Differences Among Incidence Rates of Invasive Listeriosis in the U.S. FoodNet Population by Age, Sex, Race/Ethnicity, and Pregnancy Status, 2008-2016

Abstract

Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008-2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females. For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008-2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011-2013 when compared with 2008-2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25-0.73) for 0- to 14-year olds to 44.9 (33.5-60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12-1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18-1.20) times higher among non-Hispanic Asians, 1.49 (1.22-1.83) among non-Hispanic blacks, and 1.73 (1.15-2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51-4.89) and Hispanic females 3.13 (2.12-4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds. This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.

Keywords: foodborne disease epidemiology; foodborne illness; listeriosis.

FIG. 1.

Incidence rate of listeriosis (per 100,000 population) by age (range 0–84 years): (a) Hispanic females, (b) Hispanic males, (c) non-Hispanic white females, (d) non-Hispanic white males, (e) non-Hispanic black females, and (f) non-Hispanic black males, in the FoodNet Catchment Area 2008–2016, as estimated by nonparametric logistic regression (Bowman and Azzalini, 1997). Continuous lines represent estimates; dashed lines, 95% CI bands. Black squares represent estimates for persons >85 years of age and the 95% Poisson CI. The youngest age group is 32 d to 14 years of age and does not include infants ≤31 d old. CI, confidence interval; FoodNet, Foodborne Diseases Active Surveillance Network.