Vitamin A supplementation in preschool children and risk of hearing loss as adolescents and young adults in rural Nepal: randomised trial cohort follow-up studyBMJ 2012; 344 doi: https://doi.org/10.1136/bmj.d7962 (Published 10 January 2012) Cite this as: BMJ 2012;344:d7962
- Jane Schmitz, clinical assistant professor1,
- Keith P West Jr, professor23,
- Subarna K Khatry, director3,
- Lee Wu, research associate2,
- Steven C LeClerq, field director23,
- Sureswor L Karna, chief audiologist4,
- Joanne Katz, professor23,
- Alfred Sommer, professor and dean emeritus2,
- Joseph Pillion, director of audiology5
- 1Institute for Global Health and Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
- 2Center for Human Nutrition, Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
- 3Nepal Nutrition Intervention Project-Sarlahi, National Society for the Prevention of Blindness, Kathmandu, Nepal
- 4Ear, Nose and Throat Department, Tribhuvan University Teaching Hospital, Kathmandu, Nepal
- 5Department of Audiology, Kennedy Krieger Institute, and Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Correspondence to: K P West Jr
- Accepted 14 October 2011
Objective To determine whether vitamin A supplementation administered in the preschool years can lower the risk of hearing loss in adolescence and adulthood.
Design Follow-up study of adolescents and young adults who, as preschool aged children in 1989, were enrolled into a cluster randomised, double blinded, placebo controlled trial of vitamin A supplementation.
Setting South central, rural Nepal.
Participants 2378 adolescents and young adults aged 14 to 23, representing 51% of those who finished the original trial and 71% of those living in the study area in 2006.
Interventions Every four months for 16 months preschool children were visited at home, given an oral 200 000 IU dose of vitamin A (half dose at age 1-11 months, quarter dose at <1 month) or placebo and the parents were queried about any childhood illnesses in the previous week, including purulent discharge from the ears.
Main outcome measures Prevalence of mild or worse hearing loss (≥30 dB) in the most affected ear and tympanometric measures of middle ear function (peak height, ear canal volume, and gradient).
Results During the original trial, the prevalence of middle ear infection during the preschool years did not differ between the supplement groups. By adolescence and early adulthood, a non-significant 17% reduction in hearing loss occurred among those who had periodically received vitamin A compared with placebo as preschool aged children (odds ratio 0.83, 95% confidence interval 0.62 to 1.12). Among participants with any ear discharge in early childhood, vitamin A supplementation was associated with a reduced risk of hearing loss, by 42% (0.58, 0.37 to 0.92) compared with controls, after adjusting the confidence interval for the design effect of the original trial. Abnormal tympanometric peak height of the middle ear system was less likely among participants supplemented with vitamin A in childhood.
Conclusion In undernourished settings, periodic, high dose vitamin A supplementation may reduce the risk of hearing loss associated with purulent ear infections in early childhood.
We thank Christine Stewart, Parul Christian, James Tielsch, Luke Mullany, Sharada Ram Shrestha (deceased), Darrell Mast, Andre Hackman, and Tirta Raj Sakya; field and data management staff of the study team; and hearing technicians, Jaisi Lal (deceased) and Matrika Dungel.
Contributors: JS designed the follow-up hearing study, supervised training and data collection, conducted data analysis and interpretation, and wrote the first draft of the manuscript. KPW (principal investigator of original trial and the larger cohort follow-up study) conceived and assisted in the design of the hearing study and edited the manuscript. LW contributed to data analysis and interpretation and edited the manuscript. SLC and SKK developed study procedures and supervised implementation of the original trial, larger follow-up study, and hearing study. SLK trained and provided continuing technical oversight of the hearing technicians and helped develop the hearing assessment protocol. JK assisted in the analysis and interpretation of the data and edited the manuscript. JP helped develop ear health and audiometry assessments, assisted in the interpretation of audiometric and ear health data, and edited the manuscript. All authors had full access to all of the data and can take responsibility for the integrity of the data and the accuracy of the data analysis. KPW is the guarantor.
Funding: This follow-up study was supported by grant No GH614 (Control of Global Micronutrient Deficiency) between the Bill and Melinda Gates Foundation, Seattle, and the Center for Human Nutrition, Department of International Health of the Johns Hopkins Bloomberg School of Public Health, Baltimore, and was undertaken in collaboration with the National Society for the Prevention of Blindness (Nepal Netra Jyoti Sangh), Kathmandu, Nepal. The original vitamin A supplementation trial was carried out under Cooperative Agreement No DAN 0045-A-5094 between the Office of Nutrition, US Agency for International Development, Washington, and the Johns Hopkins University, as a joint undertaking of the Dana Center for Preventive Ophthalmology and the National Society for the Prevention of Blindness, Kathmandu, Nepal, with in-kind (provision of supplements) and technical (nutrient potency analyses) assistance from Task Force Sight and Life (formerly of Roche, Basel, Switzerland, now Sight and Life, DSM, Basel, Switzerland). The funding agencies had no role in the study design, data collection, data analysis, data interpretation, or the writing of the report.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships that could appear to have influenced the submitted work.
Ethical approval: The study was jointly approved by the institutional review boards at the Institute of Medicine, Tribhuvan University, Kathmandu, Nepal and the Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Data sharing: No additional data available.
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