Obesity

1
Obesity

• And its Associated Risk Factors

Pennington Biomedical Research Center Division of
Education
2
ObesityAn Overview

• Overweight and obesity are both chronic
  conditions that are the result of an energy
  imbalance over a period of time.
• The cause of this energy imbalance can be due to
  a combination of several different factors and
  varies from one person to another.
• Individual behaviors, environmental factors, and
  genetics all contribute to the complexity of the
  obesity epidemic.

CDC
3
Energy ImbalanceWhat is it?

• Energy balance can be compared to a scale.
• An energy imbalance arises when the number of
  calories consumed is not equal to the number of
  calories used by the body.
• Weight gain usually involves the combination of
  consuming too many calories and not expending
  enough through physical activity.

Weight Gain Calories Consumed Calories
Used Weight Loss Calories Consumed Used No Weight Change Calories Consumed
Calories Used
CDC
4
Energy ImbalanceEffects in the Body

• Excess energy is stored in fat cells, which
  enlarge or multiply.
• Enlargement of fat cells is known as hypertrophy,
  
  whereas multiplication of fat cells is known as
  hyperplasia.
• With time, excesses in energy storage lead to
  obesity.

Fat cells
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Fat Cell EnlargementHypertrophy

• Enlarged fat cells produce the
  clinical problems associated with obesity,
  due to the following
• The weight or mass of the extra fat
• The increased secretion of free fatty acids and
  peptides from enlarged fat cells.

J La State Med Soc .2005 156 (1) S42-49.
6
Weight ClassificationsA Review

• Body mass index (BMI) is a mathematical ratio
  which is calculated as weight (kg)/
  height squared (m2). It is used
  to describe an individuals relative weight for
  height, and is significantly correlated with
  total body fat content. BMI
  is intended for those 20 years of age and older.

You can find tables on the web that have done the
math and metric conversions for you.
http//www.pbrc.edu/Division_of_Education/Tools/B
MI_Calculator.asp or
http//www.nhlbisupport.com/bmi
CDC
7
Mortality and MorbidityAssociated with Obesity

• The effects of excess weight on mortality and
  morbidity have been recognized for more than
  2,000 years. It was Hippocrates who recognized
  that sudden death is more common in those who
  are naturally fat than in the lean.
• Today, obesity is increasing rapidly. Research
  shows that many factors related to obesity
  influence mortality and morbidity.

Endocrinol Metab Clin N Am. 2003 32 761-786.
8
MortalityWeight, Fat Distribution, and Activity

• The following factors have been shown to increase
  mortality in
  individuals
• Excess body weight
• Regional fat distribution
• Weight gain patterns
• Sedentary Lifestyle

Endocrinol Metab Clin N Am. 2003 32 761-786.
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MortalityExcess Body Weight

• Mortality associated with excess body weight
  increases as the degree of obesity and overweight
  increases.
• It is estimated that 280,000 to 325,000 deaths a
  year can be attributed to obesity in the United
  States, more than 80 of these deaths occur among
  individuals with a BMI greater than 30 kg/m2.

Endocrinol Metab Clin N Am. 2003 32 761-786.
10
MortalityRegional Fat Distribution
Android Gynoid

• Regional fat distribution can contribute to
  mortality.
• This was first noted in the beginning of the 20th
  century.
• Obese individuals with an android (or apple)
  distribution of body fat are at a greater risk
  for diabetes and heart disease than were those
  with a gynoid distribution (pear).
• Android fat distribution results in higher free
  fatty acid levels, higher glucose and insulin
  levels and reduced HDL levels. It also results in
  higher blood pressure and inflammatory markers.

Endocrinol Metab Clin N Am. 2003 32 761-786.
11
MortalityWeight Gain

• In addition to overweight and central fatness,
  the amount of weight gain after ages 18 to 20
  also predicts mortality.
• The Nurses Health Study and the Health
  Professionals Follow-up Study showed that
  a marked increase in mortality from heart
  disease is associated with increasing
  degrees of weight gain.

Endocrinol Metab Clin N Am. 2003 32 761-786.
12
MortalitySedentary Lifestyle

• Sedentary lifestyle is another important
  component in the relationship of excess mortality
  to obesity.
• A sedentary lifestyle increases the risk of death
  at all levels of BMI.
• Unfit men in the BMI range of less than 25 kg/m2
  had a significantly higher risk than men with a
  high level of cardiovascular fitness.
• Obese men with a high level of fitness had risks
  of death that were not different from
  fit men with normal body fat.

Endocrinol Metab Clin N Am. 2003 32 761-786.
13
Morbidity Associated with Obesity

• Overweight affects several diseases, although its
  degree of contribution varies from one disease
  to another.
• Additionally, the risk of developing a disease
  often differs by ethnic group, and by gender
  within a given ethnic group.

Endocrinol Metab Clin N Am. 2003 32 761-786.
14
Morbidity Associated with Obesity

• Endometrial, prostate
  and breast cancers
• Complications of pregnancy
• Menstrual irregularities
• Psychological disorders

Individuals who are obese are at a greater risk
of developing

• Obstructive sleep apnea
• Osteoarthritis
• Cardiovascular disorders
• Gastrointestinal disorders
• Metabolic disorders

CDC
15
Cardiovascular DisordersAssociated with Obesity
Obese individuals are at a greater risk of
developing these cardiovascular disorders

• Hypertension
• Stroke
• Coronary Artery Disease

16
Hypertension

• Hypertension (HTN) is the term for high blood
  pressure.
• Hypertension is identified when a blood pressure
  is sustained at 140/90 mmHg.
• High blood pressure is referred to as the silent
  killer, since there are usually no symptoms with
  HTN.
• Some individuals find out that they have high
  blood pressure when they have trouble with their
  heart, brain, or kidneys.

NHLBI
17
HypertensionThe Dangers
Failure to find and treat HTN is serious, as
untreated HTN can cause

• The heart to get larger, which may lead to heart
  failure.
• Small bulges (aneurysms) to form in blood
  vessels.
• Blood vessels in the kidney to narrow, which may
  lead to kidney failure.
• Arteries in the body to harden faster, especially
  those in the heart, brain, kidneys,
  and legs. This can cause a heart attack, stroke,
  kidney failure, or can lead to amputation of part
  of the extremities.
• Blood vessels in the eye to burst or bleed. This
  may cause vision changes and can
  result in blindness.

NHLBI
18
Hypertension

• Blood pressure is often increased in overweight
  individuals.
• Estimates suggest that control of overweight
  would eliminate 48 of the hypertension
  in Caucasians and 28 in African Americans.
• Overweight and hypertension interact with cardiac
  function, leading to thickening
  of the ventricular
  wall and larger heart volume, and thus to a
  greater
  likelihood of cardiac failure.

J La State Med Soc .2005 157 (1) S42-49.
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Hypertension Prevalence in the Overweight
Age-adjusted prevalence of hypertension in
overweight U.S. adults
32.7
27.0
27.7
22.1
Prevalence of HTN
14.9
15.2
Adapted from http//www.obesityinamerica.org/tren
ds.html
20
Stroke

• Normally, blood containing oxygen and nutrients
  is delivered to the brain, and carbon dioxide and
  cellular wastes are removed.
• A stroke occurs when the blood supply to part
  of the brain is suddenly interrupted by a blocked
  vessel or when a blood vessel in the brain
  bursts.
• Once their supply of oxygen and nutrients from
  the blood is cut off to the brain cells, they
  die.

NINDS
21
Stroke
The symptoms of a stroke include

• Sudden numbness or weakness, especially on one
  side of the body
• Sudden confusion or trouble speaking or
  understanding speech
• Sudden trouble seeing in one or both eyes
• Sudden trouble with walking, dizziness, or loss
  of balance or coordination
• Sudden severe headache with no known cause

NINDS
22
Stroke

• There are two forms of stroke ischemic and
  hemorrhagic.
• Ischemic stroke occurs when an artery to the
  brain is blocked.
• Overweight and obesity increase the risk for
  ischemic stroke in men and women.
• With increasing BMI, the risk of ischemic stroke
  increases progressively and is doubled in those
  with a BMI greater than 30 kg/m2 when compared to
  those having a BMI of less than 25 kg/m2.
• Hemorrhagic strokes occur when a blood vessel in
  the brain erupts.
• Overweight and obesity do not increase the risk
  for hemorrhagic strokes.

NINDS
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Coronary Artery Disease

• Coronary artery disease (CAD) is a type of
  atherosclerosis that occurs when the arteries
  supplying blood to the heart muscle (coronary
  arteries) become hardened and narrowed.
• This hardening and narrowing is caused by plaque
  buildup.
• As the plaque increases in size, the insides of
  the coronary arteries get narrower, and
  eventually, blood flow to the heart muscle is
  reduced.
• This is critical because blood carries
  much-needed oxygen to the heart.

NHLBI
24
Coronary ArteriesBlood Flow
Angina This is the chest pain or discomfort that
occurs when the heart is not getting enough
blood. Heart attack This is what happens when
a blood clot develops at the site of the plaque
in a coronary artery. The result is
a sudden blockage, which may block all or most of
the blood supply to the heart muscle. Because
cells in the heart muscle begin to die when they
are not receiving adequate amount of oxygen,
permanent damage to the heart muscle can occur if
blood flow is not quickly restored.

• When the heart muscle is not receiving the amount
  of oxygen that it needs, one of two things can
  happen
• Angina
• Heart Attack

NHLBI
25
Coronary Artery Disease
Heart Failure In this condition, the heart cant
pump blood effectively to the rest of the body.
Heart failure does not mean that the heart has
stopped nor does it mean that it is about to. It
means that the heart is failing to pump blood the
way that it should. Arrhythmias Arrhytmias
are changes in the normal beating rhythm of the
heart. They can be either faster or slower than
normal. Some arrhythmias
can be quite serious.

• Over time, CAD can weaken the heart muscle and
  contribute to
• Heart Failure
• Arrhythmias

NHLBI
26
Coronary Artery Disease

• Obesity is associated with an increased risk for
  CAD.
• Abdominal fat distribution is believed to be
  related as well.
• Data from the Nurses Health Study illustrated
  that women in the lowest BMI but highest
  waist-to-hip circumference ratio had a greater
  risk of heart attack than those in
  the highest BMI but lowest waist-to-hip
  circumference ratio.
• Regional fat distribution appears to have a
  greater effect on CAD risk than BMI alone.

J La State Med Soc .2005 156 (1) S42-49.
27
Gastrointestinal DisordersAssociated with Obesity
Obese individuals are at greater risk of
developing these gastrointestinal disorders

• Colon Cancer
• Gall stones

28
Colon Cancer

• Colorectal cancer is a term used to refer to
  cancer that develops in the colon or the rectum.
• The colon (a.k.a. the large intestine) is about 5
  feet long and its role in the digestive system is
  to continue to absorb water and mineral nutrients
  from food. Once this process of absorption is
  complete, waste matter (feces) remains.
• The rectum is the final 6 inches of the digestive
  system. Feces are passed from the large intestine
  to the rectum, to exit the body through the anus.

American Cancer Society
29
Colon Cancer

• Colorectal cancer is the second leading cause of
  cancer-related deaths in the U.S.
• It is estimated to cause about 55,170 deaths
  during 2006.

American Cancer Society
30
Colon CancerFindings Relating to Obesity

• Colon cancer has been shown to occur more
  frequently in people who are obese than in people
  who are of a healthy weight.
• An increased risk of colon cancer has been
  consistently reported for men with high BMIs.
• Women with high BMI are not at increased risk of
  colon cancer.

There is evidence that abdominal obesity may be
important in colon cancer risk.
NCI
31
Gallbladder Disease

• Cholelithiasis is the primary hepatobiliary
  pathology associated with overweight.
• Cholelithiasis is a condition characterized by
  the presence or formation of gallstones in the
  gallbladder or bile ducts.
• Normally, a balance of bile salts, lecithin and
  cholesterol keep gallstones from forming.
  However, if there are abnormally high levels of
  bile salts or, more commonly, cholesterol, then
  stones can form.

NIH
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GallstonesFindings Related to Obesity

• Obesity appears to be associated with the
  development of gallstones.
• More cholesterol is produced at higher body fat
  levels.
• Approximately 20 mg of additional cholesterol is
  synthesized for each kg of extra body fat.
• High cholesterol concentrations relative to bile
  acids and phospholipids in bile increase the
  likelihood of precipitation of cholesterol
  gallstones in the gallbladder.

Endocrinol Metab Clin N Am. 2003 32 761-786.
33
GallstonesFindings Related to Obesity

• In the Nurses Health Study, when compared to
  those having a BMI of 24 or less,
• Women with a BMI 30 kg/m2 had a 2-fold
  increased risk for symptomatic gallstones.
• Women with a BMI 45 kg/m2 had a 7-fold
  increased risk for symptomatic gallstones.
• The relative increased risk of symptomatic
  gallstone development with increasing BMI appears
  to be less for men than for women.

J La State Med Soc .2005 157 (1) S42-49.
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GallstonesFindings Related to Obesity

• Ironically, weight loss leads to an increased
  risk of gallstones-- because of the increased
  flux of cholesterol through the biliary system.
• Diets with moderate levels of fat that trigger
  gallbladder contraction and subsequent emptying
  of the cholesterol content may reduce the risk of
  gallstone formation.
• Bile acid supplementation can be used to lower
  ones risk for gallstone formation.

J La State Med Soc .2005 157 (1) S42-49.
35
Metabolic DisordersAssociated with Obesity
Obese individuals are at greater risk of
developing these metabolic disorders

• Diabetes Mellitus
• Dyslipidemia
• Liver Disease

36
Diabetes Mellitus

• Type 2 diabetes mellitus (DM) is strongly
  associated with
  overweight and obesity in both genders and in all
  ethnic groups.
• The risk for Type 2 DM increases with the degree
  and duration
  of overweight in individuals.
• The risk for Type 2 DM also increases in
  individuals with a
  more central distribution of body fat
  (abdominal).

J La State Med Soc .2005 157 (1) S42-49.
37
Obesity and Type 2 DMIn the United States
Among people diagnosed with Type 2 diabetes,
55 percent have a BMI 30
(classified as obese), 30
percent have a BMI 25 or
30 (classified as
overweight), and only 15 percent have a BMI 25
(classified as normal weight).
15
55
30
Adapted from http//www.obesityinamerica.org/tren
ds.html
38
Diabetes MellitusFindings Related to Obesity

• The Nurses Health Study demonstrated the
  curvilinear relationship between increasing BMI
  and the risk of diabetes in women
• Women with a BMI below 22 kg/m2 had the lowest
  risk of DM
• At a BMI of 35 kg/m2, the relative risk of DM
  increased 40-fold or 4,000
• The Health Professionals Follow-up Study
  demonstrated a similar relationship between
  increasing BMI and the risk of diabetes in men
• Men with a BMI below 24 kg/m2 had the lowest
  risk of DM
• At a BMI of 35 kg/m2, the relative risk of DM
  increased 60-fold or 6,000

J La State Med Soc .2005 157 (1) S42-49.
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Diabetes MellitusFindings Relating to Weightloss

• Weight loss reduces the risk of developing
  diabetes.
• In the Health Professionals Follow-up Study, a
  weight loss of 5-11 kg decreased the relative
  risk for developing diabetes by nearly
  50.
• Type 2 DM was almost nonexistent with a weight
  loss of more than 20 kg (44 lbs) or in those with
  a BMI below 20.

J La State Med Soc .2005 157 (1) S42-49.
40
Dyslipidemia

• Dyslipidemia is defined as abnormal concentration
  of lipids or lipoproteins in the blood.
• As BMI increases, there is an increased risk for
  heart disease.
• This is because a positive correlation between
  BMI and triglyceride (TG) levels has been
  demonstrated.

Endocrinol Metab Clin N Am. 2003 32 761-786.
41
DyslipidemiaFindings Related to Obesity
HDL

• An inverse relationship between HDL cholesterol
  and BMI has been noted.
• This relationship may be more important than the
  relationship between
  BMI TG levels.
• Low level of HDL carries more relative risk for
  developing heart disease than do elevated
  triglyceride levels.
• Central fat distribution also plays an important
  role in lipid abnormalities.
• Excessive body fat in the abdominal region leads
  to increased circulating
  triglyceride levels.

Endocrinol Metab Clin N Am. 2003 32 761-786.
42
Liver Disease

• Nonalcoholic fatty liver disease (NAFLD) is the
  term given to describe a collection of liver
  abnormalities that are associated with obesity.
• In a cross-sectional analysis of liver biopsies
  of obese patients, it was found that the
  prevalence of steatosis, steatohepatitis, and
  cirrhosis were approximately 75, 20, and 2
  respectively.

J La State Med Soc .2005 157 (1) S42-49.
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Liver DiseaseFatty Liver

• Steatosis is the term for fatty liver and it is
  not actually a disease, but rather a pathological
  finding.
• Most cases of fatty liver are due to obesity.
• Other causes of fatty liver include
• Diabetes
• Certain drugs
• Intestinal bypass operations
• Starvation
• Protein malnutrition
• Alcoholism

The American Liver Foundation
44
Liver DiseaseFatty Liver

• A gradual weight reduction can help to reduce the
  enlargement of the liver due to fat, and it can
  normalize the associated liver test
  abnormalities.
• It is important to limit the amount of alcohol
  consumed in the diet. Alcohol can decrease the
  rate of metabolism and secretion of fat in the
  liver.

The American Liver Foundation
45
Importance of a Healthy Liver
The liver is the largest organ in the body and it
plays a vital role in performing
many complex functions that are
essential for life

• The 300 billion cells of the liver control a
  process known as metabolism. During metabolism,
  the liver breaks down nutrients into usable
  products. These products are then delivered to
  the rest of the body through the bloodstream.
• The liver also metabolizes toxins into byproducts
  that can be safely eliminated.
• The liver also produces many important
  substances, such as albumin, bile, cholesterol,
  clotting factors, globin, and immune factors.

Mayo Clinic
46
Other DisordersAssociated with Obesity

• Obstructive sleep apnea
• Osteoarthritis
• Endometrial, prostate, and breast cancers
• Complications of pregnancy
• Menstrual irregularities
• Psychological disorders

Obese individuals are at greater risk of
developing these metabolic disorders
47
Obstructive Sleep Apnea

• Obstructive sleep apnea is caused by repetitive
  upper airway obstruction during sleep
  as a result of narrowing of the respiratory
  passages.
• Patients having the disorder are most often
  overweight with associated peripharyngeal
  infiltration of fat and/or increased size of the
  soft palate and tongue.

American Academy of Family Physicians
48
Obstructive Sleep Apnea

• Common complaints are loud snoring, disrupted
  sleep, and excessive daytime
  sleepiness.
• Individuals with sleep apnea suffer from
  fragmented sleep and may develop
  cardiovascular abnormalities because of
  the repetitive cycles of snoring, airway
  collapse, and arousal.
• Because many individuals are not aware of heavy
  snoring and nocturnal arousals,
  obstructive sleep apnea may remain undiagnosed.

American Academy of Family Physicians
49
Obstructive Sleep ApneaFindings Relating to
Obesity

• Obstructive sleep apnea affects around 4 of
  middle-aged adults.
• Individuals having a BMI of at least 30 are at
  greatest risk for sleep apnea.
• Weight loss has been shown to improve the
  symptoms relating to sleep apnea.

J La State Med Soc .2005 157 (1) S42-49.
50
Osteoarthritis

• Osteoarthritis (OA) is the most common type of
  arthritis
• 40 million Americans currently have
  osteoarthritis.
• It is a degenerative disease which frequently
  leads to chronic pain and disability.
• For individuals over the age of 65, it is the
  most disabling disease.
• Currently, only the symptoms of OA can be
  treated there is no cure.

NSLS
51
Osteoarthritis Findings Relating to Obesity

• The incidence of OA is significantly increased in
  overweight individuals.
• OA that develops in the knees and ankles is
  probably directly related to the trauma
  associated with the degree of excess body weight.
• Osteoarthritis in other non-weight bearing joints
  suggests that there must be some component
  of the overweight syndrome responsible
  for altering cartilage and bone metabolism,
  independent of the actual stresses of body weight
  on joints.

Areas of the body most commonly affected by OA
NSLS
Endocrinol Metab Clin N Am. 2003 32 761-786.
52
CancerFindings Relating to Obesity

• Overweight and obesity are associated with an
  increased risk of
• esophageal, gallbladder, pancreatic,
  cervical, breast, uterine, renal, and prostate
  cancers.
• Obesity and physical inactivity may account for
  25 to 30 percent of several major cancers,
  including--- colon, breast (postmenopausal),
  endometrial, kidney, and cancer of the esophagus.

J La State Med Soc .2005 157 (1) S42-49.
53
Endocrine Changes

• There are various endocrine changes associated
  with overweight.
• Changes in the reproductive system are among the
  most common.
• Irregular menses and frequent anovular cycles are
  common.
• Rates of fertility may also be reduced.

Endocrinol Metab Clin N Am. 2003 32 761-786.
54
Endocrine ChangesAssociated with Obesity
Common hormonal abnormalities associated with
obesity

• Increased cortisol production
• Insulin resistance
• Decreased sex hormone-binding globulin in women
• Decreased progesterone levels in women
• Decreased testosterone levels in men
• Decreased growth hormone production

Endocrinol Metab Clin N Am. 2003 32 761-786.
55
Psychological DisordersAssociations with Obesity

• Obesity is associated with an impaired quality of
  life.
• Higher BMI values are associated with greater
  adverse effects.
• When compared to obese men, obese women appear to
  be at a greater risk for psychological
  dysfunction.
• This may be due to the societal pressure on women
  to be thin.

J La State Med Soc .2005 157 (1) S42-49.
Endocrinol Metab Clin N Am. 2003 32 761-786.
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Psychological DisordersWeight Loss

• Intentional weight loss has been consistently
  associated with improved quality of life.
• Severely obese patients who lost 43 kg through
  gastric bypass demonstrated improved quality of
  life scores to such an extent that their
  post-weight loss scores were equal to or even
  better than population norms.

J La State Med Soc .2005 157 (1) S42-49.
Endocrinol Metab Clin N Am. 2003 32 761-786.
57
In Conclusion
The following conditions have been found to be
associated with obesity

• Diabetes mellitus
• Hypertension
• Gallbladder Disease
• Liver Disease
• Cancer
• Coronary Artery Disease
• Cerebrovascular disease (stroke)
• Endocrine Changes

• Psychosocial Function
• Obstructive Sleep Apnea
• Osteoarthritis

These diseases have been found to be associated
with increased fat mass
These diseases have been found to be associated
with increased metabolic activity (secretion) of
fat cells in obesity
58
Pennington Biomedical Research Center

• Division of Education
• Phillip Brantley, PhD, Director
• Heli J Roy, PhD, RD, Associate Professor
• Shanna Lundy, BS

59
References

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60
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61
References

• American Liver Foundation. Diet and Your Liver.
  Available at http//www.liverfoundation.org/cgi-b
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  2view_records1
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