Low Fitness as a Predictor of Morbidity and Mortality

Steven N. Blair

Director of Research

Cooper Institute

Lecture Outline

• Cardiorespiratory fitness (CRF) as an indicator of habitual physical activity

• CRF and mortality

Health Adults

Older Women and Men

Chronic Disease

Longevity

• CRF and Functional Limitation

An Underlying Concept of the Aerobics Center Longitudinal Study

• Cardiorespiratory Fitness (CRF) is an excellent objective indicator of total physical activity in recent months

CRF increases by a predictable amount in controlled studies

CRF is strongly associated with detailed activity records - R2 0.7-0.8

Genetic contribution of CRF is 25-40%

Fitness and Mortality in Men, ACLS Fitness Categories

Table values are maximal METS attained during the exercise text

Fitness Group

20-39

30-49

50-59

60+

Low

<10.5 <9.9 <8.8 <7.5

Med. 10.6-12.7 10.0-12.1 8.9-10.9 7.6-9.7

High >12.7 >12.2 >10.9 >9.7

Age Groups (years)

Fitness Group

20-39

30-49

50-59

60+

Low

<8.1 <7.5 <6.5 <5.7

Med. 8.2-10.5 7.6-9.5 6.6-8.3 5.7-7.5

High >10.5 >9.5 >8.3 7.5

Age Groups (years)

Fitness and Mortality in Women, ACLS Fitness Categories

Questions and Issues Regarding Overweight, Obesity and Health

• How many believe that overweight is a threat to health?

• How many believe that sedentary habits are an important cause of overweight?

• How many believe that sedentary habits are a threat to health?

• Inactivity, overweight an health are highly interrelated, therefore extensive efforts must be made to disentangle this issue.

Fitness, Body Composition Distribution and Mortality in ACLS men

• Cohort of 21,925 men, followed on average 8 years (176,742 man years)

• Baseline exclusion for MI, Stroke or Cancer

• Outcomes

– All Cause Mortality (428 deaths)

– CVD mortality (144 deaths)

• Exposures:

– CRF from maximal exercise test on a treadmill as an objective marker of habitual physical activity patterns

– Body composition and fat distributions determined by hydrostatic weighing, sum of 7 skins folds and waist circumference.

Adjusted RR for All-Cause Mortality by Fitness and % Body Fat

Adj.RR*for age, exam year, smoking, alcohol, and family history

0

0.5

1

1.5

2

2.5

Lean Normal Obese

Body Fat

FitUnfit

(<16%) (>25%)(16-24%)

Lee CD et al. Am J Clin Nutr, 1999

012345678

Lean Normal Obese

Body Fat

FitUnfit

Adjusted RR for CVD Mortality by Fitness and % Body Fat

Cardiorespiratory Fitness as a Co-Morbidity of Obesity

•25,734 men in the Aerobics Center Longitudinal Study, followed <10 years

•During 258,940 man-years of observation, there were 1025 deaths (439 from CVD)

•BMI (kg/m2) distribution

–Normal=18.5-24.9 --10,623 men (41%)

–Overweight = 25.0 to 29.9--11,798 men (46%)

–Obese = 30.0--3293 men (13%)

Wei M. Et. Al. JAMA 1999;282:1547

RR for CVD and All-Cause Mortality by BMI categories,

25,714 Men, ACLS

Normal 18.5-24.9

Overweight 25.0-29.9

Obese >30.0

CVD deaths 126 237 76

RR(95%CI) 1.0 1.8 (1.4-2.2) 2.7 (2.0-3.6)

All Deaths 367 500 158

RR (95% CI) 1.0 1.3 (1.1-1.5) 1.9 (1.5-2.3)

00.5

11.5

22.5

33.5

Co-Morbidities of Obesity

Ref Category Normal OW Obese

RR of All-Cause Death by BMI Categories for Selected Mortality Predictors

Ref Category= Normal Weight without Risk Factor

RR Adj for age and Exam Year

Co-Morbidity # at Risk RR of CVD PAR % CVD

RR of Death PAR % Death

Baseline CVD 543 5.8 51 2.4 27 Diabetes 331 1.9 15 1.5 9 High Cholesterol 961 2.1 26 1.7 18 Hypertension 1370 1.4 15 1.1 4 Smoking 670 1.3 6 1.5 9 Low Fit 1674 2.0 39 2.3 44

Population Attributable Risk (PAR) for CVD and All-Cause Mortality in 3293 Obese Men, ACLS

Wei et al. JAMA, 1999;282:1547

All-Cause Mortality by BMI and # of Risk Factors, 24,335 Men, ACLS

• Men with baseline CVD or CA were excluded

• Men followed for approximately 10 years

• 809 Deaths

• Risk Factors considered--high blood pressure, high cholesterol, diabetes, smoking, history of parental CVD, and low cardiorespiratory fitness.

Relative Risk of All-Cause Mortality by BMI and # of Risk Factors, 24,335 Men, ACLS

BMI Groups 0

Any 1

Any 2

Any 3

>4

18.5-24.9 1.0* 72/4622

1.2 97/3531

1.7 78/1540

2.1 35/428

3.5 20/121

25.0-29.9 1.0 51/3373

1.2 102/3904

1.8 115/2569

2.6 75/978

4.8 52/306

>30.0 1.0 5/434

1.1 13/908

2.3 36/886

3.0 32/506

5.3 26/229

*Age-Adjusted RR

#Deaths/#Men

Number of Risk Factors

Risk Factors in 24,335 Norman Weight, Overweight, or Obese Men, ACLS

Percent of Men with 0 or 1 risk factor

Obese = 45%

Overweight = 65%

Normal Weight = 80%

Physical Inactivity Leads to Insulin Resistance Syndrome

•8,633 men with two examinations –normal ECG and free of diabetes, heart attack, stroke, or cancer at baseline–average age = 43.5 yrs. (30 to 79 yrs)

•Definitions (ADA/WHO criteria)–FPG--Fasting Plasma Glucose–Impaired fasting glucose (IFG)–110<FPG<126 mg/dl–Type 2 diabetes--FPG>126 mg/dl

•7,442 of the men were free of IFG at baseline•Average follow-up = 6 years•52,588 man-years of observation•149 new cases of type 2 diabetes•593 new cases of impaired fasting glucose•Incidence of type 2 diabetes = 2.8/1,000 man-years (similar to other white populations)

Wei M. et al. Ann Int Med 1999

Impaired Fasting Glucose by Cardiorespiratory Fitness Groups

CV Fitness Low Moderate High

Man-years 7,719 18,017 19,238

# Cases 147 254 147

Rate/1000 19.0 14.1 10.0

OR* 1.9 1.4 1.0

95% CI 1.5 – 2.4 1.2 – 1.8

*Adjusted for age, parental diabetes and follow-up

CV Fitness Low Moderate High

Man-years 9,752 21,075 21,761

# Cases 58 57 34

Rate/1000 19.0 14.1 10.0

OR* 1.9 1.4 1.0

95% CI 1.5 – 2.4 1.2 – 1.8

Type 2 Diabetes by Cardiorespiratory Fitness Groups

Fitness and Type 2 diabetes by IFG Groups

0

0.5

1

1.5

2

IFG Non-IFG

LowMediumHigh

Low Fitness an Inactivity as Mortality Predictors in Men with Diabetes

• Prospective study of 1263 men aged = 50 +10

• All men had type 2 diabetes at baseline

FPG>126 mg/dl

history of physician-diagnosed diabetes

taking anti-diabetic medication

• Low fit=least fit 20% (42% of the men)

• Physically inactive = no reported activity in the past 3 months

• Follow-up of 11.7 years, 14,777 man-years

• 180 deaths (92 CVD)

RR* for All-Cause Mortality by Fitness and BMI Levels in Men with Type 2 diabetes

RR(95% CI)* BMI RR(95%CI)*

Low 1.0 <25.0 1.0

Moderate 0.4 (0.3-0.6).

25.0-29.9 1.2 (0.8-1.77)

High 0.2 (0.2-0-0.4)

30+ 1.3 (-.9-1.9)

Cardiorepiratory Fitness and Mortality in the ACLS

• Follow-up of 891 women an 2135 men in the ACLS who were >60 years of age

• Examined at the Cooper Clinic during 1970-1994• Followed for mortality through 1994• Average Follow-up ~10years• Deaths

61 women during > 7,000 woman years

365 men during > 20,000 man years

__

Risk of Death by Fitness Groups, 749 Women and 1758 Men 60 and Older, ACLS

0

0.5

1

Woman Men

Low Medium High

Age, exam-year, BMI,cholesterol, high blood pressure, diabetes, smoking,CVC, parental CVD, adjusted RR for all cause mortality

Patients with cancer and failureto achieve at least 85% of predictedmax HR were excluded

0

40

80

120

60-69 70-79 80+

Low Moderate High

Death Rates/1000 by Fitness Groups 2135 Men aged 60 and Older, ACLS

CHD death rate /100,00 PY

# of Deaths 91 111 66 47 26 11 7 3 3

Gall Bladder DiseaseMaterials and Methods

•Study subjects were 2666 women and 7987 men age 21 to 79 years (mean 44.9 years)•97% were white, more than 75% had a college degree, and most were employed in executive or professional occupations•Follow-up period was an average of 12 years between the baseline examination and 1995 mail-back survey

Gallbladder Disease Criteria

•Outcome was self-reported physician-diagnosed gallbladder disease.•Patients were also asked the number of years since the diagnosis was made.

Relative Risk of fit groups from gallbladder disease in 10,653 persons

0

0.2

0.4

0.6

0.8

1

Age and Sex Multivariate

UnfitMed fitHigh fit

Type of Adjustment

Fitness and Functional Limitations• Prospective study of 1175 women and 3495 men age 40 years and older• Medical Exam during 1980-88• Average follow-up of 5.5 years• Self-report of functional limitations in 1990 by mail-back survey

Are your able to do?

Personal Care Activities

Household Activities

Recreational Activities• The 10 questions were scored as--

Yes = 0

Yes, with assistance or no = 1• All with a score of 1 or more were classified as having functional limitation

Huang et al. MSSE 1998,39:1430-5

Fitness and Functional Limitations

0

5

10

15

20

25

Woman Men

LowMediumHigh

The 10 questions were scored as-- Yes = 0 Yes, with assistance or no =1

All with a score of 1 or more were classified as having functional limitation

Prevalence (%) offunctional limitations

Huang et al. MSSE 1998,39:1430-5

Prevalence of Self-reported functional limitations by fitness and age groups

40-49 50-59 60+ Women Low 1.8* 2.3 4.6 Medium 8 13 26 High 7 3 18 Men Low 7 14 24 Medium 3 5 9 High 3 1 7

Huang et al. MSSE 1998,39:1430-5*Prevalence (%)

Fitness and Functional Limitations Women and Men, ACLS

0

0.5

1

Woman Men

Low Medium High

*OR for self-reported functional adjusted for age, follow-up, BMI,smoking, alcohol intake, baseline disease, and disease at follow-up

Huang et al. MSSE 1998,39:1430-5

Methods• 1635 men and 418 women >46 years of age at baseline (mean=56, range, 46-77• Received clinical assessments during 1987-1989• Reported no functional limitations in 1990• Reported functional health status on a 1995 mail-back survey• Average follow-up from baseline to 1995 survey=6.7 years (range 6-8 years)

Assessment of Functional Limitation in 1995• Series of questions on whether or not participants had difficulty performing or were not able to perform

• Moderate daily activity

– e.g. Lifting/carrying 10 pounds

– stooping, crouching, kneeling

• Strenuous daily activity

– walking 1/4 mile

– climbing 10 stairs without resting

– lifting/carrying 25 pounds

0

1

2

3

4

5

6

7

Incidence of Functional Limitation by Sex-and Age-Groups

Age groups (years)

Incidence of functional limitations (%)

0

0.2

0.4

0.6

0.8

1

Low Fit Mod Fit High Fit

Males

Females

Adjusted* Odds Ratios for Development of Functional Limitations

*Adjusted for age, BMI, length of follow-up, smoking status

Musculoskeletal Fitness, Cardiorespiratory Fitness and Functional Limitations

• 589 women and 3,069 men (30-82 years)

• Received both musculoskeletal and cardiorespiratory fitness assessments between 1980-1989

• Completed mail-back survey on functional limitations in 1990 after an average follow-up of 5 years

• Musculoskeletal fitness assessment

1 RM bench press

1 RM leg press

Maximal bent leg sit-up in 60 seconds

• Tertiles for each test were coded 0,1, or 2

• Scores summed, and those with a summary score of 5 or 6 were classified as high strength

Brill et al. MSSE 2000; 32:412-6

OR 95% CI OR 95% CI High Strength

0.54 0.21-1.39 0.5 0.34-0.93

BMI (Unit)

1.04 0.94-1.14 1.03 0.99-1.07

Treadmill Time(min)

0.90 0.83-0.98 0.90 0.86-0.93

New Health problems

2.72 1.50-4.96 2.14 1.57-2.92

Men

Age and Follow-up Adjusted OR for Functional Limitations

Women

Amount of Specific Physical Activities for Moderately Fit Women and Men

020406080

100120140160

Women Men

WalkAerobicRun

•Detailed physical activity assessments in women an men who also completed a maximal exercise test

•Average min/week for the moderately fit who reported each specific activity

Storan JR et al. AJPH;88:1807

Conclusions• Low Cardiorespiratory fitness is a strong and

independent predictor of mortality in women and men, young and old, health and unhealthy an fat and lean

• Low Cardiorespiratory fitness and low muscular strength are predictors of functional limitations

• Low fitness is highly prevalent and constitutes a major public health problem