RESUMO
BACKGROUND: The temporal relationship between length (linear) and weight (ponderal) growth in early life is important to support optimal nutrition program design. Studies based on measures of attained size have established that wasting often precedes stunting, but such studies do not capture responsiveness of growth to previous compared with current conditions. As a result, the temporality of linear and ponderal growth relationships remain unclear. OBJECTIVES: We used growth velocity indicators to assess the temporal bidirectional relationships between linear and ponderal growth in children. METHODS: Using monthly anthropometric measurements from 5039 Burkinabè children enrolled at 6 months of age and followed until 28 months from August 2014 to December 2016, we employed multilevel mixed-effects models to investigate concurrent and lagged associations between linear and ponderal growth velocity, controlling for time trends, seasonality, and morbidity. RESULTS: Faster ponderal growth is associated with faster concurrent and subsequent linear growth (0.21-0.72 increase in length velocity z-score per unit increase in weight velocity z-score), while faster linear growth is associated with slower future weight gain (0.009-0.02 decrease in weight velocity z-score per unit increase in length velocity z-score), especially among children 9-14 months. Ponderal growth slows around the same time as peaks in morbidity, followed roughly a month later by slower linear growth. CONCLUSIONS: Use of velocity measures to assess temporal dependencies between linear and ponderal growth demonstrate that the same growth-limiting conditions likely affect both length and weight velocity, that slow ponderal growth likely limits subsequent linear growth, and that linear growth spurts may not be accompanied by sufficient increases in dietary intake to avoid slowdowns in weight gain.
