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author:("Chen, hailing")
1.  The association of respiratory symptoms and indoor housing conditions among migrant farmworkers in eastern North Carolina 
Journal of agromedicine  2014;19(4):395-405.
Farm labor housing has been described as among the worst in the nation, oftentimes with poor and unsanitary, indoor living conditions. The objective of this study was to evaluate the association between indoor environmental risk factors and respiratory health among migrant farmworker occupants (N=352) living in employer-provided housing. A cross-sectional sample of adult, Latino male farm laborers were administered a questionnaire to identify the prevalence of major respiratory symptoms. Self-reported and independent observations were made to evaluate environmental respiratory risk factors and indoor housing conditions, including but not limited to, the presence of cockroaches, rodents, pesticides, and visible signs of mold. Spirometry was performed to evaluate lung function using FEV1, FVC and FEV1/FVC ratio. Bivariate analysis was applied to evaluate associations between respiratory symptoms and selected indoor environmental risk factors. Findings for respiratory health included, prevalence of wheeze (11.4%), coughing up phlegm (17.3%), tightness of chest (16.8%) and runny or stuffy nose (34.4%). Respiratory risks identified inside the dwellings included, the use of pesticides or bug sprays for cockroaches (31.5%), rat or mouse poison (19.5%), visible signs of water damage in the bathroom (22.5%) and mold in the sleeping room (11.1%). Spirometry values were normal for most occupants, although statistically significant associations were found between; mold and coughing up phlegm when not having a cold (p=0.0262); presence of mold and asthma (p=0.0084); pesticides used in the home and tightness of chest (p=0.0001) and, use of tobacco and coughing up phlegm (p=0.0131). Although causal inference can be difficult to establish from a cross sectional study, findings from this study represents suggestive evidence that indoor environmental risk factors may be contributory factors for respiratory health problems among this vulnerable population.
PMCID: PMC4185398  PMID: 25275405
Housing; respiratory health; farmworker; environmental health
2.  Muscle Intrusion as a Potential Cause of Carpal Tunnel Syndrome 
Muscle & nerve  2014;50(4):517-522.
To determine if there is an association between flexor digitorum and lumbrical muscle intrusion into the carpal tunnel and carpal tunnel syndrome (CTS).
513 manual laborers (1,026 wrists) were evaluated with ultrasound to determine if those with CTS had more muscle intrusion into the carpal tunnel than those without CTS. 190 of the participants without CTS at baseline (363 wrists) were followed over 1 year to determine if muscle intrusion at baseline predicted the development of CTS.
Participants with CTS had more muscle within the carpal tunnel with the wrist in the neutral (P = 0.026) and flexed positions (P = 0.018) than those without CTS. Baseline muscle intrusion did not predict the development of CTS at 1 year.
Muscle intrusion into the carpal tunnel is associated with CTS, but muscle intrusion alone does not predict the development of CTS over the course of a year.
PMCID: PMC4107208  PMID: 24449488
Carpal tunnel syndrome; incidence; prevalence; ultrasound; EMG
3.  Intensive Weight Loss Intervention in Individuals Ages 65 Years or Older: Results from the Look AHEAD Type 2 Diabetes Trial 
To compare the relative effects of four years of intensive lifestyle intervention on weight, fitness, and cardiovascular disease risk factors among older versus younger individuals
A randomized controlled clinical trial
16 US clinical sites
Individuals with type 2 diabetes: 1,053 aged 65–76 years and 4,092 aged 45–64 years
An intensive behavioral intervention designed to promote and maintain weight loss through caloric restriction and increased physical activity compared to a condition of diabetes support and education.
Standardized assessments of weight, fitness (based on graded exercise testing), and cardiovascular disease risk factors
Across four years, older individuals had greater intervention-related mean weight losses than younger participants, 6.2% versus 5.1% (interaction p=0.006) and comparable relative mean increases in fitness, 0.56 versus 0.53 metabolic equivalents (interaction p=0.72). These benefits were seen consistently across subgroups of older adults formed by many demographic and health factors. Among a panel of age-related health conditions, only self-reported worsening vision was associated with poorer intervention-related weight loss in older individuals. The intensive lifestyle intervention produced mean increases in high density lipoprotein cholesterol (2.03 mg/dl; p<0.001) and decreases in glycated hemoglobin (0.21%; p<0.001) and waist girth (3.52 cc; p<0.001) across 4 years that were at least as large in older compared to younger individuals.
Intensive lifestyle intervention targeting weight loss and increased physical activity is effective in overweight and obese older individuals to produce sustained weight loss and improvements in fitness and cardiovascular risk factors.
PMCID: PMC4123658  PMID: 23668423
Behavioral intervention; Weight loss; Physical activity; Type 2 diabetes mellitus; Cardiovascular disease risk factors
4.  Analysis of Cross-Reactive Neutralizing Antibodies in Human HFMD Serum with an EV71 Pseudovirus-Based Assay 
PLoS ONE  2014;9(6):e100545.
Hand, foot and mouth disease, associated with enterovirus 71 (EV71) infections, has recently become an important public health issue throughout the world. Serum neutralizing antibodies are major indicators of EV71 infection and protective immunity. However, the potential for cross-reactivity of neutralizing antibodies for different EV71 genotypes and subgenotypes is unclear. Here we measured the cross-reactive neutralizing antibody titers against EV71 of different genotypes or subgenotypes in sera collected from EV71-infected children and vaccine-inoculated children in a phase III clinical trial ( Identifier: NCT01636245) using a new pseudovirus-based neutralization assay. Antibodies induced by EV71-C4a were cross-reactive for different EV71 genotypes, demonstrating that C4a is a good candidate strain for an EV71 vaccine. Our study also demonstrated that this new assay is practical for analyses of clinical samples from epidemiological and vaccine studies.
PMCID: PMC4070950  PMID: 24964084
5.  Reproducibility of Arterial Elasticity Parameters Derived from Radial Artery Diastolic Pulse Contour Analysis: The Multi-Ethnic Study of Atherosclerosis 
Blood pressure monitoring  2010;15(6):312-315.
The aim of this report was to describe the reproducibility of arterial elasticity parameters derived from radial artery diastolic pulse contour analysis.
Two measurements were performed on the same day by the same technician with the HDI/Pulsewave CR-2000 (Eagan, MN) on each of a subset of participants selected at random from the Multi-Ethnic Study of Atherosclerosis (MESA). Large and small artery elasticity (C1 and C2), C1 and C2 each multiplied by systemic vascular resistance (C1xR and C2xR, which are functions of the radial artery pulse waveform only), and systolic and diastolic blood pressure (SBP and DBP) were evaluated.
Two measurements were performed on each of 131 participants. The mean difference ± standard deviation of the difference was −0.13 ± 3.5 mmHgx10 for C1, −0.03 ± 1.5 mmHg ×100 for C2, 0.10 ± 4.6 seconds ×10 for C1xR, 0.05 ± 1.8 seconds ×100 for C2xR, 2.8 ± 8.2 mmHg for SBP, and 1.5 ± 5.0 mmHg for DBP. The between-measure correlation was 0.74 for C1, 0.84 for C2, 0.58 for C1xR, 0.74 for C2xR, 0.90 for SBP, and 0.86 for DBP.
The reproducibility of arterial elasticity measurements is less than that of systolic and diastolic blood pressure. Multiple measurements of arterial elasticity from a participant are recommended.
PMCID: PMC4028156  PMID: 20890179
arterial elasticity; arterial compliance; reproducibility; blood pressure measurement
6.  Pesticides Present in Migrant Farmworker Housing in North Carolina 
Migrant farmworkers are exposed to pesticides at work. Housing provided to migrant farmworkers may also expose them to pesticides, increasing their health risks. This analysis (1) describes the presence of organophosphorous (OP) and pyrethroid pesticides in North Carolina migrant farmworker houses, and (2) delineates associations of farmworker camp characteristics with pesticide detection and concentration.
In 2010, 186 migrant farmworkers camps in NC were recruited (participation rate of 82.3%); pesticide wipe samples for 176 houses were analyzed. Tobacco is the predominant hand-harvested crop in this region. Two farmworkers per camp completed interviews; a third assisted with a housing inspection. Gas chromatography–mass spectrometry was used to detect OP and pyrethroid pesticides. Covariates of pesticide detection and concentration were determined with ANOVA and Tobit regression.
OPs were found in 166 of 176 houses (average of 2.4/house); pyrethroids were found in 171 houses (average of 4.3/house). The number of different OPs detected in each camp and concentrations of these OPs were not associated with camp and housing characteristics. The number of different pyrethroids detected in each camp and concentrations of these pyrethroids were associated with camps having residents with H2-A visas, a posted North Carolina Department of Labor Certificate of Inspection, no barracks, fewer residents, no bedroom weather protection or floor violations, and no roaches.
Farmworkers are exposed to pesticides where they live. Policy on removing pesticides from farmworker houses is needed. Reducing pesticides in farmworker houses will reduce one health risk confronted by this vulnerable population.
PMCID: PMC4028316  PMID: 24038176
health disparities; vulnerable population; occupational exposures; environmental exposures; agricultural workers; immigrant workers
7.  Minor Isolated Q Waves and Cardiovascular Events in the MESA Study 
The American journal of medicine  2013;126(5):450.e9-450.e16.
The significance of minor isolated Q waves in the resting electrocardiograms (ECGs) of apparently healthy individuals is unknown.
To examine the association between minor isolated Q waves and incident cardiovascular disease events in the Multi-Ethnic Study of Atherosclerosis (MESA).
This analysis included 6551 MESA participants (38% white, 28% black, 22% Hispanic, 12% Chinese) who were free of cardiovascular disease at enrollment. Cox proportional hazards models were used to examine the association between minor isolated Q waves defined by the Minnesota ECG Classification with adjudicated incident cardiovascular events.
During up to 7.8 years of follow-up, 423 events occurred, with a rate of 10.7 events per 1000 person-years. A significant interaction between minor isolated Q waves and race/ethnicity was observed (P = .030). In models stratified by race/ethnicity and adjusted for demographics, socioeconomic status, common cardiovascular risk factors, and other ECG abnormalities, presence of isolated minor Q waves was significantly associated with incident cardiovascular events in Hispanics (hazard ratio [HR] 2.62; 95% confidence interval [CI], 1.42-4.82), but not in whites (HR 0.65; 95% CI, 0.32-1.33) or blacks (HR 1.46; 95% CI, 0.74-2.89). Despite the statistically significant association in the Chinese population, the small number of events precluded solid conclusions in this race/ethnicity.
The prognostic significance of minor isolated Q waves varies across races/ethnicities; they carry a high risk for future cardiovascular events in apparently healthy Hispanics, but not in whites or blacks.
PMCID: PMC3741651  PMID: 23582938
Electrocardiography; MESA; Minor isolated Q waves; Race/ethnicity
8.  Association of Lipids With Incident Heart Failure Among Adults With and Without Diabetes Mellitus 
Circulation. Heart failure  2013;6(3):371-378.
Dyslipidemia is a known risk factor for coronary disease, but its role in heart failure (HF) development is less well-defined.
Methods and Results
We included 5688 participants, aged 45 to 84 years, without clinical cardiovascular disease, and not receiving lipid-lowering medications at baseline, from the Multiethnic Study of Atherosclerosis. Cox-proportional hazards models were used to evaluate associations of triglyceride, total cholesterol/high-density lipoprotein–cholesterol (HDL-C) ratio, HDL-C, and non HDL-C with incident HF. We investigated for effect-modification by diabetes mellitus status and sex. During a median follow-up of 8.5 years, there were 152 incident HF cases. There were no interactions by sex. We observed significant interactions between triglyceride and diabetes mellitus (Pinteraction<0.05). We stratified our analyses by diabetes mellitus status. In participants with diabetes, the hazard ratios were 2.03 (0.97–4.27) and 1.68 (1.18–2.38) for high triglyceride and log of triglyceride, respectively, after adjusting for confounders, comorbidities, and diabetes mellitus severity/treatment. The association of high triglyceride with incident HF was attenuated by interim myocardial infarction. The hazard ratios were greatest in participants with diabetes who also had high triglyceride, low HDL-C, or high total cholesterol/HDL-C ratio (3.59 [2.03–6.33], 3.62 [2.06–6.36], and 3.54 [1.87–6.70], respectively). Lipid measures were not associated with incident HF in individuals without diabetes.
The risk of incident HF is greater in individuals with diabetes mellitus who also have high triglyceride, low HDL-C, or high total cholesterol/HDL-C ratio. The association of high triglyceride with incident HF is partly mediated by myocardial infarction.
PMCID: PMC3991930  PMID: 23529112
diabetes mellitus; heart failure; lipids
9.  Genetic and pharmacologic inhibition of EPHA2 promotes apoptosis in NSCLC 
The Journal of Clinical Investigation  2014;124(5):2037-2049.
Genome-wide analyses determined previously that the receptor tyrosine kinase (RTK) EPHA2 is commonly overexpressed in non–small cell lung cancers (NSCLCs). EPHA2 overexpression is associated with poor clinical outcomes; therefore, EPHA2 may represent a promising therapeutic target for patients with NSCLC. In support of this hypothesis, here we have shown that targeted disruption of EphA2 in a murine model of aggressive Kras-mutant NSCLC impairs tumor growth. Knockdown of EPHA2 in human NSCLC cell lines reduced cell growth and viability, confirming the epithelial cell autonomous requirements for EPHA2 in NSCLCs. Targeting EPHA2 in NSCLCs decreased S6K1-mediated phosphorylation of cell death agonist BAD and induced apoptosis. Induction of EPHA2 knockdown within established NSCLC tumors in a subcutaneous murine model reduced tumor volume and induced tumor cell death. Furthermore, an ATP-competitive EPHA2 RTK inhibitor, ALW-II-41-27, reduced the number of viable NSCLC cells in a time-dependent and dose-dependent manner in vitro and induced tumor regression in human NSCLC xenografts in vivo. Collectively, these data demonstrate a role for EPHA2 in the maintenance and progression of NSCLCs and provide evidence that ALW-II-41-27 effectively inhibits EPHA2-mediated tumor growth in preclinical models of NSCLC.
PMCID: PMC4001547  PMID: 24713656
10.  Human Adipose-Derived Mesenchymal Stem Cells Are Resistant to HBV Infection during Differentiation into Hepatocytes in Vitro 
The therapeutic methods for chronic hepatitis B are limited. The shortage of organ donors and hepatitis B virus (HBV) reinfection obstruct the clinical application of orthotopic liver transplantation (OLT). In the present study, adipose-derived mesenchymal stem cells (AD-MSCs) and bone marrow-derived mesenchymal stem cells (BM-MSCs) were isolated from chronic hepatitis B patients and characterized for morphology, growth potency, surface phenotype and the differentiation potential. The results showed that both MSCs had adipogenic, osteogenic and neuron differentiation potential, and nearly all MSCs expressed CD105, CD44 and CD29. Compared with AD-MSCs, BM-MSCs of chronic hepatitis B patients proliferated defectively. In addition, the ability of AD-MSCs to differentiate into hepatocyte was evaluated and the susceptibility to HBV infection were assessed. AD-MSCs could differentiate into functional hepatocyte-like cells. These cells express the hepatic-specific markers and have glycogen production and albumin secretion function. AD-MSCs and hepatic differentiation AD-MSCs were not susceptible to infection by HBV in vitro. Compared with BM-MSCs, AD-MSCs may be alternative stem cells for chronic hepatitis B patients.
PMCID: PMC4013618  PMID: 24727377
hepatitis B; mesenchymal stem cell; adipose tissue; hepatocyte-like cell; glycogen; albumin
11.  Effects of Bazedoxifene Alone and with Conjugated Equine Estrogens on Coronary and Peripheral Artery Atherosclerosis of Postmenopausal Monkeys 
Menopause (New York, N.Y.)  2013;20(3):274-281.
The objective was to evaluate the effects of bazedoxifene acetate (BZA), a new selective estrogen receptor modulator, on coronary and peripheral artery atherosclerosis and to determine if it would antagonize the atheroprotective effects of conjugated equine estrogens (CEE) in a monkey model.
Ninety-eight surgically postmenopausal monkeys (Macaca fascicularis) were fed a moderately atherogenic diet and then randomized to receive no treatment, or women’s equivalent doses of BZA (20 mg/day), CEE (0.45 mg/day) or BZA+CEE. The experiment period was for 20 months (approximately equivalent to 5 years of patient experience) during which interim measures were made of cardiovascular risk factors. At the end of the experimental period, the extent and severity of coronary and iliac artery atherosclerosis was quantified.
Body weight, adiposity, fasting glucose concentrations and plasma lipid profiles were not different among treatment conditions. BZA had no adverse effects on coronary artery nor common iliac artery atherosclerosis extent or severity when compared to no-treatment. CEE, administered soon after inducing menopause, had a robust atheroprotective effect on both iliac and coronary artery extent and severity. The addition of BZA to the CEE treatment antagonized the atheroprotective effect of the CEE.
In this nonhuman primate trial, treatment with BZA alone, CEE alone and BZA and CEE in combination did not have significant effects on plasma lipid profiles. CEE markedly inhibited the progression and complication of both coronary and iliac artery atherosclerosis. BZA had no adverse effects on atherosclerosis but attenuated the atheroprotective effects of CEE.
PMCID: PMC3578175  PMID: 23435024
Coronary atherosclerosis; menopause; estrogens; SERMS; bazedoxifene
12.  A Bayesian Multiple Imputation Method for Handling Longitudinal Pesticide Data with Values below the Limit of Detection 
Environmetrics  2012;24(2):132-142.
Environmental and biomedical research often produces data below the limit of detection (LOD), or left-censored data. Imputing explicit values for values < LOD in a multivariate setting, such as with longitudinal data, is difficult using a likelihood-based approach. A Bayesian multiple imputation (MI) method is introduced to handle left-censored multivariate data. A Gibbs sampler, which uses an iterative process, is employed to simulate the target multivariate distribution within a Bayesian framework. Following convergence, multiple plausible data sets are generated for analysis by standard statistical methods outside of a Bayesian framework. With explicit imputed values available variables can be analyzed as outcomes or predictors. We illustrate a practical application using longitudinal data from the Community Participatory Approach to Measuring Farmworker Pesticide Exposure (PACE3) study to evaluate the association between urinary acephate concentrations (indicating pesticide exposure) and self-reported potential pesticide poisoning symptoms. Additionally, a simulation study is used to evaluate the sampling property of the estimators for distributional parameters as well as regression coefficients estimated with the generalized estimating equation (GEE) approach. Results demonstrated that the Bayesian MI estimates performed well in most settings, and we recommend the use of this valid and feasible approach to analyze multivariate data with values < LOD.
PMCID: PMC3596170  PMID: 23504271
Bayesian; Gibbs sampler; Left-censoring; Limit of detection; Longitudinal data; Multiple imputation; Multivariate; Non-detections
13.  The Relationship between Measures of Obesity and Incident Heart Failure: The Multi-Ethnic Study of Atherosclerosis 
Obesity (Silver Spring, Md.)  2013;21(9):1915-1922.
To evaluate the strength of association of body mass index (BMI) and waist circumference (WC) with incident heart failure (HF), exploring our associations by ethnicity and age.
Design and Methods
We included 6,809 participants, aged 45–84 years, without clinical cardiovascular disease (2000–2002), from the Multi-Ethnic Study of Atherosclerosis. Cox-Proportional hazards models were used to examine associations of BMI and WC with incident HF. The predictive abilities of BMI and WC were compared using receiver operating characteristic curves.
Over a median follow-up of 7.6 years, there were 176 cases. BMI and WC were associated with incident HF in men [1.33 (1.10–1.61) and 1.38 (1.18–1.62) respectively] and women [1.70 (1.33–2.17) and 1.64 (1.29–2.08) respectively]. These associations became non-significant after adjusting for obesity-related conditions (hypertension, dysglycemia, hypercholesterolemia, left ventricular hypertrophy, kidney disease and inflammation). The associations of BMI and WC did not vary significantly by ethnicity or age-group, but were inverse in Hispanic men. The area under the curve for BMI and WC was 0.749 and 0.750, respectively, in men and 0.782 and 0.777, respectively, in women.
The association between obesity and incident HF is largely mediated by obesity-related conditions. BMI and WC have similar predictive abilities for incident HF.
PMCID: PMC3664654  PMID: 23441088
Obesity; heart failure; body mass index and waist circumference
14.  OsGA2ox5, a Gibberellin Metabolism Enzyme, Is Involved in Plant Growth, the Root Gravity Response and Salt Stress 
PLoS ONE  2014;9(1):e87110.
Gibberellin (GA) 2-oxidases play an important role in the GA catabolic pathway through 2β-hydroxylation. There are two classes of GA2oxs, i.e., a larger class of C19-GA2oxs and a smaller class of C20-GA2oxs. In this study, the gene encoding a GA 2-oxidase of rice, Oryza sativa GA 2-oxidase 5 (OsGA2ox5), was cloned and characterized. BLASTP analysis showed that OsGA2ox5 belongs to the C20-GA2oxs subfamily, a subfamily of GA2oxs acting on C20-GAs (GA12, GA53). Subcellular localization of OsGA2ox5-YFP in transiently transformed onion epidermal cells revealed the presence of this protein in both of the nucleus and cytoplasm. Real-time PCR analysis, along with GUS staining, revealed that OsGA2ox5 is expressed in the roots, culms, leaves, sheaths and panicles of rice. Rice plants overexpressing OsGA2ox5 exhibited dominant dwarf and GA-deficient phenotypes, with shorter stems and later development of reproductive organs than the wild type. The dwarfism phenotype was partially rescued by the application of exogenous GA3 at a concentration of 10 µM. Ectopic expression of OsGA2ox5 cDNA in Arabidopsis resulted in a similar phenotype. Real-time PCR assays revealed that both GA synthesis-related genes and GA signaling genes were expressed at higher levels in transgenic rice plants than in wild-type rice; OsGA3ox1, which encodes a key enzyme in the last step of the bioactive GAs synthesis pathway, was highly expressed in transgenic rice. The roots of OsGA2ox5-ox plants exhibited increased starch granule accumulation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Furthermore, rice and Arabidopsis plants overexpressing OsGA2ox5 were more resistant to high-salinity stress than wild-type plants. These results suggest that OsGA2ox5 plays important roles in GAs homeostasis, development, gravity responses and stress tolerance in rice.
PMCID: PMC3903634  PMID: 24475234
Muscle & nerve  2013;48(1):10.1002/mus.23735.
Manual laborers are at increased risk for carpal tunnel syndrome (CTS), and a combination of history, physical examination, and nerve conduction studies is often used to screen for CTS in this population. Neuromuscular ultrasound may be a better screening tool, because it is painless. In this study we compare the accuracy of nerve conduction studies and ultrasound for CTS screening.
Five hundred thirteen manual laborers were screened prospectively for CTS using nerve conduction studies and neuromuscular ultrasound, and the accuracy of the 2 techniques was compared using the Katz hand diagram as the diagnostic standard.
The ROC curves for the 2 techniques were not significantly different (P = 0.542), indicating that the approaches had similar diagnostic accuracy.
Neuromuscular ultrasound is a painless technique that has diagnostic accuracy similar to nerve conduction studies and can be used to screen large populations at risk for CTS.
PMCID: PMC3878605  PMID: 23649357
accuracy; carpal tunnel syndrome; clinical neurophysiology; screening test; ultrasound
16.  Premenopausal Antimullerian Hormone Concentration is Associated with Subsequent Atherosclerosis 
Menopause (New York, N.Y.)  2012;19(12):1353-1359.
To determine if premenopausal ovarian reserve is associated with susceptibility for atherosclerosis.
Female cynomologus macaques (n = 66, women’s equivalent age = 45 yrs) consumed an atherogenic diet for ~5 months prior to the measurement of a marker of ovarian reserve (antimüllerian hormone, AMH), plasma lipids, follicular phase estradiol (E2) and body weight (BW). Monkeys were then ovariectomized (OVX, n =17) remained premenopausal (PRE, n=20) or induced to have reduce ovarian reserve (ROR, n=29). After 26 additional months on the diet, atherosclerosis measurements and risk variables were reassessed.
No differences in baseline AMH, plasma lipids, BW, E2 or post-diet lipids and BW, were observed among the groups subsequently assigned to OVX, PRE or ROR conditions. Post-diet measurements of atherosclerosis extent did not differ among the groups. However, analysis of plaque size by tertile of baseline AMH revealed that plaques were largest in monkeys that began the experiment with the lowest baseline AMH, followed by those in the middle and high tertiles (plaque extent mm2: Low AMH = 0.76 ± 0.12, Mid AMH = 0.46 ± 0.1, High AMH = 0.34 ± 0.08, p=0.02). Baseline AMH and plaque size were also correlated negatively (r = −0.31, p = 0.01). Plasma lipids were also correlated significantly with plaque extent (all p’s <0.01), but not with AMH.
We report for the first time an inverse relationship between a marker of ovarian reserve (AMH) and subsequent atherosclerosis risk.
PMCID: PMC3509243  PMID: 22929037
Atherosclerosis; antimüllerian hormone; ovariectomy; ovarian reserve; cynomologus; nonhuman primate
17.  Prevalence of bifid median nerves and persistent median arteries and their association with carpal tunnel syndrome in a sample of latino poultry processors and other manual workers 
Muscle & nerve  2013;48(4):10.1002/mus.23797.
The prevalence of bifid median nerves and persistent median arteries, their co-occurrence, and their relationship to carpal tunnel syndrome (CTS) are only understood partially.
We screened 1026 wrists of 513 Latino manual laborers in North Carolina for bifid median nerves and persistent median arteries using electrodiagnosis and ultrasound.
A total of 8.6% of wrists had a bifid median nerve, and 3.7% of wrists had a persistent median artery independent of subgroup ethnicity, age, gender, or type of work. An association with definite carpal tunnel syndrome was not found. The presence of either anatomic variant was associated with a high likelihood of co-occurrence of another variant in the same or the contralateral wrist.
The occurrence of median anatomic variants can be determined in field studies using ultrasound. Persistent median arteries and bifid median nerves tend to co-occur but do not put manual laborers at additional risk of developing CTS.
PMCID: PMC3836559  PMID: 24037717
entrapment neuropathy; epidemiology; neuromuscular ultrasound; occupational health; poultry workers
18.  Microarray Analyses and Comparisons of Upper or Lower Flanks of Rice Shoot Base Preceding Gravitropic Bending 
PLoS ONE  2013;8(9):e74646.
Gravitropism is a complex process involving a series of physiological pathways. Despite ongoing research, gravitropism sensing and response mechanisms are not well understood. To identify the key transcripts and corresponding pathways in gravitropism, a whole-genome microarray approach was used to analyze transcript abundance in the shoot base of rice (Oryza sativa sp. japonica) at 0.5 h and 6 h after gravistimulation by horizontal reorientation. Between upper and lower flanks of the shoot base, 167 transcripts at 0.5 h and 1202 transcripts at 6 h were discovered to be significantly different in abundance by 2-fold. Among these transcripts, 48 were found to be changed both at 0.5 h and 6 h, while 119 transcripts were only changed at 0.5 h and 1154 transcripts were changed at 6 h in association with gravitropism. MapMan and PageMan analyses were used to identify transcripts significantly changed in abundance. The asymmetric regulation of transcripts related to phytohormones, signaling, RNA transcription, metabolism and cell wall-related categories between upper and lower flanks were demonstrated. Potential roles of the identified transcripts in gravitropism are discussed. Our results suggest that the induction of asymmetrical transcription, likely as a consequence of gravitropic reorientation, precedes gravitropic bending in the rice shoot base.
PMCID: PMC3764065  PMID: 24040303
19.  Value of Recruitment Strategies Used in a Primary Care Practice-based Trial 
Contemporary clinical trials  2006;28(3):258-267.
“Physicians-recruiting-physicians” is the preferred recruitment approach for practice-based research. However, yields are variable; and the approach can be costly and lead to biased, unrepresentative samples. We sought to explore the potential efficiency of alternative methods.
We conducted a retrospective analysis of the yield and cost of 10 recruitment strategies used to recruit primary care practices to a randomized trial to improve cardiovascular disease risk factor management. We measured response and recruitment yields and the resources used to estimate the value of each strategy. Providers at recruited practices were surveyed about motivation for participation.
Response to 6 opt-in marketing strategies was 0.40% (53/13290), ranging from 0% to 2.86% by strategy; 33.96% (18/53) of responders were recruited to the study. Of those recruited from opt-out strategies, 8.68% joined the study, ranging from 5.35% to 41.67% per strategy. A strategy that combined both opt-in and opt-out approaches resulted in a 51.14% (90/176) response and a 10.80% (19/90) recruitment rate. Cost of recruitment was $613 per recruited practice. Recruitment approaches based on in-person meetings (41.67%), previous relationships (33.33%), and borrowing an Area Health Education Center’s established networks (10.80%), yielded the most recruited practices per effort and were most cost efficient. Individual providers who chose to participate were motivated by interest in improving their clinical practice (80.5%); contributing to CVD primary prevention (54.4%); and invigorating their practice with new ideas (42.1%).
This analysis provides suggestions for future recruitment efforts and research. Translational studies with limited funds could consider multi-modal recruitment approaches including in-person presentations to practice groups and exploitation of previous relationships, which require the providers to opt-out, and interactive opt-in approaches which rely on borrowed networks. These approaches can be supplemented with non-relationship-based opt-out strategies such as cold calls strategically targeted to underrepresented provider groups.
PMCID: PMC3760001  PMID: 17030154
20.  Stress and Cognitive Function in Latino Farmworkers 
Job stress has been associated with cognitive function, but the relationship is often overlooked when considering occupational health and safety issues of farmworkers. This study examined the relationship between stress and change in stress with change in cognitive function in a representative sample of 123 Latino farmworkers. METHODS: A prospective study design was used in which stress and cognitive function data were collected at baseline and at 3-month follow-up. Linear regression models were used for analyses. Potential confounders included baseline gender, age, education, number of years worked in U.S. agriculture, ever smoking status, self-rated health, and depressive symptoms.
Baseline stress was significantly correlated with baseline cognitive function (r = −.27; p <.001). Adjusting for confounders, increased baseline stress was associated with greater decline in cognitive function (p = .024). Short-term changes in stress were not associated with cognitive change in this cohort.
Stress at work is an important risk factor for poor cognitive function. This analysis suggests several implications for the provision of health care and for the organization of work for farmworkers.
PMCID: PMC3387348  PMID: 22431234
stress; cognitive function; occupational health; farmworkers
21.  Heat Index in Migrant Farmworker Housing: Implications for Rest and Recovery from Work-Related Heat Stress 
American journal of public health  2013;103(8):e24-e26.
Although the health risk to farmworkers of working in hot conditions is recognized, potential for excessive heat exposure in housing affecting rest and recovery has been ignored. We assessed heat index (HI) in common and sleeping rooms in 170 North Carolina farmworker camps across a summer and examined associations with time of summer and air conditioning use. Dangerous HIs were recorded in most rooms, regardless of time or air conditioning. Policies to reduce HI in farmworker housing should be developed.
PMCID: PMC3723406  PMID: 23763392
22.  Cooking and Eating Facilities in Migrant Farmworker Housing in North Carolina 
American journal of public health  2013;103(3):e78-e84.
Preparing and consuming nutritionally adequate and safe food is critical to the work capacity of migrant farmworkers. This paper: (1) describes observed cooking and eating facilities in migrant farmworker camps, (2) compares observed conditions with existing farmworker housing regulations, and (3) examines associations of violations with camp characteristics.
Data were collected in 182 farmworker camps in eastern NC during the 2010 agricultural season. Observations were compared with 15 kitchen-related housing regulations specified by federal and state housing standards.
Violations of 8 regulations were observed in at least 10% of camps: improper refrigerator temperature (65.5%), cockroach infestation (45.9%), contaminated water (34.4%), rodent infestation (28.9%), improper flooring (25.8%), unsanitary conditions (21.2%), improper fire extinguisher (19.9%), and holes/leaks in walls (12.1%). Logistic regression showed that violations were related to the time of the agricultural season, housing type, number of dwellings and residents, and presence of workers with H-2A visas.
Cooking and eating facilities for migrant farmworkers fail to comply with regulations in a substantial number of camps. Greater enforcement of regulations, particularly post-occupancy during the agricultural season, is needed to protect farmworkers.
PMCID: PMC3673492  PMID: 23327274
23.  The Quality of Drinking Water in North Carolina Farmworker Camps 
American journal of public health  2012;102(10):e49-e54.
To assess water quality in migrant farmworker camps in North Carolina (NC), and determine associations of water quality with migrant farmworker housing characteristics.
Data were collected in 181 farmworker camps in eastern NC during the 2010 agricultural season. Water samples were tested using the Total Coliform Rule (TCR) and housing characteristics were assessed using NC Department of Labor (NCDOL) standards.
A total of 61 (34%) of 181 camps failed the TCR. Total coliform bacteria were found in all 61 camps, with E. coli also being detected in 2. Water quality was not associated with farmworker housing characteristics or with access to registered public water supplies. Multiple official violations of water quality standards had been reported for the registered public water supplies.
Water supplied to farmworker camps often does not comply with current standards and poses a great risk to the physical health of farmworkers and surrounding communities. Expansion of water monitoring to more camps and changes to the regulations such as testing during occupancy and stronger enforcement are needed to secure water safety.
PMCID: PMC3490648  PMID: 22897558
Safety, security, hygiene, and privacy in migrant farmworker housing have not previously been documented, yet these attributes are important for farmworker quality of life and dignity. This analysis describes the safety, security, hygiene, and privacy of migrant farmworker housing and delineates camp characteristics that are associated with these attributes, using data collected in 183 eastern North Carolina migrant farmworker camps in 2010. Migrant farmworker housing is deficient. For example, 73.8 percent of housing had structural damage and 52.7 percent had indoor temperatures that were not safe. Farmworkers in 83.5 percent of the housing reported that they did not feel they or their possessions were secure. Bathing or toileting privacy was absent in 46.2 percent of the housing. Camps with residents having H-2A visas or North Carolina Department of Labor certificates of inspection posted had better safety, security, and hygiene. Regulations addressing the quality of migrant farmworker housing are needed.
PMCID: PMC3710588  PMID: 22776578
migrant farmworker; housing quality; occupational justice
25.  Migrant Farmworker Housing Regulation Violations in North Carolina 
The quality of housing provided to migrant farmworkers is often criticized, but few studies have investigated these housing conditions. This analysis examines housing regulation violations experienced by migrant farmworkers in North Carolina, and the associations of camp characteristics with the presence of housing violations.
Data were collected in183 eastern North Carolina migrant farmworker camps in 2010. Housing regulation violations for the domains of camp, sleeping room, bathroom, kitchen, laundry room, and general housing, as well as total violations were assessed using North Carolina Department of Labor standards.
Violations of housing regulations were common, ranging from 4 to 22 per camp. Housing regulation violations were common in all domains; the mean number of camp violations was 1.6, of sleeping room violations was 3.8, of bathroom violations was 4.5, of kitchen violations was 2.3, of laundry room violations was 1.2, and of general housing violations was 3.1. The mean number of total housing violations was 11.4. Several camp characteristics were consistently associated with the number of violations; camps with workers having H-2A visas, with North Carolina Department of Labor Certificates of Inspection posted, and assessed early in the season had fewer violations.
These results argue for regulatory changes to improve the quality of housing provided to migrant farmworkers, including stronger regulations and the more vigorous enforcement of existing regulations.
PMCID: PMC3708262  PMID: 22237961
Migrant farmworker; housing conditions; substandard housing; housing standards; enforcement

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