9.8: Epidemiological Anthropology

Anthropology In Understanding of Health & Disease

Introduction – Medical anthropology, as a sub-field of anthropology, draws upon social, cultural, biological & linguistic anthropology to better understand human health & disease, health care systems, bio cultural adaptations.

Epidemiology the study of the distribution & determinants of health related states or events (including diseases) and the application of this study to the control of diseases and other health problems. It is the corner stone method of public health research and helps in

• Informed policy decisions
• Evidence-based medicine
• Better targeting of preventive medicine→

Human growth occurs along a genetically destined trajectory, but is influenced by environmental factors consequently affecting its longevity & health status. Consequently diseases exhibit the whole spectrum of causation, raging from hereditary factors which play predominant role, to environment. We need to consider not only man’s physical environment but also his social, cultural & psychological circumstances.

Approaches in Medical Anthropology

1. Epidemiological Approach – Examines how aspects of the natural environment interact with culture to influence the occurrence & spread of disease in human population.

Case Study – In Sierra Leone, the local community would resist the authorises over removal of the dead bodies of Ebola victims. The community insisted at performing their rituals. Epidemiological anthropologists helped the authorities understand this cultural aspect. The tribal chiefs & shaman were convicted first, who then asked their people to halt burial rituals.

2. Interpretivist Approach – Looks at the way cultures use symbolic meaning to describe & understand health & disease. E.g Levi Strauss studies how a song sung by a Shaman among the Kuna Indians of Panama helps a woman through a difficult delivery.
3. Critical Medical Anthropology – Focuses on how socio-economic & political factors shape the overall status of human health. E.g disparities in the quality of health due to social inequalities.

Anthropology’s Contribution to Epidemiological study of Health & Disease

• Most of chronic, non infectious diseases are caused by a no. of life style variables which are social & cultural in nature
  • an understanding of social & cultural factors is imperative
• The spread of human diseases & their control depends to a very great extent on social & cultural factors
• Disease etiology now requires understanding psychological, biological & socio-cultural characteristics of the hosts rather than exclusive concern with exposure to particular agent.
• Anthropologists also shown increasing interest in potential contribution anthropology can make to public health, disease occurrence etc.

Thus, by its holistic outlook, anthropology helps design adequate biological, cultural & behavioural interventions to fight health related problems.  These factors led to the interdisciplinary approach of Epidemiological Anthropology.

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Epidemiological Anthropology

Introduction – Epidemiological anthropology  is a sub-field of anthropology that studies the determination, manifestation & distribution of diseases & disorders in human community.

Background – It evolved from the integration of medical anthropology with epidemiology. As compared to the later, it is wider in scope as it also includes impact of human factors & population variation in the occurrence & spread of diseases. It focus equally on biological & socio-cultural factors.

Casual Web – The interdisciplinary approach of Epidemiological Anthropology revealed that new human disease or disorder is the result of many factors within a “Causal Web” – a web of determinants. it include

• Exogenous Factors – Biotic & Non Biotic
• Endogenous Factors – Genetic
• Demographic Factors
• Behaviour – Social, Cultural & Psychological

It is the goal of EA to identify and measure the relative imp. of factors within this causal web of disease.

Case Study (Amy Maxmen, 2015)

• In Sierra Leone, the local community would resist the authorises over removal of the dead bodies of Ebola victims. The community insisted at performing their rituals. Epidemiological anthropologists helped the authorities understand this cultural aspect. The tribal chiefs & shaman were convicted first, who then asked their people to halt burial rituals.

Relevance – Helps in Understanding

• Relation of disease with cultural & ecological settings
• Accurate pattern of disease by Participant observation
• Ways to increase efficacy of medicine, gene therapy etc
• Ethnomedicine

Conclusion – with new challenges such as anti-microbial resistance and neglected tropical diseases, epidemiological Anthropology, with its holistic outlook, has huge significance for human health.

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Scope of Epidemiological Anthropology – Infection & Non Infection Disease Study

Introduction – Epidemiological Anthropology elucidates etiological factors involved in a disease incidence : and emphasis on population variation in incidence & occurrence.

Study of Diseases – Epidemiological Anthropology confers to the determination, manifestation & distribution of certain diseases and disorders in human communities spread all over the globe. The spectrum of disease causing factors ranges from genetic or env. Sociocultural background also exhibits influential role as human settlement pattern enhances the spread of disease.

It includes following studies

• Infectious Diseases
• Biological Responses
• Non infectious Diseases
• Ecology of Malnutrition
• Distribution of Deficiency Diseases
• Effects of Nutritional Stress
• Nutritional Stress in Modern Society

Infection Diseases –

• these are disease in which a biological agent / pathogen parasites or infects a host. E.g AIDS, malaria, TB
• these pathogens are classified taxonomically (e.g bacteria, virus), or by their mode of transmission (e.g Sexually transmit, airborne, waterborne), or by the organ system affected (e.g respiratory or brain infections)

Non – Infectious Diseases

• these disease are not caused by micro-organisms. There are not contagious.
• They are mainly cased by genetic, environmental or lifestyle factors. These are mainly of five types – diabetes, allergies, cardiovascular disease, cancer & genetic diseases.

Scope of Epidemiological Anthropology

It examines how aspects of the natural environment interact with culture causes such diseases & to influence their spread throughout the population. Its scope thus revolves around.

1. Understanding the impact of
   1. Family patterns – e.g genetic history, lifestyle & diet
   2. Population density
   3. Social habits – e.g hygiene & sanitary habits
   4. Temperature & humidity
   5. Migration -e.g in 19th century, a Danish traveller carrying measles virus was responsible for spreading it to 6000 inhabitants of Faroe Islands
   6. Occupation & commerce – e.g Mine workers are highly vulnerable to respiratory infections
2. Accurate cause / patterns of diseases by using participant observation
3. Ways to increase efficacy of interventions like vaccine & gene therapy
4. Ethno-medicine & its scope for wider utility E.g Himalayan Yew has been used by Bhotias of Himachal, as an anti cancer drug.

Conclusion– Thus, by its holistic outlook, epidemiological anthropology helps design adequate biological, cultural & behavioural intervention to fight such disease.

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Health

• It is defined as an ability to function effectively in complete harmony with one’s environment – the ability to meet physical, emotional & mental stresses of life. Hence it is more than physical fitness – it involves social, mental & emotional well being.
• It can be defined based on measurement of some biological criteria based on statistical concepts like temp, pulse, breathing rates, BP, height, weight etc.

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Disease

Introduction – A disease is any deviation from normal form & function(i.e Health) or behavioral. – any biomedical deviance.

Disease & Illness – are used interchangeably, but they are not same.

Illness is the subjective & social experience of disease.

• A person may have a disease for many years without even being aware of its presence i.e he is diseased but not ill
• A person with the disease Diabetes is no ill as long as he takes insulin.
• Many cancers go undetected till they cause symptoms – Disease vs Illness Dichotomy

Types of Disease

• On the basis of the duration of the disease : Acute & Chronic
  • Acute – Acute disease begin abruptly & are over soon
    • Ex. Acute appendicitis – nausea, vomiting, pain in the lower right side of the abdomen – requires immediate surgery
  • Chronic – that begins very gradually & persists over a long period of time.
    • Ex. Ulcerative Colitis – inflammatory condition limited to colon – peak incidence is in the the second decade of life – relapsing attacks of bloody diarrhea for weeks to months alternating with asymptomatic periods for weeks to months alternating with asymptomatic periods for weeks to years
• On the basis of the potentiality of causing death : Malignant & Benign 

Most often used to explain tumors & also in general sense.

• Benign – Benign diseases are generally without complications & a good prognosis (the outcome of disease) is usual
  • Ex. Wart on the skin – caused by a virus – produces no illnesses & usually disappears given time
• Malignant – Malignancy implies a process that, if left alone, will result in fatal illness
  • Cancer is a general term for malignant situations

Classification of Disease

Important in Compilation of statics on cause of illness (morbidity) & causes of death (mortality) & it is obviously imp. to know what kinds of illness disease are prevalent in an area & how these prevalence rates vary with time. Variously Classified

• Topographic – by bodily region or system
  • ex. Gastrointestinal, vascular
• Anatomic – by organ or tissue affected
  • ex. Heart disease or liver
• Physiological – by function or effect produced by a specific disorder
  • Metabolic or respiratory etc
• Pathological – by nature of disease process
  • Neoplastic (tumors,particularly cancers) or Inflammatory
• Ethiologic – Causal factors
  • Imp in consideration of biotic disease.
  • Bacterial, viral, fungal etc
• Epidemiological – by distribution, incidence etc.

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Ecology of Disease

Introduction – There exist a competitive interaction between man & environment.

• On one hand, this struggle may be against unalterable & passive opponent eg. physical and climatic factors (temp & atm. pressure)
• on the other hand, biological env. which is in itself capable of adaptive responses.

The ecological aspect of of disease can be revealed into two ways

1. Physical Environment
   • It is a direct & immediate source of injury & ill health.
   • there is consequently a clear geographical distribution of pathology manifested as a consequence of extreme climatic effect e.g. heat stroke (desert), mountain sickness (high altitude) & rodent ulcer (UV Light)
   • In recent years, air pollution due to smoke & associated substances has become an imp. environmental hazard in many countries.
2. Biotic component of the evn harbours pathogenic organism ( viruses, bacteria, protozoa, fungi) dangerous animals as well as poisonous plants & insects. In addition nutritional disorders arise due to improper utilization of food sources – animal & vegetable (also mineral)

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Infectious Diseases

Introduction -Infection is the invasion of the body by various agents – including bacteria, fungi, protozoans, virus & worms – and its reaction to them or their toxins

Mode of infection – Infectious agents can enter the body by inhalation, ingestion, sexual transmission, passage to a fetus during pregnancy or birth, wounds contamination, or animal or insect bites

Biological response to infectious diseases  – two fold responses to infectious disease :

1. Immediate responses ; These are physiological processes which counteract the effects of the invading organisms evident by symptoms & signs of the disease such as inflammation, pain, fever etc. Prolonged exposure to infection may result into immunological responses. The antibody may result in short term or lifelong immunity.
2. Long term responses ; It become evident after a long period & are action specific.

If a disease is wide spread or severe in nature then it may act as an efficient selective agent. Individuals who are able to combat the disease will survive while other are eliminated.

Such as resistance may be due to increased physiological adaptability, enhanced immune response or both. Prior exposure to such diseases ameliorates its severity in successive generations. Otherwise, the population would experience high morbidity & mortality rate.

Ecology of Infectious Diseases

• Family Patterns – Humans are social animals. → human social habits & circumstances influence the spread of infectious agents.
  • Poorer families tend to live in more crowded conditions, which facilitate the passage of disease causing organisms from one person to another.
  • Composition of family unit is also imp. In families with infants & preschool children, infection spreads more readily, for children of this age are both more susceptible to infection & b/c of this close & confined contact, infectious agents are spread more rapidly.
• Population Density – Density of population doesn’t it self determine the ease with infection spread throughout the population. In the New York City, with its many high rise dwellings, the density off population per square mile is much greater than in some of the world’s older cities, but the hepatitis virus, for example, spreads much faster in the latter.
• Social Habits – For example social habit for open defecation, use of dustbins to throw garbage etc determine the spread of infectious diseases.
• Temperature & Humidity –At a social gathering, the human density per square yard may be much greater than in any home, & humidity & temp may rise to levels uncomfortable for humans but ideal for microbes. Virus containing droplets pass easily from one person to another, & an outbreak of the common cold may result.
  • In contrast, members of scientific expeditions have spent whole winters in the Arctic or Antarctic without any respiratory illness, only to catch severe cold severe colds upon the arrival of a supply ship in the early summer. This is b/c viruses, not cold temp., cause colds.
• Migration – Movement into a new environment often is followed by an outbreak of infectious disease. On Pilgrimage & in wars, impoverished feeding & sanitation lead to outbreaks of such intestinal infection as dysentery, cholera & typhoid fever & sometimes more have died in war from these diseases than that have been killed in the fighting.
• Occupation & Commerce – In occupational & commercial undertakings, people often manipulate their env. & in so doing, expose themselves to infection.
  • A farmer in his fields is exposed to damp conditions which disease microorganisms flourish. While clearing out a ditch, he may get infection with Leptospirosis passed into the water in rat’s urine.

Thus ecological factors are responsible for infectious diseases and these factors need to be taken into account while planning to control them.

Non-Infectious Diseases

Introduction – In non-infectious disease, the whole complex of environmental factors & biological responses (inborn & acquired) must be considered to account for regional variation.

Few Examples

• The fact that Negros are more susceptible to frosbite than Eskimos or North Ameican Indians which may be attributed to both lack of acclimatisation & genetic suceptibility
• Many diseases have been accorded a racial pathology but the distribution was entirely related to environmental peculiarities.
• Striking racial differences in the incidence of coronary disease is associated with diets high in fat.
• Many disease & malformation are known to have genetic basis : the afflicted individual is ususlly homozygous for the recessive gene, though dominant genes are also involved in some conditions, Genetic diseases are rare. However, certain population have high frequency of such diseases.
• Thalassemia & sicklecell anemia are hb variants casued by mutation in hb gene.
• Haemolytic disease of the new born due to rhesus incompatibilty is characteristic of European but not of most Mongoloid or Amerindian populaitons, since they are devoid of Rh-ve individuals
• There is an inceased risk of duodenal ulcers in individuals of blood group O & individuals with blood group A are more prone to stomach cancer than others.

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Nutritional Deficiency Diseases

Human body requires many different nutrients such as proteins, carbohydrates, fats, vitamins & minerals that are crucial for both development & preventing disease. These vitamins and minerals are often referred to as micronutrients.

They aren’t produced naturally in the body, so you have to get them from your diet. The nutritional status of individuals & population span a broad range from extremes of deficiency to excess.

A nutritional deficiency occurs when the body doesn’t absorb or get from food the necessary amount of a nutrient. Deficiencies can lead to a variety of health problems.

These can include digestion problems, skin disorders, stunted or defective bone growth, and even dementia.

Malnutrition

Malnutrition refers to cellular imbalance between the supply of nutrients & energy & the body’s demand for them to ensure growth, maintenance and specific function.

This condition can result from

• fasting &
• anorexia nervosa( obsess about weigh & what they eat),
• persistent vomiting (as in bulimia nervosa)
• inability to swallow:
• impaired digestion and intestinal malabsorption;
• chronic illness that result in loss of appetite (eg. cancer, AIDS)
• limited food availability
• unwise food choices
• overzealous use of dietary supplements.

It is more prevalent among developing nations, primarily those undergoing the urbanization

Protein-caloric malnutrition/Protein Energy Malnutrition(PEM) is the most common form of under nutrition. In includes

• Kwashiorkor
  • also c/a ‘2nd child disease as usually associated with period immediately following weaning, which often takes place after the birth of second child.
  • In many parts of the world, especially in the tropics, the child is resorted from mother’s milk to a diet adequate in carbohydrates & has insufficient protein. Thus the child may receive enough food to satisfy hunger, but doesn’t receive the proteins vital for normal health, growth & development.
  • Characteristic symptoms include
    • Edema or fluid retention in the feet, lower legs & seldom in other parts of the body
    • Growth & psychomotor development is retarded
    • Severe wasting of muscle & adipose tissue can be depicted from the thinness of upper arms.
• Marasmus
  • means withering or wasting.
  • It results from a diet low in both protein & calories.
  • It is more frequent among children younger than 5 years, but usually soon after weaning.
  • Characteristic Symptoms include
    • Skin & bone appearance of body
    • extreme growth retardation,
    • Wasting of muscles & subcutaneous fat
    • Diarrhoea
    • Sever anemia
    • mental retardation, as vital nutrients are -nt during period of critical for brain growth.
  • It result into death.

Kwashiorkor & Marasmus represent extreme examples of malnutrition & growth retardation.

These can also occur in

• hospitalized patients receiving intravenous glucose for an extended time, as when recovering from surgery or
• in those with illness causing loss of appetite or malabsorption of nutrients.

Vitamin & Mineral Deficiencies

Several vitamins such as A,B,C,D etc, & micronutrients such as iron, calcium etc. are needed for normal growth & development.

Due to vitamins deficiency, human experience multiple deficiencies simultaneously. for eg.

The 8 vitamin B complex vitamins functions in coordination in numerous enzyme systems & metabolic pathways; thus a deficiency of one may affect the function of others.

practice of clay eating, it interferes with absorption of Zn, Fe & other minerals,

Excessive amount of the nutrients are also hazardous to health.

• excessive amounts of vitamin D lead to hypercalcemia, characterised by high level of calcium in the blood, It result into sluggish nerve reflexes, weak muscles & unnatural calcification of soft tissue.
• Obesity refers to excess fat accumulation which may unfavourbale affect health of an individual leading to reduced life expectancy & increased health problems.
  • An adult with BMI>30kg/m2 said to be obese while a child is considered obese when his or her body weight is 20 % greater than that for his sex & age specific weight for height standard.
  • Obese children mature earlier.

Distribution of Deficiency Disease

• American geographical soceity has provided an eminent image of the distribution of the nutritional deficiency diseases in different parts of world
• Protein deficiency is predominantly found in South America, African, Indian & South East Asian populations
• Mineral deficiencies predominate in Northern Ameican continent upper part of Southeast Asian countires & some African populations.
• The incidence of multi vitamin deficiencies is rampant in Africa, middle East & some islands of Pacific Ocean.

Effects of Nutritional Stress

• Infant Mortality & Childhood Death
  • IMR in india is high, computed as 80/1000 live births, Prolonged nutritional stress, specifically during infancy & preschool age is a major, although indirect factor leading to infant & early childhood mortality.
  • Decreased Resistance to Infection : The resistance to infections in human is adversely affected by malnutition. The skin & mucosa don’t provide effective terial infection get reduced in severedly malnourished individuals.
• Under nutition & learing AbilitesThe period of active growth of human brain extends from 30th week of gestation to the end of the second year of life. Under nutition during this period appears to adversely affect the development of brain . Evidences have been derived either from the association of malnutriton in early infancy with poor mental performance later in childhod or with the retarded brain growth or size as observed in autopsy specimens. ****

Nutritional Stress in Modern Society

Prior to middle age,

• rice was used in South East Asia & some parts of Indian subcontinent,
• maize in central America,
• potatoes in South America,
• wheat is South West Asia &
• millets in Africa & part in Chine.

However, during middle age, long voyages undertaken by several groups of people led to the world wide dispersion of new domestic crops & animals for example Rice cultivation was brought to Africa. The potatoes were also spread to many parts of the world.

Disruption of traditional diets & introductin of new food stuffs casued nutritional stress in many societies. The estimate of such a stress in earlier times in not know completely but by the begining of 20th century epidemics of goiter, pellagra & beriberi were evident.

In urban areas, movement of people into the cash economies decreased the supply of proteins, making it costlier. Poorer sections of sociey in urban area thsu became victimes of Kwashiorkor

Though nutritional stresses are declining in the contemporary society, infectious diseases are being replaced by non infectiour diseases. An increased genetic heterosis is also indicated. Children in modern society are growing faster & taller. They are maturing sexually at an earlier age. However, in many third world contires the nutritional deficiency diseases are still found in a large scale.

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Non Infectious Diseases

Diseases of Genetic Origin

Certain human diseases result from mutations in genome. i.e Any alteration of the DNA may result in the defective synthesis & subsequent malfunctioning of one or more proteins.

• if the mutated proteins is a key enzyme in normal metabolism, the error may be serious or fatal consequences.
• Mutations that occur in somatic cells cann’t be inherited & can casue congenital malformations & cancers
• mutations that occur in germ cells are transmitted to offspring & are responsible for inhertied diseases & cause a genetic disorder
• genetic disease caused by a mutation in one gene are inherited in either domiant or recessive fashion.
  • Autosomal recessive diseases are more common & include Cystic fibrosis, Tay Sachs Disease & Sickle cell anemia.
  • Autosomal dominant : Huntington’s Chorea
    • A degenerative disease of nervous system that usually doesn’t develop until the carrier is b/w 30-40 years of age so not congential.
    • delayed onset of this allows its lethal gene to passed on to offspring.
• Genetic disorder may be inherited in an autosomal or X linked manner.
  • X linked dominant disorders are rere,
  • X linked recessive are relatively common & include Duchenne’s Muscular Dystrophy & Hemophilia A

Genetic & Congenital(existing at birth) Genetic Disorders

• Most but not all genetic diseases are congenital
  • most genetic disorders can be detected at birth because the child is born with characterstic defects.
  • disease like Huntigton’s chorea is not congenital
• Some congenital diseases are not genetic in origin, instead they may from some direct injury to the developing fetus.

Diseases of Immune Origin

Disorders of immune system fail into two broad categories :

1. Arises due to immune deficiencies : immune mechanism fails to prevent infection
   • Inherited immune deficiencies : caused by genetic defect & usually manifest early in life.These undermine the immune response in variety of ways ;
     • B lymphocytes may be unable to produce antibodies,
     • phagocytes may be unable to digest microbes
     • speicfic complement components may not be produced
   • Acquited immune deficiencies : due to infectious virues, action of immunosuppressive agents & effect of certain disease processes such as cancer.Acquired Immune deficiency Syndrome (AIDS)
     • casued by infection with the human immunodeficiency virus (HIV)
     • HIV destroys certain type of T lymphocyte, the helper T cell.
     • infected individual is susceptile to a variety of infectious organisms, including Opportunistic pathogens, which may be live benignly in the human body & cause disease only when the immune system is suppressed.
     • Kaposi’s sarcoma & Pneumocystis carinii pneumonia , prevalent in the AIDS population & are often cause of mortality.
2. Arises when immune response is directed at an inappropriate antigen such as
   • noninfectious agent in an allergic reaction
   • the body’s own antigens in an autoimmune response
   • cells of transplanted organ in graft rejection

Allergies

• immune system may reach to any foeign substance & It can the respond to innocuous materials in the same way that it responds to infectious agents.
• If foreign material poses no threat to the individual, an immune response is unnessary, but it nevertheless may ensue.
• This misplaced response is c/a as allergy, or hypersensitivity &
• foreign material is referred to as an allergen & common allergens include pollen, dust , bee venom & various food such as shellfish.
• on first exposure to the allergen, & it develop antibodies & specific T cell to allergen 7 allergic rxn doesn’t usually accompany this initial event but on reexposure, the symptoms of the allergic response appear.
• these symptoms range from the mild response of sneezing & runny nose to the sometimes life threating reaction of anaphylaxia or anaphylactic shock,
  • symptoms of which include vascular collapse & potentially fatal respiratory distress.

Autoimmuen Disorder

When immune responses mounte against proteins that belong to the host & this arises when self reactive lymphocytes are activated by self antigens in the host’s own tissues, often with devastating effects.

Systemic lupus erythematosus, thyroiditis, insulin dependent diabetes mellitus & rheumatoid arthritis are ex.

Two mechanisms prevent the immune system from mounting an attack against the host’s own tissue

1. elimination of self reactive lymphocyes during their development & maturation in the thymus with the reaction with self antigen. but protective selection is not highly efficient
2. 2nd line of defence : self reactive lymphocytes lose their ability to react to self antigens when they are encountered in blood & tissues. This state is referred to as immunologic ignorance.

Graft Rejection

• Each individual’s cells have a spectrum or genetically determined cell surface protein antigens, c/a Major histocompatibility complex (MHC) antignes, or human leukocyte antigens
• MHC antigens determine a person’s tissue type just as RBC antigens determine blood type.
• Aside from siblings, especially identical twins – having the same form of each gene is extremely small. even parents have different
• this differences in tissue antigens pose an obstacle to transplantaion b/c foreing donor tissue will introduce antigens in the recipient that will trigger an immune response leading to tissue death & rejection

Diseases of Abnormal Cell Growth

Control of cell growth persists throughout life except for episodic instances such as healing of an injured tissue.

hyperplasia is the region of localized growth of cells in accelerated to reconstitute the tissue to its previous state of normal str. & funtion.

oncology

Protonco Gene to Ontogene

Diseases arising from uncontrolled cell growth & behaviour collectively constitute the second most common cause of human death ( the most common casue being heart disease)

The tumours are referred to as malignant or benign based on the structural & functional properties of their component cell & their biological behaviour.

• the cell & tissues of malignant tumours differ from the tissues from which they arise.

Disease of Endocrine Origin

Due to under or oversection of hormones or from inability of targer organs or tissue to respond to hormones effectively.

Disease of Neuropsychiatric Origin

• Three major Psychiatric Diseases – Schizoprenia, Major depression, Mania
• Three major Neurological Disorders – Alzheimer’s, Huntigton’s Chorea & Parkinson’s Disease.
• In many neurophyschiatric diseases alterations in the levels of transmitter substances appear to play a major role in pathogensis.

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Deficiency Disorders

Carbohydrates

• if dietary carbohydrate is insufficient, glucose synthesis depends on the breakdown of AAs from body protein & dietary protein & compound glycerol
• Long-term carbohydrate inadequacy →⬆️ed production of organic compounds called Ketones (condition c/a Ketosis)
  • can prevented 50-100 gm carbohydrates daily
• obtaining at least half of the daily energy from carbohydrates is recommended

Essential Fatty Acids

• minimum requirement for fatty acids only below 2 & can be met by consuming aprox. tablespoon of polyunsaturated plant oils daily .
  • Linoleic Acid (Omega 6 Fatty Acid)
  • Alpha linolenic Acid (Omega 3 Fatty Acid)
• deficiency of these two seen in
  • hospitalized patients fed exclusively with IV fluids (Intravenous) containing no fat for weeks
  • medical condition affecting the fat absorbtion
  • infants given formulas low in fat
  • young children fed nonfat milk or low fat diets
• Symptoms
  • dry skin
  • hair loss
  • impaired wound healing

Vitamin A

• deficiency
  • leading cause of preventable blindness in children
  • mild deficiency can impair immune function → low resistance to disease
• Symptoms
  • early symptoms : Night blindness
  • followed by : abnormal dryness of eye
  • Ultimately : scarring of the cornea , condition k/n as Xerophthalmia.
  • other symptoms include dry skin, hardening of epithelial cells & impaired growth & development
• A large single dose of Vitamin A every six months & GM modified rice containing beta carotene, a precursor of Vitamin A called Golden rice has potential to reduce greatly the incidence of deficiency

Vitamin D

• Synthesized in body in series of steps, starting in skin by action of UV rays on precursor compound
• can occur
  • without adequate food source of Vitamin D
  • limited exposure to sun light
    • women completely covered their bodies for religious reasons
    • elderly or homebound persons
    • those with dark skin
• Cause
  • Rickets in children
    • inadequate mineralization of bone
    • growth retardation
    • skeletal deformities , such as bowed legs
  • Osteomalacia : adult form of rickets
    • week muscles as well as bones
  • Also contribute to the thinning of bone as seen in Osteoporosis
• found in few foods naturally, so fortification of milk & other foods(e.g. margarine, cereals & breads) help population in which sun exposure is inadequate.
• Supplemental vitamin D also may protect against bone fractures in elderly.

Vitamin E

• no specific metabolic function for Vitamin E
  • important part of antioxidant system (i.e inhibit lipid peroxidation) – protect cell from damaging effects of free radicals
• deficiency rare in human,
• may develop
  • in premature infants &
    • fragility of RBC is seen ( hemolysis)
  • in people with impaired fat absorption or metabolism.
    • if prolonged deficiency : neuromuscular dysfunction involving spinal & retina may result in loss of reflexes, impaired balance & coordination, muscle weakness & visual disturbances.
• The requirement ⬆️ with ⬆️ consumption of polyunsaturated fatty acids & people who smoke, subjected to air pollution to protect against oxidative damage to the lungs

Vitamin K

• necessary for formation of prothrombin & other blood clotting factors in the liver & play role in bone metabolism
• A form of vitamin is produced by bacteria in colon & can be utilized to an extent.
• rare in adult except in syndromes with poor fat absorption, in lever disease, or during treatment with certain anticoagulant drugs, which interfere with vitamin K metabolism
• deficiency causes :
  • impaired clotting of blood & internal bleeding
• Bleeding due to its deficiency maybe be seen in patients whose gut bacteria have been killed by antibiotics

Vitamin B1 – Thiamin

• deficiency result in beriberi disease
• can occur in
  • population where white rice has been staple
  • population eating large quantities of raw fish harboring intestinal microbes that contain the enzyme thiaminase.
  • chronic alcoholism with poor diet ; manifesting as Wernicke – Korsakoff syndrome
    • condtion with rapid eye movements, loss of muscle coordination, mental confusion & memory loss.
• Symptoms
  • of dry beriberi : loss of appetite, confusion & mental symptoms, muscle weakness, painful calf muscles, poor coordination, tingling & paralysis
  • of wet beriberi : edema & possibility of enlarged heart & heart failure.

Vitamin B2 – Riboflavin

• deficiency k/n as Ariboflavinosis
• Symptoms : cracks in the skin at the corners of mouth, fissures of the lips, & inflamed, magentacoloured tongue.
• readily destroyed by UV light,
  • so jaundiced infants who are treated with light therapy are administered the vitamin
• Milk, milk products, cereals

Vitamin B3 – Niacin

• Pellagra develop after 2moths niacin withdrawl from diet.
  • Characterized by three Ds – diarrhea, dermatitis & dementia
  • if allowed to progress untreated , death sure
• can occure in people who subsist primarily on corn, niacin in corn & other cereal grains is largely in bound form & Corn is low in AA tryptophan , which can be converted in part to niacin.
  • soaking corn in lime water, practiced by Native American ; frees bound niacin
  • Sufficient high quality protein 9(containing tryptophan) in diet can protect against niacin deficiency

Vitamin B6 – Pyridoxine & related compounds

• essential in protein metablism, neurotransmitters synthesis & other critical funT in body.
• deficiency symptoms include ; dermatits, microcytic hypochromic anemia, impaired immune funT, depression, confusion & convulsions
• deficiency is rare; marginal inadequacy is more widespread,
  • especialy in elderly, (who may have reduced ability to absorb )
  • Alcohic people with liver diseases cirrhosis & hepatitis
• A no. of drugs, including the TB drug isoniazid, interfere with vitamin B6 metabolism

Folic Acid(Folate) : Type of Vitamine B

• B12 & it are closely related in FunT & notably participation in DNA synthesis.
• Symptoms : weaknesss, fatigue due to megaloblastic anemia, (RBC laking suficient DNA for cell division), disruption of cell division along the GI tract → persistent Diarrhea & impaired syntheis of WBC & platelets.
  • in early pregnancy may cause neural tube defects in fetus so women capable of pregnancy advised to take 400mg of folic acid daily
• cancer drug methotrexata interferes with folic acid metabolism, causing side effects such as hair loss & diarrhea.
• may also result from heavy use of alchohol, which interferes with absorption of vitamin

Vitamin B12 – Cobalamin

• additional maintains the myelin sheath
• symptoms – megaloblastic anemia
• Only animal food is reliable sources of it.
  • so vegans are at risk
• In order to be absorbed it must be bound to intrinsic factor, a substance secreted by the stomach.
• deficiency due to absorbtion disorder
  • due to autoimmune disorder ; pernicius anemia(occure often in elderly) : intrinsic factor is -nt
  • low HCL production by stomach

Vitamin B5 – Panthothenic Acid

• deficiency only in individual fed semisynthetic diets defcient in vitamins or due to dose of antagonist of its.
• Syptoms : fatigue, irritability, sleep disturbances, abdominal distress & neurological symptoms such as tingling in the hands
• deficiency supected in WWII : burning feet synrome

Biotin

• rare deficinecy b/c to syntheis also by bacteria in the colon, although imp.of this source is unclear.
• observed in people :
  • who regularly eat large quantities of raw egg white, contains glycoptotein (avidin) that binds biotin & prevents its absorption.
  • rare genetic defect in infanct , unable to absorb form of biotin in food
  • long term anticonculsant drugs may also impair biotin absorption.
• Symptoms of deficiency include skin rash, hair loss, & eventually neurological abnormalilities.

Vitamin c : Ascorbic Acid → Scurvy

• funT – as water soluble antioxidant & as cofector in various enzyme systems; involved in
  • systhesis of connective tissue componets & neurotransmitters.
• Scurvy seen
  • in people consuming few fruits & vegetables
  • in infants fed boiled cow’s milk & no source of vitamin C
• Symptoms of Scurvy ; pinpoint hemorrhages (petechiae) under skin, bleeding gums, joint pain & impaired wound healing.
• 100mg per day recommended

Iron

• most common of all nutritional deficiencies
• Young children & premenopausal women most vulnerable.
• most common in
  • late infancy & early childhood, when Fe store +nt from birth are exhusted & milk, which is poor in Fe, is a primary food.
  • during adolescent gowth spurt ;
  • In women during childbearing years,
    • blood loss during menstruation
    • additional iron needs of pregnancy.
  • Intestinal blood loss from ulcers, heamorrhoids, tumours or chronic use of certain drugs such as aspirin.
  • blood loss due to hookworm & other infections
  • inadequate dietary iron intake.
• Microcytic hypochromic anemia → due to iron store depletion → small RBC containing less hb than normal
• Symptoms of Fe deficiet anemia : fatigue, weekness, apathy, pale skin, difficulty breathing on exertion, low resistance to cold temp.
  • In childhood- can affect behaviour & learning ability as well as growth & development.
  • In pregnancy – pregnancy complications & maternal death

Iodine

• deficiency common casue of preventable brain damage
• deficiency during pregnancy
  • impair fetal development → cretinism
  • miscarriage & stillbirth
• lesser cognitive & neuromuscular deficits.
• Goitre
  • Goitrogens : members of cabbage family, cassava, millet, sweet potato & certain beans.
• Universal iodization of salt strategy adpted in 1993

Zinc

• play str.al role in proteins & regulates gene expression.
• +nt high in protein rich food, spl, red meat & shellfish
• deficiency first reported in 1960s in Egypt & Iran
• Found
  • diet with low Zn
  • Clay eating
  • in patients of Acrodermatitis enteropathica
  • low in Protein energy malnutrition
• Symptoms – skin lesions, diarrhea, increased susceptibility to infections, night blindness, reduced taste & smell acuity, poor appetite, hair loos, slow wound healing, low sperm count & impotence.

Calcium

• skeleton serve as reservoir for Ca needed in the blood & elesewhere.
• during childhood & adolescece, Ca intake is critical for bone growth & calcification.
• Osteoporosis , also strongly influencedy by heredity
  • Postmenopausal women in indusrial societies

Fluoride

• contributes : mineralization of bones, teeth & protects against tooth decay.
• fluoride toothpastes are imp. source

Sodium

• ample amount in food + table salt + developed Na conservation mechanisms in body → rare deficiency
• may occur during
  • prolonged heavy sweating
  • vomiting or diarrhea
  • kidney diseases.
• Symptoms of Hypernatremia (low Na level) → muscle cramps, nausea, dizziness,weakness& eventually shock & coma.
• 1/3 teaspoon of salt in 1 liter water sufficient
• Cl loss (result in metabolic alkalosis→excess alkalinity in body fluids) is parallel to Na loss.

Pottassium

• rarely deficient in food
• deficiency due to
  • some diuretics used in treatment of hypertension deplete K.
  • lost during sustained vomiting or diarrhea
  • chronic use of laxatives
• Symptoms – weakness, loss of appetite, muscle cramps, confusion
• Severe hypokalemia (low blood K) → cardiac arrhythmias.
• K rich food → Bananas or oranges

Water Deficiency – Dehydration

• 2-4 Lof daily fluid consumption in cool climates & 8-16L in hot climates
• Dehydration may develop if
  • water consumption fails to satisfy thirst ; if discrepancy in thirst mechanism
  • excessive fluid loss, as with diarrhea & vomiting
• vulnerable
  • elderly (with dulled thirst sensation)
  • ill people
  • flying in airplanes
  • infants & children with chronic undernutrition → gastroenteritis →diarrhea or vomiting →dehydration
• Symptoms → dry mouth, sunken eyes, poor skin turgor, cold hands & feet, weak & rapid pulse, rapid & shallow breathing ,confusion , exhaustion ,coma
• Loss of fluid constituting more than 10% of body weight is fatal.
• Treatment → IV or oral solution of glucose & salts.

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What is meant by epidemiological transition? Elaborate upon its causes and consequences highlighting major health problems of our adult population today. (15Marks 2013)