title: Relative risk of listeriosis in Foodborne Diseases Active Surveillance Network (FoodNet) sites according to age, pregnancy, and ethnicity.
abstract: BACKGROUND
  Quantitative estimates of the relative risk (RR) of listeriosis among higher-risk populations and a nuanced understanding of the age-specific risks are crucial for risk assessments, targeted interventions, and policy decisions.
  
  
  METHODS
  The RR of invasive listeriosis was evaluated by age, pregnancy status, and ethnicity using 2004-2009 data from the Foodborne Diseases Active Surveillance Network (FoodNet). Nonparametric logistic regression was used to characterize changes in risk with age and ethnicity. Adjusted RRs and 95% confidence intervals (CIs) were evaluated using negative binomial generalized linear models.
  
  
  RESULTS
  Among non-pregnancy-associated cases, listeriosis incidence rates increased gradually with age (45-59 years: RR, 4.7; 95% CI, 3.3-6.8; >85 years: RR, 53.8; 95% CI, 37.3-78.9; reference: 15-44 years). The RR was significantly higher for Hispanics than for non-Hispanics (RR, 1.8; 95% CI, 1.3-2.5). Among women of reproductive age (15-44 years), pregnant women had a markedly higher listeriosis risk (RR, 114.6; 95% CI, 68.9-205.1) than nonpregnant women. The RR was higher for Hispanic than non-Hispanic women, regardless of pregnancy status, and this increased during the study period (2004-2006: RR, 1.9; 95% CI, 1.0-3.3; 2007-2009: RR, 4.8; 95% CI, 3.1-7.1).
  
  
  CONCLUSIONS
  This study quantifies the increases in risk of listeriosis among older persons, pregnant women, and Hispanics in the United States. Additional research is needed to better describe the independent effects of age on risk while accounting for underlying conditions. These estimates are needed both to optimize risk assessment models and to inform targeted interventions and policy decisions.
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, 5100 Paint Branch Pkwy, College Park, MD 20740-3835, USA. regis.pouillot@fda.hhs.gov
authors.forename: Régis
authors.initials: R
authors.lastname: Pouillot
authors.forename: Karin
authors.initials: K
authors.lastname: Hoelzer
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Jackson
authors.forename: Olga L
authors.initials: OL
authors.lastname: Henao
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Silk
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002487:Centers for Disease Control and Prevention, U.S.; D002648:Child; D002675:Child, Preschool; D005260:Female; D005517:Foodborne Diseases / Q000208:ethnology* / Q000382:microbiology; D006630:Hispanic or Latino; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008088:Listeriosis / Q000208:ethnology* / Q000382:microbiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011159:Population Surveillance; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000208:ethnology* / Q000382:microbiology; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology / Q000208:ethnology; D055815:Young Adult