Obesity Flashcards
Formula for BMI?
BMI= wt (kg)/ht (m)^2
BMI classification:
BMI: 25- 29.9 overweight 30-34.9 obesity class 1 35-39.9 obesity class 2 >40 class 3 or morbidly obese
BMI in US children and adolescent?
- 85th-95th percentile at risk for being overweight
- > 95th percentile for age obesity
- if both parents are obese: 87% chance child will be obese
Obesity prevalence 2009-2010
- obesity prevalence: age 2-19
all groups: 35.7%
males: 35.8%, females: 35.5%
Cost of childhood obesity?
- national epidemic
- costs 3 billion dollars annually
- economic calculations will clim higher: consider long term disability, lost earnings
Cost of obesity and overweight all ages?
- direct cost: preventive, dx and tx services
- indirect cost: value of lost wages
- cost now est at $270 billion a year
Why are there limitations to BMI?
- fat mass versus lean mass
- distribution of fat
- ethnic differences
What is the most accurate way to assess body composition? what is a cheaper way?
- most accurate: DEXA scan, CT (expensive)
- less accurate but lower cost: bioimpendance, water displacement
What is worse, an android fat distribution or gynoid?
- apple/andriod is worse: excess fat in the abdomen, its more common in men, significant correlation with metabolic syndrome
- pear/gynoid: is excess fat on thighs and buttocks, common in women, and no significant correlation with metabolic syndrome
Distribution of adipose tissue?
- upper body: subq, superficial and deep
- lower body: visceral - worse, hold all the toxic hormones and enzymes that promotes metabolic syndromes
- also ectopic, and IMAT
Why is there a BMI limitation because of ethnic differentiation?
- at any given BMI the % FM of asians 5% higher compared to caucasians
- african americans>jamaicans> nigerians
Prevalence of obesity?
- BMI>25 68%
- > 30 35%
- > 40 6.5%
(people who are overweight are becoming obese)
Why are we becoming an obese society?
- genetics
- cultural
- societal
Genetics of obesity?
- obesity isn’t a simple mendelian trait
- single genes are only found in the mouse
- there is an autosomal recessive mutation, chromosome 6, the leptin gene (obese people develop resistance to leptin)
- multiple genes and it is transgenic
- there are so far 176 different himan cases of obesity due to single gene defects
What is genetical obesity related to?
- autosomal dominant: PCOS prader-willi syndrome (most common) - autosomal recessive: Bradet-Biedl syndrome (polydactyly) facial features, wide eyes, mental retardation cushing syndrome x linked wilson turner
Other enviro causative agents of obesity?
- convenience foods
- portion size
- increased flight transportation
- adeno 13 virus
- societal issues
- post viename society: YOLO
- sedentary behavior
Medical complications of obesity?
- pumonary disease: OSA, restrictive lung disease
- nonalcoholic fatty liver
- OB/GYN: infertility
- osteoarthritis
- idiopathic intracranial HTN
- CVA
- CAD
- CHF, dyslipidemia, HTN
- diabetes
- cancer: breast, colon, pancreas, uterus, cervix, esophagus, kidney, prostate
- DVT, phlebitis, venous stasis
How much of a wt loss is beneficial?
- 10% wt loss will beneficially improve the following conditions:
RA, OA, cancer, CAD, DM, DVT, HTN, lung disease, OSA, OBGYN complications, incontinence, pancreatitis
What diseases are made worse with wt loss?
- paradoxical effect on CHF if you already have HF and become obese, HF wont get worse
- body mass loss leading to sarcopenia (because bones are carrying so much wt when obese)
- 5 fold increase successful suicide rate following gastric bypass surgery (don’t feel safe anymore)
Relationship of obesity and mortality
- increased mortality in all age groups (35-89)
- lowest mortality rates are for those with BMI 20-22
- mortality begins to increase modestly with BMI > 25
- BMI > 30, all cause mortality rates increase by 50-100%
Relationship b/t adipocytes and inflammation?
resistin: increased level in obesity, DM
resistin increases pro inflammatory cytokines: IL, TNF, intracellular adhesion molecule-1
- found that pts that lost wt didn’t need ortho surgery anymore because inflammatory cytokines were decreased because of decreased wt load
CVD risk and obesity? CV risk factors
- wt gain is directly related to these CV risk factors:
- dyslipidemia
- HTN
- elevated insulin
- elevated fibrinogen
- OSA
insulin resistance has a direct effec on what and why is this?
- direct effect on myocardium
- epicardial fat deposition
- increased intra-myocardial triglyceride deposition
- lipotoxicity
- cardiomyocyte apoptosis producing cardiac dysfunction
How does obesity cause HTN?
- enhanced sodium retention
- vascular smooth muscle hypertrophy
- stimulation of renin-angiotensin aldosterone pathway
- increased activation of sympathetic NS increased vasoconstriction
- decreased NO mediated vasodilation
How does obesity cause LVH?
- due to need for high cardiac output
- increases risk for SCD
- increases risk for CHF
- dx on ECG when sum of S in V1 and R in V5 > 35 mm
Relationship b/t obesity and CHF?
- frequent complication of severe obesity
- severe hypoxemia of OSA is one of several possible causes
- each increase in BMI of 1 unit increases risk of CHF 5% man, and 7% in women
- paraox of est. CHF: once HF est, higher BMI has improved outcome
Relationship b/t obesity and stroke?
- for each increase of 1 unit BMI - hemorrhagic stroke increases 6% and ischemic stroke increases by 4%
Relationship b/t obesity and pulmonary dysfunction?
- a restrictive ventilatory defect (diaphragm pushed up against lungs because of fat tissue, so total lung capacity is decreased -> hypoxia)
- increased RR and decreased tidal volume and TLC
- hypoxic arterial blood gases in moderate/severe obesity
- dyspnea is common (w/ and w/o exercise)
- increased risk for asthma
Relationship b/t alzheimers and BMI?
obesity at high ages increases risk for AD in women
- for every 1 unit increase BMI at age 70 AD risk increases by 36%
- these associations weren’t found in men because they didn’t live that long
Obesity and OSA?
- occurs in 50% of severly obese
- OSA presents in up to 90% of obese pts seeking bariatric surgery
- potentially life threatening
Risk factors for OSA?
- upper body obesity
- more common in males
- associated with snoring (tiredness in morning more specific than snoring)
- large neck girth in those who snore is highly predictiv of OSA (circumference > 17 in in men and 16 inches in women)
CV complications of OSA
- acute coronary syndrome: increase risk of plaque rupture, increase risk of thrombosis
- increased risk of stroke
- HTN
- increased platelets aggregation
- increased platelets aggregation
Effect of wt loss and OSA?
p 10% of wt reduction iproves severity of OSA by more than 50%
Obesity and non-alcoholic fatty liver?
- occurs > 66% in obese, > 90% in BMI > 40, precursor to liver failure, transient increase in transaminases with wt loss, especially rapid wt loss (after a couple of months liver enzymes will go back down to normal levels)
What percentage of cancer deaths are attributed to dietary factors?
- 35%
relationship b/t obesity and cancer?
- wealth of epidemiological data connecting obesity and various malignancies: post menopausal breast cancer, colon, pancreas, endometrium, kidney, and esophageal cancer
- premenopausal breast cancer: 2 large studies revealed that a 70% increased risk of premenopausal breast canacer vs. normal wt
