Peer-reviewed article

PREVENT 1, a nationwide Swedish infant cohort for longitudinal gut microbiome profiling and early-life health outcomes: cohort profile.

Orwa S, Vlajic M, Cavani E, Devall AE, Hugerth LW et al. · 28 Aug 2026

Abstract

Purpose PREVENT 1 is a nationwide, prospective Swedish infant cohort established to characterise gut microbiome development during the first 2 years of life and to relate microbial trajectories to feeding, infections, growth and everyday well-being. The study integrates repeated infant stool sampling with shotgun metagenomics analysis with aligned parental questionnaires, stool photographs and infant cry recordings collected at three approximately 3-month intervals for each infant. Participants Families were recruited nationwide in Sweden from September 2023 through targeted digital channels. Eligible participants were term-born infants residing in Sweden and aged <1 year at enrolment. Baseline questionnaire data and stool samples were collected from 253 infants. Parents completed questionnaires covering socio-demographic characteristics and health, pregnancy and delivery, postnatal factors, infant environment, feeding and growth, infections and other health outcomes, gastrointestinal symptoms and everyday well-being. Findings to date Retention was high, with 248 families completing at least one follow-up questionnaire at Phase 2 and 243 at Phase 3. For stool samples, 250 infants provided at least two samples and 241 provided all three. At enrolment, 42.3% of infants were older than 7 months, 73.9% had weight-for-length z-scores in the normal range and exclusive breastfeeding at 4 months was reported for 58.9%. Future plans Three-phase sample and questionnaire data collection was completed in December 2024. Future analyses will examine microbiome features, resistome profiles and functional pathways in relation to antibiotic exposure, feeding, growth and infant health outcomes. Subject to ethical approval and participant consent, follow-up may include further stool collection and Swedish register linkage. Trial registration number NCT06285630.