Iron deficiency is associated with sensitivity and vulnerability to pain: a scoping review of the evidence and review of potential mechanisms

Objective: The objective of this scoping review is to understand the extent and type of evidence for associations between iron deficiency and sensitivity and vulnerability to pain, and the potential mechanisms behind this association. Introduction: Chronic pain is a significant global health burden, while iron deficiency is one of the most prevalent nutritional disorders worldwide. Evidence suggests that a lifetime history of iron deficiency is associated with sensitivity and vulnerability to pain and to multiple regional, widespread, and primary chronic painful conditions. However, the mechanisms behind this association are poorly understood. This scoping review aims to map current evidence examining associations between iron deficiency and pain to identify knowledge gaps and inform future research. Inclusion criteria: Studies will be eligible for inclusion if they meet the following criteria: (1) human participants (any age or sex), (2) studies that describe relationships or associations between iron deficiency and pain, (3) original research published in English language in a peer-reviewed journal, with (4) all settings and contexts considered . Methods: This scoping review will be conducted in accordance with JBI methodology. The search strategy will use search term combinations of ‘iron deficiency’ and ‘pain’, with terms combined using Boolean logic. Searches will be conducted in January 2026 in Embase, PubMed and CINAHL to identify published and unpublished evidence. Titles and abstracts will be screened against predefined inclusion criteria, before data are extracted and summarised. Results will be presented using tables and narrative synthesis. The study will be reported in accordance with PRISMA-ScR.