Mediation analysis between maternal BMI, age and the Rohrer Index in adult women: a cross-sectional study

Gordillo Cortaza J.D.R.; Touriz Bonifaz M.A.; Mendoza Ramírez V.A.; Mendoza Ramírez R.J.; Prado Matamoros A.M.; Cedeño Robalino Z.S.; Feraud Ibarra F.V.; Ochoa Montoya Y.T.; Jiménez Jiménez W.J.; Paladines Zapata N.C.; González García W.A.; Castro Mattos M.A. · Nutricion Clinica y Dietetica Hospitalaria (2025) · DOI: 10.12873/454gordillo

Resumen

Introduction: Maternal body mass index (BMI) is a robust predictor of adiposity in children; therefore, birth weight index allows for the assessment of nutritional status and body composition, identifying alterations in fetal growth and long-term risks. Objective: To assess the association between maternal BMI and Rohrer Index (PI), exploring the mediating role of women’s age. Methodology: Cross-sectional study using secondary data from the Demographic and Family Health Survey (ENDES) of Peru, 2012–2020. A total of 31,742 records of full-term newborns (≥37 weeks) without congenital malformations and with available data on maternal gestational BMI and maternal age at delivery were included. Premature births, multiple pregnancies, cases of intrauterine growth restriction, and incomplete records were excluded. Maternal BMI was calculated using data from the first antenatal visit and PI as birth weight divided by height3. The Rohrer´s Index was used for its ability to reflect relative adiposity compared to birth weight or BMI in neonatal populations. Mediation analysis was performed using the JAMOVI software, estimating direct, indirect, and total standardized effects with 95% confidence intervals. Results: The mediation model met the statistical assumptions (linearity, normality of residuals, and absence of multicollinearity). Maternal BMI showed a high direct effect on PI (β = 0.97; p < .001). The indirect effect through female age was statistically significant, but small in magnitude (β = 0.0086; p < .001), accounting for only 0.88 % of the total effect. Conclusions: The influence of maternal BMI on offspring corpulence is mainly exerted through direct pathways, while female age plays a marginal mediating role. These findings underscore the importance of interventions targeting maternal BMI as a strategy to prevent intergenerational obesity.

Instituciones: Universidad Nacional de Educación Enrique Guzmán y Valle