Male US Research Articles

Testosterone and type 2 diabetes in men

Objective: To assess from observational data if low testosterone in men is an independent risk factor for high fasting glucose (FG) and for a diagnosis of type 2 diabetes (T2D).Methods: Multivariate analysis of data from 991 male US Air Force veterans who completed six medical examinations over 20 years.Results: Low testosterone was moderately related to high FG, independent of age and obesity. Low testosterone is a very weak predictor of a diagnosis of T2D.Conclusions: In men, low testosterone is an independent risk factor for high FG, comparable to aging and obesity. Low testosterone is a weak predictor of a diagnosis of T2D.

Prospective Study of Breakfast Eating and Incident Coronary Heart Disease in a Cohort of Male US Health Professionals

Eating breakfast is associated with significantly lower coronary heart disease risk in a cohort of male health professionals.

Sexual fluidity in young adult women and men: associations with sexual orientation and sexual identity development

This research investigated sexual fluidity in attractions and sexual identity and associations with sexual orientation dimensions and sexual identity development in 199 (124 female, 75 male) US sexual minority young adults, ages 18–26 years. Participants completed an online questionnaire measuring sexual fluidity in attractions and sexual identity, sexual orientation dimensions (sexual identity, attractions, sexual behaviour) and sexual identity development. Sexual fluidity in attractions was reported by 64% of women and 52% of men, with 49% of those women and 36% of those men reporting sexual fluidity in sexual identity based on experiencing changes in attractions, with no significant gender differences. Sexually fluid women used a range of sexual identities, whereas most sexually fluid men identified as completely homosexual/gay. Sexually fluid people were more likely than non-sexually-fluid people to have engaged in past sexual behaviours with both genders. Sexual fluidity in attractions was not related to the timing of sexual identity developmental milestones; however, women reached some milestones at a later age than men. Findings from this research shed light on the complexities of sexual fluidity and sexual identity development in both women and men.

Increased body mass index is associated with improved overall survival in diffuse large B-cell lymphoma

Obesity is a well-known risk factor for the development of several types of cancer including lymphomas, but its influence on the course of disease is fairly unknown. Recently, a retrospective cancer registry analysis demonstrated significantly prolonged survival for overweight and obese patients with diffuse large B-cell lymphoma (DLBCL). The study population almost exclusively consisted of male US American patients of lower socioeconomic status and one-fifth of patients received cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) chemotherapy without rituximab. Therefore, it remains unclear if these results can be extrapolated to the general DLBCL population. This retrospective single-center analysis included 183 unselected DLBCL patients who were treated with rituximab and standard-dosed anthracycline-based chemoimmunotherapy as first-line therapy between January 2004 and December 2012. Patients were stratified by body mass index (BMI) into 'low BMI' (<25.0 kg/m(2)) and 'high BMI' (≥25.0 kg/m(2)). The two groups were well balanced regarding age, performance score, international prognostic index, B-symptoms and extranodal involvement. However, there was a trend for male sex (P = 0.053) and higher-stage disease (P = 0.066) in the high-BMI group. Patients with higher BMI had significantly longer overall survival (OS; hazard ratio [HR] 0.546; P = 0.035) with 80.9% of patients alive at 3 years versus 64.2% in the low-BMI group. BMI was also an independent prognostic factor for OS in multivariate analysis (HR 0.557; P = 0.043). We could show a significant association between overweight/obesity and improved OS in an unselected DLBCL cohort.

Traffic-related exposures and biomarkers of systemic inflammation, endothelial activation and oxidative stress: a panel study in the US trucking industry

BackgroundExperimental evidence suggests that inhaled particles from vehicle exhaust have systemic effects on inflammation, endothelial activation and oxidative stress. In the present study we assess the relationships of short-term exposures with inflammatory endothelial activation and oxidative stress biomarker levels in a population of trucking industry workers.MethodsBlood and urine samples were collected pre and post-shift, at the beginning and end of a workweek from 67 male non-smoking US trucking industry workers. Concurrent measurements of microenvironment concentrations of elemental and organic carbon (EC & OC), and fine particulate matter (PM2.5) combined with time activity patterns allowed for calculation of individual exposures. Associations between daily and first and last-day average levels of exposures and repeated measures of intercellular and vascular cell adhesion molecule-1 (ICAM-1 & VCAM-1), interleukin 6 (IL-6) and C-reactive protein (CRP) blood levels and urinary 8-Hydroxy-2′-Deoxyguanosine (8-OHdG) were assessed using linear mixed effects models for repeated measures.ResultsThere was a statistically significant association between first and last-day average PM2.5 and 8-OHdG (21% increase, 95% CI: 2, 42%) and first and last-day average OC and IL-6 levels (18% increase 95% CI: 1, 37%) per IQR in exposure. There were no significant findings associated with EC or associations suggesting acute cross-shift effects.ConclusionOur findings suggest associations between weekly average exposures of PM2.5 on markers of oxidative stress and OC on IL-6 levels.

Health and Education: Understanding the Gradient

This study presents a novel view on education and health behavior of individu- als constrained by aging bodies. The aging process, i.e. the accumulation of health decits over time, is built on recent insights from gerontology. The loss of body functionality, which eventually leads to death, can be accelerated by unhealthy behavior and delayed through health expenditure. The proposed theory rationalizes why better educated people optimally choose a healthier lifestyle, that is why they spend more on health and indulge less in unhealthy behavior. The model is calibrated for the average male US citizen. In the benchmark case a dierence of the return to education that motivates one year more of education motivates also about 8 percent less unhealthy behavior and 5 percent more health expenditure and thus explains half a year gain of longevity. Progress in medical technology explains why the education gradient gets larger over time.

The Impact of HIV Viral Control on the Incidence of HIV-Associated Anal Cancer

Recent studies have shown that the incidence of squamous cell cancer of the anus (SCCA) has increased in the combined antiretroviral therapy (cART) era. The effect of undetectable HIV viral loads as a result of successful cART has not been evaluated. We performed a retrospective cohort study among male US veterans diagnosed with HIV and followed between 1985 and 2009 using the Veterans Affairs Immunologic Case Registry (VA-ICR). We calculated age-adjusted incidence rates and rate ratios for SCCA. We conducted Cox proportional hazards ratios of SCCA in a multivariable model including time-varying covariates of nadir CD4 count and overall percentage of time with an undetectable HIV viral load. The age-adjusted SCCA incidence rate among the group who ever received cART was 146.8/100,000 person-years (95% confidence interval, 124.1 to 172.6) and was not significantly higher than the SCCA rate of those who never received cART (134.3/100,000 person-years; 95% confidence interval, 112.5 to 159.0). In a multivariable model limited to veterans who had ever received cART (adjusted for demographic variables, nadir, and most recent CD4 counts) individuals who had 61%-80% or 81%-100% of follow-up time with undetectable HIV viral loads had significantly decreased SCCA risk compared with those who had undetectable HIV viral loads <20% of the time (odds ratio, 0.56; P = 0.040 and odds ratio, 0.55; P = 0.0004, respectively). HIV control as measured by the percent of time with undetectable HIV viral load seems to decrease the risk of SCCA. Optimizing cART adherence and HIV viral load control may decrease the risk of subsequent SCCA.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Prospective study of breakfast eating and incident coronary heart disease in a cohort of male US health professionals.

Among adults, skipping meals is associated with excess body weight, hypertension, insulin resistance, and elevated fasting lipid concentrations. However, it remains unknown whether specific eating habits regardless of dietary composition influence coronary heart disease (CHD) risk. The objective of this study was to prospectively examine eating habits and risk of CHD. Eating habits, including breakfast eating, were assessed in 1992 in 26 902 American men 45 to 82 years of age from the Health Professionals Follow-up Study who were free of cardiovascular disease and cancer. During 16 years of follow-up, 1527 incident CHD cases were diagnosed. Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals for CHD, adjusted for demographic, diet, lifestyle, and other CHD risk factors. Men who skipped breakfast had a 27% higher risk of CHD compared with men who did not (relative risk, 1.27; 95% confidence interval, 1.06-1.53). Compared with men who did not eat late at night, those who ate late at night had a 55% higher CHD risk (relative risk, 1.55; 95% confidence interval, 1.05-2.29). These associations were mediated by body mass index, hypertension, hypercholesterolemia, and diabetes mellitus. No association was observed between eating frequency (times per day) and risk of CHD. Eating breakfast was associated with significantly lower CHD risk in this cohort of male health professionals.

Spontaneous brain activity in combat related PTSD

Posttraumatic stress disorder (PTSD) is a prevalent psychiatric disorder, especially in combat veterans. Existing functional neuroimaging studies have provided important insights into the neural mechanisms of PTSD using various experimental paradigms involving trauma recollection or other forms of emotion provocation. However it is not clear whether the abnormal brain activity is specific to the mental processes related to the experimental tasks or reflects general patterns across different brain states. Thus, studying intrinsic spontaneous brain activity without the influence of external tasks may provide valuable alternative perspectives to further understand the neural characteristics of PTSD. The present study evaluated the magnitudes of spontaneous brain activity of male US veterans with or without PTSD, with the two groups matched on age, gender, and ethnicity. Amplitudes of low frequency fluctuation (ALFF), a data driven analysis method, were calculated on each voxel of the resting state fMRI data to measure the magnitudes of spontaneous brain activity. Results revealed that PTSD subjects showed increased spontaneous activity in the amygdala, ventral anterior cingulate cortex, insula, and orbital frontal cortex, as well as decreased spontaneous activity in the precuneus, dorsal lateral prefrontal cortex and thalamus. Within the PTSD group, larger magnitudes of spontaneous activity in the thalamus, precuneus and dorsal lateral prefrontal cortex were associated with lower re-experiencing symptoms. Comparing our results with previous functional neuroimaging findings, increased activity of the amygdala and anterior insula and decreased activity of the thalamus are consistent patterns across emotion provocation states and the resting state.

Risk Profile of Hepatocellular Carcinoma Reveals Dichotomy among US Veterans

Hepatocellular carcinoma (HCC) is traditionally associated with chronic liver injury resulting from hepatitis B virus (HBV) and hepatitis C virus (HCV) infection or excessive consumption of alcohol. In addition, recent evidence links HCC to diabetes. Since these risk factors are prevalent among US veterans, we analyzedcontribution of various etiologies toHCC incidence in this population. Clinicopathological correlates of 150 male US veterans diagnosed with HCC between 2001 and 2010 were analyzed and compared to frequency-matched (2:1) non-cancer controls in a single center. HCC was associated with cirrhosis (odds ratio [OR], 250.84; 95 % confidence interval [CI], 86.92-723.88; p < 0.0001), chronic hepatitis B (OR, 34.30 95 % CI, 1.97-598.47; p = 0.015), chronic hepatitis C (OR, 6.84; 95 % CI, 3.89-12.04; p < 0.0001), alcohol use (OR, 6.76; 95 % CI, 4.35-10.52; p < 0.0001), and smoking (OR, 1.83; 95 % CI, 1.23-2.89; p = 0.009), but surprisingly not with diabetes. Only in a subgroup of HCC patients with no "traditional" risk factors did diabetes become a strong independent predictor of HCC when compared to HCC patients with at least one such risk factor (OR, 10.69; 95 % CI, 1.88-60.63, p = 0.007). This subgroup was further distinguished by older age, increased prevalence of hypertension, nonsmoking, and a trend to develop noncirrhotic HCC. While HCC in US veterans is overwhelmingly linked to cirrhosis due to "traditional" risk factors, it also occurs with a separate clinical profile characterized by diabetes and no evidence of cirrhosis, suggesting distinct mechanisms of hepatocarcinogenesis and needs for surveillance.

An anthropometric analysis of Korean male helicopter pilots for helicopter cockpit design

This study measured 21 anthropometric dimensions (ADs) of 94 Korean male helicopter pilots in their 20s to 40s and compared them with corresponding measurements of Korean male civilians and the US Army male personnel. The ADs and the sample size of the anthropometric survey were determined by a four-step process: (1) selection of ADs related to helicopter cockpit design, (2) evaluation of the importance of each AD, (3) calculation of required sample sizes for selected precision levels and (4) determination of an appropriate sample size by considering both the AD importance evaluation results and the sample size requirements. The anthropometric comparison reveals that the Korean helicopter pilots are larger (ratio of means = 1.01–1.08) and less dispersed (ratio of standard deviations = 0.71–0.93) than the Korean male civilians and that they are shorter in stature (0.99), have shorter upper limbs (0.89–0.96) and lower limbs (0.93–0.97), but are taller on sitting height, sitting eye height and acromial height (1.01–1.03), and less dispersed (0.68–0.97) than the US Army personnel. Practitioner summary: The anthropometric characteristics of Korean male helicopter pilots were compared with those of Korean male civilians and US Army male personnel. The sample size determination process and the anthropometric comparison results presented in this study are useful to design an anthropometric survey and a helicopter cockpit layout, respectively.

The height gap in 19th-century America: Net-nutritional advantage of the elite increased at the onset of modern economic growth

We present evidence on the 19th-century trend in the height of male US passport applicants. These men represent a much wealthier segment of contemporary society than found in most stature samples previously analyzed. The height trend among the wealthy is much more robust in comparison to the average population that experienced a decline in stature. The resulting increase in the ‘height gap’—by roughly 1in. between cohorts born around 1820 and 1860—is in congruence with evidence on rising wealth inequality and the notion of dietary change in antebellum America.

Survival Advantage in Black Versus White Men With CKD: Effect of Estimated GFR and Case Mix

Black dialysis patients have significantly lower mortality compared with white patients, in contradistinction to the higher mortality seen in blacks in the general population. It is unclear whether a similar paradox exists in patients with non-dialysis-dependent chronic kidney disease (CKD), and if it does, what its underlying reasons are. Historical cohort. 518,406 white and 52,402 black male US veterans with non-dialysis-dependent CKD stages 3-5. Black race. We examined overall and CKD stage-specific all-cause mortality using parametric survival models. The effect of sociodemographic characteristics, comorbid conditions, and laboratory characteristics on the observed differences was explored in multivariable models. During a median follow-up of 4.7 years, 172,093 patients died (mortality rate, 71.0 [95% CI, 70.6-71.3] per 1,000 patient-years). Black race was associated with significantly lower crude mortality (HR, 0.95; 95% CI, 0.94-0.97; P < 0.001). The survival advantage was attenuated after adjustment for age (HR, 1.14; 95% CI, 1.12-1.16), but was magnified after full multivariable adjustment (HR, 0.72; 95% CI, 0.70-0.73; P < 0.001). The unadjusted survival advantage of blacks was more prominent in those with more advanced stages of CKD, but CKD stage-specific differences were attenuated by multivariable adjustment. Exclusively male patients. Black patients with CKD have lower mortality compared with white patients. The survival advantage seen in blacks is accentuated in patients with more advanced stages of CKD, which may be explained by changes in case-mix and laboratory characteristics occurring during the course of kidney disease.

Synthetic Cannabinoid Overdose in a 20-Year-Old Male US Soldier

ABSTRACT Popularity of synthetic cannabinoids among US military service members has risen over the last several years, leading to an increase in hospitalizations and legal actions stemming from its use and possession. Although synthetic cannabinoids, collectively referred to as “Spice,” are similar in structure to the active metabolites found in cannabis, significant concerns exist regarding the severity of short- and long-term medical and psychiatric sequelae. This article presents a case, in which a patient experienced severe medical and psychiatric symptoms far exceeding the severity and duration typically resulting from cannabis use.

Multivitamins in the prevention of cancer in men: the Physicians' Health Study II randomized controlled trial.

Multivitamin preparations are the most common dietary supplement, taken by at least one-third of all US adults. Observational studies have not provided evidence regarding associations of multivitamin use with total and site-specific cancer incidence or mortality. To determine whether long-term multivitamin supplementation decreases the risk of total and site-specific cancer events among men. A large-scale, randomized, double-blind, placebo controlled trial (Physicians" Health Study II) of 14 641 male US physicians initially aged 50 years or older (mean [SD] age, 64.3 [9.2] years), including 1312 men with a history of cancer at randomization, enrolled in a common multivitamin study that began in 1997 with treatment and follow-up through June 1, 2011. Daily multivitamin or placebo. Total cancer (excluding nonmelanoma skin cancer), with prostate, colorectal, and other site-specific cancers among the secondary end points. During a median (interquartile range) follow-up of 11.2 (10.7-13.3) years, there were 2669 men with confirmed cancer, including 1373 cases of prostate cancer and 210 cases of colorectal cancer. Compared with placebo, men taking a daily multivitamin had a statistically significant reduction in the incidence of total cancer (multivitamin and placebo groups, 17.0 and 18.3 events, respectively, per 1000 person-years; hazard ratio [HR], 0.92; 95% CI, 0.86-0.998; P=.04). There was no significant effect of a daily multivitamin on prostate cancer (multivitamin and placebo groups, 9.1 and 9.2 events, respectively, per 1000 person-years; HR, 0.98; 95% CI, 0.88-1.09; P=.76), colorectal cancer (multivitamin and placebo groups, 1.2 and 1.4 events, respectively, per 1000 person-years; HR, 0.89; 95% CI, 0.68-1.17; P=.39), or other site-specific cancers. There was no significant difference in the risk of cancer mortality (multivitamin and placebo groups, 4.9 and 5.6 events, respectively, per 1000 person-years; HR, 0.88; 95% CI, 0.77-1.01; P=.07). Daily multivitamin use was associated with a reduction in total cancer among 1312 men with a baseline history of cancer (HR, 0.73; 95% CI, 0.56-0.96; P=.02), but this did not differ significantly from that among 13 329 men initially without cancer (HR, 0.94; 95% CI, 0.87-1.02; P=.15; P for interaction=.07). Conclusion In this large prevention trial of male physicians, daily multivitamin supplementation modestly but significantly reduced the risk of total cancer. clinicaltrials.gov Identifier: NCT00270647.

Multivitamins in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial.

Although multivitamins are used to prevent vitamin and mineral deficiency, there is a perception that multivitamins may prevent cardiovascular disease (CVD). Observational studies have shown inconsistent associations between regular multivitamin use and CVD, with no long-term clinical trials of multivitamin use. To determine whether long-term multivitamin supplementation decreases the risk of major cardiovascular events among men. The Physicians' Health Study II, a randomized, double-blind, placebo-controlled trial of a common daily multivitamin, began in 1997 with continued treatment and follow-up through June 1, 2011. A total of 14,641 male US physicians initially aged 50 years or older (mean, 64.3 [SD, 9.2] years), including 754 men with a history of CVD at randomization, were enrolled. Daily multivitamin or placebo. Composite end point of major cardiovascular events, including nonfatal myocardial infarction (MI), nonfatal stroke, and CVD mortality. Secondary outcomes included MI and stroke individually. During a median follow-up of 11.2 (interquartile range, 10.7-13.3) years, there were 1732 confirmed major cardiovascular events. Compared with placebo, there was no significant effect of a daily multivitamin on major cardiovascular events (11.0 and 10.8 events per 1000 person-years for multivitamin vs placebo, respectively; hazard ratio [HR], 1.01; 95% CI, 0.91-1.10; P = .91). Further, a daily multivitamin had no effect on total MI (3.9 and 4.2 events per 1000 person-years; HR, 0.93; 95% CI, 0.80-1.09; P = .39), total stroke (4.1 and 3.9 events per 1000 person-years; HR, 1.06; 95% CI, 0.91-1.23; P = .48), or CVD mortality (5.0 and 5.1 events per 1000 person-years; HR, 0.95; 95% CI, 0.83-1.09; P = .47). A daily multivitamin was also not significantly associated with total mortality (HR, 0.94; 95% CI, 0.88-1.02; P = .13). The effect of a daily multivitamin on major cardiovascular events did not differ between men with or without a baseline history of CVD (P = .62 for interaction). Among this population of US male physicians, taking a daily multivitamin did not reduce major cardiovascular events, MI, stroke, and CVD mortality after more than a decade of treatment and follow-up. clinicaltrials.gov Identifier: NCT00270647.

Large caliber ballistic fragment within the spinal canal

Gunshot wounds to the spine continue to be a prodigious clinical problem. We report a case of a 28-year-old male US Marine after a high-energy penetrating spinal cord injury, with associated injuries including a left hemopneumothorax and an open left comminuted scapula body fracture. Computed tomography demonstrated a retained highcaliber (7.62 mm) ballistic fragment within the spinal canal at the level of T6–T7 (Figs. 1 and 2). On physical examination, the patient had an incomplete spinal cord injury (American Spinal Injury Association Grade B) with sacral sparing demonstrating normal rectal tone, voluntary rectal squeeze, and bulbocavernosus reflex. The patient had 0/5 motor strength in bilateral lower extremities, normal sensation T6 right/T5 left, intact proprioception in bilateral ankles and toes, and normal strength/sensation in bilateral upper extremities. On Postinjury Day 5, the patient underwent a T6 laminectomy, removal of the bullet, and subsequent repair of a dural defect. This is the first case of a large caliber bullet being lodged in the spinal canal, with only a few reported case series of combat casualties treated for high-velocity ballistic injuries to the spinal column [1,2]. When treating gunshot wounds to the spine, it is of the utmost importance to differentiate between high- and low-energy ballistic injuries as this dictates the appropriate management [3]. Highenergy ballistic injuries are more common in combat casualties compared with civilian trauma patients and are often associated with significantly greater soft-tissue devitalization and a larger zone of injury. Treatment of high-energy ballistic injuries should consist of early broad-spectrum intravenous antibiotics, aggressive surgical debridement, and, when indicated, decompressive laminectomy with instrumentation at a Level 4 or 5 treatment facility. Fractures of the spine caused by low-velocity bullet wound or ballistic fragmentation are usually stable, and surgical intervention is often unnecessary. Most cases of spine instability and late deformity after penetrating injury have been associated with overly aggressive laminectomy [3,4].

Analysis of the Facial Anthropometric Data of Korean Pilots for Oxygen Mask Design

The present study measured Korean pilots’ facial dimensions to design a pilot oxygen mask which would fit Korean pilots, and compared Korean pilots’ facial dimensions to Korean male civilians and US male pilots’ facial characteristics. The present study selected the 22 facial anthropometric dimensions related to oxygen mask design by referring to previous studies. The facial dimensions of 366 Korean male and female pilots (including 52 female cadets of the Korean Air Force Academy) were measured using Martin’s anthropometer and 3D scanner. Korean male pilots’ faces were significantly larger (mean difference = 1.3 ~ 27.0 mm) and less variable (ratio in SD = 0.29 ~ 0.85) than Korean male civilians’ faces ( α = 0.05), which indicates that facial anthropometric data derived from Korean pilots should be used to design the oxygen mask for Korean pilots. In terms of criteria of the oxygen mask sizing system which is currently based upon the US Air Force anthropometric data (face length and lip width), Korean male pilots were significantly longer on face length (mean difference = 4.7 mm) and narrower on lip width (mean difference = -2.4 mm) than US male pilots ( α = 0.05), which indicates that the oxygen mask sizing system as well as the oxygen mask shape should be changed for Korean pilots. Additionally, Korean male pilots have wider nasal roots (mean difference = 5.2 mm) than US male pilots, which indicates that the shape of nose of the current oxygen mask should be widened. Lastly, Korean female pilots’ facial dimensions were significantly smaller (mean difference = 0.6 ~ 26.1 mm) than Korean male pilots ( α = 0.05), which indicates that Korean female pilots’ facial characteristics need to be considered in the design of oxygen masks which fit Korean pilots.

Cognitive ability in early adulthood as a predictor of habitual drug use during later military service and civilian life: The Vietnam Experience Study

BackgroundRecent reports have linked cognitive ability (IQ) with alcohol dependency, but the relationship with illegal drug use is not well understood. MethodsParticipants were 14,362 male US Vietnam veterans with IQ test results at entry into military service in 1965–1971 (mean age 22.58) who participated in a telephone interview in 1985–1986. A structured diagnostic telephone interview was used to ascertain habitual drug use during military service (for once a week, ≥3 months) and in civilian life (in the past 12 months, ≥once a week), combat exposure, and post-traumatic stress disorder according to established Diagnostic and Statistical Manual of Mental disorders criteria (version III). ResultsIn unadjusted analysis, men with high IQ scores were less likely to be habitual users of cannabis (OR=0.89, 95% CI=0.86, 0.93), cocaine (OR=0.69, 95% CI=0.61, 0.78), heroin (OR=0.80, 95% CI=0.73, 0.88), amphetamines (OR=0.90, 95% CI=0.83, 0.98), barbiturates (OR=0.79, 95% CI=0.72, 0.86) and LSD (OR=0.91, 95% CI=0.82, 0.99) during military service and civilian life. These associations were markedly attenuated after adjustment for socioeconomic status in early and later civilian life. ConclusionIn this cohort, socioeconomic position might lie on the pathway linking earlier IQ and later habitual drug use but might also act as a surrogate for IQ. This suggests interventions to prevent drug use could attempt to improve early life IQ and opportunities for employment.