Obesity Paul R. Earl Facultad de Ciencias Biol

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Obesity Paul R. Earl Facultad de Ciencias
BiológicasUniversidad Autónoma de Nuevo LeónSan
Nicolás de los Garza, NL, 66540 Mexico
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The backgroundOverweight and obesity in about
3-4 decades have reached worldwide epidemic
proportions from China to Argentina. In 1976, 15
of Americans were obese. This rate doubled by
2006. It is impossible to explain this epidemic
by a) urbanization
and b) an escape from hunger as the Industrial
revolution of perhaps 1850 is far earlier.
Taking an escalator instead of the stairs is
part of today's story. Obesity can be controlled
by rationing food, especially energy-dense foods
like french fries..
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The milestone discovery of the hormone leptin by
Jeff Friedman and colleagues in 1994 is one key
to understanding obesity. Also, leptin connects
with insulin. In 1988 another giant step was
taken by Gerald Reavens who diagnosed metabolic
syndrome (Diabetes 37 1595-607). It is caused by
being overweight, physical inactivity and by
genetic factors. We do not yet have a crystal
clear view of our energy metabolism, although we
are close.
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Leptin, the product of the ob (obese) gene, is a
singlechain 16 kiloDalton protein consisting of
146 amino acid residues. It is produced mainly in
the adipose tissue. It controls appetite, fat
metabolism and body weight regulation via signals
to the hypothalamus.In humans, leptin levels
correlate with body mass index (BMI) and
percentage body fat, and are elevated even in
obese individuals. Leptin has a dual action,
decreasing appetite and increasing energy
consumption.
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If the body's energy system begins to store FAT,
disease is a likely consequence.An increase in
mortality is associated with overweight and
obesity. Individuals who are obese have a 50-100
increased risk of premature death from all
causes compared to normal weight individuals.
Life insurance companies will charge fat people
more and smokers more. An estimated 300,000
deaths a year may be attributable to obesity in
the US. Most of the cost associated with obesity
is due to a/ type 2 diabetes, b/ coronary heart
disease and c/ hypertension.
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The worldwide malnutritional extremes of rural
hunger with stunting and urban obesity need to be
much better understood through nutritional
education, demography and ecology. Policies to
reverse environmental degradation and reduce
population pressure seem essential. More
overpopulation can soon swallow the world's grain
production whether or not policymakers continue
to be deluded by "sustainable development."Calori
e intake is much of the story and physical
INACTIVITY via desk jobs is also much of it. If
a larger percentage of population became
physically active, the public health burden
associated with obesity would be greatly
reduced." Gregory J. Welk, Iowa State University,
Ames, and Steven N. Blair, The Cooper Institute,
Dallas.
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Body mass index (BMI)BMI is a measure
of weight in relation to height. BMI is
calculated as weight in pounds divided by the
square of the height in inches, multiplied by
703. BMI is more usually calculated as weight in
kilograms divided by the square of the height in
meters. This is (W/HH).BMI is significantly
correlated with total body fat content for most
people, but can overestimate body fat in persons
who are very muscular. It can underestimate body
fat in persons who have lost muscle mass, such as
many of the elderly.
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The simple measurement of the waist will
always be popular 2.54 cm 1
inch.Health risk Men waist size Women-
waist sizeHealthy lt 94 cm lt 80 cmIncreased
health 94-101cm 80 to 88cmrisk
(37-40 inches) (32-35 inches)Highest health
More than 101cm More than 88cmrisk
(gt40 inches) (gt35 inches)By order
(sequence), BMI has the following
equation given in the graph.
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The worldwide epidemic of obesityThe table gives
you a rough idea of how obesity is distributed in
the world. There is no attempt to treat the BMI
for each nation separately. The sitting height
measurement should be added in to find leg length
(LL). Shorter races have larger BMIs. LL/H is a
useful index.The striking feature in the table
is the extremely low obesity rate in Japan, which
is combined with an extremely high longevity.
Such gains in the length and quality of life
should not be destroyed by the new threat
obesity.
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Physical inactivity combined with energy-dense
foods
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Two priority testsWhen a
person is obviously overweight, they should
obtain test results from 1/ the glucose tolerance
test and 2/ the cholesterol level test.Glucose
tolerance testAfter an overnight fast, a sample
of blood is taken. Then 75 g of glucose dissolved
in 250-350 ml of water is drunk. Two hours later
another blood sample is taken. The levels of
glucose in the 2 samples are then measured.
Account is taken of the fact that the
concentration of glucose measured in plasma is 10
higher than in whole blood.Diabetes is present
when the fasting blood sample is over 6.7 mmol/l
or the level in plasma is over 7.8 mmol/l, or the
second sample has 10 mmol/l and 11.1 mmol/l.
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The cholesterol testCholesterolol is a fat
(lipid) in your blood. High-density lipoprotein
(HDL) ("good" cholesterol) helps protect your
heart, but low-density lipoprotein (LDL) ("bad"
cholesterol) can clog the arteries of your heart.
Triglycerides are another type of fat in the
blood. As high level cholesterol is associated
with hardening of the arteries, heart disease and
a higher risk of death from hear attacks.
Cholesterol testing is a routine part of
preventive medicine.
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Excercise1/ Causes a very modest weight loss,
2/ Decreases abdominal fat, 3/ Increases
cardiorespiratory fitness and4/ Helps to
maintain weight loss.Build physical activity
into regular routines and playtime for all
children and their families. Ensure that adults
get at least 30 minutes of moderate physical
activity on most days of the week. Children and
adolescents should aim for 1-2 hours in school
games, often after classes at 3 PM.Do the
primary and secondary schools have enough space
devoted to competitive games? The probable answer
is No.
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How many meters can you walk in 6 minutes? Were
you short of breath? Were your muscles fatigued?
What was your pulse? Blood pressure? 140/80 ?
Oxygen saturation percent? 97 ? What do you
weight? Distance times weight is equal to work
done.Can the 6-minute walk test predict your
longevity ? How old are you now ?Ensure daily,
quality physical education in all school grades.
Such education can develop the knowledge,
attitudes, skills, behaviors and confidence
needed to be physically active for life. This
instruction often is handled rather poorly.
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Obesity is associated with an increased risk of
Premature death Type 2 diabetes Heart disease
Stroke Hypertension Gallbladder disease
Osteoarthritis (degeneration of cartilage and
bone in joints) Sleep apnea (breath stopping in
sleep!) Asthma Breathing problems, perhaps from
smoking
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PrevalenceThe prevalence ranges from 6.7 at
ages 2029 to 43.5 for ages 6069 and 42.0
for those aged 70 and older. The age-adjusted
prevalence is 24.0 for men and for women at
23.4 .Mexican Americans have the highest
age-adjusted prevalence of obesity at 31.9 ).
The lowest prevalence is among whites (23.8 ),
Blacks (21.6 ) and other ethnicities at 20.3 .
However, LL is unfortunately not usually
considered in prevalence. Races like some
Mexicans have shorter legs therefore higher BMIs.
When YOU DO NOT HAVE the sitting height, the
racial meaning of BMI is hidden. You do not have
a BMI scale for each race.
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Height, weight and morbidityAn inheritable
optimal metabolic rate is associated with the
lowest mortality risk (M), greatest height (H)
and a desirable body weight (W). Deviations from
this rate are reflected in high BMI, overweight
and higher mortality. Negative deviations occur
with shorter H. The population optimal metabolic
rate may differ among genotypes. Those with
higher rates are the ones who can translate more
energy intake into growth in H. They are able to
reach greater final adult H with a lower BMI than
genotypes with a lower optimal rate.
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Insulin resistanceLack of energy, low metabolism
and some obesity can be the first symptoms of
insulin resistance. In order to use sugar, the
body releases the insulin required by cells to
convert it into energy. Since our modern diet
can be so heavily comprised of carbohydrates and
sugar, cells can start to be insensitive to your
own insulin due to this chronic abundance. Do the
salivary glands and other glands produce
anti-insulin ? When your cells start to resist
your own insulin and therefore, your body has to
produce more insulin to get the same job done.
Left untreated over time, your over-production of
insulin will reach chronic levels.
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Metabolic syndromeThis syndrome known as
metabolic syndrome can be defined as a cluster of
abnormalities, including obesity, hypertension,
dyslipidemia and type 2 diabetes, that are
associated with insulin resistance and
compensatory hyperinsulinemia. However, a
cause-and-effect relationship between insulin
resistance, these diseases and the mechanisms
through which insulin resistance influences their
development has yet to be proven sufficiently.
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More vital informationOverweight, obesity and
their associated health problems have substantial
economic consequences. Direct health care costs
refer to preventive, diagnostic and treatment
services like home care. Indirect costs refer to
lost wages, etc.Morbidity from obesity may be
as great as those from poverty, smoking or
problem drinkings. Overweight and obesity are
associated with an increased risk of cancer such
as endometrial, colon and postmenopausal breast
cancer.
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Racial and ethnic disparities in overweight may
also occur in children and adolescents. Mexican
American boys tended to have a higher prevalence
of overweight than non-Hispanic black and
non-Hispanic white boys. Black girls tended to
have a higher prevalence of overweight compared
to non-Hispanic white and Mexican American
girls.In addition to racial, ethnic and gender
disparities, the prevalence of overweight and
obesity also varies by age. Among both men and
women, the prevalence of overweight and obesity
increases with advancing age until the sixth
decade, after which it starts to decline.
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AdultsThe age-adjusted prevalence of overweight
(BMI of 25.0 or higher) increased from 55.9 in
NHANES III (US Nacional Health and Nutrition
Estimate Studies 3) (198894) to 65.1 in NHANES
(19992002). The prevalence of obesity (BMI of
30.0 or higher) also increased during this period
from 22.9 to 30.4 . Extreme obesity (BMI of
40.0 or higher) increased from 2.9 to 4.9 (JAMA
2004 291 28472850).Since 1991 the prevalence
of those who are obese increased 75 . Among
states in 2001, Mississippi had the highest rate
of obesity and Colorado had the lowest.In
participants ages 1824, studied from 19902000,
obesity increased among every ethnic group,
especially in Black women. Almost 20 of Black
women were obese by ages 1824, increasing to
over 35 by ages 2544.
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Heart Disease and Stroke StatisticsAmerican
Heart Association 2005 Update. The Third
Report of the National Cholesterol Education
Program (NCEP) Expert Panel on Detection,
Evaluation and Treatment of High Blood
Cholesterol in Adults (ATP III, NHLBI) defines
the metabolic syndrome as 3 or more of the
following abnormalities Waist circumference
greater than 102 cm (40 inches) in men and 88 cm
(35 inches) in women. Serum triglyceride level
of 150 mg/dL or higher. High-density lipoprotein
(HDL) cholesterol level less than 40 mg/dL in men
and less than 50 mg/dL in women. Blood pressure
of 130/85 mm Hg or higher. Fasting glucose level
of 110 mg/dL or higher.
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Prevalence of Metabolic Syndrome Among
AdolescentsThe prevalence of metabolic syndrome
(Mets) among 1219 year old U.S. adolescents was
estimated in an analysis of NHANES III data, by
applying a modification of the ATP III definition
for adults. MetS during adolescence was defined
as 3 or more of the following abnormalities
Serum triglyceride level of 110 mg/dL or higher.
High-density lipoprotein (HDL) cholesterol level
of 40 mg/dL or lower. Elevated fasting glucose
of 110 mg/dL or higher. Blood pressure at or
above the 90th percentile for age, sex and
height. Waist circumference at or above the 90th
percentile for age and sex.
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Prevalence of Metabolic Syndrome Among AdultsThe
prevalence ranges from 6.7 at ages 2029 to
43.5 for ages 6069 and 42.0 for those aged
70 and older. The age-adjusted prevalence is
similar for men at 24.0 and for women at 23.4
.Mexican Americans have the highest
age-adjusted prevalence of MetS at 31.9 ). The
lowest prevalence is among whites (23.8 ),
African Americans (21.6 ) and it is other race
or ethnicity at 20.3 . Among Blacks, women had
about a 57 higher prevalence of Mets than men
had. Among Mexican Americans, women had a 26
higher prevalence than men had.
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We need much more health applications-Teach
nutrition in the primary schools.- Increase
playgrounds.- Increase research on behavioral
and environmental causes of overweight and
obesity. - Increase research and evaluation on
prevention and treatment interventions for
overweight and obesity, and develop and advertize
the bestguidelines.- Increase research on
disparities in the prevalence of overweight and
obesity among racial and ethnic, gender,
socioeconomic and age groups, and use this
research to identify effective and culturally
appropriate interventions.
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We need much more health applications- Develop
and use noninvasive sensors for the Basal
Metabolic Rate (BMR).- Create more opportunities
for physical activity at worksites. Encourage all
employers to make facilities and opportunities
available for physical activity for all
employees.- Make community facilities more
available and accessible for physical activity
for all people, including the elderly.- Promote
more healthful food choices, including at least 5
servings of fruits and vegetables each day, and
reasonable portion sizes at home, in schools and
at worksites.