Richard Kwok

Dr. Richard Kwok

National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC 27709, USA
orcid

Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 July 2011 in American Journal of Epidemiology
Verified
Journal Article
Open access
PDF file
CHCarol M. Hamilton
Carol M. Hamilton
LSLisa C. Strader
Lisa C. Strader
JPJoseph G. Pratt
Joseph G. Pratt
DMDeborah Maiese
Deborah Maiese
THTabitha Hendershot
Tabitha Hendershot
JHJonathan Haines
Jonathan Haines
The potential for genome-wide association studies to relate phenotypes to specific genetic variation is greatly increased when data can be combined or compared across multiple studies. To facilitate replication and validation across studies, RTI International (Research Triangle Park, North Carolina) and the National Human Genome Research Institute (Bethesda, Maryland) are collaborating on the consensus measures for Phenotypes and eXposures (PhenX) project. The goal of PhenX is to identify 15 high-priority, well-established, and broadly applicable measures for each of 21 research domains. PhenX measures are selected by working groups of domain experts using a consensus process that includes input from the scientific community. The selected measures are then made freely available to the scientific community via the PhenX Toolkit. Thus, the PhenX Toolkit provides the research community with a core set of high-quality, well-established, low-burden measures intended for use in large-scale genomic studies. PhenX measures will have the most impact when included at the experimental design stage. The PhenX Toolkit also includes links to standards and resources in an effort to facilitate data harmonization to legacy data. Broad acceptance and use of PhenX measures will promote cross-study comparisons to increase statistical power for identifying and replicating variants associated with complex diseases and with gene-gene and gene-environment interactions.

1 April 2017 in Environmental Health Perspectives
Verified
Journal Article
Open access
Richard KwokRichard Kwok
Richard Kwok
LELawrence S. Engel
Lawrence S. Engel
AMAubrey K. Miller
Aubrey K. Miller
ABAaron Blair
Aaron Blair
MCMatthew D. Curry
Matthew D. Curry
DSDale P Sandler
Dale P Sandler
A peer-reviewed open access journal published by the National Institute of Environmental Health Sciences

1 August 2016 in Environmental Health Perspectives
Verified
Journal Article
Open access
YCYuxia Cui
Yuxia Cui
DBDavid M. Balshaw
David M. Balshaw
Richard KwokRichard Kwok
Richard Kwok
CTClaudia L. Thompson
Claudia L. Thompson
GCGwen W. Collman
Gwen W. Collman
LBLinda S. Birnbaum
Linda S. Birnbaum
Summary: Environmental exposures are ubiquitous and play a fundamental role in the development of complex human diseases. The exposome, which is defined as the totality of environmental exposures over the life course, allows for systematic evaluation of the relationship between exposures and associated biological consequences, and represents a powerful approach for discovery in environmental health research. However, implementing the exposome concept is challenged by the ability to accurately assess multiple exposures and the ability to integrate information across the exposure–disease continuum. On 14–15 January 2015, the National Institute of Environmental Health Sciences (NIEHS) held the Exposome Workshop where a group of international and U.S. scientists from different disciplines gathered to review the state of the science in research areas related to the exposome and to provide recommendations for incorporating the exposome concept into each research area. To move the field forward, the NIEHS is establishing a Children’s Health Exposure Analysis Resource (CHEAR) to provide infrastructure support for access to laboratory and statistical analyses to children’s health studies. It is recognized that incorporating the exposome concept into exposure and environmental health research will be a long journey and will require significant collaborative efforts from different scientific disciplines, nations, and stakeholders.

20 March 2017 in Annual Review of Public Health
Verified
Journal Article
Open access
JSJeanette Stingone
Jeanette Stingone
GLGermaine M. Buck Louis
Germaine M. Buck Louis
Shoji NakayamaShoji Nakayama
Shoji Nakayama
RVRoel Vermeulen
Roel Vermeulen
Richard KwokRichard Kwok
Richard Kwok
STSusan L. Teitelbaum
Susan L. Teitelbaum
Investigating a single environmental exposure in isolation does not reflect the actual human exposure circumstance nor does it capture the multifactorial etiology of health and disease. The exposome, defined as the totality of environmental exposures from conception onward, may advance our understanding of environmental contributors to disease by more fully assessing the multitude of human exposures across the life course. Implementation into studies of human health has been limited, in part owing to theoretical and practical challenges including a lack of infrastructure to support comprehensive exposure assessment, difficulty in differentiating physiologic variation from environmentally induced changes, and the need for study designs and analytic methods that accommodate specific aspects of the exposome, such as high-dimensional exposure data and multiple windows of susceptibility. Recommendations for greater data sharing and coordination, methods development, and acknowledgment and minimization of multiple types of measurement error are offered to encourage researchers to embark on exposome research to promote the environmental health and well-being of all populations.

1 May 2007 in Environmental Health Perspectives
Verified
Journal Article
Open access
JMJudy L. Mumford
Judy L. Mumford
KWKegong Wu
Kegong Wu
YXYajuan Xia
Yajuan Xia
Richard KwokRichard Kwok
Richard Kwok
ZYZhihui Yang
Zhihui Yang
WSWilliam E. Sanders
William E. Sanders
Background: Chronic arsenic exposure is associated with cardiovascular abnormalities. Prolongation of the QT (time between initial deflection of QRS complex to the end of T wave) interval and profound repolarization changes on electrocardiogram (ECG) have been reported in patients with acute promyelocytic leukemia treated with arsenic trioxide. This acquired form of long QT syndrome can result in life-threatening arrhythmias. Objective: The objective of this study was to assess the cardiac effects of arsenic by investigating QT interval alterations in a human population chronically exposed to arsenic. Methods: Residents in Ba Men, Inner Mongolia, have been chronically exposed to arsenic via consumption of water from artesian wells. A total of 313 Ba Men residents with the mean arsenic exposure of 15 years were divided into three arsenic exposure groups: low (≤ 21 μg/L), medium (100–300 μg/L), and high (430–690 μg/L). ECGs were obtained on all study subjects. The normal range for QTc (corrected QT) interval is 0.33–0.44 sec, and QTc ≥ 0.45 sec was considered to be prolonged. Results: The prevalence rates of QT prolongation and water arsenic concentrations showed a dose-dependent relationship (p = 0.001). The prevalence rates of QTc prolongation were 3.9, 11.1, 20.6% for low, medium, and high arsenic exposure, respectively. QTc prolongation was also associated with sex (p < 0.0001) but not age (p = 0.486) or smoking (p = 0.1018). Females were more susceptible to QT prolongation than males. Conclusions: We found significant association between chronic arsenic exposure and QT interval prolongation in a human population. QT interval may potentially be useful in the detection of early cardiac arsenic toxicity.

19 August 2009 in Journal of Epidemiology and Community Health
Verified
Journal Article
Closed access
PDF file
SMS L Myers
S L Myers
DLD T Lobdell
D T Lobdell
ZLZ Liu
Z Liu
YXY Xia
Y Xia
HRH Ren
H Ren
PMPauline Mendola
Pauline Mendola
Background Bayingnormen is a region located in western Inner Mongolia China, with a population that is exposed to a wide range of drinking water arsenic concentrations. The relationship between maternal drinking water arsenic exposure and perinatal endpoints (term birth weight, preterm birth, stillbirth and neonatal death) in this region was evaluated in this study. Methods An analysis was conducted of all singleton deliveries in a defined geographical area of Inner Mongolia from December 1996 to December 1999 (n=9890). Outcome and covariate data were abstracted from prenatal care records. Exposure was based on well-water measures for the maternal subvillage. Mean birth weight at term was compared across four arsenic categories using analysis of covariance. ORs for stillbirth, preterm birth and neonatal death were estimated by logistic regression with arsenic exposure dichotomised at 50 μg/l. Results Term birth weight was 0.05 kg higher (95% CI 0.02 to 0.08) in the highest exposure category (>100 μg/l) compared to the reference (below limit of detection to 20 μg/l). Arsenic >50 μg/l was associated with an increased risk of neonatal death (OR 2.01, 95% CI 1.12 to 3.59). No relationship was found between maternal arsenic exposure and preterm or stillbirth delivery. Conclusions At the levels observed in our study, arsenic does not appear to contribute to adverse birth outcomes. Exposure may play a role in neonatal death; however, the neonatal death rate in this population was low and this potential association merits further research.