GLOBAL HEALTH AND EMERGING DISEASES

Transcription

1 GLOBAL HEALTH AND EMERGING DISEASES Public Health and Environmental Vision Section Symposium American Academy of Optometry Jeffrey L. Weaver, OD, MS, FAAO 3662 Boston s Farm Drive Bridgeton, MO (314) JLWeaverOD@gmail.com Pierre Buekens, MD, MPH, PhD W.H. Watkins Professor and Dean Department of Epidemiology pbuekens@tulane.edu John Mason, PhD Professor Department of Global Community Health and Behavioral Sciences masonj@tulane.edu Susan McLellan, MD, MPH Clinical Associate Professor of Public Health smclell@tulane.edu OUTLINE: 1. Overview of Global Health Issues a. Are we Globalizing Global Health? i. Increasing consensus among experts 1. Global Health should link domestic and international health issues and solutions. ii. Current academic programs 1. Still focused on low-resource countries only. iii. Ongoing challenges 1. Increase efforts to Globalize Health 2. Do not lose the emphasis on the most deprived populations.

2 2. Trends in Nutrition and Vitamin Deficiency a. Vitamin A interventions prevent blindness and could have much wider benefits b. A brief history of Vitamin A i. Function and vitamin A deficiency (VAD) recognized (all still true) 1. Vitamin A as anti-infective agent, Mellanby and Green, 1928; 2. vitamin A deficiency the most lethal of deficiencies Moore, 1965; 3. no nutritional deficiency more synergistic with infection.. Scrimshaw/WHO low tissue concentrations of vitamin A adverse health consequences even in the absence of clinical signs Underwood/IOM, i. Xerophthalmia and blindness fixed, Periodic massive doses of vitamin A (200,000 IUs/6 months or even one-time) prevent night blindness and corneal damage 2. India, Bangladesh, Indonesia, Nepal: e.g. Sinha and Bang, India, 1976 Tarwotjo 1989: one dose effective up to at least 6 months. 3. Fortification (and frequent low dose VA) already shown to be as effective (e.g. Solon and Latham, Philippines, 1979) ii. Mortality impact of high-dose VA 1. In blindness trial, Indonesia (Aceh), Sommer, Several more trials, meta-analysed as 23% reduction in 1-5 yr MR, Massive programs launched, never evaluated until 2004, with dramatic claims of lives saved: see below. c. Policy success: Blindness prevention. i. Early high-dose VA programs plus improved diet and health led to rapid reduction in xerophthalmia and blindness caused by VAD. ii. Process involved international agreement (WHO) and support for VAC distribution. iii. Assessment difficult on population basis: 1. clinical signs prevalence ~= <5%; 2. sub-clinical (serum retinol) nearer 50%, but requires blood and expensive assay 3. functional tests hardly available

3 d. Policy failure: persistent VAD not addressed i. International agreements ( e.g. International Conference on Nutrition, FAO/WHO, 1992), and inter-agency (UN-SCN, 1994) all stressed need for mixed approach, with high dose intermittent VA capsules (VACs) as stop-gap measure ii. However, VACs were only intervention widely implemented, as magic bullet. iii. As serum retinol began to be measured nationally, clear that problem persisted despite VACs; e.g. Philippines with about 90% VAC coverage, VAD (low SRF, as now defined by WHO) had these prevalences: 1993, 36%; 1998, 38%; 2003, 41%. iv. Several studies showed that SR response to 6-monthly high-dose VACs was small and transient; even 3-monthly did not raise SR (in contrast to fortification), Mason et al, This is why VACs do not affect VAD. v. Recent studies (India: DEVTA, Awasthi, Peto, , published 2014; Guinea-Bissau: Benn, Aaby 2014) showing zero mortality impact suffered extraordinarily long and unexplained publication delays. vi. VACs reached 8 billion! e. The complex function of VA leads to obfuscation i. VA s known function expanded in last decade or so: gene expression, immune competence, epithelial integrity, immunomodulation (but no clear mechanism for mortality effect) ii. VA in periodic high doses prevents xerophthalmia and blindness iii. VA in periodic high doses does not prevent VAD iv. VA in periodic high doses may have reduced 1-5 yr MR in past, through affecting diarrheal and measles mortality; as these have declined its impact may be less or zero (or negative). v. Holding these ideas together at one time is not encouraged by the international agencies, who have a vested interest in continuing VAC distribution all over the globe (about 70% of 1-5 year old kids in poor countries get 1-2 dose per year). f. The paradigm may be shifting, to commonsensical frequent low dose VA i. Recent evidence is for zero 1-5 yr mortality impact (Mason et al, ) ii. Recent calculations are that only 1.7% of overall U5MR could be due to VAD (Stevens/Ezzati/WHO, Lancet Sept 2015); we estimated (by a

4 different calculation) that 2-3% of U5MR at most could be prevented by VACs. iii. A prudent shift from periodic high dose VACs to frequent low dose VA, from better diet, supplements (daily or weekly), or fortification, is clearly indicated; the level of vehemence in rejecting this solution by those vested in VACs suggest that the paradigm (a la Kuhn) may indeed be shifting. iv. And, by the way, women cannot receive VACs in high dose which should be a clincher g. Which brings us to the key issue, how to ensure access to VA in poor countries i. Which brings us to the same issues as other deficiencies, and to malnutrition in general ii. Implement PHC finally, and support community-based programs, now being shown as the most effective direct way to improve nutrition in women and children in poor countries. iii. This, plus fortification, could quite rapidly reduce vitamin A deficiency, with likely extensive benefits to health as the anti-infective vitamin. 3. Ebola and Other Emerging Diseases that Affect the Eye a. Global Health concept has spread into every field of medicine. i. Increasing global mobility ii. Clinical practitioners in developed countries still encounter diseases not commonly seen in the Western setting. iii. More practitioners are interested in contributing to the care of individuals in resource-limited settings 1. Providing direct clinical care 2. Contributing to programs which address the health care needs of populations. iv. Understanding the range of pathologies which may present in resource poor settings is important for clinicians of any specialty 1. Ophthalmology 2. Optometry b. Review of infectious diseases i. Infectious causes of eye problems which are more prevalent in resourcepoor settings. 1. Clinical aspects

5 2. Public health approaches to management on a population basis a. Diseases which have a large public health impact i. Trachoma ii. Onchocerciasis c. Ebola i. Newly recognized information about ophthalmologic complications ii. Impact on the lives of survivors from the recent extensive outbreak 4. Panel Discussion