213 portable stadiometer

As previously described, trained fieldworkers measured infant anthropometrics including weight and length, once within 24 hours of birth^{23 (link)} and at ages three, six, nine and twelve months of age^{9 (link)}. Length was measured to the nearest 0.1 centimeter (Ayrton Infantometer Model M-200, Ayrton Corp, MN, USA) and weight was measured to the nearest 0.1 kilogram (Tanita digital scale model BD-590, Tanita Corp, Il, USA). We created Ghanaian-specific birth weight for gestational week curve following methodology described by the World Health Organization^{24 (link)}. We considered an infant small for gestational age if the infant was born alive with a birth weight less than the 10^th percentile for that specific week gestation.
At the age four lung phenotyping visit, we performed duplicate measures of weight (Seca 803 Clara Digital Floor Scale) to the nearest 0.1 kilogram and height (Seca 213 Portable Stadiometer) to the nearest 0.1 centimeter. We calculated HAZ, WAZ, WHZ at three, six, nine, and twelve months and four years of age using the 2006 WHO child growth standard reference for age and sex²⁵ . Stunting, underweight or wasting was defined as an infant or child with an HAZ, WAZ, or WHZ, respectively, less than two standard deviations below the WHO child growth standard reference median for age and sex.