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Biological Anthropological

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Title: Biological Anthropological


1
Biomedical Anthropology
  • Biological Anthropological
  • by Stanford, Allen, Anton
  • Professor Bender

2
Are we healthier today?
  • Today
  • Get vaccinated
  • Live longer, more parasite free
  • Children at school, often lack PE because of
    budget cuts
  • Eat high sugar, fat foods (lack balanced diet)
  • 20,000 years ago
  • Grows slower
  • Had stronger, lean body with more muscle than fat
  • If avoided infectious disease, injury and famine
    would have middle age with no worries of heart
    disease, high blood pressure, diabetes and even
    some types of cancer

3
Biomedical anthropology and illness
  • Illness is a product of our genes and culture,
    our environment and evolution, the economic and
    educational systems we live under, and the things
    we eat
  • Biomedical anthropology deals with issues of
    health and illness
  • Brings issues of evolution, human variation,
    genetics to the study of medically related
    phenomena
  • Biomedical anthropology is like cultural medical
    anthropology in its comparative outlook and its
    attempt to understand illness in the context of
    specific cultural environments

4
Epidemiology Basic tools
  • Looks to understand the expression of disease at
    the population level
  • So does epidemiology quantitative study of the
    occurrence and cause of disease in a population
  • Compared to anthropologist, they are
    number-crunchers
  • Rate Events/population at risk (usually denoted
    per 1,000 individuals, or 1,000,000 for rare
    diseases)
  • Mortality rates are measures of the probability
    of dying within a population over a given period
    of time
  • Incidence rate (Number of new cases of a
    disease/Total population) / period of time
    (usually a year)
  • Prevalence rate total number of cases of a
    disease at a given time / total population
  • Prevalence rate is a function of both incidence
    and duration
  • HIV / AIDs and new drugs

5
Epidemiological transitions
  • Epidemiological transitions describe changes in
    patterns of disease and mortality in developed
    countries
  • In less developed socieities, most deaths are
    caused by infectious disease
  • In developed societies, most deaths are caused by
    chronic diseases of old age
  • Big 3 for US in 2000 heart disease, cancer,
    stroke (60 of deaths)
  • In 1900 they were 16
  • Armelagos (1997) second epidemiological
    transition came with agriculture and increase of
    people living in small area

6
Biocultural evolutionary approaches to disease
  • Biocultural approach behavior is shaped by both
    evolutionary and cultural histories
  • Behavior influences expression of disease at both
    the individual and population level
  • Anorexia nervosa (prevalence rate 0.5-1.0, about
    90 are female)
  • Deals with ideal female attractiveness
  • Biological factors
  • Anorexia in Hong Kong females lack the fat
    phobia factor, a Westernized issue

7
The evolutionary approach
  • Defenses versus defects
  • Defect results from the disease process itself
  • Defense part of the bodys attempt to fight the
    disease
  • Example, pale person with pneumonia
  • Defect darkening of the skin color, due to
    reduced hemoglobin
  • Defense cough, to eject materials from the
    throat and lungs
  • Infection and arms races
  • Pathogens infectious agents (bacteria and
    viruses)
  • As our bodies build defenses, so too does theirs
  • Antibiotic resistance in bacteria

8
The evolutionary approach
  • Environmental mismatch
  • Mismatch between forager lifestyle evolved for
    and one we live
  • Fatty diets, low reproductive rates, and noise
  • Pleiotropic gene effects
  • Genes (and mutations) that did not lead to
    adaptations in past environments but since we
    live longer they may now be expressed, such as
    Alzheimer disease and cancer
  • Design compromises
  • Back pain, due to S-shaped, combined with
    sedentary lifestyle
  • Causes 50-80 of all people in industrialized
    societies suffer from back pain at some time in
    their life

9
Birth, growth and aging
  • Human childbirth
  • 4 million births in US in 2000, 90 occurred in
    hospitals
  • In 2001, 24.4 were Cesarean
  • In 1900, only 5 of US births occurred in a
    hospital because it was so much more likely to
    get an infectious disease when there
  • Human females are not much larger than female
    chimpanzees, yet infant humans brains are the
    size of adult chimpanzees
  • Could not evolve a larger pelvis, because it is
    inefficient in bipedals
  • Tight fit between infants head and moms pelvis
  • Infant has to twist to be delivered, umbilical
    cord can get twisted

10
Birth, growth and aging
  • Traditional cultures uses midwife
  • Cross-cultural studies show almost all women have
    emotional reactions to onset of childbirth and
    seek assistance
  • Biocultural adaptation increases chance of
    successful birth
  • Besides supporting the newborn through the
    contractions and birth canal, also emotional
    support for mother
  • This support is often lacking
    in contemporary hospitals
  • Is this changing?

11
Birth, growth and aging
  • Auxology study of patterns of human growth
  • Patterns of growth that emerge under different
    environmental conditions can provide us with
    clear examples of biological plasticity
  • What environmental conditions can speedup/ slow
    growth cycles?

12
Birth, growth and aging
  • Altitude, food, and stressors can change growth
    rates
  • Can be seen as context of nongenetic adaptation
    (anthropological)
  • Lack of food, heavy infectious disease load, and
    pollution
  • Can be seen as any change is seen as evidence of
    ill health (medical)
  • Biomedical sees it as a combination
  • Stages of human growth
  • Prenatal (gestational) stage from conception to
    birth
  • Embryonic stage (first 8 weeks) fertilized ovum
    increases 275,000 times
  • During rest of pregnancy (fetal period) growth
    continues at about 90 times the initial weight (8
    week mark) PER WEEK
  • Fetal alcohol syndrome (FAS) and excessive noise
    in the environment can reduced/affect prenatal
    growth and development

13
Birth, growth and aging
  • Stages of human growth
  • Infancy, Juvenile stage, Adolescence and
    Adulthood
  • Infancy birth to appearance of first permanent
    tooth (5-6)
  • Juvenile stage lasts until the eruption of the
    last permanent tooth (M3, age 15-25)
  • Adulthood follows, after wisdom tooth
  • In primates there is very much variation in the
    patterns of growth and development, and length of
    stages

14
Birth, growth and aging
  • Stages of human growth
  • Adolescence begins at puberty literally
    development of pubic hair
  • Period of rapid growth and maturation of the body
  • Tremendously variable between and within
    populations
  • Happens sooner in industrial societies
  • Juvenile periods are longest in highly
    social mammals
  • Have most of brain mass at 6-7 but grey
    matter growth at adolescence

15
The secular trend in growth
  • Since collecting data in 18th century girls and
    boys are growing larger and maturing more rapidly
    in industrialized countries with each passing
    decade
  • Better nutrition
  • Reduction of impact of infectious disease
  • Used migration study to see impact of
    variables
  • Even tends to obscure variation within
    populations by socioeconomic factors
    (can still be seen in extreme cases)

16
Menarche and menopause
  • Decrease in menarche girls first menstrual
    period
  • From 180s until the 1970s Westernized populations
    dropped from around 16-17 years to 12-13 years
  • What do you think can affect this?
  • Menopause end of menstrual period
  • Only humans have a significant life span beyond
    this period
  • All human females ages are produced around 5th
    month of gestation
  • Birth 2,000,000
  • Puberty 400,000
  • Ovulation 400 mature
  • Grandmothering hypothesis

17
Aging
  • Maximum lifespan potential is 120 years
  • Senescence starts much earlier
  • As young as 20, and steeper between 40-50
  • DNA replication/ mutations
  • Cataracts and osteoporosis
  • Free radicals molecules with at least one
    unpaired electron
  • Vitamins C and E help this
  • In wild most animals die from something other
    than old age
  • Pleiotrophy traits different expressions at
    different times

18
Human variation and health skin color
  • Skin has several functions
  • Fluid barrier
  • Keeping body protected from most chemicals in the
    environment
  • Thermoregulation
  • Metabolism of various vitamins
  • What colors the skin
  • Oxidized hemoglobine red
  • Carotene yellow
  • Melanin dark pigment

19
(Dis)Advantages of light dark skin color
  • Sunburn and skin cancer
  • UVR can cause sunburn which is not only painful
    but may interfer with the cooling of the body,
    and lead to wounds
  • Most skin cancer, while uncomfortable, are benign
  • Malignant melanoma spreads easily throughout the
    body
  • Melanin blocks or filters out incoming UV rays
  • Vitamin D Synthesis
  • Essential compound in calcium metabolism
  • Found in large quantities in some fish oils and
    lesser degree in eggs and butter
  • Can get from sun
  • Deficient can lead to rickets (highest in cities)
  • Dark skin takes 6 times longer to make vitamin D
    as light skin
  • Cold weather requires covering skin, reducing
    intake of sunlight
  • Folate (Folic Acid) is a B vitamin essential
    for DNA synthesis and cell replication
  • Exposure to UVR breaks down folate
  • Too little folate causes neural tube birth
    defects in developing embryo

20
Infectious disease and biocultural evolution
  • Infectious diseases are those in which a
    biological agent, or pathogen, parasitizes or
    infects a host
  • Are classified by modes of transmission
  • Sexually transmitted
  • Airborne
  • Waterborne
  • Etc.
  • Or by organ system infected
  • Respiratory infections
  • Encephalitis
  • Digestive tract food poisoning
  • Some can only survive when in host, others for
    awhile outside
  • Some have single host species lifecycle, others
    multiple species lifecycles

21
Human behavior spread of infectious disease
  • Food preparation practices
  • Toiletry habits
  • Sex practices
  • Whether one spends time in proximity to large
    numbers of adults or children
  • Overall nutritional health and well being
  • People who are weakened by food shortage,
    starvation, or another disease are especially
    vulnerable to infectious illness
  • Sharing a communal cup (or water source)
  • Agriculture more people closer together
  • Incubation time (time to see symptoms)
  • Standing pools of water parasites
  • Mobility and migration disease on the move

22
Infectious disease evolutionary arms race
  • For past 50 years seemed science getting jump on
    infectious disease
  • Now HIV, AIDs, other STDs and antibiotic
    resistant bacteria
  • Immune system
  • Main line of defense in fight against infectious
    disease
  • Must be able to distinguish itself from nonself
  • Antigens whole/part of an invading organism
    that prompts a response
  • Antibodies proteins formed by immune system to
    bind to and neutralize invading antigens
  • Vaccination exposure to killed or inactivated
    form of an antigen
  • Believe to have been devised in Turkish Empire
  • Introduced to western civilization in 18th
    century
  • Quarantine isolation from exposure
  • Evolutionary adaptations enzymes (lysozymes)
    attack cell wall structure of some bacteria
  • Found in high concentrations in the tear ducts,
    salivary glands, and other sites of bacterial
    invasion

23
Diet and disease
  • Cholesterol is needed in synthesis of may steroid
    hormones
  • Carbohydrates, fat, and proteins are all sources
    of energy
  • Proteins for tissue growth
  • Fatty acids for building and supporting nerve
    tissue
  • Vitamins
  • Inorganic materials such as iron and zinc
  • Paleolithic diet was more varied
  • Agriculture less variation

24
Agriculture and nutrition
  • With agriculture came creation of stratified
    societies
  • More nutritional deficiencies in lower classes
  • Evidence of malnutrition, especially in cities
  • Unbalanced diets
  • Agriculture and abundance
  • Nutritional excess
  • Bodies set to store rare treats that are needed
    for proper function
  • Thrifty genotype efficient in storing food in
    fat
  • Non-western people who more likely to get fat
    on westernized diet
  • More likely for diabetes (especially type-2)
  • Actually were BETTER adapted to famine and lived
    longer off of feast period

25
Comparison Paleolithic / contemporary diet
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