008 ) . in univariate analysis ,
age more than 60 , body mass index more than 30 , smoking and baldness were among the predictors of a high gensini score . in multivariate analysis , only age more than 60 ( p  <  0.001 ; odds ratio 2.590 ; 95  % confidence interval 1.6374.098 ) , smoking ( p  <  0.001 ; odds ratio 2.385 ; 95  % confidence interval 1.4963.802 ) and body mass index more than 30 ( p  =  0.012 ; odds ratio 1.937 ; 95  % confidence interval:1.1543.252 ) were independent predictors of a high gensini score ( table  4 ) . after adjusting for age , presence and severity of baldness was not an independent predictor of a high gensini score.table 4independent predictors of gensini score >  20 ( multivariate logistic regression analysis)variableodds ratio95  % confidence intervalage >  602.5901.6374.098smoking2.3851.4963.802bmi >  30 
kg / m 
 1.9371.1543.252 
 bmi body mass index independent predictors of gensini score >  20 ( multivariate logistic regression analysis )
in the present study , we aimed to investigate whether there is an association between male pattern baldness and angiographic cad severity and collateral development , which has not been reported previously . according to our findings , although subjects with higher gensini scores had more frequent and severe baldness , they were older than the group with lower gensini scores .
after adjusting for age , presence and severity of baldness lost its value in predicting the severity of cad .
additionally , there were no differences in terms of presence and severity of baldness in subjects with and without adequate collateral development . because cad is the leading cause of morbidity and mortality worldwide , researchers aim to investigate potential novel risk factors or associated conditions which might enable the early detection of cad .
male pattern baldness is androgen - dependent miniaturisation and loss of frontal and/or vertical hair .
it generally starts at the second or third decades and effects almost half of middle - aged men .
therefore , it is quite reasonable that investigators are trying to clarify the presence and extent of a potential interaction between cad and male pattern baldness .
although the exact reason for the association between baldness and cad is unclear , several mechanisms have been proposed .
first , elevated androgen levels and increased peripheral sensitivity to androgens have been reported , both in subjects with androgenetic alopecia and cad [ 1921 ] .
second , it has been suggested that they have common atherosclerosis risk factors such as hypertension , dislipidaemia , smoking , hyperinsulinaemia / insulin resistance , metabolic syndrome and chronic inflammation [ 2224 ] .
third , it has been proposed that the two conditions might share a similar pattern of inheritance [ 12 , 25 ] . in 1972 , cotton et al .   for the first time
reported that patients with myocardial infarction had no increase in male pattern alopecia . in 1979 , cooke   reported that there was no association between cad and either male pattern alopecia or premature male pattern alopecia in 478 male caucasian hospital inpatients . in 1993 , in a case - control study , lesko et al .   reported that vertex baldness ( threefold higher risk of myocardial infarction ) but not frontal baldness was associated with myocardial infarction among men younger than 55 years . in the framingham heart study , 30-year follow - up revealed that progression of hair loss during adulthood but not extent of baldness was associated with cad in men
additionally , the first national health and nutrition examination survey reported an association between severe baldness and cad mortality in men younger than 55 years , but not among older men .
in two recent studies , sharma et al . reported that early - onset androgenetic alopecia in male individuals ( less than 40 and 45 years old , respectively ) is independently associated with cad [ 27 , 28 ] . in contrast , in 2007 , shahar et al .  
investigated the association of androgenetic alopecia with cad in 5000 men aged 5275 years , of whom 767 had a history of myocardial infarction and concluded that male pattern baldness can not be used as a risk factor for myocardial infarction or asymptomatic atherosclerosis . to date , there are no other studies in the literature investigating the association between androgenetic alopecia and angiographic cad severity and collateral development ; therefore , we can not make a direct comparison with published data .
we were not able to detect any relation between presence , severity and age of occurrence of male pattern baldness and gensini and rentrop scores , which are important measures of presence and severity of cad . in our study , although subjects with higher gensini scores had more frequent and severe baldness , they were older than the group with lower gensini scores . and after adjusting for age , presence and severity of baldness lost its value in predicting severity of cad
additionally , there were no differences in terms of presence and severity of baldness in subjects with and without adequate collateral development .
thus , the previously reported association between cad and androgenetic alopecia was not confirmed in our angiographic study .
reported that men with vertex - type androgenetic alopecia ( n  =  41 ) had higher levels of serum lipoprotein ( a ) and triglyceride when compared with the group with normal hair status ( n  =  36 ) . in their recent study , dogramaci et al .  
reported that male individuals with androgenetic alopecia had higher levels of triglycerides and lower levels of high - density lipoprotein . in our study ,
subjects with vertex baldness but not frontal baldness had significantly higher triglyceride levels supporting the results of the studies by sasmaz et al . and dogramaci et al .
in our study , the rest of the lipid parameters were comparable between bald and non - bald subjects regardless of the severity of baldness .
interestingly , of the lipid parameters only triglyceride level was higher in subjects with higher gensini scores .
the physicians health study , which included 19,112 subjects who were free of cad at baseline with a follow - up of 11 years , reported that vertex pattern but not frontal baldness was associated with increased risk of coronary events and this association was more robust among men with hypertension or hyperlipidaemia .
reported that men with baldness before the age of 35 years had an increased risk for needing early coronary revascularisation . in our study , presence and severity of androgenetic alopecia before the age of 35 was not associated with angiographic cad ( gensini and rentrop scores ) .
reported that androgenetic alopecia significantly correlated with cad and previous history of myocardial infarction in women under the age of 55 .
we did not study women ; however , we did not find an association between androgenetic alopecia and angiographic cad in men .
in a recent meta - analysis , yamada et al . investigated six observational studies with a total of 36,690 participants .
they reported that vertex baldness but not frontal baldness increased the risk of cad , and the relationship was more robust with severe baldness . as it was a meta - analysis and
first , despite the fact that the majority of published data reports an association between androgenetic alopecia and cad , our study argues against this relationship .
second , our study is the first in the literature to investigate the association between male pattern baldness and angiographic cad severity and collateral development .
third , our study gathered designs and settings of several previously published studies , such as presence , severity and age of occurrence of male pattern baldness , associated hypertension and hyperlipidaemia .
fourth , regardless of the results , the present study provides more in - depth data in this issue that we believe will shed light for prospective large - scale studies .
first , the sample size of the present study is relatively small , especially for the collateral data .
second , this is a cross - sectional study ; therefore , it would provide more valuable information if we were able to follow - up the study population , especially to draw conclusions about clinical coronary events .
third , we asked each participant which category best describes his hair status when he was 35 years old .
in summary , although the majority of studies reported an association between androgenetic alopecia and cad , we were not able to detect any relation between presence , severity and age of occurrence of male pattern baldness and gensini and rentrop scores , which are important measures of presence and severity of cad .
the potential interaction of male pattern baldness with cad warrants large - scale prospective studies .
 objectivewe aimed to investigate whether there is an association between male pattern baldness and angiographic coronary artery disease ( cad ) severity and collateral development , which has not been reported previously.methodscoronary arteriograms , cad risk factors , lipid parameters and presence and severity of baldness in 511 male patients were prospectively evaluated . 
 baldness was classified into five groups . 
 severity of cad was evaluated with the gensini scoring system and collateral development with rentrop scores.resultsalthough subjects with a higher gensini score had more frequent and severe baldness , they were older than the group with lower gensini scores . 
 bald patients had a higher gensini score when compared with their non - bald counterparts . 
 in univariate analysis , age more than 60 , body mass index more than 30 , smoking and baldness were predictors of high gensini scores . in multivariate analysis , only age more than 60 , body mass index more than 30 and smoking were independent predictors of a high gensini score . 
 there were no differences in terms of presence and severity of baldness in subjects with and without adequate collateral development.conclusionsthere was no relation between presence , severity and age of occurrence of male pattern baldness and gensini and rentrop scores , which are important measures of presence and severity of cad . 