Cardiovascular Toxicity of Illicit Anabolic-Androgenic Steroid Use
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Circulation/May 22, 2017
Body-Building Steroids May Promote CAD, Ventricular Dysfunction
June 01, 2017
BOSTON, MA - Long-term illicit use of anabolic-androgenic steroids (AAS) by recreational weightlifters may lead to reduced ventricular function, which may persist even after the drugs are stopped, warn US researchers based on their cross-sectional cohort study.
Their analysis, published in the May 23, 2017 issue of Circulation, showed that LV function by transthoracic echocardiography was significantly reduced among AAS users compared with nonusers. Users also showed a significantly greater burden of coronary atherosclerosis as measured by CT angiography, which appeared to worsen with cumulative lifetime use.
Use of AAS should be considered in the workup of young men showing signs of impaired heart function, lead author Dr Aaron L Baggish (Massachusetts General Hospital, Boston) told heartwire from Medscape.
"The type of people that we studied are going to end up being sent to cardiologists because of lower ejection fractions or premature coronary disease," he said.
"I think the paradigm shift that we'd like to see occur is that cardiovascular practitioners recognize that steroid use is a possible explanation for some of these [signs] in otherwise-healthy young men," Baggish said.
"They won't know unless they ask, so the first place to start is really by encouraging doctors to ask their patients about drug abuse."
The issue of illicit steroid use is not confined to elite competitive athletes, Baggish observed, and "there's a misconception in the general population, as well as in the medical world, that the people you read about in the newspapers" are the ones who are the primary users of AAS.
"In fact, it's much more of a mainstream, general-population problem," he said.
"Some work that we did prior to this study, which was more epidemiologic in focus, suggested that approximately a million US men have a steroid dependence problem, which means that this is something that's affecting people in every community."
The researchers measured LV systolic and diastolic function and coronary artery plaque volume in 140 experienced male weightlifters aged 34 to 54 years. The group consisted of 54 nonusers of AAS and 86 users, of whom 58 were using the drugs at the time and 28 had used them a median of 15 months before the evaluation.
There were few significant baseline differences between users and nonusers of AAS, although users had a significantly higher mean body mass index and fat-free mass index, which is consistent with AAS use.
Overall, AAS users had significantly reduced LV systolic function compared with nonusers, at 52% vs 63% respectively (P<0.001). Their LV relaxation velocity as a reflection of diastolic function was also down at 9.3 cm/s vs 11.1 cm/s (P<0.001).
Users of AAS also showed significant greater plaque volume, with an estimated mean difference of 0.46 mm3 (P=0.012).
The analyses were adjusted for age, race/ethnicity, history of tobacco use, cocaine and/or alcohol dependence, weekly hours of aerobic activity in the past 10 years, and reported family history of coronary artery disease.
The team found that there was a significant difference in the estimated mean difference of LV systolic function between AAS users who were still taking the drugs and those who had stopped before the study, at -9.5% (95% CI -13.8 to -5.2; P<0.001).
There was also a still significant but less pronounced difference in the LV diastolic function between current and former AAS users, at an estimated mean difference of -1.1 cm/second (P=0.035).
Lifetime AAS dose was strongly linked to coronary atherosclerotic burden, with each 10-year increase in the cumulative duration of AAS use elevating the standardized rank plaque volume by 0.60 SD units (P=0.008).
"The hypothesis that some cardiovascular phenotypes associated with AAS use may wax and wane with drug exposure," such as LV systolic dysfunction, "while others may be more permanent, perhaps irreversible," such as LV diastolic dysfunction and coronary atherosclerosis, "deserves rigorous assessment."
Cardiovascular Toxicity of Illicit Anabolic-Androgenic Steroid Use
May 22, 2017
Background: Millions of individuals have used illicit anabolic-androgenic steroids (AAS), but the long-term cardiovascular associations of these drugs remain incompletely understood.
Methods: Using a cross-sectional cohort design, we recruited 140 experienced male weightlifters 34 to 54 years of age, comprising 86 men reporting ≥2 years of cumulative lifetime AAS use and 54 nonusing men. Using transthoracic echocardiography and coronary computed tomography angiography, we assessed 3 primary outcome measures: left ventricular (LV) systolic function (left ventricular ejection fraction), LV diastolic function (early relaxation velocity), and coronary atherosclerosis (coronary artery plaque volume).
Results: Compared with nonusers, AAS users demonstrated relatively reduced LV systolic function (mean±SD left ventricular ejection fraction = 52±11% versus 63±8%; P<0.001) and diastolic function (early relaxation velocity = 9.3±2.4 cm/second versus 11.1±2.0 cm/second; P<0.001). Users currently taking AAS at the time of evaluation (N=58) showed significantly reduced LV systolic (left ventricular ejection fraction = 49±10% versus 58±10%; P<0.001) and diastolic function (early relaxation velocity = 8.9±2.4 cm/second versus 10.1±2.4 cm/second; P=0.035) compared with users currently off-drug (N=28). In addition, AAS users demonstrated higher coronary artery plaque volume than nonusers (median [interquartile range] 3 [0, 174] mL3 versus 0 [0, 69] mL3; P=0.012). Lifetime AAS dose was strongly associated with coronary atherosclerotic burden (increase [95% confidence interval] in rank of plaque volume for each 10-year increase in cumulative duration of AAS use: 0.60 SD units [0.16-1.03 SD units]; P=0.008).
Conclusions: Long-term AAS use appears to be associated with myocardial dysfunction and accelerated coronary atherosclerosis. These forms of AAS-associated adverse cardiovascular phenotypes may represent a previously underrecognized public-health problem.
An estimated 2.9 to 4.0 million Americans have used supraphysiologic doses of illicit anabolic-androgenic steroids (AAS), including testosterone and its synthetic relatives, to gain muscle mass for athletics or personal appearance.1 About 1 million of these individuals, almost all of whom are male, have developed AAS dependence, often leading to years of chronic AAS exposure.2 Illicit AAS use did not become widespread in the general US population until the 1980s.3 Thus, the oldest AAS users, who initiated AAS as youths in the 1980s, are only now reaching middle age, when the adverse effects of long-term use may become apparent. Therefore, these effects remain incompletely understood.
Previous studies have suggested an association between AAS use and cardiovascular disease, with a pathophysiologic link first proposed by early case reports of sudden cardiac death or ischemic stroke among young AAS-using men.4-6 Subsequently, preclinical studies have shown that AAS exposure at supraphysiologic doses causes dyslipidemia,7-9 stimulates cardiomyocyte hypertrophy,10,11 impairs coronary arterial function,12,13 reduces cardiac β-adrenoreceptor sensitivity,14 potentiates oxidative cardiac stress,15 lowers arrhythmic thresholds,16 and induces myocyte apoptosis.17 Most recently, investigations utilizing noninvasive cardiac imaging in human users have demonstrated preliminary evidence of AAS cardiotoxicity in the forms of myocardial dysfunction,18-22 myocardial fibrosis,23 and increased coronary artery calcification.24
In aggregate, data from these earlier studies suggest that illicit AAS use may cause a form of cardiomyopathy characterized by decreased left ventricular (LV) function18,19,21-23,25,26 and may increase the risk of atherosclerotic disease.1,7,8,24 To date, definitive associations between AAS exposure and either myocardial or coronary artery disease have yet to be demonstrated in a large human study. To address this issue, we conducted comprehensive cardiovascular evaluations of 86 long-term AAS users and 54 nonusers.
Illicit AAS use is widespread, but its long-term adverse effects remain poorly understood. A growing literature, largely comprised of case reports and small observational studies, suggests that AAS use may cause cardiovascular disease. We undertook the present study to examine cardiovascular health measures among long-term AAS users and otherwise similar nonusers with the following 4 key findings. First, AAS users demonstrated substantial impairment of LV systolic function as assessed by LVEF and longitudinal strain. This finding was driven almost entirely by those AAS users who were on-drug at the time of evaluation, suggesting that LV dysfunction may be a dynamically related to AAS-use patterns. Second, AAS users also showed impaired LV diastolic dysfunction, both relative to nonusers and also as defined by current diagnostic criteria.44 In contrast to systolic function, which appeared largely normal among off-drug AAS users, LV diastolic function was impaired in both on-drug and off-drug users, suggesting a more permanent form of acquired pathology. Third, AAS users had significantly more LV hypertrophy, as reflected by LV mass index, than nonusers, suggesting an anabolic effect on cardiac muscle mass. In addition, the magnitude of LV hypertrophy among AAS users was directly related to the degrees of both systolic and diastolic function, suggesting a mechanistic link between LV hypertrophy and functional deterioration. Fourth, AAS use was associated with increased coronary atherosclerosis, and the severity of atherosclerotic disease was strongly associated with cumulative lifetime duration of AAS use. In aggregate, our findings suggest that long-term AAS use is associated with adverse cardiovascular phenotypes characterized by both myocardial pathology and coronary artery pathology, which may represent a clinically substantial and largely unrecognized public health problem.
Several scientific and clinical implications emerge from this study. First, improved identification of the adverse cardiovascular associations of AAS use may deter potential future users. Second, clinicians may be better informed about the potential adverse cardiovascular effects of AAS. It is important to note that participants in the present study were not elite or professional athletes, the small subset of the general population most commonly tied to AAS exposure, but rather a sample of middle-age men representing a reasonably broad socioeconomic and racial/ethnic distribution. Thus, when comparable men are found to have impaired LV function or premature coronary artery disease, it seems prudent for clinicians to now include AAS use on the differential diagnosis of possible causes. Third, data derived from the present cross-sectional study provide a foundation for critical future work. The hypothesis that some cardiovascular phenotypes associated with AAS use may wax and wane with drug exposure (eg, LV systolic dysfunction) while others may be more permanent, perhaps irreversible (eg, LV diastolic dysfunction and coronary atherosclerosis), deserves rigorous assessment. Longitudinal studies of illicit AAS users with hard clinical end points, and with interventions to impact drug exposure patterns and treat detected disease, are also of importance.
Several threats regarding the internal validity of this study, as previously delineated in general for cross-sectional cohort studies,27,29 deserve consideration. First, bias might arise through exiting from the underlying conceptual cohort (ie, becoming unavailable for study in the present) that is differential with respect to exposure status. For example, AAS users might be more likely than nonusers to develop cardiovascular morbidity, stop weightlifting, and hence be unavailable for recruitment. Any resulting bias, however, would likely underestimate the effects of AAS use. Second, as in all observational studies, we cannot exclude residual confounding. However, given the lack of confounding seen with our measured potential confounders-as evidenced by similar estimates in sensitivity analyses using both reduced and augmented sets of potential confounders-it is unlikely that substantial residual bias remains because of unmeasured confounders. Third, because both AAS users and nonusers were weightlifters, the effects of AAS might be clouded if weightlifting contributed to cardiovascular pathology. However, our ancillary study comparing non-AAS-using weightlifters with nonweightlifters demonstrated that weightlifting alone (of the duration and intensity exhibited by our sample) had little effect on cardiac adaptation or pathology. Fourth, bias could arise from measurement error, particularly in the exposure variables (eg, misclassifying surreptitious AAS users as nonusers or inaccurately assessing the type, duration, dose, and currency of use). In particular, AAS users provided retrospective accounts, often spanning many years of time, of the use of illicit drugs of uncertain potency or authenticity. As such, estimates of participants’ lifetime duration of AAS use and total lifetime AAS dose were only approximations. The effect of these various sources of measurement error would be expected to be differential for between-group comparisons (because of the potential for inclusion of surreptitious AAS users in the nonuser group and the much less likely inclusion of individuals falsely reporting AAS use in the user group) and random for within-group comparisons among AAS users (because of the low likelihood of an association between cardiac outcomes and error in the predictor variables). Both of these sources would likely bias results toward the null, thereby yielding an underestimate of the effects of AAS use.
Potential threats to external validity (generalizability) also require consideration. First, we recruited AAS users from gymnasiums. Thus, our results might not generalize to other AAS-using groups (eg, elite athletes). However, most AAS users are recreational weightlifters, and thus our results likely generalize to the population of AAS users of greatest public health importance. Second, despite the demographic diversity of our sample, white non-Hispanic men were overrepresented, and therefore our results might not generalize to the full racial/ethnic spectrum of AAS users. Overall, however, these potential threats to internal and external validity appear modest. Thus, our findings likely represent reasonably unbiased estimates of the associations of AAS exposure with adverse cardiovascular phenotypes.
Our findings suggest that AAS use is associated with LV dysfunction and premature coronary artery disease. These findings may inform public health initiatives to curb drug exposure and provide clinicians with information that will translate into improved patient care.
We conducted an observational study using a cross-sectional cohort design. We have previously presented the formal properties of this design,27 which has been used both explicitly28-31 and implicitly32,33 in many earlier studies. This method identifies a dynamic cohort of individuals drawn from a given source population who in principle could have been enumerated in the past and followed to the present (termed the conceptual cohort). Instead of sampling from the conceptual cohort, one samples in the present from those currently available (the study cohort). With this design, estimates of effects derived from the study cohort are valid with respect to the conceptual cohort, subject to similar conditions for validity as other retrospective designs (eg, retrospective cohort and case-control studies).27 We chose the cross-sectional cohort design because it can efficiently assess the association of outcomes with an uncommon exposure (eg, AAS use) in the same manner that a case-control design can efficiently assess the association of exposures with an uncommon outcome.
For the present study, we sampled from a source population of men who lift weights in gymnasiums and then compared exposed (ie, AAS-using) and nonexposed (ie, non-AAS-using) men from this group. We chose this source population because almost all long-term AAS users are male2 and lift weights regularly.1,34 We did not recruit from sporting venues because most AAS users are not competitive athletes but simply recreational weightlifters.1,35,36
Although this approach minimized the effects of confounding variables inherent to weightlifting, we considered that weightlifting or its associated lifestyle might be associated with specific cardiovascular characteristics. Therefore, in an ancillary study, we recruited a group of nonweightlifting and non-AAS-using men (frequency-matched in age to the weightlifters but never weightlifting >30 minutes per week at any time since 18 years of age), drawn from a roster of potential study volunteers maintained by Massachusetts General Hospital, and compared these nonweightlifters to the subgroup of non-AAS-using weightlifters from the primary study. These 2 groups (AAS nonusers and nonweightlifting and non-AAS-using men) exhibited no scientifically important or statistically significant differences on measures of cardiovascular physiology or pathology (Tables I-III in the online-only Data Supplement), indicating that weightlifting per se, of the duration and intensity selected by our recruitment techniques, was associated with little or no cardiovascular adaptation or pathology.
As described in our previous cross-sectional cohort studies involving AAS,28,29 we advertised in gymnasiums for men 34 to 54 years of age who could bench-press 275 pounds for at least one repetition, currently or in the past to recruit AAS users and nonusers. On telephone screening, advertisement respondents were invited to participate without inquiring about AAS use to minimize selection bias that might arise if they knew in advance the exposure variable of interest. It is notable that AAS are typically ingested in courses or cycles, with deliberate intervening off-drug intervals.1 Thus, our design anticipated that the AAS-using weightlifters would include 2 subgroups: those on-drug and those off-drug at the time of evaluation. We excluded AAS users reporting <2 years of cumulative lifetime AAS exposure. We imposed no specific exclusions for medical or psychiatric history.
Qualifying participants were evaluated at a screening interview, where they provided written informed consent for the study as approved by the McLean Hospital Institutional Review Board. We then obtained demographic data, lifetime exercise history (ie, exercise modalities, duration, intensity, and consistency), and fat-free mass index, a validated measure of muscularity.29,37,38 Psychiatric and substance-use histories were obtained using the Structured Clinical Interview for DSM-IV.39 We next assessed history of AAS use, including age at onset of use, maximum weekly dose of AAS (calculated as mg of testosterone equivalent),40 cumulative lifetime years of use, lifetime dose ingested, time of most recent use, and types and doses of AAS taken during most recent (or current) use. We also assessed use of other performance-enhancing substances, including over-the-counter substances (eg, creatine) and illicit drugs (eg, human growth hormone, clenbuterol). Participants then provided urine samples to be tested for AAS29,38 and head or axillary hair to be tested for opiates, cannabis, phencyclidine, amphetamines, and cocaine.29,38 Men showing urine or hair findings inconsistent with their reported substance-use history were excluded from further evaluation. We also excluded men denying AAS use but exhibiting a fat-free mass index >26 kg/m2 together with body fat <10% based on previous work showing that a combination of leanness and muscularity beyond these limits strongly suggests surreptitious AAS use.37,41
Men found to qualify after the screening interviews were then referred for a cardiovascular evaluation performed by investigators blinded to AAS status to characterize LV structure, LV function, and coronary atherosclerosis. Two-dimensional transthoracic echocardiography (iE33, Philips Medical Systems) was used to develop profiles of LV structure and function as previously detailed by our group.42 The primary outcome variables for LV systolic and diastolic function were left ventricular ejection fraction (LVEF) as measured using the modified biplane method of disks43 and early LV relaxation velocity (E'; average of basal septum and lateral wall values44), respectively. Second, coronary computerized tomography angiography (CTA) was performed using a dual-source 128-slice CT scanner (Definition Flash, Siemens Medical Systems), with a primary outcome variable of total coronary artery plaque volume.45 Secondary CTA measures included number of atherosclerotic coronary segments, degree of stenosis of the worst segment, and Agatston calcium score.46 Detailed echocardiographic and CTA methods are provided in the online-only Data Supplement.
Based on our pilot data18 and those of others,1,24 our primary hypotheses were that AAS users would exhibit: (1) decreased LVEF, (2) decreased E', and (3) increased coronary plaque volume compared with non-AAS-using weightlifters. We further hypothesized that within the AAS-user group, greater pathology on these variables would be associated with currency of AAS use (ie, on-drug versus off-drug status at the time of evaluation) and with cumulative lifetime duration of AAS exposure.
Using linear regression, we estimated the mean difference between groups on the outcome measures (technically, the estimated mean difference was the estimated beta coefficient corresponding to group status in a linear model that also included a set of covariates and was fitted using ordinary least-squares linear regression). To control for confounding, our primary analysis adjusted for a set of plausible confounding variables including: age; race/ethnicity (modeled as black versus all others); history of tobacco use, cocaine dependence, and alcohol dependence; weekly hours of aerobic activity in the last 10 years (modeled in tertiles of the distribution); and reported family history of coronary artery disease as defined by the presence of angina, myocardial infarction, angioplasty/stent, or coronary bypass surgery in a first-degree relative. For echocardiographic measures, we additionally adjusted for body surface area as calculated by the Mosteller formula. To explore the relationship between LV mass, a potentially important mechanistic mediator of LV functional impairment, and our primary functional outcome variables, we performed post hoc analyses examining the association of LV mass index with LVEF and E' among AAS users and nonusers. Specifically, we used linear regression with the same set of potential confounding variables and the addition of a term for AAS-user versus nonuser group status to examine the relationships between LV mass index (LV mass in g/body surface area in m2) and the primary cardiac function outcomes. Also, because resting heart rate could influence cardiac functional outcomes, we performed additional analyses of the primary cardiac functional outcomes by adding resting heart rate as a covariate. Note that heart rate may influence functional outcomes and also might be affected by current AAS use. In the latter eventuality, the estimated mean difference between groups adjusted for resting heart rate would likely be biased toward the null (ie, would potentially represent an overadjustment), thus producing an underestimate of the effect of AAS use.
In subsequent sensitivity analyses assessing the influence of adjustments using alternative sets of potential confounders, we repeated all comparisons (1) with no adjustment for any covariates, (2) with the adjustment covariates reduced to only age and race (plus body surface area for echocardiographic measures), and (3) with the adjustment covariates augmented to include hypertension and dyslipidemia (as defined in Tables X-X in the online-only Data Supplement). It is important to note that the augmented set of covariates would be expected to yield underestimates of the effect of AAS use because hypertension and dyslipidemia are often effects of AAS use,1,7,9,47 and adjustment for these variables would consequently adjust out effects of AAS mediated by these variables.
Because the distributions of coronary CTA measures contained many zero values (ie, no measurable coronary artery disease), we used ranked data for these analyses. Within the AAS-user group, we evaluated the association of all outcome measures with duration of use and currency of use (ie, on-drug versus off-drug) using linear regression with adjustment for the same set of covariates. To aid in interpretation of comparisons between groups and associations within groups involving rank-transformed data, we used standard deviation (SD) units to express the estimated difference in ranks for binary predictor variables and the estimated change in ranks for each 1-unit increase in continuous predictor variables. The SD units were calculated by dividing the estimated beta coefficient for the predictor variable from the linear regression model by the SD of the ranks for the entire sample used for a given model.
All models were fitted using Stata 14.1 software (StataCorp). We set α=0.05, 2-tailed. We did not perform corrections for multiple comparisons, so that the statistical significance of P-values for secondary outcomes, particularly those between 0.01 and 0.05, should be interpreted with caution.
We screened 165 men, of whom 25 were excluded from medical evaluation as follows: 10 qualified for participation but withdrew before medical evaluation (9 AAS users, 1 nonuser), 12 reported AAS use of <2 years duration, and 3 showed findings on drug testing or fat-free mass index inconsistent with their self-reports. The remaining sample comprised 86 AAS users and 54 nonusers. Among the AAS users, 58 (67%) were on-drug and 28 (33%) off-drug at evaluation. The off-drug users had last used AAS a median (interquartile range) of 15 (5, 70) months before evaluation.
AAS users and nonusers were similar on most characteristics (Table 1), but users showed higher body mass index and fat-free mass index, consistent with known effects of AAS.
Compared with nonusers, AAS users displayed higher blood pressure (mean±SD systolic, 118±11 versus 115±10 mm Hg; diastolic, 76±9 versus 72±9 mm Hg) and a higher prevalence of dyslipidemia (N [%] with low-density lipoprotein cholesterol >160 mg/dL: 20 [23%] versus 7 [13%]).
Cardiac Structure and Function
For the primary outcome variables of LVEF and E', AAS users showed significant deficits compared with nonusers (Table 2). In models further adjusted for resting heart rate, the estimated mean differences between groups were reduced by 15%, and this change had no impact on the statistical significance of these findings (P<0.001 for both). On other measures, AAS users exhibited higher LV mass index, thicker LV walls, and more concentric LV geometry than nonusers. On subsequent analyses examining the association of outcomes with duration and currency of AAS use, currency of use was strongly associated with greater pathology (Figure 1 and Table IV in the online-only Data Supplement).
Specifically, 41 (71%) of the 58 on-drug users showed LVEFs falling below the normal threshold of 52%,43 whereas off-drug users showed largely normal LVEFs. Twenty-nine (50%) on-drug users fell below the normal E' threshold of 8.5 cm/second,44 with off-drug users showing only partially normalized E'. Similar associations with currency of AAS use were found across other echocardiographic measures (Table IV in the online-only Data Supplement). In contrast, we found no significant associations between duration of AAS use and the primary outcome variables (for each additional 10 years of AAS exposure, the estimated mean change [95% confidence interval] in LVEF was -3.3% [-8.3 to 1.6], P=0.19; and the estimated mean change in E' was 0.1 cm/second [-1.0 to 1.2 cm/second], P=0.90).
Because LVEF and E' differed by group (ie, AAS user versus nonuser) and by subgroup based on currency of use (ie, current versus past AAS users), we further tested for interactions of group and subgroup status with LV mass index for each of these associations and found evidence for a significant interaction with AAS user group status (P=0.046 and P=0.016 for LVEF and E', respectively) but not for currency of use among AAS users (P=0.21 and P=0.86, respectively). Therefore, we assessed the associations separately for AAS users and nonusers. Examining LVEF, among AAS users, a significant association occurred between increased LV mass index and decreased LVEF (estimated mean change [95% confidence interval] in LVEF for each 10 g increase in LV mass index -1.6% [-2.4 to -0.8], P<0.001). In contrast, among the nonusers, no significant association occurred between LV mass index and LVEF (estimated mean change in LVEF for each 10 g increase in LV mass index -0.2% [-1.5 to 1.2], P=0.80). Examining E', among AAS users, a significant association occurred between increased LV mass index and reduced E' (estimated mean change in E' for each 10 g increase in LV mass index -0.31 cm/second [-0.49 to -0.13 cm/second], P<0.001). Among nonusers, the relationship was of approximately equal magnitude but in the opposite direction, with a significant association between increased LV mass index and increased E' (estimated mean change in E' for each 10 g increase in LV mass index 0.36 cm/second [0.04-0.68 cm/second], P<0.001).
Coronary Artery Atherosclerosis
AAS users showed significantly higher coronary plaque volume than nonusers (Table 3 and Figure 2). On examining the association of CTA measures with currency and duration of AAS use, we found strong associations between lifetime duration of use on all angiographic measures of coronary pathology (Table 4 and Figure 3). However, we found no significant association between currency of use and plaque volume (estimated mean difference between on-drug and off-drug users in ranks: -0.07 SD units [-0.56 to 0.41], P=0.76). It is notable that 3 (3%) AAS users had experienced earlier myocardial infarctions because of underlying atherosclerotic disease, documented by cardiac catheterization, occurring at 38 years of age (ST-segment myocardial infarction with complete occlusion of left anterior descending artery), 43 years of age (non-ST-segment myocardial infarction with 99% occlusion of both the right coronary and left circumflex coronary arteries), and 46 years of age (ST-elevation myocardial infarction with complete occlusion of a second obtuse marginal artery) and after 17, 11, and 5 years of cumulative lifetime AAS exposure, respectively. In addition, 1 AAS user had presented at 42 years of age after 20 years of cumulative lifetime AAS exposure with congestive heart failure and underwent stenting of the left circumflex and first obtuse marginal arteries. None of the 54 nonusers had a history of myocardial infarction or stenting.
Assessing the influence of alternative sets of potential confounders, using models with both reduced and augmented sets of covariates, we obtained results similar to those of the primary analysis, with <15% change in the estimates for the primary outcomes and preservation of statistical significance for all results identified as such in the primary analysis (Tables V-VII in the online-only Data Supplement). We also reanalyzed the echocardiographic findings while omitting the 3 men with previous myocardial infarctions. This analysis produced negligible changes in the findings, with the estimated mean differences between users and nonusers on the 2 primary outcome variables changing by <2% when these 3 men were excluded.