Pica practices, anemia, and oral health outcomes: a systemic review

Objectives: Pica is a non-nutritive eating behavior. The potential impact of pica on oral health and the association between pica and anemia are understudied. We examined the current evidence on the relationship between pica practices, anemia, and oral health outcomes.

Methods: We used Population, Intervention, Control, and Outcomes (PICO) terms to create MeSH terms to assess 1) the relationship between pica and iron deficiency anemia (IDA), 2) the relationship between IDA and oral health, and 3) the relationship between pica, anemia, and oral health outcomes. The review was registered on Prospero [CRD42022349022]. We searched databases including PubMed, Embase, Web of Science, Cochrane Library, and, clinicaltrials.gov in June 2022.

Results: From 4,159 searched articles, 89 met the inclusion criteria. Studies were published between 1959 and 2022 from 33 countries. Nearly half of these studies (55.1%, n = 49) were case reports. The most common picas included geophagia (soil/dirt) (44.9%, n = 40 papers), pagophagia (ice) (22.5%, n = 20), amylophagia (starch) (15.7%, n = 14), paint/metal (5.6%, n = 5), paper (5.6%, n = 5) and others such as pica for foam and hair. Fifteen case reports and one intervention study showed the effects of pica practice on oral health, such as tooth abrasion, dental caries, and de-papillated tongue. Furthermore, 81% of the papers reported the co-occurrence of pica with anemia and 15 papers reported a significant association (p < 0.05) between pica and low hemoglobin levels ranging from < 12.0 to 2.7g/dL among all age groups, including among pregnant and postpartum women. Pica practices were strongly associated with IDA (serum ferritin < 15.0 - 4.3 mcg/ml) but showed a non-statistically significant trend of association with oral health outcomes.

Conclusion: Pica was strongly associated with anemia and IDA. Tooth abrasion and dental caries were observed among pica users. Future studies could define the strength of the pica-oral health association, and the potential mediators, such as anemia.