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Geographic variation of GI diseases.

Geographic variation of GI diseases. R. Fielding Department of Community Medicine, HKU. Learning objectives. Discuss the relationship between diet & GI disease, giving at least two examples to illustrate this

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Geographic variation of GI diseases.

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  1. Geographic variation of GI diseases. R. Fielding Department of Community Medicine, HKU

  2. Learning objectives • Discuss the relationship between diet & GI disease, giving at least two examples to illustrate this • Give meaningful examples of relationships between poverty & disease & realistic estimates of the scale of the problems arising from this • Give at least two examples of GI diseases arising from different geographic environments • Outline main components of the politics of infantile gastroenteritis • Describe the prevalence of under-nutrition, list most common causes and those most at risk

  3. Introduction • Both infectious and non-infectious GI diseases vary drastically by geographic location • Main influences: • socio-economic gradients • diet (foods, preparation & preservation) • political economics. • Infections contribute to number of important neoplasms (stomach; hepatic)

  4. Public health principle

  5. Cancers: Upper GIT • Oesophagus: was declining, but remains high in France, Iran, Kashmir, Khazakstan, China. Now increasing in west over past 20 yr: gastric reflux • Stomach: declines worldwide since 1970. Most common Ca in Japan. Japan, Korea & Sabah, Iran & Kashmir, (China: Qinghai, Ningxia) highest (about 26-33% of ca deaths in men). S & SE Asia, lowest prevalence in Asia.

  6. Incidence of gastric cancer /100,000

  7. What has changed? • Diet - • Food preservation methods • Increased screening, earlier detection but survival remains poor (50% 5 yr, 21% 10 yr Eckert etal, 1998) • Recognition of Helicobacter pylori too recent to impact on incidence rates.

  8. Cancers: lower GIT Whereas age standardized incidence of upper GIT cancers have declined, lower GIT cancer incidence has increased. Colorectal cancer incidence in West has increased (E.Europe 11% / 5 years) but mortality declining.

  9. GIT cancer incidence

  10. Contributing factors • Agent, vector, host changes in: • diet • activity • technology • social behaviour • living conditions • tobacco / alcohol use • persistence of infectious agents (Opisthorciasis / Hep B/C and hepatic ca.

  11. Infectious GI diseases • Increasingly serious problem in developed and well as developing world • Oro-feacal contamination: Major infectious GIDs are water- or food-borne. • Resulting from • poor hygiene / contamination • inadequate or improperly implemented food regulation • Many common GI infections not problematic unless immune-compromised

  12. Socio-economics of infantile diarrhoea • 40,000 infant deaths weekly <5 years old due to diarrhoea. • Principally contaminated water, (not boiled). • Baby milk formula food expensive, therefore made more weakly than required. • Lack of clean oral rehydration > death. • WHO estimates 1.5 million deaths / year avoidable by effective breast feeding protection.

  13. Why do poor mothers use baby formula? • Heavily promoted to doctors and in maternity units • “Free samples” given (which once used prevent baby reverting to breast feeding). Mother then dependant on formula food, which: • uses significant financial resources • cannot be administered properly as most women are illiterate • principle cause of infantile diarrhoea

  14. Poverty and GIDs Access to uncontaminated water more difficult for poor people. • combined with: • under or poor nutrition • tobacco / alcohol use • crowded living conditions • lack of toilets, sanitation • exposure to toxins and other carcinogens • greater risk of • diarrhoeal • parasitic diseases

  15. Malnutrition 1: overnutrition • Excess dietary intake: BMI >25 = overweight • Appears first among affluent then lower class. • In adults high refined protein, carbohydrate and fat intake and too low fruit/veg. • Predisposing factors are malnutrition during foetal and childhood periods. • 30% of Latin Am, Caribb, N.Africa, Pac.Is. and urban Asia

  16. 2. Undernutrition • Insufficient dietary intake. Protein-calorific or trace nutrient (eg iron, zinc). • Prevalent -Famine: war, drought, pests, floods unemployment, dislocation. • Primary (insufficient food); secondary ( parasitosis). • Growth delay, cognitive impairments in children • Risk factor for infectious GIDs, acute Ris and other infections.

  17. Summary • Where people live. • tropical / temperate, wet / dry, nomadic / rural / urban, developed / under-developed • What they do there… • agriculture/ fishing/ livestock, industry / service / homemaker • How they can live • trad/modern, poor/affluent, education / none, available health care, costs, market conditions • major determinants of their host status and exposure to vectors and agents of GIDs

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