Relationships between growth and acute lower-respiratory infections in children aged less than 5 y in a highland population of Papua New Guinea.

One hundred fifty-six children in the highlands of Papua New Guinea aged less than 5 y, studied for a total of 7019 child-weeks, had an incidence of 1.3 episodes per child-year of acute lower-respiratory-tract infections (ALRIs). There was a marked age trend with an incidence of almost three times this average for children aged less than 6 mo. Those with low weight-for-age or low height-for-age had a higher ALRI incidence rate, with no evidence of cutoffs above which nutritional status had no effect; there was no association between low weight-for-height and increased risk of ALRI. A slow weight gain was not a significant risk factor in the short term but weight gain was reduced during episodes of ALRI.