Microbial exposures in infancy predict levels of the immunoregulatory cytokine interleukin-4 in Filipino young adults.
OBJECTIVE
Infancy represents a window of development during which long-term immunological functioning can be influenced. In this study, we evaluate proxies of microbial exposures in infancy as predictors of interleukin-4 (IL-4) in young adulthood. IL-4 is an immunoregulatory cytokine that plays a role in the pathogenesis of atopic and allergic diseases.


METHODS
Data were obtained from 1,403 participants in the Cebu Longitudinal Health and Nutrition Survey, an ongoing population-based study in the Philippines. Relationships between microbial and nutritional environments in infancy and plasma IL-4 concentrations in adulthood were evaluated using tobit regression models.


RESULTS
Having older siblings and more episodes of respiratory illness in infancy significantly predicted lower concentrations of plasma IL-4 in adulthood. Unexpectedly, more episodes of diarrheal illness in infancy were associated with higher IL-4 in adulthood. Interactions between a composite household pathogen exposure score and the duration of exclusive breastfeeding approached significance. This interaction showed that the negative association between household pathogen exposure in infancy and adult IL-4 was only significant for individuals who had been exclusively breastfed for a short duration of time. Finally, currently living in an urban household was unexpectedly, negatively associated with adult IL-4. Associations were independent of early nutrition, socioeconomic status (SES), and urbanicity, as well as current measures of infection, body fat, SES, and smoking.


CONCLUSIONS
This study builds on a growing body of literature demonstrating that early ecological conditions have long-term effects on human biology by providing evidence that multiple proxies of microbial exposures in infancy are associated with adult IL-4.
Department of Anthropology, Northwestern University, Chicago, Illinois 60201, USA. paulaskye@u.northwestern.edu
Paula Skye
PS
Tallman
Christopher
C
Kuzawa
Linda
L
Adair
Judith B
JB
Borja
Thomas W
TW
McDade
D000367:Age Factors; D001722:Birth Order; D001942:Breast Feeding; D015331:Cohort Studies; D003141:Communicable Diseases / Q000453:epidemiology* / Q000382:microbiology; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology; D005191:Family Characteristics; D005243:Feces / Q000382:microbiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D007231:Infant, Newborn; D015847:Interleukin-4 / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D010679:Philippines / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012044:Regression Analysis; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000382:microbiology; D012307:Risk Factors; D013997:Time Factors; D014505:Urban Population; D055815:Young Adult
D015847:Interleukin-4