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

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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

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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

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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

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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

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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

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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?

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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?

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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

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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

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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)

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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

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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

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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

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(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

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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

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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

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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

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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

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Comparison Paleolithic / contemporary diet