Nutritional Epidemiology

The discipline of nutritional epidemiology involves methodological approaches to determine the association between dietary factors and the occurrence of human health-related outcomes. The ascertainment of dietary and nutritional exposures within human populations is a methodologically challenging undertaking. Thus, a multidisciplinary approach is needed to assess the relation between diet and disease occurrence. When examining the role that diet plays in health outcomes, Exponent relies upon the expertise of staff from a broad range of health and food-related disciplines.
Our epidemiologists and statisticians have extensive experience in the following:

  • Conducting large scale critical reviews and primary data analyses of dietary and nutritional factors as they relate to a variety of health outcomes, such as cardiovascular disease, cancer, infant allergy, childhood and adult obesity, and behavior and lifestyle patterns. 

  • Conducting dietary exposure assessment and modeling for estimating long-term health benefits and risks. The food safety and nutrition staff develops exposure assessments with a variety of large databases from the US and other countries; examples of databases used in recent analyses include various releases of NHANES (National Health and Nutrition Examination Survey), the United Kingdom’s National Diet and Nutrition Survey (NDNS), EFSA’s Comprehensive European Food Consumption Database and Brazil’s Consumer Expenditure Survey.  Design and completion of large-scale systematic reviews of pre-clinical, clinical and epidemiological data in support of safety and efficacy evaluations for food ingredients and food products

  • Nutrition science reviews to support product development, marketing initiatives, and revisions to dietary guidance. 

Our epidemiology, nutrition, and statistics staff have published extensively on a variety of nutritional epidemiology topics in well-known peer reviewed scientific journals.

  • In 2014, Exponent scientist Dr. Ellen Chang, along with another co-author, published a study in the journal of Advances in Nutrition evaluating whether the sodium-to-potassium ratio or either sodium or potassium alone is more strongly associated with blood pressure and related factors in humans. At the time the study was published, this was the first systematic review to investigate this issue and helped to shed light on the need for further research on this topic as the associations remain unclear for normotensive and childhood populations as well as other related health outcomes. 

  • In 2013, Exponent Scientists Dr. Ellen Chang and Dr. Laura Elkayam, along with other co-authors, published a study in the Journal of the American College of Nutrition to better understand the health-related effects associated with the consumption of multivitamin-multimineral supplements (MVM). This systematic review among prospective studies examined the relationship between MVM supplementation and all-cause and cause-specific mortality, as well as cardiovascular disease (CVD) and cancer incidence. Though further research is needed, the findings suggested that supplementation with MVMs does not increase the risk of these adverse health effects and instead may provide a modest protective benefit.

  • Exponent scientists Mary Murphy and Dr. Leila Barraj have analyzed national data to model the nutritional impact of various fortification scenarios, including an assessment in 2013 of the effects of proposed revisions to daily values on estimates of nutrient intake adequacy assuming that manufacturers choose to maintain current label claims for micronutrients from voluntarily fortified foods. This study, conducted in response to proposed changes in food labeling regulations, found that nutrient intake adequacy of some nutrients of concern could be affected under some scenarios of revisions to the daily values. The research was published in The Journal of Nutrition.

  • Dr. Nga Tran and Dr. Leila Barraj have developed models to apportion the relative risk of dietary and lifestyle factors associated with health outcomes and developing models to apportion the relative risk of dietary and lifestyle factors associated with health outcomes. For example, their research on the role of dietary cholesterol in eggs was published in Risk Analysis.

  • Several of our scientists have also collaborated with academic institutions to investigate the association between dietary patterns and health outcomes using data from ongoing prospective cohort studies. For example, Dr. Barraj and Dr. Carolyn Scrafford collaborated with researchers at the University of Minnesota to quantify the association between dietary flavonoid intake and heart health using the Iowa Women’s Health Study. This research was published in The American Journal of Clinical Nutrition.

Examples of Exponent’s Publications and Presentations Pertaining to Nutritional Epidemiology

Murphy MM, Barraj LM, Toth LD, Harkness LS, Bolster DR. Daily intake of dairy products in Brazil and contributions to nutrient intakes: a cross-sectional study. Public Health Nutr. 2015 Jun 19:1-8.

Perez V, Chang ET. Sodium-to-potassium ratio and blood pressure, hypertension, and related factors. Adv Nutr. 2014 Nov 14; 5(6):712-41.

Edinboro CH. ICCIDD Iodine Deficiency Symposium. Iodine in Veterinary Populations (invited). American Thyroid Association 84th Annual Meeting, Coronado, CA, October-November 2014.

Tran NL, Barraj LM, Scrafford C, Bi X, Troxell T. Partitioning of Dietary Metal Intake-A Metal Dietary Exposure Screening Tool. Risk Anal. 2014 Dec 24. doi: 10.1111/risa.12322.

Murphy MM, Barraj LM, Spungen JH, Herman DR, Randolph RK. Global assessment of select phytonutrient intakes by level of fruit and vegetable consumption. Br J Nutr. 2014 Sep 28;112(6):1004-18.

Tran NL, Barraj LM, Heilman JM, Scrafford CG. Egg consumption and cardiovascular disease among diabetic individuals: A systematic review of the literature. Diabetes, Metabolic Syndrome and Obesity. 2014 Mar; 7:121–137.

Barraj LM, Murphy MM, Heshka S, Katz DL. Greater weight loss among men participating in a commercial weight loss program: a pooled analysis of 2 randomized controlled trials. Nutr Res. 2014 Feb;34(2):174-7. doi: 10.1016/j.nutres.2013.11.002.

Murphy MM, Barraj LM, Bi X, Stettler N. Body weight status and cardiovascular risk factors in adults by frequency of candy consumption. Nutr J. 2013 Apr 30;12:53. doi: 10.1186/1475-2891-12-53.

Alexander, DD., Douglas LW, Chang ET, Miller PE, Mohamed MA, Elkayam L. A systematic review of multivitamin–multimineral use and cardiovascular disease and cancer incidence and total mortality. Journal of the American College of Nutrition 2013; 32(5): 339-354.

Edinboro CH, Pearce EN, Pino S, Braverman LE. Iodine concentration in commercial cat foods from three regions of the USA, 2008-2009. J Feline Med Surg 2013; 15(8):717–724. Epub ahead of print: 2013 Feb 25.

Murphy MM, Spungen JH, Barraj LM, Bailey RL, Dwyer JT. Revising the daily values may affect food fortification and in turn nutrient intake adequacy. J Nutr. 2013 Dec;143(12):1999-2006.

Stettler N, Murphy MM, Barraj LM, Smith KM, Ahima RS. Systematic review of clinical studies related to pork intake and metabolic syndrome or its components. Diabetes Metab Syndr Obes. 2013 Sep 25;6:347-57.

Murphy MM, Barraj LM, Herman D, Bi X, Cheatham R, Randolph RK. Phytonutrient intake by adults in the United States in relation to fruit and vegetable consumption. Journal of the Academy of Nutrition and Dietetics 2012; 112:222–229.

Edinboro CH. Updates on Risk Factors for Feline Hyperthyroidism, or “Not All Those Who Wander Are Lost.” Peninsula Veterinary Medical Association (invited), Belmont, CA, May 2011.

Edinboro CH. Endocrine Disruption: How Much is Too Much for the Public’s Health? Topics in Public Health Seminar (invited), University of California, Davis, CA, May 2011.

Scrafford CG, Tran NL, Barraj LM, Mink PJ. Egg consumption and CHD and stroke mortality: A prospective study of US adults. Public Health Nutrition 2011 Feb; 14(2):261–270.

Edinboro CH, Scott-Moncrieff JC, Glickman LT. Feline hyperthyroidism: Potential relationship with iodine supplement requirements of commercial cat foods. J Feline Med Surg 2010; 12(9):672–679.

Edinboro CH. Companion Animals and Humans as Sentinels of Health Risk. 26th Annual Alltech Symposium (invited), Lexington, KY, May 2010.

Tran NL, Barraj LM, Murphy MM, Bi X. Dietary acrylamide exposure and hemoglobin adducts--National Health and Nutrition Examination Survey (2003–04). Food and Chemical Toxicology 2010; 48(11):3098–3108. 

Examples of Nutritional Epidemiology Publications and Presentations by Exponent Staff Academic Affiliations

Epstein MM, Chang ET, Zhang Y, Fung TT, Batista JL, Ambinder RF, Zheng T, Mueller NE, Birmann BM. Dietary pattern and risk of Hodgkin lymphoma in a population-based case-control study. Am J Epidemiol. 2015 Jul 15. doi: 10.1093/aje/kwv072.

Volberg V, Heggeseth B, Harley K, Huen K, Yousefi P, et al. Adiponectin and leptin trajectories in Mexican-American children from birth to 9 years of age. PLoS ONE 2013; 8(10):e77964.

Volberg V, Harley G, Aguilar R, Rosas L, Huen K, Yousefi P, Davé V, Phan N, Lustig R, Eskenazi B, Holland N. Associations between perinatal factors and adiponectin and leptin in 9-year-old Mexican-American children. Pediatric Obes 2013 Dec; 8(6): 454-63. doi: 10.1111/j.2047-6310.2012.00127.

Gao Y, Li Q, Bassig BA, Chang ET, Dai M, Qin Q, Zhang Y, Zheng T. Subtype of dietary fat in relation to risk of Hodgkin lymphoma: a population-based case-control study in Connecticut and Massachusetts. Cancer Causes Control. 2013 Mar;24(3):485-94. doi: 10.1007/s10552-012-0136-2.

Chang ET, Canchola AJ, Clarke CA, Lu Y, West DW, Bernstein L, Wang SS, Horn-Ross PL. Dietary phytocompounds and risk of lymphoid malignancies in the California Teachers Study cohort. Cancer Causes Control. 2011 Feb;22(2):237-49. doi: 10.1007/s10552-010-9692-5.

Chang ET, Canchola AJ, Cockburn M, Lu Y, Wang SS, Bernstein L, Clarke CA, Horn-Ross PL. Adulthood residential ultraviolet radiation, sun sensitivity, dietary vitamin D, and risk of lymphoid malignancies in the California Teachers Study. Blood. 2011 Aug 11;118(6):1591-9. doi: 10.1182/blood-2011-02-336065.

Kasperzyk JL, Chang ET, Birmann BM, Kraft P, Zheng T, Mueller NE. Nutrients and genetic variation involved in one-carbon metabolism and Hodgkin lymphoma risk: a population-based case-control study. Am J Epidemiol. 2011 Oct 1;174(7):816-27. doi: 10.1093/aje/kwr190.