Association between maternal body mass index and hospital admissions for infection in offspring: longitudinal cohort study.

Abstract

Objective: To investigate the relation between maternal body mass index and hospital admissions for infections in their offspring, and to identify potentially modifiable mediators.

Design: Longitudinal cohort study.

Setting: Born in Bradford longitudinal, multi-ethnic birth cohort, Bradford, UK. Secondary analysis linked to routine hospital admission data, January 2007 to 3 October 2022.

Participants: 9540 singleton births between 2007 and 2011, born to 9037 mothers, followed up from birth to about age 15 years.

Main outcome measures: Total number of hospital admissions related to infections, between birth and age 15 years, in age categories <1 year, 1-4 years, and 5-15 years.

Results: The main study cohort comprised 9540 children and 9037 mothers. About 56% of mothers were overweight or obese. First trimester maternal body mass index was positively associated with rates of hospital admissions for infection across all ages, but associations were significant (P<0.05) only for children born to women with the highest body mass index (obesity grades 2-3). Compared with women with a healthy body mass index, children born to women with obesity grades 2-3 had an adjusted rate ratio of 1.41 (95% confidence interval 1.13 to 1.77) at <1 year and an adjusted rate ratio of 1.53 (1.19 to 1.98) for hospital admissions for infection by age 5-15 years. Similar trends were seen for respiratory and gastrointestinal infections, and multisystem viral infections. Being born by caesarean section and child obesity at aged 4-5 years accounted for 21% and 26% of the association, respectively.

Conclusions: In this study, a modest but consistent association between maternal obesity (grades 2-3) and hospital admissions for infection throughout childhood was found. Healthcare professionals and public health campaigns should continue to support mothers to achieve and maintain a healthy body weight before conception and during the postpartum period.