Early growth faltering in healthy term infants predicts longitudinal growth
Introduction
Growth monitoring is an integral part of routine well-child visits designed to monitor health and development. Yet there are few data to suggest that it is effective in identifying infants and young children early in the course of growth faltering [1], [2], [3]. Growth often begins to slow in the first 6 months of life in infants later diagnosed with growth faltering [4]; this is the same time interval when well-child visits are most frequent, allowing multiple opportunities to identify slowing growth in infants who later become underweight. However, Chen and Shiffman found that in 55% of the charts they reviewed, a growth perturbance was either not identified or not documented [2]. In a busy clinical practice, practitioners need a method of identifying those infants whose growth may indicate a need for further probing of feeding interactions.
One reason growth monitoring may be ineffective in identifying growth faltering is the fact that many infants cross percentile channels (both up and down) on the growth chart, making it difficult for the primary care provider to accurately identify those infants whose growth is problematic [5]. Identifying percentiles that are shifting away from the mean may be useful as an early prognosticator for growth perturbations. However, a defined or recognized rate of deceleration that is indicative of increased risk of adverse outcomes and that is easily implemented into clinical practice is lacking. A standard of growth velocity for identification of infants who are at risk for later growth faltering may be advantageous.
The goal of the research was to identify whether early deceleration in weight-gain could be used to predict subsequent early childhood growth faltering. The authors endeavored to identify a level of slowed weight-gain that is predictive of reaching a weight-for-length ≤ 5th percentile, using information gathered during regularly-scheduled well-child visits between two and six months of age. The age interval of four-to-six months was chosen initially because it reflects the typical timing of well-child visits and there are a number of developmental changes related to feeding skill development and changing nutritional requirements that could influence growth [6], [7]. Additionally, there are data that suggest weight-gain prior to six months of age is predictive of increased risk of overweight [8], [9], [10]. The authors tested the hypothesis that a change in weight-for-age in a negative direction of more than − 0.85 standard deviation between the four and six month well-child visit was predictive of a child reaching a weight-for-length ratio ≤ 5th percentile (“underweight”) at some point during the first two years of life. A negative change of more than − 0.85 was chosen a priori based upon data published by Mei et al. [5] that suggested approximately 17% of infants demonstrated a negative change in weight-for-age ≥ 1 standard deviation between birth and six months of age, and this study was examining a shorter time interval. A second hypothesis tested was whether a similar change in the two-to-four month time period would be equally predictive, as we were interested in finding the earliest time interval useful for prognostic purposes. We conducted sensitivity analyses to determine the effect of the growth reference (2006 WHO vs. 2000 CDC) on the robustness of the model.
Section snippets
Methods
This study was a secondary database analysis of healthy, term infants born in the years 1999–2001, who were served by a private comprehensive health care system for the first two consecutive years of life. Weights, lengths and demographic information were extracted from the electronic medical record database. Inclusion criteria consisted of term gestation (≥ 37 weeks, ≤ 42 weeks), birth weight > 2.5 kg, no known prenatal exposure to alcohol or illicit drugs, and an initial hospital stay of ≤ four days.
Results
Table 1 describes the maternal and infant demographic characteristics of those infants included in the analysis. To examine the potential bias created by limiting the initial birth cohort, the characteristics for full received cohort (FRC, n = 3727) as well as the cohort used for final analyses (FC, n = 1978) were compared to the 2000 census data published for the State of Colorado to determine how similar the infants were to those born within the state during the same time period. The infants in
Discussion
This study provides evidence that early deceleration in weight-gain is useful in identifying infants who later become underweight. Infants whose WAZ dropped more than − 0.85 standard deviations between either the two-to-four month or four-to-six month intervals were at increased risk of reaching underweight status by 24 months of age compared to those with a more modest change. This study also demonstrated that this drop in weight-for-age (≥− 0.85 sd) is predictive as early as two-to-four months
Conflict of Interests
We have no conflicts of interest or corporate sponsors to disclose.
Acknowledgements
Kaiser-Permanente of Colorado provided the data for this study and funded this dissertation project. NIH #5T32 DK 07658-17 (Krebs, PI) provided funding for manuscript preparation and publication. We would like to acknowledge the support of Kaiser-Permanente, as well as the research and clinical expertise of Susan Pharo, M.D., and Kimberly Bischoff, MSPH, both of whom provided supports from within Kaiser-Permanente to see this project to completion. We would also like to acknowledge Allan
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