Project 2: Environmental and Lifestyle Factors
This project, led by Frank Hu, MD, PhD, will examine the association of behavioral and environmental factors with circulating levels of cancer-related biomarkers among 750 middle aged women in the Nurses’ Health Study, and will evaluate whether selected genetic characteristics modify the associations between behavioral and environmental factors and risk of obesity.
The specific aims are:
- to examine associations between energetic factors (energy expenditure measured by doubly labeled water, physical activity, dietary insulin demand, and sleep duration) and cancer-related biomarkers (insulin/IGF pathway, adipokines, and sex hormones)
- to examine the relationships of neighborhood social economical status (SES) and built environment (assessed by the county sprawl index) with cancer-related biomarkers and delineate the pathways linking the built environment, energetic factors, obesity and biomarker levels
- to examine whether genetic factors related to insulin resistance or insulin secretion modify the associations between behavioral (dietary insulin demand, physical activity, and sleep duration) and structural (neighborhood SES and built environment) factors and risk of obesity and long-term weight gain. These analyses will be conducted among 8,000 participants with existing genome-wide association study (GWAS) data in the Nurses’ Health Study and Health Professionals’ Follow-up Study.
This project has been designed to provide thematic continuity with project 1 in two regards: sleep patterns will be one of the behavioral factors examined, and there will be substantial overlap in the biomarkers (including insulin/IGF pathway and adipokines) examined as outcomes in Projects 1 and 2. The primary aims of this project are to investigate the relation of objectively measured energy expenditure, physical activity, and dietary insulin index/insulin load with the same biomarkers of cancer risk, to study the association between different aspects of the built environment and biomarkers of cancer risk, and to evaluate whether specific genetic variants modify how sleep, nutrition, and the built environment influence cancer-related biomarkers. This project will enhance our understanding of how multiple novel factors, from genes to geography, influence circulating levels of biomarkers of cancer risk on their own and by interacting with each other.