Connecting Early Life Undernutrition to Hearing Loss: Evidence from Nepal

Abstract

ObjectiveAssess influences of early life undernutrition on young adult hearing loss in Nepal.Design: Ear health was assessed in 2378 Nepalese young adults (14‐23 y) who as preschoolers participated in a 4‐monthly placebo‐controlled, randomized vitamin A (VA, 200,000 IU) supplement trial ('89‐'92). At baseline, children were measured for WT, HT and MUAC. Parents were queried about ear discharge at each visit. Sixteen years later, audiometry and tympanometry were performed, blinded to original supplement receipt. Hearing loss was defined as pure‐tone average>30dB (0.5,1,2,4kHz) and middle ear dysfunction (MED) as abnormal tympanometric peak height (<0.3‐>1.4mmho) or width (<50‐>110daPa). Children were classified as stunted (<‐2 HAZ) or wasted (<‐2 MUAC & <‐2 BMI‐for‐age Z).Results: Hearing loss and MED affected 5.9% and 16.6% of subjects, respectively. Wasting was associated with odds ratios of 1.8‐2.2 for hearing loss and 1.4‐1.8 for MED, and stunting with ORs of 2.2‐1.7 for hearing loss, irrespective of MED (all 95% lower CL>1). For subjects with preschool ear discharge, VA receipt was protective against hearing loss, OR=0.58 (95% CI 0.37‐0.92). Further, we posit human antenatal VA deficiency may cause MED‐independent hearing loss (S Emmett, Med Hypotheses 2014;82:6), as reported in animals, similar to that associated with stunting.ConclusionPreventable early childhood and possibly fetal undernutrition, including VA deficiency, may predispose children to permanent hearing loss. Hearing loss should be considered a nutrition‐related public health burden.Funded by Gates Foundation (OPP614)