Journal of Neonatal-Perinatal Medicine 16 (2023) 491–500 DOI:10.3233/NPM-221180 IOS Press 491 Original Research Food environment index and preterm birth rate in the counties of the United States A. Das a,∗ , M.M. Trivedi b and D.A. Bellingham-Young c a Department of Neonatology, Cleveland Clinic, Cleveland, OH, USA b Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, OH, USA c The University of Liverpool, Liverpool, UK Received 7 November 2022 Revised 5 April 2023 Accepted 12 May 2023 Abstract. OBJECTIVES: To determine the relationship between Food Environment Index (FEI) and Preterm Birth (PTB) rate at the county level of the United States of America (USA) (primary), while evaluating the interaction of multiple factors within a framework of sociodemographic, maternal health, maternal behavioral, and environmental factors. METHODS: This is a population-based retrospective cohort ecological study from 2015-2018. The study compares the characteristics of the population of the counties of the USA. All counties with complete data on their PTB rate and the independent variables were included in the study. Independent variables with greater than 20% missing data were excluded from the study. Purposive sampling technique was applied. A total of 2983/3142 counties were included in the study. RESULTS: The median PTB rate of all counties was 9.90%. The highest PTB rate (23.3%) was in Tallapoosa County, Alabama and the lowest (3.4%) in San Juan County, Washington State. After adjusting for variables, PTB rate had a significant association with FEI (coefficient of correlation –0.36, p < 0.01, 95% CI –0.19 to –0.04). Increase in the rate of unemployment, African American race, adult smoking, obesity, uninsured rate, sexually transmitted diseases (STD), high school education and air pollution was associated with an increase in PTB rate, while an increase in FEI and alcohol abuse rates was associated with a decrease in PTB rate. CONCLUSIONS: FEI can predict the PTB rate in USA counties after adjusting for sociodemographic, health, behavioral and environmental factors. Future studies are needed to confirm these associations and consider them when making policies to reduce PTBs. Keywords: Ecological study, Food Environment Index, premature birth, preterm, social determinants of health 1. Introduction and background Preterm Birth (PTB) is defined by the World Health Organization (WHO) as any delivery that occurs at less than 37 completed weeks of gestation [1]. ∗ Address for correspondence: Anirudha Das, MD, MPH., De- partment of Neonatology, Cleveland Clinic Foundation, 9500 Euclid Avenue, Mail Code-M31, Cleveland OH 44195, USA. Tel.: +1 216 219 9767; Fax: +1 517 201 0853; E-mail: anirudhdas 26@gmail.com. An estimated 15 million infants are born prema- turely every year globally, of which 1 million dies from the complications of prematurity [1]. PTB is the number one cause of perinatal mortality in the United States of America (USA). The PTB rate had declined in the USA from 12.8% in 2006 to 9.5% in 2014 with an increasing trend to 9.9% since then, in 2018, per 100 live births [2]. The infant mortal- ity rate (IMR) in the US was 5.42 deaths per 1000 live births in 2020 but the IMR in infants born at ISSN 1934-5798/$35.00 © 2023 – IOS Press. All rights reserved.