Differences in sibling temperament are associated with differences in maternal use of food to soothe during infancy: A sibling analysis

Background: Firstborn children are more likely to have obesity than secondborns, which may partially be explained by differential use of food to soothe (FTS) infant distress, which has been inked to higher weight status. Objectives: To test associations between the birth order and maternal FTS and whether differences in sibling temperament and body mass index (BMI) z-scores were associated differences in maternal FTS. Methods: Random effect models assessed associations between birth order and FTS. Linear regressions examined associations between differences in maternal FTS and sibling differences in temperament at 16 weeks and BMI z-scores at 1 year. Results: Mothers (n = 117) used contextual-based FTS more with firstborns than secondborns (2.70 vs. 2.38, p < 0.0001). Sibling differences in negative affect were associated with differences in maternal contextual-based (R² = 0.09, p = 0.002) and emotion-based (R² = 0.09, p = 0.001) FTS. Sibling differences in effortful control were associated with differences in maternal emotion-based FTS (R² = 0.04, p = 0.04). Finally, differences in maternal emotion-based FTS were associated with sibling differences in BMI z-scores at age 1 year (R² = 0.14, p = 0.006). Conclusions: To promote healthy child weight, mothers should learn to respond to each child's temperament and use alternatives to FTS infant distress.