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Research
Statement
My research is in the area of
biological anthropology, with an emphasis on human population biology. I am broadly interested in understanding
how diverse social, cultural, economic, and physical ecological factors shape
variation in human physiological systems and health, and I have focused
primarily on immune function and inflammation as important systems that
link environments and health across the life course. Despite current calls for multi-level,
integrative research on human health, most research happens
in silos: Biomedical and life
scientists unravel the molecular mechanisms of disease, but often ignore
the broader social contexts; social scientists enrich our
understanding of how social, economic, and cultural factors shape human
health in diverse communities, but rely on limited measures of health. A comprehensive understanding of
human biology and health demands an integration of these perspectives. The holistic tradition of anthropology
provides a framework for such an integration, and I have devoted
considerable effort to developing tools to advance theoretically driven,
methodologically grounded, biocultural research in human biology and
health.
Three common threads weave their
way through my work. The first
emphasizes the importance of understanding human biology in relation to the
surrounding ecological contexts that shape the development and function of
biological systems. The immune
system represents a particularly illuminating example in this regard, since
input from the environment is essential to the process of generating
effective anti-pathogen defenses that are specifically tailored to the
local ecology. While my work
involves analysis of several biological mechanisms and outcomes, my emphasis
on context and population-level processes distinguishes it from the
molecular level of analysis that characterizes current research in
biomedicine. Over the past several
years I have spent much of my time in collaborative, multi-disciplinary
research settings, and through this experience it has become increasingly
clear to me that the holistic, ecologically grounded, adaptationist
perspective of human biology/biological anthropology is absolutely
essential.
A primary focus on human
development and the life course is the second theme in my work. Much research in biological anthropology
centers on the well-being of adults at one end of the life course, and
infants at the other. In between are
the childhood and adolescent years, which—with the exception of research on
growth and pubertal timing—have been relatively neglected. From a life course perspective, infancy,
childhood, and adolescence are important periods for establishing
trajectories of physiological function, with implications for health later
in life. Adults are products of
their current as well as early life environments, and a developmental
perspective provides a more comprehensive understanding of human biology
and health.
Lastly, careful consideration of
difficult methodological issues has been a central theme in my work. Much research in biological anthropology
(as well as recent work in social epidemiology and biodemography)
attempts to link social/cultural and ecological contexts to variation in
growth and health outcomes through proximate physiological mechanisms. However, investigations into these
mechanisms have been hampered by constraints imposed by conducting research
in field settings. As such, I have
invested extensive effort into the development and application of new
methods that allow the study of physiology and health outside the clinic or
lab. A community-based approach to
research in human biology opens up a wider range of research questions and
foregrounds the ecological factors that may be important determinants of
human biological variation.
I.
Integrative, biocultural perspectives on stress and health
A holistic approach to understanding
human diversity and human origins has been a foundational, signature
contribution of anthropology.
Despite divisive tendencies within anthropology in general, and
increased specialization within physical anthropology in particular, a
strong tradition of biocultural research continues to draw on conceptual
and methodological tools from anthropology as well as allied biological and
social/behavioral sciences.
Attention to the health impact of cultural and economic transitions
has been a major theme of biocultural research, and for my dissertation I
investigated culture change as a source of stress for children and
adolescents in the islands of Samoa.
More recently, I have developed a
U.S.-based program of research on socio-cultural environments, stress, and
health. I am currently PI of an RO1
award from NICHD that is directly supporting this line of research. The project team includes five faculty,
three postdoctoral researchers, and two graduate student RAs, and together
we are investigating the impact of social and economic stressors on
biomarkers of health in a nationally representative sample of more than
15,000 individuals. The National
Longitudinal Study of Adolescent Health (Add Health) is the flagship study
of health in young adulthood in the US, and for the first time in its 15
year history the study is collecting a panel of minimally invasive
biological measures from participants.
The study provides an opportunity of unprecedented magnitude to
integrate detailed contextual and lifestyle information with objective
physiological data on the function of cardiovascular, metabolic, endocrine,
and immune/ inflammatory systems.
The data have just been released, and we are pursuing several
analyses to examine the mechanisms through which social contexts “get under
the skin” to shape human physiology and health.
Key papers
McDade,
T.W., Chyu, L., Duncan, G.J., Hoyt,
L.T., Doane, L.D. and E.K. Adam (2011). Adolescents’ expectations for the future
predict health behaviors in early adulthood. Social Science and Medicine 73:
391-8.
McDade, T.W., S.T. Lindau, and K. Wroblewski (2011).
Predictors of C-reactive protein the National Social Life, Health,
and Aging Project. Journals of
Gerontology Series B: Psychological Sciences and Social Sciences 66:
129-36.
McDade, T.W. (2009) Beyond the gradient: An integrative
anthropological perspective on social stratification, stress, and health.
In Health, Risk, and Adversity,
C. Panter-Brick and A. Fuentes (eds.).
Sweet, E., McDade, T.W., Kiefe, C.I., Liu, K. (2007). The Interaction between
skin color, income, and blood pressure among African Americans in the CARDIA
Study. American Journal of Public Health 97: 2253-2259.
McDade, T.W., Reyes-García,
V., Blackinton, P., Tanner, S., Huanca, T, and W.R. Leonard. (2007). Ethnobotanical knowledge is associated with indices of
child health in the Bolivian Amazon. Proceedings of the National Academy of
Sciences 104: 6134-6139.
McDade,
T.W. (2007). Challenges and opportunities for integrative health research
in the context of culture: A commentary on Gersten,
“Neuroendocrine biomarkers, social relations, and
the costs of cumulative stress in Taiwan”. Social Science and Medicine.
McDade, T.W., Hawkley,
L.C. and J.T. Cacioppo (2006).
Psychosocial and behavioral predictors of inflammation in middle-age and
older adults: The Chicago Health, Aging, and Social Relations Study. Psychosomatic
Medicine 68: 376-81.
McDade, T.W. (2002). Status incongruity
in Samoan youth: A biocultural analysis of culture change, stress,
and immune function. Medical Anthropology Quarterly 16:
123-150.
McDade,
T.W., Stallings, J.F. and C.M. Worthman (2000).
Culture change and stress in Western Samoan youth: Methodological
issues in the cross-cultural study of stress and immune function. American
Journal of Human Biology 12: 792-802.
II.
Developmental ecology of immune function and inflammation
Current biomedical research on immune
function illuminates the cellular and molecular mechanisms that
characterize immune defenses, but the human immune system is a product of
natural selection that develops and functions in whole organisms that are
integral parts of their surrounding environments. Similarly, inflammation—a central part of
innate immune defenses against infectious disease—has generated intense
clinical and epidemiological interest due to its association with the
progression of a wide range of chronic degenerative diseases, including
cardiovascular disease and metabolic syndrome. However, current understandings of
inflammation are based almost exclusively on research conducted in affluent
industrialized settings with low burdens of infectious disease. A comparative, developmental, ecological
perspective is therefore a necessary complement to current biomedical
research, and I have been working to establish human ecological immunology
as an important domain of inquiry in biological anthropology that can
address this gap. Ongoing NSF and
NIH funded research in Bolivia, Ecuador, and the Philippines has provided
data to test several new hypotheses regarding the development and function
of the human immune system.
Key papers
McDade,
T.W., Tallman, P.S., Adair, L.S., Borja, J. and
C.W. Kuzawa (in press). Comparative insights into the regulation
of inflammation: Levels and predictors of interleukin 6 and interleukin 10
in young adults in the Philippines. American Journal of Physical
Anthropology.
McDade, T.W., Rutherford, J.N., Adair, L. and C. Kuzawa (2010). Early origins of inflammation: microbial
exposures in infancy predict lower levels of C-reactive protein in
adulthood. Proceedings of the
Royal Society B 277: 1129-37.
McDade, T.W., Rutherford, J.N., Adair, L. and C. Kuzawa (2009). Population differences in associations
between C-reactive protein concentration and adiposity: comparison of young
adults in the Philippines and the United States. American Journal of Clinical Nutrition
89: 1237-45.
McDade, T.W., Reyes-García,
V., Tanner, S., Huanca, T., and W.R.
Leonard.(2008). Maintenance vs. growth: Investigating the costs of
immune activation among children in lowland Bolivia. American Journal of
Physical Anthropology.
McDade, T.W., Rutherford, J.N., Adair L.S., Kuzawa, C. (2008). Adiposity and Pathogen Exposure
Predict
C-Reactive Protein in Filipino Women. Journal of Nutrition 138:
2442-2447
McDade, T.W., Leonard, W.R., Burhop,
J., Reyes-García, V., Vadez,
V., Huanca, T. and R.A. Godoy (2005). Predictors
of C-reactive protein in Tsimane’ 2-15 year-olds
in lowland Bolivia. American Journal of Physical Anthropology.
McDade, T.W. (2005). The ecologies of human
immune function. Annual Review of Anthropology.
McDade, T.W. (2005). Life history,
maintenance, and the early origins of immune function. American
Journal of Human Biology 17: 81-94.
McDade, T.W. (2003). Life history theory
and the immune system: Steps toward a human ecological
immunology. Yearbook of Physical Anthropology 46:
100-125.
McDade,
T.W., Beck, M.A., Kuzawa, C. and L.S. Adair
(2001). Prenatal undernutrition, postnatal environments, and
antibody response to vaccination in adolescence. American Journal
of Clinical Nutrition 74: 543-548.
McDade, T.W. and C.M. Worthman
(1999). Evolutionary process and the ecology of human immune
function. American Journal of Human Biology 11: 705-717.
III.
Development of minimally-invasive field methods in human biology
Biological anthropologists often
choose to conduct research in remote field settings in order to explore the
range of human variation in biological processes and outcomes. However, methodological constraints
associated with venipuncture blood sampling impose significant obstacles to
field-based physiological research, which further reinforces the status quo
understanding of human biology that is based on work in affluent,
industrialized populations, usually conducted in clinical or laboratory
settings with non-representative samples.
In an attempt to overcome some of these challenges, a major focus of
my work has been the development of minimally-invasive, “field-friendly”
methods for assessing aspects of human biology and health. In particular, I have focused on dried
blood spots (DBS) as a convenient means for collecting, transporting, and
processing blood samples in community settings. In contrast to the relative invasiveness
of venipuncture, whole blood samples can be collected from a simple finger
prick. Samples are dried on filter
paper, and—unlike plasma samples—do not need to be centrifuged or
immediately frozen.
To date, I have successfully used this
technique to collect blood samples from children and adolescents in Samoa,
Kenya, and Bolivia for my own research, and I have worked with
collaborators to implement these methods in Afghanistan, Brazil, China,
Indonesia, Kuwait, Mexico, Nepal, and the US. I have validated laboratory methods for
measuring aspects of immune function (antibodies against the Epstein-Barr
virus, antibodies against the Cytomegalovirus, C-reactive protein, total IgE) and nutritional status (serum transferrin
receptor, leptin) in DBS. Two recent grants are supporting the
development of methods for anti-mullerian hormone
(AMH), as well as a multiplex panel of pro- and anti-inflammatory
cytokines. These
methods are significant in that they facilitate the study of physiological
mechanisms in relation to social and ecological contexts in diverse
population-based settings, promote future field-based research into the
ecology of immune function and health, and expand the range of questions
that can be addressed by human population biology.
Key papers
McDade, T.W. and
M.D. Hayward (2009). Rationale and
methodological options for assessing infectious disease and related
measures in social science surveys. Biodemography
and Social Biology 55: 159-177.
Lindau, S.T. and T.W.
McDade. (2008) Minimally-invasive and innovative methods for biomeasure collection in population-based research. In Biosocial
Surveys, M. Weinstein, J.W. Vaupel, and K.W. Wachter (eds). Washington,
D.C.: National Academies Press.
McDade, T.W., Williams, S., and J.J. Snodgrass.
(2007) What a drop can do: Dried blood spots as a minimally-invasive method
for integrating biomarkers into population-based research. Demography 44:
899-925.
Miller,
A., Sharrock, K., and T.W. McDade. (2006).
Measurement of leptin in dried blood spot
samples. American Journal of Human Biology. 18: 857-60.
McDade, T.W., Burhop,
J., and J. Dohnal (2004). High
sensitivity enzyme immunoassay for C-reactive protein in dried blood
spots. Clinical Chemistry 50: 652-654.
McDade,
T.W. and B. Shell-Duncan (2002). Whole blood collected on filter
paper provides a minimally-invasive method for assessing human transferrin receptor. Journal of Nutrition
132: 3760-3763.
McDade, T.W., Stallings, J.F., Angold, A., Costello, E.J., Burleson, M., Cacioppo, J.T., Glaser, R. and C.M. Worthman
(2000). Epstein-Barr virus antibodies in whole blood spots:
A minimally-invasive method for assessing an aspect of cell-mediated
immunity. Psychosomatic Medicine 62: 560-568.
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