Exam 1 Flashcards
Since 1971, obesity rates have increased by how much in people aged 2-19?
From 5% to 17%, tripled
Health effects of obesity in youth
Poor academic performance
Adult obesity
CVD risk factors
Metabolic disease
Asthma
NAFLD
Sleep apnea
Musculoskeletal problems
What is the overall negative effect of obesity on life expectancy in the US.
1/3 to 3/4 of a year
Measuring body fatness tools
DEXA
MRI
Bioelectrical impedance
Bod pod
DEXA
Costly
Radiation exposure
Influenced by hydration
Fat mass Vs. Fat free mass
MRI
Very accurate
Body fat distribution
No radiation exposure
Costly
Time consuming
Anthropometry
BMI (kg/m2)
Skinfold measures (error prone)
Circumference measures
BMI normal weight range
18.5 - 24.9
BMI overweight range
25-29.9
BMI obese range
30+
BMI percentile 2-18 years
95+ obese
85-95 overweight
True or false: BMI is a better indicator of fatness in fatter youth than thinner youth
True
True of false: most children who have a BMI for age between 85-95th percentile do not have excess body fat
True
High BMI risk factors
Triglycerides
LDL cholesterol
HDL cholesterol
Fasting insulin
Blood pressure
NHANES
National health and nutrition examination survey
Assess health + nutrition of adults + children
Interviews + physical examinations
What percent of 2-19 year olds are above 95th percentile
17%
True or false: other countries use different measures of body composition
True
Western diet qualities
High in saturated fat, sugar, refined foods,
IOW in fiber
Which areas of the world have the highest prevalence of overweight children
North America, Europe, western pacific
What are critical periods in life
Periods that may be more sensitive to exposure/ perturbations
Potential determinants of critical periods for abnormal weight gain
Genetics
Biological
Environmental
Behavioral
Biological determinants
Development of adipocytes
Hormones
Metabolic rate
pregnancy
Environmental determinants
Food availability
Neighborhood parks/recreation
School/home/work
Behavioral determinants
Breastfeeding
Physical activity
Sedentary time
Critical periods
Adipocyte development
Intrauterine life
First year of life
Preschool-school age
Adolescence
Why are critical periods important
Identification of individuals at high risk for overweight and prevention of excess weight gain
Adipocyte development
Adipocytes develop at 15 weeks gestation
Adipocytes grow more in size than number during infancy
Age 2-14, obese increase In fat cell size + number
Hyperplasia + hypertrophy
Intrauterine factors
Low and high birth weight
Gestational diabetes
Gestational diabetes
Maternal hyperglycemia leads to excess fetal insulin production
Acts as a growth stimulator for the fetus
Low birth weight
Under-nutation may lead to energy efficiency and thrifty metabolic program
High birth weight
Over nutrition may be over development of fat cell size, number, or signaling
First year of life
Rapid growth
Double birth wight in first 4-6 months
Feeding practices
Locomotion
Pre school (2-6)
Transition to real food
Locomotion and physical activity
Adiposity (BMI) rebound
Adiposity (BMI) rebound
BMI increases then decreases, at 5yo it increases again
Earlier rebound may mean obesity
School age (6-11)
Physical activity patterns
Physical inactivity
Eating habits
Sleep patterns
Psychosocial factors
Adolescence (12-18+)
Puberty
Boys: fat free increase, body fat decrease
Girls: fat mass and fat free mass increase
Leisure time physical activity
Social networks
Contraceptive use
Tanner scale (sexual maturity rating)
Scale of physical development in children and adolescence
Breast size
Testicular volume
Pubic hair development
What happens at 12 years old regarding fat free mass
Begins to plateau in girls
Gains rate increased in boys
When is fat free mass stable
Girls: 15 - 16
Boys: 17-19
Growth hormone
Stimulates lipolysis
Adiposity suppresses GH
Testosterone on body composition
Increases lipless, protein synthesis, muscle fiber growth
Estrogen on body composition
Inhibits lipless
Why is breastfeeding better
Active suckle required unlike bottle
Promotes self-regulation
Thrifty genotype hypothesis
Evolution from famine led to more efficient fat storage
Heritability definition
The relative proportion of the total phenotypic variance in a complex trait that is attributable to the additive effects of genes
Assertive mating
The propensity for individuals to select romantic partners with similar behaviors and body types
Genome wide association studies (GWAS)
Scan sets of DNA in large populations to see whether genetic variations are more common in affected individuals than controls
Provide clues into potential biological pathways that may be associated with obesity
Single nucleotide polymorphism (SNP)
A change in a single nucleotide pair
Can act as genetic warning signs
Fat mass obesity gene (FTO)
T is protective allele
A is the risk allele
Suggests a role in central control of energy balance
What influence does FTC have on children
Associated with energy intake and energy density of meal
What drives pediatric obesity?
Energy intake vs energy expenditure
Basal metabolism
65%
Energy intake vs expenditure
Eating
Basal metabolism/ growth spurts
Physical activity
Thermogenesis (NEAT)
Obesity epidemic flood factors
Availability of energy dense foods
Marketing of products to kids
Replacing manual labor with technology
Eliminating recess and PE
Lack of time/attention/aptitude for cooking
Suburban sprawl (built environment)
Energy (im)balance theory
Emphasizes restriction of dietary energy intake with increases in general physical activity as a a supporting role
Only useful with obese people
Vigorous physical activity in obese youth
