Overweight and Obesity: Prevalence and Health Risks Dr. David L. Gee FCSN/PE 446.
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Transcript of Overweight and Obesity: Prevalence and Health Risks Dr. David L. Gee FCSN/PE 446.
Overweight and Obesity:Prevalence and Health
RisksDr. David L. Gee
FCSN/PE 446
Overweight vs. ObeseTraditional Definitions
– Obese: Body fatness above population norm
– Overweight: Body weight above population norm
Current NIH Definition– Obese is a more severe form of
overweight
Body Mass IndexBMI = BW / H2
where: –BW = kilograms
–H = meters
Body Mass IndexExample:
– BW = 165 lbs / 2.2 lbs/kg = 75 kg
– H = 70 in x 2.54 cm/in = 178 cm = 1.78 m
BMI = 75 / 1.782 = 24BMI is not a direct measure of body
fatness
1998 NIH-NHLBI Clinical Guidelines
Expert Panel (24 members)Systematic Literature Review (1980-
1997)394 randomized controlled trialsExecutive summary 1998Arch Int Med (Sept ‘98), JADA (Oct
‘98), NHLBI Web page
1998 NIH-NHLBI Guidelines
Overweight: BMI 25 - 29.9Obese: BMI > 30
–Obesity Class I: 30 - 34.9
–Obesity Class II: 35 - 39.9
–Extreme Obesity: >40
Prevalence of Overweight and Obesity in the United States, 1999-2004
JAMA 295: 1549-1555 (2006)
2003-2004 NHANESAll adults Males Females
OverweightBMI > 25
66% 71% 62%
ObeseBMI > 30
32% 31% 33%
Severely ObeseBMI > 40
5% 3% 7%
Obesity Trends Among U.S. Adults between 1985 and 2005
Obesity Trends Among U.S. Adults between 1985 and 2005
Source of the data: CDC’s Behavioral Risk Factor Surveillance
System (BRFSS). – state health departments – monthly telephone interviews with U.S. adults.
Source of the data: CDC’s Behavioral Risk Factor Surveillance
System (BRFSS). – state health departments – monthly telephone interviews with U.S. adults.
Is being overweight really that dangerous?
Excess Deaths Associated with Underweight, Overweight, and Obesity
JAMA 2005:293:1861-1867 “Underweight and obesity… were
associated with increased mortality…” “Overweight was not associated with
excess mortality.” “Study finds government overstated danger
of obesity” – USA Today – 4/19/05– http://www.usatoday.com/news/health/2005-04
-19-obesity-danger_x.htm
For adults ages 25-59, increased mortality in underweight and obese categories, but not overweight category.
Is being overweight really that dangerous?
Other interpretations: While risk of mortality may not be greater in
overweight subjects, risk of chronic disease is greater in overweight and obese subjects– Improved detection and treatment of risk factors result
in reduced mortality in overweight subjects Hypertension, diabetes, dyslipidemia Quality of life
Overweight is a temporary state– Most/many overweight become obese– Obese state is clearly a health risk
Prevalence and Trends in Obesity Among US Adults, 1999-2000
JAMA 288(14)1723-1727 (2002)
Childhood Obesity
Overweight Prevalence in
Children & Adolescents: Definitions
Criteria based on NHANES 1976-1980
Higher BMI criteria– >95th percentile = overweight, medical
follow-up (~BMI=30 in adults)– 85-95th pct = risk of overweight (~BMI=25
adults)
American children are getting fatter…
Prevalence of Overweight* Among U.S. Children and Adolescents (Aged 2 –19 Years)National Health and Nutrition Examination Surveys
American boys of all ethnicities are getting fatter
Adolescent Boys Prevalence of Overweight* by Race/Ethnicity (Aged 12–19 Years)
National Health and Nutrition Examination Surveys
American girls, especially African-American girls, are getting fatter
Adolescent Girls Prevalence of Overweight* by Race/Ethnicity (Aged 12–19 Years)
National Health and Nutrition Examination Surveys
The Spread of the Obesity Epidemic in the US, 1991-1998JAMA 282: 1519-1522 (1999)cross sectional random telephone
survey>100,000 subjectsobesity = BMI > 30self-reported data
– probable underestimation of obesity
Changes of Obesity Prevalence:Gender
1991 1998 %increase
men 11.7% 17.7% 51.5%
women 12.2% 18.1% 47.1%Although the prevalence of obesity is higher in women than in men,
The rate of increase in obesity is greater in men than in women.
Changes of Obesity Prevalence:Age
Age 1991 1998 % increase
18-29 7.1% 12.1% 69.9%30-39 11.3% 16.9% 49.5%40-49 15.8% 21.2% 34.3%50-59 16.1% 23.8% 47.9%60-69 14.7% 21.3% 44.9%> 70 11.4% 14.6% 28.6%
Although the prevalence of obesity is greater in older Americans,The rate of increase in obesity is rising faster among younger Americans
Changes of Obesity Prevalence:Ethnicity
Ethnicity 1991 1998 % increase
White 11.3% 16.6% 47.3%
Black 19.3% 26.9% 39.2%
Hispanic 11.6% 20.8% 80.0%
Other 7.3% 11.9% 62.0%
Prevalence of obesity is highest among African-Americans,The rate of obesity rising fastest in the Hispanic population.
Changes of Obesity Prevalence:Education Level
EducationLevel
1991 1998 %increase
< Highschool
16.5% 24.1% 46.0%
Highschool
13.3% 19.4% 46.1%
Somecollege
10.6% 17.8% 67.5%
>College
8.0% 13.1% 62.9%
Prevalence of obesity is higher in less educated Americans, butThe rate of obesity is faster among more educated Americans.
Obesity is growing worldwideScience: 7 January 2005: vol. 307. no. 5706, p. 38
Obesity and HealthContributes to over half of Western
chronic diseases.– Coronary heart disease
– All major cancers except lung cancer
– Diabetes
– Stroke
Obesity and Mortality Rate
Lowest mortality–BMI = 19-25–10% to 20% under average BW
Mortality rate increases exponentially above BMI of 25–CDC 2005 study, above 30
Overweight and Coronary Heart Disease
70% of CHD cases are overweight Being overweight
– increases CHD mortality risk
– increases Total Cholesterol & LDL-C
– decreases HDL-C
– increases VLDL-TG
BMI and Prevalence of HypercholesterolemiaNHANES III
BMI and Prevalence of Low HDLNHANES III
Obesity and Diabetes Mellitus
80% of diabetics are overweightPrevalence
– 7th most frequent cause of death
– 11 million cases in US
Diabetes Prevalence1994 & 2002
Millions of Cases of Diabetes in 2000 and Projections for 2030, with Projected Percent Changes. NEJM 356:213-215(2007)
Obesity and Diabetes Mellitus
Type 1 DM (IDDM) (10-15%)– absolute deficiency of insulin
– not associated with obesityType 2 DM (NIDDM) (80%)
– peripheral insulin resistance
– highly associated with overweight
– weight loss cornerstone of treatment
Complications of Diabetes
Micro-angiopathies– blindness– renal failure– amputations
uncontrolled infections, numbness
Macro-angiopathies– coronary heart disease
Diagnostic Criteria for Diabetes (2005)
Fasting blood glucose > 126 mg/dl– 110-125mg/dl impaired glucose tolerance
Testing for all adults over 45 years every 3 years Testing earlier or more frequently
– if BMI > 25 plus CVD risk factors At risk ethnicity Family history Chronic inactivity History of gestational diabetes
Obesity and StrokeHypertension and StrokeObesity and Hypertension Prevalence
– 35% of obese have hpt
– 17% of desirable BMI have hpt
Diagnostic Criteria– systolic BP > 140 or– diastolic BP > 90
BMI and Prevalence of Hypertension
Prevalence of the Metabolic Syndrome Among US AdultsJAMA, 287: 356-359 (2002)
Definition– Cluster of risk factors resulting in substantial increased
risk for developing diabetes and cardiovascular disease (NCEP-ATP III)
Criteria: three or more of the following– Abdominal obesity (m>40”, f>35”)– Hypertriglyceridemia (>150mg/dl)– Low HDL-C (m<40mg/dl, f<50mg/dl)– Hi blood pressure (>130/85)– Hi fasting blood glucose (>110 mg/dl)
Prevalence of the Metabolic Syndrome Among US AdultsJAMA, 287: 356-359 (2002)
NHANES III (1988-1994)– 8814 adults
Results:– Age adjusted prevalence: 24%– Prevalence increased with age– Prevalence increased in Hispanic-Americans– Prevalence similar in white males & females
Higher in black and Hispanic females than males
Obesity and CancerPositive association with:
– Breast Cancer (post menopause)– Colon Cancer– Prostate Cancer– Endometrial Cancer
Essentially all except lung cancer
Overweight, Obesity, and Mortality from Cancer in a Prospectively
Studied Cohort of U.S. Adults NEJM 348:1625(April 2003)
900,000 adults – Prospective study, free of cancer
Self reported height/body weight in beginning
– 16 year follow up– ~57,000 cancer deaths
Obesity and Mortality from CancerNEJM April 2003
Under Fitness vs Over Fatness?
Association of Physical Activity and Body Mass Index With Novel and Traditional Cardiovascular Biomarkers in Women Samia Mora, MD, MHS; I-Min Lee, MBBS, ScD; Julie E. Buring, ScD; Paul M Ridker, MD, MPH JAMA. 2006;295:1412-1419.
Women’s Health Study– 27,158 healthy women (mean age = 55yrs)– Randomized, placebo controlled for low-dose asprin
and vitamin E in primary prevention of CVD and Cancer.
– Main outcome measures of this study: Association of physical activity and BMI on CVD risk factors
Copyright restrictions may apply.
Mora, S. et al. JAMA 2006;295:1412-1419.
Adjusted Odds Ratios for the Association of Quintiles of Physical Activity and Quintiles of Body Mass Index With Elevated Biomarker Levels*
After adjusting for age, race, smoking, systolic blood pressure, diabetes, menopausal status, hormone use, and eitherBMI or physical activity, both physical activity and BMI remained significantly associated in a linear manner with most biomarker levels, with greater odds ratios (ORs) for BMI compared with physical activity
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Mora, S. et al. JAMA 2006;295:1412-1419.
Association of Physical Activity and Body Mass Index Categories With Cardiovascular Biomarkers
High BMI showed stronger associations with these biomarkers than physical inactivity,but within BMI categories, physical activity was generally associated with more favorable cardiovascular biomarker levels than inactivity.
Association of Physical Activity and Body Mass Index With Novel and Traditional Cardiovascular
Biomarkers in Women Samia Mora, MD, MHS; I-Min Lee, MBBS, ScD; Julie E. Buring, ScD; Paul M Ridker, MD, MPH JAMA. 2006;295:1412-1419.
Conclusions: Both lower levels of physical activity and higher levels of
BMI were strongly and independently associated with adverse inflammatory and lipid biomarker levels.
BMI showed greater magnitude of association with the biomarkers
A modest level of physical activity was significantly associated with more favorable biomarker profiles, even in overweight or obese individuals.
The most favorable inflammatory and lipid levels were found in women who had at least moderate physical activity levels and were normal weight.
Another view:Cardiorespiratory Fitness, Macronutrient Intake,
and the Metabolic Syndrome: The Aerobics Center Longitudinal StudyJADA 2006; 106:673-679
~12,000 adult men and women enrolled in prospective trial at the Cooper Clinic, Dallas, TX
Cross-sectional epidemiological study
Odds of prevalent m etabolic syndrom e by fitness groups and BMI categories
0
0.2
0.4
0.6
0.8
1
1.2
Normal w eight Overw eight
Odd
s R
atio Low f itness
Moderate f itness
High f itness
Fitness was significantly and inversely associated withprevalent metabolic syndrome in both normal and overweight subjects. (however, researchers did notreport absolute risk of normal and overweight subjects)
The Cost of ObesityHealth Affairs, Aug 2006
Year % of Medicare Patients with
obesity
% of Medicare spending on
obese patients
1987 11.7% 9.4%
2002 22.5% 24.8%
$336 billion 2005 total Medicare expenses
Effects of Weight Loss on HealthThe good news!
Reduces overall mortalityReduces risk factors
– decreases plasma TG– decreases blood pressure– increases HDL-C, decreases LDL-C– decreases fasting blood glucose
The Effect of Weight Loss on Left Ventricular Mass
NEJM 314: 334-339 (1986)
21 week, randomized control trial, n=41, young overweight patients
Hypertension and Weight Loss in Men
Conclusion:– modest weight loss results in
lowering of blood pressure in obese men.
– effect of weight loss is comparable if not better than with medication
Women, Weight Change, & Hypertension
Ann. Internal Med. 128: 81-88 (1998)
Nurse’s Health Study– 1976 – 1992 (16 yr)
– 82,473 healthy females– 16,395 new cases of hypertension
Women, Weight Change, & Hypertension
no change mod wt loss sig wt loss mod wt gain severe wt gain
1 0.85 0.74
1.74
5.21
0
1
2
3
4
5
6
RR
no change mod wt loss sig wt loss mod wt gain severe wt gain
Long-term effects of modest weight loss in Type II diabetic patients.Arch. Int. Med. 147:1749-1753 (1987)
1 year,Behavioral weight controlprogram,N=114 type 2diabetics
Long-term effects of modest weight loss in Type II diabetic
patients.Conclusions:
–Modest weight loss results in improved glucose control improved insulin sensitivity reduced triglycerides increased HDL-C
Prevention of Type 2 Diabetes Mellitus by Changes in Lifestyle among Subjects with
Impaired Glucose Tolerance NEJM - May 2001 522 middle age males
– BMI = 31– w/ impaired glucose tolerance
3.2 year follow-up– Intervention group
individualized wt. loss counseling
– Control group standard advice
Prevention of Type 2 Diabetes Mellitus by Changes in Lifestyle among Subjects with
Impaired Glucose ToleranceWeight Loss
– Intervention = 4.2 kg– Control = 0.8 kg
Diabetes Incidence @ 3 years– Intervention = 11%– Control = 23%
“The reduction in the incidence of diabetes was directly associated with changes in lifestyle”
Weight Cycling - Risk Factor?
Significant and deliberate fluctuations in body weight– Yo-yo dieting
Framingham Studies (1991)– individuals with greatest weight fluctuations
had highest risk of overall mortality and mortality & morbidity to coronary heart disease.
Variability of body weight and health outcomes in the Framingham population.
NEJM 324: 1839-1844 (1991)
Weight Cycling and Cholecystectomy in Women
Ann. Internal Med. (Mar 1999) Nurse’s Health Study
– (47,153 women, 30-55yr, w/o gall bladder disease, 1972-1988)
Weight cycling history (1 episode intentional)– light = 5-9 lbs (20.1% of subjects)– moderate = 10-19 lbs (18.8%)– severe = >20 lbs (16%)
Weight Cycling and Cholecystectomy in Women
Adjusted relative risk for cholecystectomy compared to women who maintained their weight:– 1.20 for light cyclers– 1.31 for moderate cyclers– 1.68 for severe cyclers
Caused by:– weight cycling?– severity of obesity?
Intentional vs Unintentional Weight Loss and Mortality in
Older Women.Iowa Women’s Health Study
– 25,897 women (55-69 yrs)
– questionnaire regarding wt loss since 18 yrs old
– followed 4 years
Intentional vs Unintentional Weight Loss and Mortality in
Older Women.Intentional wt loss (> 20 lbs):
– risk of total or CHD mortality not affectedUnintentional wt loss:
– 26-57% greater mortality risk, – 51-114% greater CHD risk
Increased mortality due to wt loss due to pre-existing disease.
Weight Cycling: Health Risk Factor?
NIH/NIDDK/WIN statementsrisk of remaining obese vs.
risk(?) of weight cyclingunderscores importance of life-
long changes in behaviors to attain a healthy weight.
A Prospective Study of Weight Change and Health-Related Quality of Life in
WomenJAMA Dec. 1999Nurse’s Health Study
– 40,098 women, 4 yr longitudinal study– Weight changes– Quality of life questionnaire
Physical function Vitality Freedom from bodily pain Mental health
The effect of weight gain/loss on:Vitality Score
Weight gain:– associated with
declines in vitality scores in all BMI categories
Weight loss– associated with
improved vitality scores only in women with BMI>25
The effect of weight gain/loss on:Mental Health Score
Weight gain– associated with a
decline in mental health scores in all weight categories
Weight loss– associated with
improved mental health scores only in obese class I women and declined in normal weight women.
A Prospective Study of Weight Change and Health-Related Quality of Life in Women.
Conclusions: For women at all BMI categories:
– Don’t gain weight– Reduced quality of life
For overweight and obese women:– Weight loss is generally associated with
improved quality of life For normal weight women
– Weight loss does not improve quality of life May actually reduce quality of life
Lose weight to improve health– Optimal health attained at BMI = 18,5-25
Avoid trying to lose weight to look like a media star– Media stars often may
Be genetically thin Lose weight in unhealthy ways Actually not be all that thin
Jamie Lee CurtisBefore and after work with 13 experts & 3 hours
“True Thighs” More magazine, August 2002
"The retouching is excessive. I do not look like that and more importantly I don't desire to look like that," she said. "I actually have a Polaroid that the photographer gave me on the day of the shoot… I can tell you they've reduced the size of my legs by about a third. For my money it looks pretty good the way it was taken."