-
Body mass index (BMI)
- Measure of weight in relation to height
- sometimes used as a diagnostic tool, but it should not
- BMI = weight/2(height) x 703
-
BMI for different sizes
- Healthy adult 18.5-24.9
- Overweight 25-29.9
- Obesity >30
- Morbidly obese >40
-
Other ways to measure obesity
- BMI
- weight circumference
- skinfold thickness
- hydrodensitometry
- bioimpedence
-
Childhood obesity facts
- prevalence of pediatric overweight and obesity in the US has more than quadrupled over the past 40 years
- 25% children overweight
- 75% of parents of obese children think their child's weight is normal
- 70% of obese children grow up to be obese adults
-
Childhood mortality
- lowers child's life expectancy by 8 - 20 years
- very high adolescent BMI associated with 30-40% higher adult mortality
- obese teenagers died on average at the age of 46
-
Prevalence of obesity among US adolescents
- more prevalent among native american boys
- most groups fall b/w 10-20% range
- US falls into 20-25% range
-
Contributing factors
- evolution
- genetics
- environmental
-
Evolution
humans are predisposed to prefer sweet and fatty tastes and reject sour and bitter tastes
-
Genetic factors
- genetic studies have shown lifetime obesity risk to be due to genetics
- twin studies show that genetics account for as much as 50-90%
- wide array of rare mutations and chromosomal abnormalities are now known to cause severe, early onset obesity
-
monogenic
- single gene mutation
- many in the leptin/melanocortin pathway
- very rare
-
syndromic
genetic defects causing obesity, mental retardation, dysmorphic features, and organ specific developmental abnormalities
-
polygenic
- individual's genetic makeup is susceptible to an environment that promotes energy consumption over energy expenditure
- most common
-
Environmental factors
- movement, activity, exercise
- dietary
- school
- fat, carbs
- health
- SES
- dieting
-
fat increases energy intake
- passive over-consumption: signals may not reflect actual nutrient content
- minimal appetite suppressant effect
- high energy density
- high palatability and hedonic value
- aggressive marketing by the food industry
- culturally acceptable
-
Exercise/activity
- 25% decrease in play and 50% decrease in outdoor activities during school
- time spend doing hw and sitting in cars -> increased
- children in unsafe neighborhoods watch more TV than kids in safe neigh
- time spent watching TV has increased by 40 min per day
-
Less labor in jobs
- shift toward capital intensive and knowledge based employment
- increased mechanization or previously labor intensive jobs
-
Travel
- less energy expended getting to and from work
- increased use of transportation
- suburbs
- more technology at home
- less energy expended to get food
-
SES
low SES associated with higher obesity
-
health factors
- endocrine disorders -> hypothyroidism, Cushing's disease
- hypothalamic obesity -> trauma, tumors
- genetic syndromes -> prader-willi syndrome
-
sleep problems
- sleep affects weight
- ghrelin: hormone that tells body it is hungry -> produced more when can't sleep
- kids who received less than 9 hours of sleep a night more likely to be overweight
- once overweight, they can develop sleep disorders making it hard for them to sleep
-
medical complications
- left-side of heart become enlarged
- high cholesterol
- high blood pressure
- thickening of arteries
- heart disease, diabetes, stroke
- higher risk for cancers
- strained or broken joints
-
metabolic syndrome
- 3 of these symptoms means they are on their way to heart disease
- high degree of belly fat
- high blood pressure
- glucose intolerance
- high triglycerides
- low good cholesterol (HDL)
-
Type II diabetes
- increased body fat and high dietary sugar -> increased insulin release -> insulin receptors become insensitive
- fat cells become stressed
- obesity and diabetes -> increase
-
discrimination
- characteristics
- children's attitudes related to body weight
- obese people report discrimination in jobs, by doctors...
- discrimination is overt and hostile
- discrimination can have a negative impact on health
-
psychological health
- psychopathology
- only in BED -> overtime they gain weight
- subthreshold depression, anxiety
- self-esteem
- lower in obese people
- fewer social interactions by obese people
-
Access to health care
- embarrassment and discrimination
- criticism and cruel remarks by physicians
- blaming any health problem on weight
- economic hardships
- obesity more prevalent in lower SES in the US
- overweight during adolescence has been associated with decreased SES in adulthood
-
health risks
- obesity does not cause the health risks
- interacting factors, including obesity, lead to health risks
-
prevention
- research and prevention resources are more focused on obesity prevention than they ever were on eating disorders
- obesity prevention could trigger an eating disorder b/c it is so weight focused
- collaboration: obesity and eating disorder prevention
|
|