relation of serum testosterone levels to high...

307

Relation of Serum Testosterone Levels toHigh Density Lipoprotein Cholesterol and

Other Characteristics in MenDavid S. Freedman, Thomas R. O'Brien, W. Dana Flanders,

Frank DeStefano, and Joseph J. Barboriak

Although levels of high density lipoprotein (HDL) cholesterol in males decrease duringadolescence and after treatment with testosterone derivatives, several studies have reportedthat levels of HDL cholesterol are positively associated with endogenous levels of testosteronein men. This association was further examined using data collected during 1985 and 1986 from3,562 white and 500 black men who ranged in age from 31 to 45 years. Black men had highermean levels of both HDL cholesterol (8 mg/dl) and total testosterone (33 ng/dl) than white men,and positive associations were observed between testosterone and HDL cholesterol levels(r=0.22, whites; r=0.26, blacks). In addition, levels of testosterone were related positively toalcohol consumption and cigarette smoking and negatively to age, Quetelet index, and use of0-blockers. We used stratification and regression analyses to determine if any of thesecharacteristics could account for the positive association between levels of HDL cholesterol andtotal testosterone. Although controlling for most factors had little influence, adjusting forQuetelet index reduced the strength of the association between levels of testosterone and HDLcholesterol by approximately 30%. These findings suggest that the positive association betweenlevels of testosterone and HDL cholesterol may not be causal. Multivariable analyses thatcontrol for obesity and other potentially confounding characteristics should be used in studiesthat assess the relation of testosterone levels to coronary heart disease. (Arteriosclerosis andThrombosis 1991;ll:307-315)

Middle-aged men in industrialized countriesare at a threefold to 10-fold higher riskfor coronary heart disease (CHD) than

are women.1 Several investigators1"3 have assessedpossible determinants of this sex differential, and ithas been suggested that sex hormones play an impor-tant role, possibly through their regulation of lipo-protein metabolism. During adulthood, premeno-pausal women have higher levels of high densitylipoprotein (HDL) cholesterol but lower levels oftriglycerides and low density lipoprotein (LDL) cho-lesterol than do men.4

From the Agent Orange Projects (D.S.F., W.D.F.), Center forEnvironmental Health and Injury Control, and the Center forInfectious Diseases (T.R.O.'B., F.D.), Centers for Disease Con-trol, Public Health Service, US Department of Health and HumanServices, Atlanta, Ga., and the Department of Pharmacology andToxicology (JJ.B.), Medical College of Wisconsin, MilwaukeeVeterans Affairs Medical Center, Milwaukee, Wis.

Data for this study were gathered under an interagency agree-ment with the Veterans Administration.

Address for reprints: David S. Freedman, PhD, Centers forDisease Control, A-41, 1600 Clifton Road, Atlanta, GA 30333.

Received August 27, 1990; revision accepted October 23, 1990.

Some evidence suggests that estrogen and testos-terone are important determinants of levels of HDLcholesterol. During adolescence, levels of HDL cho-lesterol decline by more than 10 mg/dl in boys but notin girls,5'6 and large decreases are seen after treat-ment with testosterone derivatives.67 Although levelsof HDL cholesterol increase after administration ofestrogenic hormones,8 levels are low among womenusing oral contraceptives containing norgestrel, aprogestin with androgenic activity.9 Because of theseassociations, it has been thought that the sex differ-ential in CHD may be due to the influence of sexhormones on levels of lipids and lipoproteins.

In contrast to these findings, however, severalunexpected associations with endogenous levels ofestrogen and testosterone have been reported. Forexample, in contrast to what might be anticipated onthe basis of the lower incidence of CHD amongwomen, Phillips10 reported that 15 men who surviveda myocardial infarction had higher levels of estrogenthan men in a control group. In addition, althoughthere are exceptions,11 most cross-sectional studies ofmen have reported a positive association betweenendogenous levels of testosterone and HDL choles-

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308 Arteriosclerosis and Thrombosis Vol 11, No 2 March/April 1991

terol,12"17 with correlation coefficients ranging ashigh as 0.65.1<s These studies, however, have includedonly whites, and most were relatively small.

Some investigators11114 have suggested that thepositive association between levels of testosteroneand HDL cholesterol may be due to the confoundingeffects of obesity, alcohol intake, or sex hormone-binding globulin (SHBG).1-11-14 Although age-relateddecreases in testosterone levels are well established,relatively few investigators have examined other cor-relates of testosterone. Limited evidence, however,suggests that testosterone levels are associated in-versely with relative weight and positively with ciga-rette smoking.1417"19 The objective of this study of4,062 men, 500 of whom are black, is to examinefurther the association between levels of total tes-tosterone and HDL cholesterol. In addition^ theinfluence of several characteristics (e.g., race, relativeweight, alcohol consumption, cigarette smoking, andvarious medications) on the association between lev-els of testosterone and HDL cholesterol in these 31-to 45 -year-old men will be assessed.

MethodsPopulation

Subjects were participants in a historical cohortstudy comparing the health of Vietnam veterans withveterans who served elsewhere. Although the studywas designed to examine the general experience ofmilitary service in Vietnam, much of the initialconcern focused on exposure to Agent Orange andits contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin.Data were obtained during 1) a telephone interviewand 2) a medical examination of a random sample oftelephone interviewees. Sample selection, interviews,and examinations were performed in 1985 and 1986and have been described in detail elsewhere.20

Briefly, a random sample of 48,500 men whoentered the US Army between 1965 and 1971 wasgenerated. To increase the baseline comparability ofmen who were stationed in Vietnam with otherveterans, participation was limited to men who 1)served only one term, 2) had 16 weeks or more ofactive service, 3) earned a military occupationalspecialty other than "trainee" or "duty soldier," and4) had a pay grade at discharge no higher than that ofsergeant. A total of 17,867 veterans were consideredeligible for the study, with 9,078 (51%) having servedin Vietnam.

Of these men, 15,288 (87% of Vietnam veteransand 84% of non-Vietnam veterans) were located andgiven a structured interview by telephone. Of thoseinterviewed, 6,443 men were randomly selected toparticipate in medical and psychological examina-tions conducted at the Lovelace Medical Foundationin Albuquerque, N.M. Of those invited to the exam-ination, 4,462 men (75% of Vietnam veterans and63% of other veterans) actually participated.

Our analyses are restricted to the 3,562 white menand 500 black men who were between the ages of 31

and 45 years at the time of the medical examination.Men were excluded for one or more of the followingreasons: Hispanics (n=200), Asians (rc=34), NativeAmericans (n=49), and men older than 45 years of age(n=5). Also excluded were men who reported that theyhad not fasted before the examination (n=47), whoseweight was not recorded at the medical examination(n=l), or who had been told by a physician that theywere diabetic (n=46) or had suffered a heart attack(n=18). In addition, men who did not answer questionsconcerning frequency of alcohol consumption (n=10)or cigarette smoking (n=2) were deleted from analysesinvolving these variables.

Risk Factor InformationTelephone interview and medical examination. Infor-

mation on race was obtained during the telephoneinterview for more than 99% of the veterans, andArmy records were used to find this information forthe remaining men. Data on household income andeducational achievement were also obtained duringthe telephone interview. Data on cigarette smoking(current smoking status and mean number of dailycigarettes) and alcohol consumption (average num-ber of days per month during which alcohol wasconsumed and mean number of daily drinks) wereobtained in a standardized interview during themedical examination. Information on the current useof medications, including specific names, was alsocollected. Use of £-blockers, hydantoins, and ana-bolic steroids is included in several analyses becauseof reported associations with levels of HDL choles-terol.21 Quetelet index, a measure of relative weight,was calculated as weight in kilograms divided byheight in meters squared.

Data collected during the telephone interviews wereused to assess the similarity between the 4,462 men whoparticipated in the medical examination and the 10,826men who did not, and only minor differences werefound. For example, 11% of the 10,826 men inter-viewed by telephone only were black, whereas 12% ofthe 4,462 men who participated in the medical exami-nation were black. Furthermore, participation in themedical examination was not associated with maritalstatus, household income, cigarette smoking status,Quetelet index (calculated from self-reported weightand height), or alcohol consumption. Men who partic-ipated in the medical examination, however, tended tobe slightly more educated than those interviewed onlyby telephone.22

Laboratory determinations. Because animal studieshave suggested that exposure to 2,3,7,8-tetrachloro-dibenzo-p-dioxin may lead to hyperlipidemia23 anddecreased levels of testosterone,24 these characteris-tics were measured as part of the medical examina-tion. Venipuncture was performed after an overnightfast. Although levels of testosterone exhibit a strongdiurnal cycle, the effects of this variation on the studyresults should be minimal because all blood sampleswere obtained between 8 and 10 AM, near the time ofpeak testosterone levels.25


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Freedman et al Levels of Testosterone and HDL Cholesterol 309

TABLE 1. Comparison of Selected Characteristics in Men: Vietnam Experience Stndy, 1985-1986

VariableWhites

(0=3,562)Blacks

(n=500)Difference*

Age (yr)

Military service in Vietnam (%)

Total cholesterol (mg/dl)

Trigfycerides (mg/dl)

HDL cholesterol (mg/dl)

Total/HDL cholesterol

Total testosterone (ng/dl)

Quetelet index (kg/m2)

Current smoker (%)

Cigarettes/dayt

Current drinker (%)

Frequency (days/mo)$

Annual household income>$40,000 (%)

Completed 2:4 yr college (%)

38±2

56

213±41

117±111§

44±12§

5.2±2§

676±230|

26.8±4

44§

27±12§

75

12±10

23§

23§

38±3

54

210+43

86±66§

52±16§

4.4±2§

709±248|]

26.7±5

53§

17±10§

78

13±10

14§

13§

0

4

1

26

-18

16

- 5

0

-20

37

- 4

39

43

HDL, high density lipoprotein.Except for percentages, all values are mean±SD.'Percentage difference between blacks and whites: [(mean level among whites—mean level among blacks)] + (mean level among whites).tRestricted to current smokers (1,572 whites, 264 blacks).^Restricted to current drinkers (2,672 whites, 387 blacks).p values were assessed using t tests or \ 2 tests: §p<0.001, |[p<0.01.

Levels of total cholesterol were assayed by anen2ymatic method, and HDL cholesterol was mea-sured after precipitating the LDL and very low densitylipoprotein cholesterol fractions with dextran sulfate.The laboratory used an Ektachem 700 (Eastman Ko-dak, Rochester, N.Y.), and in addition to internalcontrols, the Centers for Disease Control standard-ized and monitored the laboratory.26 Levels of trigryc-erides were determined by an enzymatic method, andlevels of total testosterone were measured with astandard, double-antibody radioimmunoassay system(Leeco Diagnostics, Inc., Southfield, Mich.).27

All laboratory determinations were monitored byusing bench and "blind" repeat quality control pro-cedures. The coefficient of variation for the variouslaboratory measurements ranged from 2.6% to 3.7%for HDL cholesterol and from 4.5% to 9.7% fortestosterone.26

Statistical MethodsUsing t tests, we assessed differences in mean

levels of HDL cholesterol, testosterone, and othercharacteristics between black and white men; differ-ences in categorical variables were assessed using x2

tests. In addition to regression analyses, we examinedgraphically the association between levels of tes-tosterone and age using smoothed medians28 becauseof 1) the small numbers of black men at various agesand 2) uncertainty concerning the shape of theassociation between age and testosterone. We exam-ined race-specific associations between levels of tes-tosterone and other characteristics using stratifica-tion and age-adjusted correlation coefficients; bothPearson and Spearman correlations yielded similarresults. F tests were used to examine linear trends in

levels of testosterone across categorical variableshaving more than two levels.

We then examined whether the observed associa-tion between levels of testosterone and HDL choles-terol was due to confounding by extraneous variables.The association between levels of testosterone andHDL cholesterol was examined within strata of sev-eral covariates (e.g., age and cigarette smoking).With HDL cholesterol as the dependent variable inregression analyses, we also examined changes in themagnitude of the coefficient for testosterone afteradjusting for additional covariates.29 In all analyses,the use of logarithmically transformed values fortestosterone and HDL cholesterol yielded resultssimilar to those obtained by using the original values.

ResultsDescriptive Characteristics andBlack/White Comparisons

Levels of selected characteristics are compared be-tween white and black men in Table 1. The mean ageamong both groups was 38 years, and similar propor-tions of black men and white men were Vietnamveterans. Levels of total cholesterol, Quetelet index,and alcohol consumption were also similar for bothgroups. Among blacks, however, mean levels of triglyc-erides were 26% (31 mg/dl) lower, while mean HDLcholesterol levels were 18% (8 mg/dl) higher thanamong whites. We also found smaller but statisticallysignificant differences in testosterone levels, with meanlevels 5% (33 ng/dl) higher among black men thanamong whites. A larger proportion of black mensmoked cigarettes than did whites, but among thesmokers, white men reported smoking more cigarettes


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100

if ?5

I£ 50

125

Whites / / Blacks FIGURE 1. Cumulative frequency

curve showing distribution of tes-tosterone levels (mg/dl) in 3,562white and 500 black 31- to 45-year-old men. Among whites, the levelsfor the 10th, 50th, and 90th percen-tiles are 405, 656, and 974 ngldl,respectively. Corresponding levelsamong blacks are 415, 684, and1,027 ngldl, respectively.

0 200 400 600 800 1000

Total Testosterone (ng/dl)

1200 1400 1600

per day. Fewer than 1% of the examined men reportedusing J3-blockers, hydantoins, or anabolic steroids.

B

S

5

300

55

50

45

40

35

30

40 45

/ -

Whites

V Blacks

-

•

30 35 40 45

Age(yeara)

FIGURE 2. Line graphs showing median levels o)'testosterone(ng/dl) (panel A) and high density lipoprotein (HDL) choles-terol (mgldl) (panel B) by age in blacks (-) and whites ( — ) .Median values have been smoothed in groups of three becauseof the small sample sizes at various ages.

Although levels of total testosterone were posi-tively skewed (Figure 1), the difference in medianlevels between the two groups (684 ng/dl in blacksversus 656 ng/dl in whites) was comparable to the 33ng/dl difference in mean levels. Despite these differ-ences in average levels, similar proportions of blackand white men had low levels of testosterone: thefifth percentiles were 341 and 349 ng/dl, and the 10thpercentiles were 405 and 415 ng/dl, respectively.

Despite the relatively young ages of the subjects,levels of testosterone were inversely associated withage: correlation coefficients were -0.17 amongwhites and —0.29 among blacks. An examination ofmedian testosterone levels by age (Figure 2) sug-gested that the difference between black and whitemen decreased with age. As estimated by regressionanalyses that included race x age terms, the highermean testosterone levels among blacks decreasedfrom 97 ng/dl (among 31- to 35-year-olds) to 7 ng/dl(among 41- to 45-year-olds), a significant (p<0.01)interaction. In contrast to these associations, HDLcholesterol levels were not linearly associated withage (r=-0.01 [whites] and -0.04 [blacks]), and agedid not modify the black/white difference, p=Q37.

Association Between Levels of Testosterone and HighDensity Lipoprotein Cholesterol

Mean levels of the lipids and lipoproteins accord-ing to testosterone quintile and correlation coeffi-cients are shown in Table 2. Levels of total testoster-one showed little association with total cholesterolbut were associated inversely with levels of triglycer-ides (r=-0.18 to -0.19) and positively with levels ofHDL cholesterol (r=0.22 to 0.26). Men in the highesttestosterone quintile had mean levels of HDL cho-lesterol that were 7 mg/dl (whites) to 12 mg/dl(blacks) higher than those observed among men in


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TABLE 2. Mean Levels of LJpids and Lipoproteins According to Qnintiles of Testosterone: Vietnam Experience Study, 1985-1986

Variable

n

WhitesBlacks

Testosterone (ng/dl)WhitesBlacks

TotaJ cholesterol (mg/dl)WhitesBlacks

Triglycerides (mg/dl)WhitesBlacks

HDL cholesterol (mg/dl)WhitesBlacks

Total/HDL cholesterolWhitesBlacks

1

734

80

393

378

215

210

151

115

40

45

5.7

5.1

2

705

102

544

549

215

218

126

91

43

49

5.5

4.7

Quin tiles

3

716

99

656

659

213

213

111

81

44

50

5.2

4.6

4

717

97

776

783

212

208

101

76

46

55

4.9

4.1

5

690

122

1,0251,043

209

201

92

74

47

57

4.7

3.8

Difference*(%)

62%

64%

- 3 %

- 4 %

-64%- 5 5 %

15%

2 1 %

- 2 1 %-34%

Correlation with

Unadjusted

-0.06-0.08t

-0.18-0.19

0.220.26

-0.18-0.27

testosterone

Age adjusted

-0.05t-0.06t

-0.18-0.18

0.220.26

-0.18-0.26

HDL, high density lipoprotein.'Calculated as [(mean level among men in quintile 5-mean level among men in quintile l)]+(mean level among men in quintile 5).Allp values are <0.001 unless noted; t/>>0.001.

the lowest quintile. Adjustment for age did not affectthe magnitudes of the examined associations.

Adjustment for Other Characteristics

Table 3 shows mean age-adjusted levels of HDLcholesterol and testosterone within categories ofseveral characteristics. Although there were smalldifferences between blacks and whites in the magni-tudes of the observed associations, levels of HDLcholesterol were, as expected, related inversely toboth Quetelet index and cigarette smoking and pos-itively to alcohol consumption. (As compared withwhite men, the association between smoking andlevels of HDL cholesterol in blacks was more stronglyconfounded by alcohol consumption.) Levels of tes-tosterone were most strongly associated with Quete-let index, with the heaviest men (>28 kg/m2) havingmean levels that were about 200 ng/dl lower thanmen who were relatively thin (^24.5 kg/m2). Al-though alcohol consumption was positively associ-ated with levels of testosterone, the relations ofsmoking to levels of HDL cholesterol and testoster-one differed. Cigarette smoking was related inverselyto levels of HDL cholesterol but positively to tes-tosterone, with mean testosterone levels 120 ng/dl(743-623 ng/dl) higher among white men whosmoked more than 20 cigarettes per day than amongnonsmokers. The comparable difference amongblack smokers and nonsmokers was 93 ng/dl.

Despite the small number of men reporting use ofvarious drugs, several medications were also associ-ated with levels of testosterone or HDL cholesterol(Table 3). Among whites, men who reported using

/3-blockers had lower mean levels of HDL cholesterol(-8 mg/dl) and testosterone (-130 ng/dl) than othermen. The two men who reported using anabolic ste-roids had HDL cholesterol levels of 16 mg/dl and 20mg/dl. In contrast, hydantoin users had higher levels ofHDL cholesterol: whites, 6 mg/dl; blacks, 16 mg/dl.

We then examined the magnitude of the associa-tion between levels of HDL cholesterol and testoster-one after controlling for several characteristics bystratification and partial correlations (Table 4). Ad-justment for most characteristics, however, had littleinfluence on the strength of the association. Amongwhite men, for example, correlations within each agegroup were identical to the unadjusted association(r=0.22) between testosterone and HDL cholesterollevels. The association between levels of HDL cho-lesterol and testosterone, however, increased slightlyafter controlling for cigarette smoking, with correla-tion coefficients of 0.27 among both white and blackmen. The largest effect, however, was seen aftercontrolling for Quetelet index: partial correlationcoefficients were reduced to 0.13 (whites) and 0.15(blacks). Similar results were seen in the stratum-specific analyses, with a correlation coefficient of only0.09 among white men who had a Quetelet indexbelow 24.5 kg/m2.

Coefficients from several regression models exam-ining the cross-sectional association between levels ofHDL cholesterol and several characteristics are shownin Table 5. Before adjustment for any covariate (mod-el 1), a 100 ng/dl increase in testosterone was associ-ated with a 1.2 mg/dl increase in levels of HDL


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TABLE 3. Mean Levels of High Density Lipoprotein Cholesterol and Testosterone by Categories of Selected Characteristics: VietnamExperience Study, 1985-1986

Characteristic

Military service inVietnamNo

Yes

Quetelet index (kg/m2)S24-524.6-28.0>28

Cigarettes/day0

1-20>20

Alcohol consumption(days/mo)0

1-8

>8

0-BlockersNo

Yes

HydantoinsNo

Yes

Anabolic steroidsNo

Yes

n

1,5681,994

1,1261,2581,178

1,990723

849

884

13751,297

3,53626

3,54616

3,5602

Whites

HDLcholesterol

(mg/dl)

44

44

49t44

39

45t43

41

41t43

47

44t36

44

50

44t18

Testosterone(ng/dl)

676

675

764t681

585

623t742

743

648f670

700

677*547

676

672

676

644

n

231

269

164

165

171

234

224

40

109

175

212

497

3

494

6

500

0

Blacks

HDLcholesterol

(mg/dl)

51

52

58t51

46

51

52

50

46t52

54

52

52

51t77

Testosterone(ng/dl)

710

709

820t708

604

671

743

764

685

693

739

710

632

708

821

•All values have been age adjusted.p values were assessed by a test for a linear trend (polychotomous variables) or a test for difference in means or medians: tp< 0.001,

lp<0.01.

cholesterol, and adjustment for race (model 2) did notalter this association. (Results of model 2 also indicatethat the higher mean HDL cholesterol level amongblacks exists independently of differences in levels oftestosterone.) The association between several cova-riates and levels of HDL cholesterol is shown in model3: HDL cholesterol was associated positively with useof alcohol and hydantoins and inversely with cigarettesmoking, Quetelet index, and use of ^-blockers oranabolic steroids. Controlling for most covariatesslightly increased the magnitude of the associationbetween levels of testosterone and HDL cholesterol(model 4). Further adjustment for Quetelet index(model 5), however, indicated that an increase of 100ng/dl in levels of testosterone was associated with anincrease of 0.91 mg/dl in levels of HDL cholesterol,about 30% less than that predicted in model 4.

DiscussionResults of prospective studies30-32 have shown that

baseline levels of testosterone and estrogen are notstrongly predictive of subsequent CHD, and it hasbeen suggested that the associations between levels

of sex hormones and risk factors be studied further.In agreement with the results of previous studies,12"17

our cross-sectional findings indicate that levels oftotal testosterone and HDL cholesterol are positivelyassociated (r=0.22 to 0.26). Furthermore, we ob-served that mean levels of HDL cholesterol andtestosterone were higher among black men thanamong whites and that both were related similarly toobesity (inversely) and alcohol consumption (posi-tively). We found different relations, however, withage and cigarette smoking. Age was inversely associ-ated with testosterone levels (estimated yearly dec-rements of 15 ng/dl for whites and 25 ng/dl forblacks) but not with levels of HDL cholesterol.Cigarette smokers had lower mean levels of HDLcholesterol but higher levels of testosterone than didnonsmokers. Analyses indicated that the positiveassociation between levels of HDL cholesterol andtestosterone was, at least in part, due to their inverseassociations with obesity.

Levels of total testosterone were measured in thecurrent study, and only a small proportion of totaltestosterone exists unbound to protein, with most


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TABLE 4. Association Between Levels of Testosterone and HighDensity Upoproteln Cholesterol, Controlling for Various Charac-teristics: Vietnam Experience Study, 1985-1986

Pearson correlation coefficients

Whites (n=3,562) Blacks (n= 500)

Characteristicadjusted for

Withinstrata Adjusted*

Withinstrata Adjusted*

UnadjustedAge (yr)

31-3536-4041-45

Cigarettes/day01-20>20

Alcohol consumption(days/mo)01-8>8

Quetelet index

0.22 0.26

0.22

0.27

0.26

0.27

0.170.200.23

• 0.200.210.280.27

0.25

<24.524.6-28.0>28

0.130.160.160.16

0.15

'Value is partial correlation coefficient for the associationbetween levels of testosterone and high density lipoprotein cho-lesterol, adjusted for individual characteristic.

fLevels of Quetelet index were divided into tertiles: samplesizes among whites range from 1,126 to 1,178; among blacks, from164 to 171.

bound to SHBG. Although it is uncertain whetherour findings would also apply to levels of free tes-tosterone, some evidence suggests that they would.Gutai et al13 reported 1) a strong correlation(r=0.76) between levels of free and total testosteroneand 2) that levels of free and total testosteronefollowed the same pattern of association with levelsof HDL cholesterol and other characteristics. Otherinvestigators have also reported positive associationsbetween levels of free testosterone and HDL choles-terol.1416 Lindstedt et al33 have suggested that someof the protein-bound testosterone may be biologicallyactive.

Although we observed, as have others,12"17 a pos-itive association between levels of testosterone andHDL cholesterol, this relation is somewhat surprisingsince 1) men have a higher incidence of CHD thanwomen and 2) HDL cholesterol levels decrease inboys during puberty and after administration oftestosterone derivatives.6 Furthermore, there is aplausible biologic mechanism that may explain theinverse association, with decreased levels of HDLcholesterol resulting from a testosterone-stimulatedincrease in hepatic lipase activity.34 To reconcilethese differences, it has been suggested1.11-14 that thepositive association between levels of endogenoustestosterone and HDL cholesterol is not direct but is

due to their joint association with another factor.Investigators have found that several indexes ofobesity are inversely related to levels of both HDLcholesterol35 and testosterone,11141517 and we foundthat controlling for Quetelet index reduced thestrength of the association between levels of tes-tosterone and HDL cholesterol by about 30%.

In agreement with these results, Dai et al15 ob-served that controlling for relative weight reducedthe longitudinal association between changes in tes-tosterone and HDL cholesterol. SHBG may be in-volved in these joint associations with obesity, and aninverse association between levels of testosteroneand HDL cholesterol has been reported after con-trolling for SHBG.36 An increased peripheral conver-sion of testosterone to estradiol in obese men mayalso be important.

Although we found a positive association betweenlevels of testosterone and HDL cholesterol even aftercontrolling for Quetelet index, this index is a veryindirect measure of obesity.37 If adiposity was moreaccurately assessed (e.g., by measurement of skinfoldthicknesses), the association between testosteroneand HDL cholesterol may have been further re-duced. In addition, body fat distribution is correlatedwith levels of both HDL cholesterol and SHBG,38

and it may also play a role in the association betweenlevels of testosterone and HDL cholesterol. Othermechanisms, however, may also be involved. Forexample, testosterone may lead to a generalizedincrease in microsomal enzyme activity, resulting inincreased HDL production by the liver.15

Previous reports have shown that testosteronelevels in middle-aged men are associated negativelywith age and positively with cigarette smoking.17"19

Although we found similar associations, testosteronelevels appear to decrease with age beginning withmen in their early 30s, a younger age than is generallyrealized. The positive correlation that we observedbetween alcohol consumption and levels of testoster-one does not agree, however, with findings of aprevious study18 and needs confirmation. To ourknowledge, differences in testosterone levels be-tween black and white men have not been previouslydescribed: we found that mean levels were approxi-mately 5% higher among black men. This black/whitedifference, however, is 1) smaller than the correspond-ing 18% difference in mean levels of HDL cholesteroland 2) not constant across age groups. As observed byother investigators, only a small proportion of thevariability in levels of testosterone can be accountedfor by the examined characteristics, and other factors,such as physical activity and diet,39 may be important.

The importance of testosterone levels in the etiol-ogy of CHD is uncertain. Although some case-controlstudies indicate that testosterone levels among myo-cardial infarction survivors do not differ significantlyfrom levels among controls,10-40-41 there are severalreports of lower testosterone levels among men withCHD17-42-43 and with arteriographically confirmedstenotic disease.44-46 Breier et al45 have suggested that


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TABLE 5. Prediction of High Density Lipoprotein Cholesterol Levels in Various Linear Regression Models: VietnamExperience Study, 1985-1986

Independent variable

Total testosterone (100 ng/dl)Race (0=white, l=black)Age (yr)Alcohol consumption

(days/mo)Cigarettes/dayQuetelet index (kg/m2)Medication use (0=no, l=yes)

^-BlockersHydantoinsAnabolic steroids

Multiple R2

1

1.23 (15)t

0.05

2

1.18(15)7.3 (13)

0.09

Regression model*

3

6.8 (13)-0.04 (1)

0.26 (15)-0.17 (14)-0.84 (21)

-63 (3)11.2(5)

-25.8 (3)0.22

4

133 (17)63 (12)0.09 (1)

0.27 (15)-0.19 (16)

-5.8 (3)13.2(5)

-25.1 (3)0.19

5

0.91 (11)6.4 (12)0.09 (1)

0.25 (14)-0.19(16)-0.70 (17)

-5.4 (3)

11.5 (5)-25.6 (3)

0.24

•All analyses are restricted to the 4,051 men for whom values for all variables were available.fValues are regression coefficient and, in parentheses, the absolute value of the t statistic; a t value of 2.6 is

statistically significant at the 0.01 level; a value of 3.3 is statistically significant at the 0.001 level.

the decreased levels of HDL cholesterol among menwith CHD may be secondary to the association be-tween testosterone and lipoprotein lipase activity.Interestingly, some results suggest that levels of totaltestosterone are as strongly associated with CHD asare levels of free testosterone.42-46

Because levels of sex hormones may be altered by amyocardial infarction, the results of prospective stud-ies may be more valid. Results of a nested case-control study, in which sex hormone levels were mea-sured in plasma samples obtained as many as 12 yearsbefore the clinical event, suggest that high levels oftestosterone may be somewhat protective againstCHD mortality.32 The results, however, were notstatistically significant. Two other similarly designedstudies30-31 provide no evidence that testosterone lev-els are related to CHD risk, but relatively few caseswere studied. Deterioration of sex hormones duringlong-term storage of blood samples31 may reduce themagnitude of the association between levels of tes-tosterone and CHD in nested case-control studies.

Our results are based on men who entered the USArmy between 1965 and 1971, and extrapolations tothe general population should be made with caution.Furthermore, as a result of the multistep procedureleading to inclusion of men in the current analyses,which included tracing the veterans and obtainingtheir agreement to take part in both the telephoneinterview and medical examination, final participa-tion rates ranged from 53% (non-Vietnam veterans)to 66% (Vietnam veterans). Several of the findings,however, suggest that the observed associations maybe generalizable. Mean levels of testosterone amongmen in our study were comparable with those previ-ously reported among similarly aged men18-32 andslightly higher than those reported among 45- to59-year-old men.17 Other findings in this study, suchas differences between black and white men in levelsof HDL cholesterol and the relation of HDL choles-

terol levels to relative weight, cigarette smoking, andalcohol consumption, also agree with the results ofother investigations.35

Although a previously reported cross-sectional as-sociation between levels of testosterone and CHDwas reduced after controlling for levels of triglycer-ides,17 others have found that the association isindependent of HDL cholesterol levels.46 Our find-ings concerning the interrelations among levels oftestosterone, HDL cholesterol, cigarette smoking,and obesity emphasize the importance of multivari-able analyses in studies that examine the relation oftestosterone levels to CHD.

AcknowledgmentsWe thank the leaders of veterans service organiza-

tions who provided important input and support forthe study and the veterans whose cooperation madethis study possible.

References1. Godsland IF, Wynn V, Crook D, Miller NE: Sex, plasma

lipoproteins, and atherosclerosis: Prevailing assumptions andoutstanding questions. Am Heart J 1987;114:1467-1503

2. Nikkila EA, Tikkanen MJ, Kuusi T: Gonadal hormones,lipoprotein metabolism, and coronary heart disease, in OliverMF, Vedin A, Wilhelmsson C (eds): Myocardial Infarction inWomen. Edinburgh, Churchill Livingstone, 1986, pp 34-43

3. Hazzard WR: Atherogenesis: Why women live longer thanmen. Geriatrics 1985;40:42-52

4. The Lipid Research Clinics Population Study Data Booh Volume1. The Prevalence Study. Bethesda, Md, National Institutes ofHealth, 1980, DHHS publication No. (NIH) 80-1527

5. Berenson GS, Srinivasan SR, Cresanta JL, Foster TA, WebberLS: Dynamic changes of serum lipoproteins in children duringadolescence and sexual maturation. Am J Epidemiol 1981;113:157-170

6. Kirkland RT, Keenan BS, Probstfleld JL, Patsch W, Lin TL,Clayton GW, Insull W: Decrease in plasma high-densitylipoprotein cholesterol levels at puberty in boys with delayedadolescence: Correlation with plasma testosterone levels.JAMA 1987;257:502-507


Dow

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7. Taggart HM, Applebaum-Bowden D, Haffner SM, WarnickGR, Cheung MC, Albers JJ, Chestnut CH, Hazzard WR:Reduction in high-density lipoproteins by anabolic steroid(stanozolol) therapy for postmenopausal osteoporosis. Metab-olism 1982;31:1147-1152

8. Albers JJ, Wahl PW, Cabana VG, Hazzard WR, Hoover JJ:Quantitation of apolipoprotein A-I of human plasma highdensity lipoprotein. Metabolism 1976;25:633-644

9. Wahl P, Walden C, Knopp R, Hoover J, Wallace R, Heiss G,Rifkind B: Effect of estrogen/progestin potency on lipid/lipoprotein cholesterol. N Engl J Med 1983;308:862-867

10. Phillips GB: Evidence for hyperoestrogensemia as a risk factorfor myocardial infarction in men. Lancet 1976;2:14-18

11. Stefanick ML, Williams PT, Kiauss RM, Terry RB, VranizanKM, Wood PD: Relationships of plasma estradiol, testoster-one, and sex hormone-binding globulin with lipoproteins,apolipoproteins, and high density lipoprotein subtractions inmen. / Clin Endocrinol Metab 1987;64:723-729

12. Nord0y A, Aakvaag, Thelle D: Sex hormones and high densitylipoproteins in healthy males. Atherosclerosis 1979;34:431-436

13. Gutai J, LaPorte R, Kuller L, Dai W, Falvo-Gerard L, CaggiulaA: Plasma testosterone, high density lipoprotein cholesterol andother lipoprotein fractions. Am J Cardiol 1981;48:897-902

14. Heller RF, Wheeler MJ, Micallef J, Miller NE, Lewis B:Relationship of high density lipoprotein cholesterol with totaland free testosterone and sex hormone binding globulin. AdaEndocrinol 1983;104:253-258

15. Dai WS, Gutai JP, Kuller LH, LaPorte RE, Falvo-Gerard L,Caggiula A: Relation between plasma high-density lipoproteincholesterol and sex-hormone concentrations in men. Am JCardiol 1984^3:1259-1263

16. Hamalainen E, Adlercreutz H, Ehnholm C, Puska P: Rela-tionships of serum lipoproteins and apoproteins to sex hor-mones and to the binding capacity of sex hormone bindingglobulin in healthy Finnish men. Metabolism 1986;35:535-541

17. Iichtenstein M, Yarnell JWG, Ehvood PC, Beswick AD,Sweetnam PM, Marks V, Teale D, Riad-Fahmy D: Sexhormones, insulin, lipids, and prevalent ischemic heart dis-ease. Am J Epidemiol 1987;126:647-657

18. Dai WS, Kuller LH, LaPorte RE, Gutai JP, Falvo-Gerard L,Caggiula A: The epidemiology of plasma testosterone levels inmiddle-aged men. Am J Epidemiol 1981;114:804-816

19. Desrypere JP, Vermeulen A: Leydig cell function in normalmen: Effect of age, lifestyle, residence, diet, and activity. / ClinEndocrinol Metab 1984;59:955-962

20. Centers for Disease Control Vietnam Experience Study:Health status of Vietnam veterans: I. Psychosocial character-istics. JAMA 1988;259:2701-2707

21. Wallace RB, Hunninghake DB, Reiland S, Barrett-Connor E,Mackenthun A, Hoover J, Wahl P: Alterations of plasma high-density lipoprotein cholesterol levels associated with consump-tion of selected medications: The Lipid Research Clinics Pro-gram Prevalence Study. Circulation 1980;62(suppl IV):IV-77-IV-82

22. Freedman DS, Strogatz DS, Eaker E, Joesoeph MR, DeSte-fano F: Differences between black and white men in correlatesof HDL cholesterol. Am J Epidemiol 1990;132:656-669

23. Martin JV: Lipid abnormalities in workers exposed to dioxin.BrJ Ind Med 1984;41:254-256

24. Moore RW, Potter CL, Theobald HM, Robinson JA, PetersonRE: Androgenic deficiency in male rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Appl Pharmacol 1985;79:99-111

25. Faiman C, Winter JSD: Diurnal cycles in plasma FSH, tes-tosterone and cortisol in men. / Clin Endocrinol Metab 1971;33:186-192

26. Centers for Disease Control Vietnam Experience Study:Health Status of Vietnam Veterans: Supplement A: LaboratoryMethods and Quality Control Atlanta, Ga, Centers for DiseaseControl, 1989

27. Leeco Diagnostics: Testosterone Diagnostic Kit Test ProtocolSouthfield, Mich, Leeco Diagnostics, 1983

28. Tukey JW: Exploratory Data Analysis. Reading, Mass, Addi-son-Wesley Publishing Co, 1977, pp 205-236

29. Neter J, Wasserman W, Kutner MH: Applied Linear StatisticalModels, ed 2. Homewood, 111, Richard D. Irwin, Inc, 1985, pp271-299

30. Cauley JA, Gutai JP, Kuller LH, Dai WS: Usefulness of sexsteroid hormone levels in predicting coronary artery disease inmen. Am J Cardiol 1987;60:771-777

31. Phillips GB, Yano K, Stemmermann GN: Serum sex hormonesand myocardial infarction in the Honolulu Heart Program:Pitfalls in prospective studies on sex hormones. / Clin Epide-miol 1988;41:1151-1156

32. Barrett-Connor E, Khaw KT: Endogenous sex hormones andcardiovascular disease in men: A prospective population-based study. Circulation 1988;78:539-545

33. Lindstedt G, Lundberg PA, Hammond GL, Vihko R: Sexhormone-binding globulin: Still many questions. Scand J ClinLab Invest 1985;45:l-6

34. Tikkanen MJ, Nikkila EA: Regulation of hepatic lipase andserum lipoproteins by sex steroids. Am Heart J 1987;13:562-567

35. Heiss G, Johnson NJ, Reiland S, Davis CE, Tyroler HA: Theepidemiology of plasma high-density lipoprotein cholesterollevels: The Lipid Research Clinics Program Prevalence Study:Summary. Circulation 1980;62<suppl IV):rV-116-IV-136

36. Semmens J, Rouse I, Beilin LJ, Masarei JRL: Relationship ofplasma HDL cholesterol to testosterone, estradiol, and sex-hormone-binding globulin levels in men and women. Metabo-lism 1983;32:428-432

37. Willet WD: Nutritional Epidemiology. New York, Oxford Uni-versity Press, 1990, pp 217-244

38. Kissebah AH, Evans DJ, Peiris A, Wilson CR: Endocrinecharacteristics in regional obesities: Role of sex steroids, inVague J, Bjorntorp P, Guy-Grand B, RebufK-Scrive M, VagueP (eds): Metabolic Complications of Human Obesities. Amster-dam, Elsevier, 1985, pp 115-129

39. Gutin B, Alejandro D, Duni T, Segal K, Phillips GB: Levels ofserum sex hormones and risk factors for coronary heartdisease in exercise-trained men. Am J Med 1985;79:79-83

40. Heller RF, Jacobs HS, Vermeulen A, Deslypere JP: Andro-gens, oestrogens, and coronary heart disease. Br Med J 1981;282:438-439

41. Phillips GB, Castelli WP, Abbott RD, McNamara PM: Asso-ciation of hyperestrogenemia and coronary heart disease inthe Framingham cohort. Am J Med 1983;74:863-869

42. Sewdarsen M, Jialal I, Vythilingum S, Desai R: Sex hormonelevels in young Indian patients with myocardial infarction.Arteriosclerosis 1986;6:418-421

43. Mendoza SG, Zerpa A, Carrasco H, Colmenares O, Rangel A,Gartside PS, Kashyap ML: Estradiol, testosterone, apolipo-proteins, lipoprotein cholesterol and lipolytic enzymes in menwith premature infarction and angiographically assessed cor-onary occlusion. Artery 1983;12:l-23

44. Barth JD, Jansen H, Hugenholtz PG, Birkenhager JC: Post-heparin lipases, lipids and related hormones in men undergo-ing coronary arteriography to assess atherosclerosis. Athero-sclerosis 1983;48:235-241

45. Breier C, Muhlberger V, Drexel H, Herald M, Lisch HJ,Knapp E, Braunsteiner H: Essential role of post-heparinlipoprotein lipase activity and of plasma testosterone in coro-nary artery disease. Lancet 1985;1:1242-1244

46. Chute CG, Baron JA, Kiel DP, Plymate SR, Pavia AT, LoznerEC, O'Keefe T, MacDonald GJ: Sex hormones and coronaryartery disease. Am J Med 1987;83:853-859

KEY WORDS • high density lipoprotein cholesterol • testosterone• blacks


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D S Freedman, T R O'Brien, W D Flanders, F DeStefano and J J Barboriakcharacteristics in men.

Relation of serum testosterone levels to high density lipoprotein cholesterol and other

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