The double burden of malnutrition among women of reproductive age and preschool children in low- and middle-income countries: A scoping review and thematic analysis of literature

•Double burden of malnutrition (DBM) is a loosely understood construct in research.•We reviewed literature concerning the definition, etiology, and risk factors of DBM.•Anthropometric measurements are mostly used for the operational definition of DBM.•Nutrition transition dominates the literature as the underlying mechanism of DBM.•Studies have shown that DBM is driven by changes in sociodemographic risk factors. The aim of this review was to map the literature on the double burden of malnutrition (DBM) among women of reproductive age (WRA) and preschool children in low- and middle-income countries (LMICs). The study aimed to provide an understanding of how DBM construct has been defined in the current literature and to elucidate plausible mechanisms underlying DBM development and its common risk factor among the two subgroups. We systematically searched for literature from the following databases: EMBASE, CINAHL, MEDLINE, LILACS, Scopus and ProQuest Dissertations & Thesis Global and identified articles that specifically reported on the coexistence of undernutrition and overnutrition sequalae at the population, household, or individual levels among WRA and preschool children in LMICs. A thematic analysis using the Braun and Clarke approach was conducted on excerpts from the articles to reveal emerging themes underlying the occurrence of DBM from the included studies. Of the initial 15 112 articles found, 720 met the inclusion criteria. Anthropometric measures for overnutrition and undernutrition including body mass index for WRA and height-for-age, weight-for-age, and weight-for-height Z-scores for preschool children were frequently used indicators for defining DBM across all levels of assessment. In fewer cases, DBM was defined by the pairing of cardiometabolic risk factors (e.g., hypertension) as measures for overnutrition and micronutrient deficiency (e.g., iron deficiency) as measures for undernutrition. The following themes emerged as plausible mechanisms for DBM development: nutrition transition, breastfeeding, diet behavior, biological mechanism, and statistical artifact. Factors such as child age, child sex, maternal age, maternal education, maternal occupation, household food security, household wealth, urbanicity, and economic development were commonly associated with most of the DBM phenotypes. Our review findings showed that the understanding of the DBM in current literature is very ambiguous. There is need for future research to better underst