My research focuses on population-based studies of environmental, occupational, genetic (and gene-environment interactions) and lifestyle risk and protective factors for neurodegenerative diseases, specifically Parkinson’s disease and dementias/ cognitive impairment; cancers and cardiovascular disease. I have a special research interest in Hispanic/Latino and low-income populations and in developing educational interventions aimed at childhood obesity prevention.

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Study showing that consumption of water from private wells located in areas with documented historical agricultural pesticide use and presumably contaminated with pesticides is associated with an increased Parkinson’s disease risk.

A gene-environment analysis which examined whether PD risk depended on the combined presence of alpha-synuclein gene polymorphisms, pesticide exposures, and smoking, and whether effects varied by age-of-onset.

Study associating components of ambient air pollution (O3, PM2.5 and NO2) with cognitive dysfunction in healthy cognitively intact adults in Los Angeles.

Organochlorine chemicals, specifically DDT/DDE and PCBs, measured in the serum are not associated with breast cancer.



Observed physical function is associated with better cognition among elderly adults: the Adventist Health Study-2. published article

An exploratory study of vegetarian dietary patterns and cognitive function among elderly adults: the Adventist Health Study-2 *submitted



Passive smoking exposure from home, work and other social settings is not convincingly protective of Parkinson's disease.

Vitamin D receptor polymorphisms, but not ultraviolet radiation (UVR), may modulate Parkinson's disease risk in a population highly exposed to UVR throughout lifetime.

A functional vitamin D receptor polymorphism is associated with cognitive decline in Parkinson's disease in a case-only analysis.

Childhood obesity

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Compared to their classmates who did not participate in the intervention, LA Sprouts participants had significantly greater reductions in BMI z-scores and waist circumference and significant increases in dietary fiber intake.

LA Sprouts participants also had improvements in motivation to eat fruits and vegetables and a greater change in their perceptions of their ability to cook and garden.

Cardiovascular disease


Studies of subclinical atherosclerosis measured by carotid artery intima-media thickness and the clustering of risk factors in the metabolic syndrome on different aspects of cognitive function among middle-aged and older adults.

Markers of arteriosclerosis in the retinal microvasculature are associated with lower cognitive function.

Longitudinal analysis showing that brachial artery vasoreactivity and anatomical measures of atherosclerosis are correlated among subjects with coronary artery disease.