Pacifier Use and Early Life Weight Outcomes in the Intervention Nurses Start Infants Growing on Healthy Trajectories Study

Abstract

Background: Although widely used by infants, little is known about the long-term effects of pacifiers. We investigated relationships between pacifier use in infancy and appetite, temperament, feeding, and weight outcomes through age 2 years using data from the Intervention Nurses Start Infants Growing on Healthy Trajectories study.

Methods: Mother-newborn dyads were randomized to a responsive parenting intervention for obesity prevention or a control group. Infants with data on pacifier use (n = 250) were categorized as using a pacifier beyond early infancy (≥4 months of age) or not. Anthropometrics were measured at 6 months, 1, and 2 years with overweight defined as weight-for-length ≥95th percentile at 1 year and BMI ≥85th percentile at 2 years. Mothers completed questionnaires on temperament, appetite, and feeding.

Results: Infants who used a pacifier at 4 months or later (68%) had greater conditional weight gain from birth to 6 months (p = 0.01), weight-for-length z-score at 1 year (p < 0.001), and BMI z-score at 2 years (p < 0.001) than infants who did not. Infants using a pacifier at ≥4 months were more likely to be overweight at ages 1 year (11.7% vs. 1.3%, p = 0.03) and 2 years (20.1% vs. 7.9%, p = 0.03). Pacifier use was associated with shorter breastfeeding duration and less responsive parent feeding styles, but these variables did not mediate the relationship between pacifiers and weight. Parent-reported temperament and appetite were unrelated to pacifier use.

Conclusions: Pacifier use beyond early infancy is associated with accelerated infant growth and toddler overweight, although the reasons for this relationship are unclear.

Keywords: child obesity; infant; pacifier; parenting; weight.

Figure 1.

Mediation model for pacifier analyses. Step 1: Regression with pacifier use predicting weight outcomes is tested without the mediator (pathway c, not shown). Step 2: Regression with pacifier use predicting mediator is tested (pathway a). Step 3: Regression with mediator predicting weight outcome is tested (pathway b). If steps 1–3 reveal significant relationships, mediation is tested in Step 4: Regression with mediator (pathway b) and pacifier use (pathway c’) predicting weight outcomes.

Figure 2.

Prevalence of pacifier use among infants participating in the Intervention Nurses Start Infants Growing on Healthy Trajectories study (n = 250).

Figure 3.

Pacifier use duration (months) is positively associated with (A) weight-for-length z-score at 1 year (p = 0.005) and (B) BMI z-score at 2 years (p = 0.001) Values are mean ± standard error.

Figure 4.

Pacifier use at 4 months or later is associated with greater conditional weight gain from 0 to 6 months (p = 0.01), greater weight-for-length percentile at 1 year (p < 0.001), and greater BMI percentile at 2 years (p < 0.001). Values are mean ± standard error.

Figure 5.

A greater percentage of infants who used pacifiers at 4 months or later than those who did not use pacifiers was overweight at 1 year (weight-for-length ≥95th percentile) and 2 years (BMI ≥85th percentile). *p < 0.05 for difference between pacifier users and nonusers.