MED ANTHRO EXAM #2

Why study growth?

• Child growth as an indicator of population health

• “Better than any other single index, the average values of children’s heights and weights reflect accurately the state of a nation’s public health and the average nutritional status of its citizens...This is especially so in developing or disintegrating countries. Thus a well- designed growth study is a powerful tool with which to monitor the health of a population, or to pinpoint subgroups of a population whose share in economic and social benefits is less than it might be.”

  • (Eveleth and Tanner 1990; p. 118-119 in Wiley and Allen)

Factors that influence growth

• Nutrition

  • Growth is at the front line of responses to nutritional challenges

  • Growth as a way to track population health

• Disease

  • Metabolically expensive to be sick

• Physical enviorment (pollution, lead)

• Social enviorment (psychological stress, trauma)

Genotype

heritiable information (genes) carried by an indivudal

Phenotype

expression of the interaction between genotype and environment

Phenotypic Plasticity

Ability to adjust somatic, behavioral or physiological traits in response to interaction with the environment

Human Life History Stages

• Gestation

• Infancy

  • birth through weaning; includes neonatal (up to 28 days) and postnatalstages (1 month- 3 years)

  • Most rapid growth

• Childhood/juvenile period (3 years to 10-12 years)

  • Slower growth than infancy

• Adolescence (growth spurt, sexual maturation)

• Adulthood (Maturity reached)

• Old age/ sensescence

Gestation- Age range

full term pregnancy (38 weeks divided into trimesters)

First trimester

• zygote grows into an embryo

  • Genetic abnormalies and certain infectious diseases can result in a spontaneous abortion (10%)

  • Mirconutrient deficicies contribute to congetial disease (ex. folate and spina bifida)

Second trimester

• Rapid skeletal growth, weight gain, fat deposition of the fetus; maturation of respiratory, gastrointestinal and circuloatory systems

  • Undernutriion, infection or stress of the mther can result in decresed linear growth and decreased birth weight

Third trimester

• rapid growth in weight and deposition of fat; final naturation of respiratory, gastrointestinal and circulatory systems

  • Undernutrition, infection or stress of the mother can result in decreased birth weight

Birth weight

Trade-off between maternal condition and offspring size

• Lower birth weight:

  • Reduced probability of offspring survival

  • Increased maternal condition

• Higher birth weight:

  • Increased probability of offspring survival (except at extreme weight)

  • Decreased maternal survival, ability to care for existing, children, chances of reproducing again

Stabilizing selection

average weight has highest survival probability

Determinants of birth weight

• Maternal age - younger maternal age (< 20 years) and older maternal age(> 35 years) associated with lower birth weight

• Parity (# of children/pregnancies): first borns are lighter than later borns

• Nutritional status of mother - current dietary behavior, weight, height or fatness

• Infectious disease

• Smoking - results in low birth weight babies

• Altitude - higher altitude associated with lower birth weight

• Sex - females are lighter than males

• Gestational age - preterm babies are lighter than full term

• Low income (stressful env., high disease rate) low birth weight (esp in US,UK less in Canada and Aus due to healthcare)

Long term health effects of low birth weight

• “Thrifty phenotype”/DoHAD

  • poor fetal nutrition results in impairedgrowth and programs fetal metabolism for nutritional adversity, morelikely to develop type 2 diabetes and obesity

• Fetal nutritional status → developmental adaptations that permanently change structure, physiology, and metabolism

• Predisposes the individual to cardiovascular, metabolic, and endocrine disease in adulthood

  • All-cause mortality, CVD, type 2 diabetes, obesity, and hypertension

Infancy Age range

period from birth through weaning

Neonatal period

days 1-28

Postnatal

1 month- 3 years

• Transition: stable and regulated enviorment (intrauterine) → more variable

Growth patterns of Infancy

• Rapid rate of growth

• 1st year:

  • 200% increase in weight (3.4 to >10 kg)

  • 50% increase in height (50 to 75 cm)

Composition of breastmilk

• Sugar, fat, protein, micronutrients; designed to be consumed frequently(more sugar, less fat than other mammals)

• Hormones that promote tissue growth

• Antibodies

• Breastmilk is not just “food”

Duration of breastfeeding

Varies from 0 to 3 years

Worldwide breastfeeding rates - 41% overall

Many people chose not to breastfeed because of workforce demands, lackof info and support for BF and widespread availability of formula due tomarketing and Nestle

WHO recommendation: exclusive breastfeeding up to 6 months of age,with continued breastfeeding along with appropriate complementary foodsup to two years of age or beyond

Population variation and explanations for this variatio

Growth charateristics for breastfed babies vs. bottle fed infants

Breastfed babies grow more slowly and are leaner than formula fed babies

• Use of inappropriate standard led to categorizing BF babies as“falling behind” on growth

Weaning

time period when solid/complementary foods are introduced (usuallly around 6 months) critical time from growth and health

Best complementary foods

• Variety of nutrient-dense foods, variety of animal and plant source

Worst complementary foods

• Cooked cereals (high in energy, low in mirconutrients; potential for contamination and exposure to pathogens)

Why are cooked cerals a potential risk for contamination?

When access to clean water and sanitation is limited, risk of infection increases (malnutrition and infection can go hand in hand)

Reasons for why weaning presnts a risk for growth disruption

• Growth disruptions dependent on quality of supplemented foods

• Dcreased antibodies avaliable through breast milk

Growth- childhood age range

3 to 10-12 years

Growth charactertistics of childhood

• Weaned but still dependant for food, protection

• Relatively slow growth

• 3-8 years, relatively constant but slow growth

• High metabolic costs of brain

• Maturation of dietary and immunological systems

Juvenile- Age range

• 8-12 years

Juvenile Growth charactertistcis

• Slowest rate of growth since birth

• Fairly stable and predicatble

Adolescent growth spurt

• Begins 2 years later in boys than girls (10 vs. 12 years)

• Dramatic growth in most body measure (long bone length, vertebtebrae, skull and facial bones, heart, lungs)

Measuring undernourishment (for children under 5)

Stunting

Wasting

Overweight

Stunting

low height-for-age→ lower than 2 standard deviations below WHO(world health organization) child growth median (Most severe and payed attention to)

• Health impacts: weakened immune system; developmental delays/impairment: adult risk of obesity and type 2 diabetes, CVD

• Globally over 20% of children are stunted (mostly Africa and South-East Asia)

Wasting

low weight- for- height (lower than 2 standard deviations below WHO child growth median

• Health impacts: weakened immune system; developmetal delays/impairments

Overweight

weight-for-height greater than 2 standard devitions over the WHO child groiwth median

• Health impacts: risk of obesity and associated metabolic disease

Maya in Disneyland study

• Growth and health of teh children of immigrants in teh US

• Compared teh growth of Guatelalan kids in teh Guatemala to immigrant children in America

• Guatemelaan children of immigranst in the U.S are on average smaller than American children but bigger than the kids in Guatemala

• EX. of phenotypic plasticity

“Small but Healthy” controversy David Seckler 1980

Thought mild to moderate malnutrirtion lead to small growth to fit imnto enviorment, smallness as adaptive (stunting, but not wasting)

• His ideas are exrremely flawed. Adaptations does’nt mean healthy and it makes you more vulnerable to disease

Lead Posioning what is lead?

• a naturally heavy metal, soft, malleable and poor conductor of electricity

• In paint/varnish (made colors pop and last longer) and gasoline (Inc. efficiently)

• Banned from commercial use in 1978

Main risk factors of lead

• Living in a home built before 1978 (74% of teh homes in Broome County and 86% of homes in Binghamton)

• Children under the age of 6 (absorb 40%-50% more from the things they ingest)

• Main sources of lead are paint (friction, mouthable, exterior, and impact) and soil

• Other sources are hobby exposure (fishing, shooting, pottery, and jewelry making)

• Work→ painters, contractors, renovators, battery work

• Things → old toys, spices, and cookware

Biological Effects of Lead

• Brain damage, changes in behavior, speech and hearing problems, organ damage, growth delays

• For eery 10 ug/dL increase in BLL(Blood Lead level), 6 IQ points are lost

• Can lead to special education, juvenile deliquency, and joblessness

Treatments for lead

• Blood test to determine lead concentration

• No cure just prevention such as cleaning and nutrtion such as iron, calcium, and vitamin C

How BCHD helps? (Broome County Health Department)

• Healthy neighborhoods Program (HNP) → free home safety inspection

• Childhood Lead Poisoning Prevention Program → case managment for children with lead posioning

• HUD Lead Hazard Reduction Program → gives money to renovate homes with lead

Menarche Definition

• First period

• Onset of menstruation and ovulation (release of fertilized egg) ; however, not all cycles are ovulatory

• Regular menstrual cycles take 2-3 years to establish

  • Not all cycles are ovulatory

• Worldwide age range: 12 - 18 years (Wiley & Allen)

  • As young as 8

  • Average is around 12 years

• Full reproductive maturation is not established until the pelvis is fully developed in the late teens

Determinants of Menarche

• Genetics

• Body fat and nutritional status (higher body fat= younger and low nutritional status= older)

• Physical activity level (more physical activty=older)

• Psychosocial variables (stress=sometimes younger, sometimes older)

• Socioeconomic factors (poor=younger)

• Environmental factors (chemicals in env.)

Timing and health risks of menarche

Menstruation- definitions and characteristics

• Menstrual cycle, menses, period, monthly

• About once a month, the uterus growth a new lining (endometrium) in preperation for a fertilized egg. If pregancy does not occur, the endometrium (blood and tissue) is dischraged through the vagnia

• Unique to primates, bats elephants, and shrews

  • Most mammals have estrous cycle, but not menstruation

The menstrual cycle

• Hormone patterns in each phase and their effects

Patterns across cycle and effects

Differences in the timing and duration of reproductive events and behaviors

Relationship to dosing of oral contraceptitives

• Oral contraceptives pills (OCPs) were developed to mimic natural (Western) hormonal cycles

• Is it “natural” to have so many more periods?

• Seasonale: 12 weeks w/no period

PMS and medicalization

• Women’s health = reproductive health

• 1993: Congress requires NIH to include women in clinical trials;“complicated physiology”

• Scrutiny and oversight of female reproductive health (Menarche and menstruation, pregnancy)

Follicle

sacs found in ovaries that obtain an immature egg

Oocyte

latin word for “egg”

Corpus luteum

a temporary organ in the ovary that produces hormones (such as progesterone) to prepare the uterus for pregnancy

Endometrium

the lining of the uterus, which thickens during the mentursual cycle in preperation for possible implanation of embryo

Estrogen

A female hormone helps maintain the reproductive system

• Having a lot of periods in not normal for people in the past

Progesterone

a hormone that plays a vital role in the menstrual cycle and maintains the endometrium in pregnancy

Follicile Stimulaing Hormone (FSH)

triggers the growth of eggs in the ovaries and gets the egg ready for ovulation

Luteinizing Hormone (LH)

helps control the menstrual cycle and triggers the release of an egg from the ovary

Fertility

having a live birth

Fecundability

ability to conceive

Main proximate determinants of fertility

• Age

• Lactational infecundability

• Sexually transmitted infections (STIs) that inhibit fertility

Age of fertility

• (age at menarche, age at menopause)

• Pattern of fecundability by age - increases from 15 , peaks ataround 22-25 then declines from there

• Trend of first-time births to older mothers - increases over time espcially at 35-39 years as age of marriage increases and more women have jobs

Lactational infecundability/ amenorrhea (duration)- definiton

• Infertility as a result of breastfeeding (amenorrhea= absense of menses)

Characteritstics - Lactational infecundability/ amenorrhea

• Dependent upon

  • duration of breastfeeding

  • frequency of breastfeeding

Mechanisms of Lactational infecundability/amenorrhea

• Infant suckling stimulates the release of the hormone prolactin,

which stimulates milk production in the breast

• Suckling suppresses secretion of GnRH (gonadatrophin-releasing

hormone) from the hypothalamus → suppresses LH and FSH from

the pituitary → follicles do not develop

Mechanisms of Lactational infecundability/amenorrhea (duration)

Frequent intense suckling
increases prolactin production
in the anterior pituitary, which
inhibits secretion of GnRH
(gonadotropin releasing
hormone)
• Irregular secretion of GnRH
interferes with release of LH
(luteinizing hormone) and FSH
(follicle-stimulating hormone)
• Decreased LH and FSH
disrupts follicular
development in the ovary to
suppress ovulation

Duration of Lactational infecundability/amenorrhea (duration)

• Without breastfeeding, amenorrhea only lasts 3 weeks

• With 100% on demand breastfeeding (no supplements tobaby) amenorrhea lasts 6 months

Sexual trasmitted infections (STIs) inhibit…

fertility

Infertility

absense of conception after 24 months of regular unprotetced intercourse, STIs can cause infertility

Examples of STIs

Gonorrhea and chlamydia can lead to pelvic inflammatorydisease (PID), silent infections, risk of infertility increaseswith increasing number of STIs

Sex difference in Infertility

30% cases contributed by females, 30%of cases contributed by men, 40% idiopathic (unknown cause)

Prevelace

8-12% of couples worldwide, higher rates insub-saharan Africa (10-30%)

Psychological, social, and physical consequences of infertility (vary by culture and society)

• fear, guilt, tension in relationship

• Level 6- last dignity in death (some cultures view it as your worth)

Pelvic inflammatory disease (PID)

• Infection of the uterus, fallopian tubes or ovaries

• Symptoms can range from none to serve (ex. pelvic pain, fever/chills, vaginal discharge, nausea/vomiting)

• Affects 1 million women in the US

• Most cases caused by STIs (chlamydia and gonorrhea)

• Most common preventable cause of infertility

Prolactin

a hormone made by your pituitary gland at the base of your brain

Gonadotropin-releasing hormone (GnRH)

• a peptide hormone produced by nerve cells in the hypothalamus of the brain

• It plays a central role in regulating reproduction

Childbirth- characteristics of maternal mortality

• Every day in 2020, 800 women dies from childbirth, 95% of maternal death occur in low middle income countries

• Maternal mortality is higher in rural areas in poorer communities

• Mothers 14 years and younger face a higher mortality risk ofcomplications and death as a result of pregnancy than older women

• Between 2000 and 2020 maternal mortality ratio dropped by 34% due toaccess to healthcare

Why is human birth fo risky?

• Obstetric dilemma

• Anatomical, biological, and cultural solutions that mitigate the risks of childbirth

Medicalization of birth

• C-section rates

• Birth doulas

Causes of maternal mortality

• Complications that develop during pregnancy and are preventable or treatable

• 75% of maternal deaths are attributable to
  these complications

  • Severe bleeding after childbirth

  • Infections after childbirth

  • High blood pressure during pregnancy (pre-eclampsia and eclampsia)

  • Complications from delivery

  • Unsafe abortion

Birthing process differences

• Most mammals

  • Labor and deliver alone

• Humans

  • Require assistance to:

    • Guide baby out of birth canal

    • Clear baby’s breathing passage

    • Untwist umbilical cord

    • Lift baby to mother’s breast

Pelvic differences

• Quadrupeds

  • Flat shape – only constraint on birth is width of pelvic outlet

• Humans

  • 3D bowl shape pelvis evolved for bipedalism

  • Trade-off between pelvic width and walking efficiency (“obstetric dilemma”)

    • Babies are born at earlier stage of maturity v. chimps

Brain differences

small pelvis big brain

Solutions that mitigate the risk of childbirth

• Rotation

• Relaxin and headmolding

• Standing/squatting during labor and delivery

• Supported birth

Rotation

• constraints of the human pelvis/cephlopelvic delievy, baby’s head starts sideways and rotates vertically

Relaxin and head molding

• Relaxin is a hormone produced by teh ovaries & placenta to loosen ligaments and dilate cervix to ake birth easier

• Head molding→ the skull is made up of several different bones that can pass over one another to beocme smaller, eventually hardens and skull forms together.

Standing/ squattting durig labor and delievery

• cultural solution, lets gravity help. Many cultures still give birth in this position

Supported birth

• a care approach during labor and delivery that combines physical, emotional, and educational backing to help a parent feel safe, informed, and empowered

Obstetric dilemma

an evolutionary hypothesis that explains why human childbirth is uniquely difficult and risky compared to that of other primates

Lithotomy position

• lying down on back, legs up

Episiotomy

an incision made in perineum - between vaginal opening andanus- cutting better than tearing

Pitocin

mediation that brings on contractions, overused fordoctors convenience)

Doula

• a trained, non-medical professional who provides continuous physical, emotional, and informational support to individuals and families during significant life transitions

Medicalization of labor and delivery

• Lithotomy position for delivery (lying down on back, legs up)

• Shaving

• Episiotomy (an incision made in perineum - between vaginal opening andanus- cutting better than tearing)

• Pain numbing medication

• Limitations on social support in delivery room

• Over reliance on technology inhibiting movement and confront

• Induction with Pitocin (mediation that brings on contractions, overused fordoctors convenience)

• OB’s convenience- a lot of interactions are not necessary

Menopause

• The cessation of menses for one year

• Natural decrease in oocytes through follicular atresia and ovulation

Oocytes by the numbers

• 5 months in utero: 7 million
• At birth: 2 million
• Menarche: 400,000
• 38 years: 25,000
• Menopause: <1000

Population variation in symptoms of menopause

• a lot of African Americans, Hispanic andCaucasian populations experience symptoms, less for Chinese and Japanese

• In japan there is a lower prevalence of sleep problems, hot flashes and night sweats compared to U.S. 27% of women report no symptoms (15%in US)

• Possible explanations: language, symptom reporting , dietary changes,physical activity, attitudes/expectations about aging and menopause

Medicalization of menopause

• “Estrogen deficiency” and “ovarian failure”

• Treatment for menopause

  • Hormone replacement theory (HRT)

    • Estrogen + progestin

    • Benefits: easing of symptoms, decreased cardiovasculardisease risk, decreased risk of osteoporosis

    • Costs: increased risk of breast cancer

    • Until recently, routinely prescribed to women atmenopausal transition, but now only when symptoms aresevere and there is no/low risk of breast cancer

Breast cancer

• Most common cancer among women worldwide

• 2.3 million cases diagnosed in 2022; 670,000 deaths

• Increasing prevalence worldwide, though higher risk in high income countries than in low-income countries