Application of linear mixed-effects model with LASSO to identify metal components associated with cardiac autonomic responses among welders: a repeated measures study.

BACKGROUND: Environmental and occupational exposure to metals is ubiquitous worldwide, and understanding the hazardous metal components in this complex mixture is essential for environmental and occupational regulations. OBJECTIVE: To identify hazardous components from metal mixtures that are associated with alterations in cardiac autonomic responses. METHODS: Urinary concentrations of 16 types of metals were examined and 'acceleration capacity' (AC) and 'deceleration capacity' (DC), indicators of cardiac autonomic effects, were quantified from ECG recordings among 54 welders. We fitted linear mixed-effects models with least absolute shrinkage and selection operator (LASSO) to identify metal components that are associated with AC and DC. The Bayesian Information Criterion was used as the criterion for model selection procedures. RESULTS: Mercury and chromium were selected for DC analysis, whereas mercury, chromium and manganese were selected for AC analysis through the LASSO approach. When we fitted the linear mixed-effects models with 'selected' metal components only, the effect of mercury remained significant. Every 1 µg/L increase in urinary mercury was associated with -0.58 ms (-1.03, -0.13) changes in DC and 0.67 ms (0.25, 1.10) changes in AC. CONCLUSION: Our study suggests that exposure to several metals is associated with impaired cardiac autonomic functions. Our findings should be replicated in future studies with larger sample sizes.

Risk of gynecomastia and breast cancer associated with the use of 5-alpha reductase inhibitors for benign prostatic hyperplasia.

BACKGROUND: Clinical trial results suggest that 5-alpha reductase inhibitors (5ARIs) for the treatment of benign prostatic hyperplasia (BPH) may increase the risk of gynecomastia and male breast cancer, but epidemiological studies have been limited. PATIENTS AND METHODS: We conducted a cohort study with nested case-control analyses using the UK Clinical Practice Research Datalink. We identified men diagnosed with BPH who were free from Klinefelter syndrome, prostate, genital or urinary cancer, prostatectomy or orchiectomy, or evidence of gynecomastia or breast cancer. Patients entered the cohort at age ≥40 years and at least 3 years after the start of their electronic medical record. We classified exposure as 5ARIs (alone or in combination with alpha blockers [ABs]), AB only, or unexposed to 5ARIs and ABs. Cases were men who had a first-time diagnosis of gynecomastia or breast cancer. Incidence rates and incidence rate ratios (IRRs) with 95% confidence intervals (CIs) in the gynecomastia analysis and crude and adjusted odds ratios (ORs) with 95% CIs in both analyses were calculated. RESULTS: Compared to no exposure, gynecomastia risk was elevated for users of 5ARIs (alone or in combination with ABs) in both the cohort (IRR=3.55, 95% CI 3.05-4.14) and case-control analyses (OR=3.31, 95% CI 2.66-4.10), whereas the risk was null for users of AB only. The increased risk of gynecomastia with the use of 5ARIs persisted regardless of the number of prescriptions, exposure timing, and presence or absence of concomitant prescriptions for drugs known to be associated with gynecomastia. The risk was higher for dutasteride than for finasteride. 5ARI users did not have an increased risk of breast cancer compared to unexposed men (OR=1.52, 95% CI 0.61-3.80). CONCLUSION: In men with BPH, 5ARIs significantly increased the risk of gynecomastia, but not breast cancer, compared to AB use and no exposure.

An epigenome-wide association analysis of cardiac autonomic responses among a population of welders.

DNA methylation is one of the potential epigenetic mechanisms associated with various adverse cardiovascular effects; however, its association with cardiac autonomic dysfunction, in particular, is unknown. In the current study, we aimed to identify epigenetic variants associated with alterations in cardiac autonomic responses. Cardiac autonomic responses were measured with two novel markers: acceleration capacity (AC) and deceleration capacity (DC). We examined DNA methylation levels at more than 472,506 CpG probes through the Illumina Infinium HumanMethylation450 BeadChip assay. We conducted separate linear mixed models to examine associations of DNA methylation levels at each CpG with AC and DC. One CpG (cg26829071) located in the GPR133 gene was negatively associated with DC values after multiple testing corrections through false discovery rate. Our study suggests the potential functional importance of methylation in cardiac autonomic responses. Findings from the current study need to be replicated in future studies in a larger population.

Association of air particulate pollution with bone loss over time and bone fracture risk: analysis of data from two independent studies.

BACKGROUND: Air particulate matter (PM) is a ubiquitous environmental exposure associated with oxidation, inflammation, and age-related chronic disease. Whether PM is associated with loss of bone mineral density (BMD) and risk of bone fractures is undetermined. METHODS: We conducted two complementary studies of: (i) long-term PM <2.5 µm (PM2.5) levels and osteoporosis-related fracture hospital admissions among 9.2 million Medicare enrollees of the Northeast/Mid-Atlantic United States between 2003-2010; (ii) long-term black carbon [BC] and PM2.5 levels, serum calcium homeostasis biomarkers (parathyroid hormone, calcium, and 25-hydroxyvitamin D), and annualized BMD reduction over a 8-year follow-up of 692 middle-aged (46.7±12.3 yrs), low-income BACH/Bone cohort participants. FINDINGS: In the Medicare analysis, risk of bone fracture admissions at osteoporosis-related sites was greater in areas with higher PM2.5 levels (Risk ratio [RR] 1.041, 95% Confidence Interval [CI], 1.030, 1.051). This risk was particularly high among low-income communities (RR 1.076; 95% CI, 1.052, 1.100). In the longitudinal BACH/Bone study, baseline BC and PM2.5 levels were associated with lower serum PTH (Estimate for baseline one interquartile increase in 1-year average BC= -1.16, 95% CI -1.93, -0.38; Estimate for baseline one interquartile increase in 1-year average PM2.5= -7.39; 95%CI -14.17, -0.61). BC level was associated with higher BMD loss over time at multiple anatomical sites, including femoral neck (-0.08%/year per one interquartile increase; 95% CI -0.14, -0.02%/year) and ultradistal radius (-0.06%/year per one interquartile increase; 95% CI -0.12, -0.01%/year). INTERPRETATION: Our results suggest that poor air quality is a modifiable risk factor for bone fractures and osteoporosis, especially in low-income communities.

Validity of Self-Reported Tobacco Smoke Exposure among Non-Smoking Adult Public Housing Residents.

INTRODUCTION: Tobacco smoke exposure (TSE) in public multi-unit housing (MUH) is of concern. However, the validity of self-reports for determining TSE among non-smoking residents in such housing is unclear. METHODS: We analyzed data from 285 non-smoking public MUH residents living in non-smoking households in the Boston area. Participants were interviewed about personal TSE in various locations in the past 7 days and completed a diary of home TSE for 7 days. Self-reported TSE was validated against measurable saliva cotinine (lower limit of detection (LOD) 0.02 ng/ml) and airborne apartment nicotine (LOD 5 ng). Correlations, estimates of inter-measure agreement, and logistic regression assessed associations between self-reported TSE items and measurable cotinine and nicotine. RESULTS: Cotinine and nicotine levels were low in this sample (median = 0.026 ng/ml and 0.022 µg/m(3), respectively). Prevalence of detectable personal TSE was 66.3% via self-report and 57.0% via measurable cotinine (median concentration among those with cotinine>LOD: 0.057 ng/ml), with poor agreement (kappa = 0.06; sensitivity = 68.9%; specificity = 37.1%). TSE in the home, car, and other peoples' homes was weakly associated with cotinine levels (Spearman correlations rs = 0.15-0.25), while TSE in public places was not associated with cotinine. Among those with airborne nicotine and daily diary data (n = 161), a smaller proportion had household TSE via self-report (41.6%) compared with measurable airborne nicotine (53.4%) (median concentration among those with nicotine>LOD: 0.04 µg/m(3)) (kappa = 0.09, sensitivity = 46.5%, specificity = 62.7%). CONCLUSIONS: Self-report alone was not adequate to identify individuals with TSE, as 31% with measurable cotinine and 53% with measurable nicotine did not report TSE. Self-report of TSE in private indoor spaces outside the home was most associated with measurable cotinine in this low-income non-smoking population.

Environmental and occupational particulate matter exposures and ectopic heart beats in welders.

OBJECTIVES: Links between arrhythmias and particulate matter exposures have been found among sensitive populations. We examined the relationship between personal particulate matter ≤2.5 µm aerodynamic diameter (PM2.5) exposures and ectopy in a panel study of healthy welders. METHODS: Simultaneous ambulatory ECG and personal PM2.5 exposure monitoring with DustTrak Aerosol Monitor was performed on 72 males during work and non-work periods for 5-90 h (median 40 h). ECGs were summarised hourly for supraventricular ectopy (SVE) and ventricular ectopy (VE). PM2.5 exposures both work and non-work periods were averaged hourly with lags from 0 to 7 h. Generalised linear mixed-effects models with a random participant intercept were used to examine the relationship between PM2.5 exposure and the odds of SVE or VE. Sensitivity analyses were performed to assess whether relationships differed by work period and among current smokers. RESULTS: Participants had a mean (SD) age of 38 (11) years and were monitored over 2993 person-hours. The number of hourly ectopic events was highly skewed with mean (SD) of 14 (69) VE and 1 (4) SVE. We found marginally significant increases in VE with PM2.5 exposures in the sixth and seventh hour lags, yet no association with SVE. For every 100 µg/m(3) increase in sixth hour lagged PM2.5, the adjusted OR (95% CI) for VE was 1.03 (1.00 to 1.05). Results persisted in work or non-work exposure periods and non-smokers had increased odds of VE associated with PM2.5 as compared with smokers. CONCLUSIONS: A small increase in the odds of VE with short-term PM2.5 exposure was observed among relatively healthy men with environmental and occupational exposures.

Sexual Health in Male and Female Iraq and Afghanistan U. S. War Veterans With and Without PTSD: Findings From the VALOR Cohort.

We sought to determine whether posttraumatic stress disorder (PTSD) was associated with sexual health in returned warzone-deployed veterans from the recent Iraq and Afghanistan conflicts. We studied 1,581 males and females from the Veterans After-Discharge Longitudinal Registry, a gender-balanced U.S. Department of Veterans Affairs registry of health care-seeking veterans with and without PTSD. Approximately one quarter (25.1%) of males (n = 198) and 12.7% of females (n = 101) had a sexual dysfunction diagnosis and/or prescription treatment for sexual dysfunction. Both genders were more likely to have a sexual dysfunction diagnosis and/or prescription treatment if they had PTSD compared with those without PTSD (male: 27.3% vs. 21.1%, p = .054; female: 14.9% vs. 9.4%, p = .022). Among the 1,557 subjects analyzed here, males with PTSD had similar levels of sexual activity compared to those without PTSD (71.2% vs. 75.4%, p = .22), whereas females with PTSD were less likely to be sexually active compared to females without PTSD (58.7% vs. 72.1%, p < .001). Participants with PTSD were also less likely to report sex-life satisfaction (male: 27.6% vs. 46.0%, p < .001; female: 23.0% vs. 45.7%, p < .001) compared with those without PTSD. Although PTSD was not associated with sexual dysfunction after adjusting for confounding factors, it was significantly negatively associated with sex-life satisfaction in female veterans with a prevalence ratio of .71, 95% confidence interval [.57, .90].

Long-Term Metal PM2.5 Exposures Decrease Cardiac Acceleration and Deceleration Capacities in Welders.

OBJECTIVE: The aim of the study was to clarify whether long-term metal particulates affect cardiac acceleration capacity (AC), deceleration capacity (DC), or both. METHODS: We calculated chronic exposure index (CEI) for PM2.5 over the work life of 50 boilermakers and obtained their resting AC and DC. Linear regression was used to assess the associations between CEI PM2.5 exposure and each of AC and DC, controlling for age, acute effects of welding exposure, and diurnal variation. RESULTS: Mean (standard deviation) CEI for PM2.5 exposure was 1.6 (2.4) mg/m-work years and ranged from 0.001 to 14.6 mg/m-work years. In our fully adjusted models, a 1 mg/m-work year increase in CEI for PM2.5 was associated with a decrease of 1.03 (95% confidence interval: 0.10, 1.96) ms resting AC, and a decrease of 0.67 (95% confidence interval: -0.14, 1.49) ms resting DC. CONCLUSIONS: Long-term metal particulate exposures decrease cardiac accelerations and decelerations.

Are the Associations of Cardiac Acceleration and Deceleration Capacities With Fine Metal Particulate in Welders Mediated by Inflammation?

OBJECTIVE: The aim of this study was to investigate whether associations of acceleration capacity (AC) and deceleration capacity (DC) with metal-PM2.5 are mediated by inflammation. METHODS: We obtained PM2.5, C-reactive protein, interleukin (IL)-6, 8, and 10, and electrocardiograms to compute AC and DC, from 45 male welders. Mediation analyses were performed using linear mixed models to assess associations between PM2.5 exposure, inflammatory mediator, and AC or DC, controlling for covariates. RESULTS: The proportion of total effect of PM2.5 on AC or DC (indirect effect) mediated through IL-6 on AC was 4% at most. Controlling for IL-6 (direct effect), a 1 mg/m increase of PM2.5 was associated with a decrease of 2.16 (95% confidence interval -0.36 to 4.69) msec in AC and a decrease of 2.51 (95% confidence interval -0.90 to 5.93) msec in DC. CONCLUSION: IL-6 may be mediating the effect of metal particulates on AC.

Effects of Personal Exposure to Ambient Fine Particulate Matter on Acute Change in Nocturnal Heart Rate Variability in Subjects Without Overt Heart Disease.

The immediate effect within minutes to hours of personal exposure to ambient fine particulate matter (PM2.5) on cardiac autonomic function is limited, particularly at night. Our study aimed to assess the lagged association between personal exposure to PM2.5 and nocturnal heart rate variability. Repeated measures panel study among 21 community adults recruited from a local health clinic during the period of March 1, 2004, to August 31, 2004, in Boston, Massachusetts, in the United States. Ambulatory electrocardiogram and continuous monitoring of personal exposure to PM2.5 and were measured for up to 2 consecutive days. We calculated 5-minute time-specific average PM2.5 exposure for each participant. Mixed-effects models were fit for 5-minute SD of normal-to-normal intervals (SDNN) and 5-minute heart rate in relation to 5-minute PM2.5 exposure lagged in 5-minute intervals up to 4 hours. We found an 8.4% decrease in nocturnal SDNN (95% confidence interval [CI] -11.3% to -5.5%) and a 1.9% increase in nighttime heart rate (95% CI 1.1% to 2.7%) for an interquartile range increase in PM2.5 (13.6 µg/m(3)), after adjusting for confounders. Significant decreases in nocturnal SDNN associated with PM2.5 exposure occurred within 2.5 hours. The largest decrease in nocturnal SDNN of -12.8% (95% CI -16.4 to -9.1%) that was associated with PM2.5 exposure was found with a lag of 25 minutes. Rapid changes in nocturnal heart rate variability associated with personal PM2.5 exposure occurred within the previous 2.5 hours, with the largest effects at 25 minutes, suggesting immediate cardiac autonomic effects of fine particulate exposure.

Assessment of Residents' Attitudes and Satisfaction Before and After Implementation of a Smoke-Free Policy in Boston Multiunit Housing.

INTRODUCTION: In 2012, the Boston Housing Authority (BHA) in Massachusetts implemented a smoke-free policy prohibiting smoking within its residences. We sought to characterize BHA resident experiences before and after the smoke-free policy implementation, and compare them to that of nearby residents of the Cambridge Housing Authority, which had no such policy. METHODS: We recruited a convenience sample of nonsmoking residents from the BHA and Cambridge Housing Authority. We measured residents' awareness and support of their local smoking policies before and 9-12 months after the BHA's policy implementation, as well as BHA respondents' attitudes towards the smoke-free policy. We assessed tobacco smoke exposure via saliva cotinine, airborne apartment nicotine, and self-reported number of days smelling smoke in the home. We evaluated predictors of general satisfaction at follow-up using linear regression. RESULTS: At follow-up, 91% of BHA respondents knew that smoking was not allowed in apartments and 82% were supportive of such a policy in their building. BHA residents believed enforcement of the smoke-free policy was low. Fifty-one percent of BHA respondents indicated that other residents "never" or "rarely" followed the new smoke-free rule and 41% of respondents were dissatisfied with policy enforcement. Dissatisfaction with enforcement was the strongest predictor of general housing satisfaction, while objective and self-reported measures of tobacco smoke exposure were not predictive of satisfaction. At follow-up, 24% of BHA participants had complained to someone in charge about policy violations. CONCLUSIONS: Resident support for smoke-free policies is high. However, lack of enforcement of smoke-free policies may cause frustration and resentment among residents, potentially leading to a decrease in housing satisfaction. IMPLICATIONS: Smoke-free housing laws are becoming increasingly prevalent, yet little is known about satisfaction and compliance with such policies post-implementation. We evaluated nonsmoking residents' attitudes about smoke-free rules and their satisfaction with enforcement 1 year after the BHA implemented its comprehensive smoke-free policy. We found that while residents were supportive of the policy, they believed enforcement was low, a perception that was associated with a drop in housing satisfaction. Our findings point to a desire for smoke-free housing among public housing residents, and the importance of establishing systems and guidelines to help landlords monitor and enforce these policies effectively.

Short-term metal particulate exposures decrease cardiac acceleration and deceleration capacities in welders: a repeated-measures panel study.

OBJECTIVE: Acceleration (AC) and deceleration (DC) capacities measure heart rate variability during speeding up and slowing down of the heart, respectively. We investigated associations between AC and DC with occupational short-term metal PM2.5 exposures. METHODS: A panel of 48 male welders had particulate matter less than 2.5 microns in diameter (PM2.5) exposure measurements over 4-6 h repeated over 5 sampling periods between January 2010 and June 2012. We simultaneously obtained continuous recordings of digital ECG using a Holter monitor. We analysed ECG data in the time domain to obtain hourly AC and DC. Linear mixed models were used to assess the associations between hourly PM2.5 exposure and each of hourly AC and DC, controlling for age, smoking status, active smoking, exposure to secondhand smoke, season/time of day when ECG reading was obtained and baseline AC or DC. We also ran lagged exposure response models for each successive hour up to 3 h after onset of exposure. RESULTS: Mean (SD) shift PM2.5 exposure during welding was 0.47 (0.43) mg/m(3). Significant exposure-response associations were found for AC and DC with increased PM2.5 exposure. In our adjusted models without any lag between exposure and response, a 1 mg/m(3) increase of PM2.5 was associated with a decrease of 1.46 (95% CI 1.00 to 1.92) ms in AC and a decrease of 1.00 (95% CI 0.53 to 1.46) ms in DC. The effect of PM2.5 on AC and DC was maximal immediately postexposure and lasted 1 h following exposure. CONCLUSIONS: There are short-term effects of metal particulates on AC and DC.

Changes in Tobacco Smoke Exposure following the Institution of a Smoke-Free Policy in the Boston Housing Authority.

INTRODUCTION: To protect residents from tobacco smoke exposure (TSE), the Boston Housing Authority (BHA) prohibited smoking in BHA-owned apartments beginning in 2012. Our goal was to determine if the smoke-free policy reduced TSE for non-smoking BHA residents. METHODS: We compared TSE before the smoke-free policy (2012) and one year later among BHA residents as well as residents of the neighboring Cambridge Housing Authority (CHA) where no such policy was in place. Participants were a convenience sample of adult non-smoking BHA and CHA residents cohabitating with only non-smokers. Main outcomes were 7-day airborne nicotine in participants' apartments; residents' saliva cotinine; and residents' self-reported TSE. RESULTS: We enrolled 287 confirmed non-smokers (192 BHA, 95 CHA). Seventy-nine percent (229) were assessed at follow-up. At baseline, apartment and resident TSE were high in both housing authorities (detectable airborne nicotine: 46% BHA, 48% CHA; detectable saliva cotinine: 49% BHA, 70% CHA). At follow-up there were significant but similar declines in nicotine in both sites (detectable: -33% BHA, -39% CHA, p = 0.40). Detectable cotinine rose among BHA residents while declining among CHA participants (+17% BHA vs. -13% CHA, p = 0.002). Resident self-reported TSE within and outside of the housing environment decreased similarly for both BHA and CHA residents. CONCLUSIONS: Apartment air nicotine decreased after the introduction of the smoke-free policy, though the decline may not have resulted from the policy. The BHA policy did not result in reduced individual-level TSE. Unmeasured sources of non-residential TSE may have contributed to BHA residents' cotinine levels.

Psychosocial Functioning and Health-Related Quality of Life Associated with Posttraumatic Stress Disorder in Male and Female Iraq and Afghanistan War Veterans: The VALOR Registry.

OBJECTIVES: Iraq and Afghanistan war veterans suffer from high rates of posttraumatic stress disorder (PTSD). Given the growing number of women in the military, there is a critical need to understand the nature and extent of potential gender differences in PTSD-associated psychosocial functioning and health-related quality of life (HRQOL) in Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) veterans, which has not been studied to date. METHODS: We used data from a gender-balanced national patient registry of warzone-deployed OEF/OIF veterans (Project VALOR: Veterans After-Discharge Longitudinal Registry) to determine the impact of gender on PTSD-related psychosocial functioning and HRQOL in 1,530 United States Iraq and Afghanistan war veterans (50% female) with and without PTSD. Overall psychosocial functioning was assessed with the Inventory of Psychosocial Functioning (IPF) and mental and physical HRQOL with the Veterans RAND 12-item Health Survey (VR-12) Mental and Physical Component Summary scores, respectively. Stratified linear regression models estimated gender-specific associations, controlling for demographic, deployment, and postdeployment factors. Interaction models tested for significant effect moderation by gender. RESULTS: In gender-stratified models, PTSD was strongly associated with higher IPF scores (greater functional impairment), with similar associations by gender. PTSD was also associated with lower Mental Component Summary scores (lower mental HRQOL) in both men and women, with no evidence of effect moderation by gender. PTSD was associated with lower Physical Component Summery scores in women but not men in adjusted models; however, interactions were not significant. CONCLUSION: PTSD among warzone-deployed OEF/OIF veterans is associated with significant impairments in both overall psychosocial functioning and HRQOL, with associations that are largely similar by gender. Findings support the need for thorough and continuous assessment of functional impairment and HRQOL during treatment of PTSD for both male and female OEF/OIF veterans.

Racial ethnic differences in type 2 diabetes treatment patterns and glycaemic control in the Boston Area Community Health Survey.

OBJECTIVES: Numerous studies continue to report poorer glycaemic control, and a higher incidence of diabetes-related complications among African-Americans and Hispanic-Americans as compared with non-Hispanic Caucasians with type 2 diabetes. We examined racial/ethnic differences in receipt of hypoglycaemic medications and glycaemic control in a highly insured Massachusetts community sample of individuals with type 2 diabetes. SETTING: Community-based sample from Boston, Massachusetts, USA. PARTICIPANTS: 682 patients with physician-diagnosed diabetes from the third wave of the Boston Area Community Health Survey (2010-2012). The study included approximately equal proportions of African-Americans, Hispanics and Caucasians. METHODS: We examined racial/ethnic disparities in diabetes treatment by comparing proportions of individuals on mutually exclusive diabetes treatment regimens across racial/ethnic subgroups. Using multivariable linear and logistic regression, we also examined associations between race/ethnicity and glycaemic control in the overall population, and within treatment regimens, adjusting for age, gender, income, education, health insurance, health literacy, disease duration, diet and physical activity. RESULTS: Among those treated (82%), the most commonly prescribed antidiabetic regimens were biguanides only (31%), insulin only (23%), and biguanides and insulin (16%). No overall racial/ethnic differences in treatment or glycaemic control (per cent difference for African-Americans: 6.18, 95% CI -1.00 to 13.88; for Hispanic-Americans: 1.01, 95% CI -10.42 to 12.75) were observed. Within regimens, we did not observe poorer glycaemic control for African-Americans prescribed biguanides only, insulin only or biguanides combined with insulin/sulfonylureas. However, African-Americans prescribed miscellaneous regimens had higher risk of poorer glycaemic control (per cent difference=23.37, 95% CI 7.25 to 43.33). There were no associations between glycaemic levels and Hispanic ethnicity overall, or within treatment regimens. CONCLUSIONS: Findings suggest a lack of racial/ethnic disparities in diabetes treatment patterns and glycaemic control in this highly insured Massachusetts study population. Future studies are needed to understand impacts of increasing insurance coverage on racial/ethnic disparities in treatment patterns and related outcomes.

Biogeographic ancestry is associated with higher total body adiposity among African-American females: the Boston Area Community Health Survey.

OBJECTIVES: The prevalence of obesity is disproportionately higher among African-Americans and Hispanics as compared to whites. We investigated the role of biogeographic ancestry (BGA) on adiposity and changes in adiposity in the Boston Area Community Health Survey. METHODS: We evaluated associations between BGA, assessed via Ancestry Informative Markers, and adiposity (body mass index (BMI), percent body fat (PBF), and waist-to-hip ratio (WHR)) and changes in adiposity over 7 years for BMI and WHR and 2.5 years for PBF, per 10% greater proportion of BGA using multivariable linear regression. We also examined effect-modification by demographic and socio-behavioral variables. RESULTS: We observed positive associations between West-African ancestry and cross-sectional BMI (percent difference=0.62%; 95% CI: 0.04%, 1.20%), and PBF (ß=0.35; 95% CI: 0.11, 0.58). We also observed significant effect-modification of the association between West-African ancestry and BMI by gender (p-interaction: <0.002) with a substantially greater association in women. We observed no main associations between Native-American ancestry and adiposity but observed significant effect-modification of the association with BMI by diet (p-interaction: <0.003) with inverse associations among participants with higher Healthy Eating Scores. No associations were observed between BGA and changes in adiposity over time. CONCLUSION: Findings support that West-African ancestry may contribute to high prevalence of total body adiposity among African-Americans, particularly African-American women.

The relationship between occupational metal exposure and arterial compliance.

BACKGROUND: The objective of this study was to evaluate the relationship between cumulative occupational exposure to various metals and arterial compliance in welders. METHODS: The observational follow-up study consisted of 25 subjects. Levels of nickel (Ni), lead, cadmium, manganese, and arsenic from toenails were assessed using mass spectrometry. Arterial compliance as reflected by augmentation index (AIx) was measured using SphygmoCor Px Pulse Wave Analysis System. Linear regression models were used to assess the associations. RESULTS: For every 1 unit increase in log-transformed toenail Ni, there was a statistically significant 5.68 (95% confidence interval, 1.38 to 9.98; P = 0.01) unit increase in AIx. No significant associations were found between AIx and lead, cadmium, manganese, and arsenic. CONCLUSIONS: Cumulative Ni exposure is associated with increased arterial stiffness in welders and may increase risk of adverse cardiovascular outcomes.

Disentangling racial/ethnic and socioeconomic differences in self-reported sleep measures: the Boston Area Community Health Survey.

BACKGROUND: Racial/ethnic differences in sleep are widely reported. However, the extent to which socioeconomic factors account for crude variation in sleep parameters by racial/ethnic groups is not clearly understood. METHODS: We studied 4144 individuals in the Boston Area Community Health Survey (2006-2010), a racially/ethnically balanced population-based cohort of black, Hispanic, and white men and women. Self-reported sleep measures were sleep duration, sleep latency, restless sleep, risk for sleep apnea, and sleep medication use. We assessed changes in the age- and sex-adjusted association between race/ethnicity and sleep measures after additional adjustment for individual socioeconomic factors (income, education, and employment) and lifestyle and behavioral factors. RESULTS: Self-identified non-Hispanic black race/ethnicity was significantly associated with higher odds of short sleep duration (fully adjusted odds ratio [OR], 1.93; 95% confidence interval [CI], 1.41-2.64), longer sleep latency (fully adjusted, 20.9% longer; 95% CI, 4.1-41.9), and lower odds of pharmaceutical sleep aid use (fully adjusted OR: 0.47, 95% CI: 0.34, 0.65) than white race/ethnicity. Education level accounted for the most substantial reduction in estimates of the age- and sex-adjusted association between black race/ethnicity and short sleep duration and sleep latency. Having less than a 4-year college education was associated with approximately 55% lower sleep latency than having postgraduate education. No significant associations were observed comparing Hispanic to white participants. CONCLUSIONS: Significant variation was observed between black and white race/ethnicity in short sleep duration, sleep latency, and sleep aid use. Although considerable variation in sleep by race/ethnicity was explained by education level, additional variation in self-reported sleep by race/ethnicity may be due to other unmeasured socioeconomic, lifestyle, or behavioral factors.

Geographic variations in sleep duration: a multilevel analysis from the Boston Area Community Health (BACH) Survey.

BACKGROUND: Sleep plays an important role in health and varies by social determinants. Little is known, however, about geographic variations in sleep and the role of individual-level and neighbourhood-level factors. METHODS: We used a multilevel modelling approach to quantify neighbourhood variation in self-reported sleep duration (very short <5 h; short 5-6.9 h; normative 7-8.9 h; long ≥9 h) among 3591 participants of the Boston Area Community Health Survey. We determined whether geographic variations persisted with control for individual-level demographic, socioeconomic status (SES) and lifestyle factors. We then determined the role of neighbourhood SES (nSES) in geographic variations. Additional models considered individual health factors. RESULTS: Between neighbourhood differences accounted for a substantial portion of total variability in sleep duration. Neighbourhood variation persisted with control for demographics, SES and lifestyle factors. These characteristics accounted for a portion (6-20%) of between-neighbourhood variance in very short, short and long sleep, while nSES accounted for the majority of the remaining between-neighbourhood variances. Low and medium nSES were associated with very short and short sleep (eg, very short sleep OR=2.08; 95% CI 1.38 to 3.14 for low vs high nSES), but not long sleep. Further inclusion of health factors did not appreciably increase the amount of between-neighbourhood variance explained nor did it alter associations. CONCLUSIONS: Sleep duration varied by neighbourhood in a diverse urban setting in the northeastern USA. Individual-level demographics, SES and lifestyle factors explained some geographic variability, while nSES explained a substantial amount. Mechanisms associated with nSES should be examined in future studies to help understand and reduce geographic variations in sleep.

Traffic-related air pollution and sleep in the Boston Area Community Health Survey.

Little is known about environmental determinants of sleep. We investigated the association between black carbon (BC), a marker of traffic-related air pollution, and sleep measures among participants of the Boston Area Community Health Survey. We also sought to assess the impact of sociodemographic factors, health conditions, and season on associations. Residential 24-h BC was estimated from a validated land-use regression model for 3821 participants and averaged over 1-6 months and 1 year. Sleep measures included questionnaire-assessed sleep duration, sleep latency, and sleep apnea. Linear and logistic regression models controlling for confounders estimated the association between sleep measures and BC. Effect modification was tested with interaction terms. Main effects were not observed between BC and sleep measures. However, in stratified models, males experienced 0.23 h less sleep (95% CI: -0.42, -0.03) and those with low SES 0.25 h less sleep (95% CI: -0.48, -0.01) per IQR increase in annual BC (0.21 µg/m(3)). In blacks, sleep duration increased with annual BC (ß=0.34 per IQR; 95% CI: 0.12, 0.57). Similar findings were observed for short sleep (≤5 h). BC was not associated with sleep apnea or sleep latency, however, long-term exposure may be associated with shorter sleep duration, particularly in men and those with low SES, and longer sleep duration in blacks.