Exercise, body mass index and heart disease survival

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Hi All,

Does lower body mass index mean that exercise is of less benefit?

See the below pdf-available comments and article addressed in the comments. It

seemed to be from Table 3 that the patients of diabetes with lower body mass

indices

more significantly had an association of exercise with survival from heart

disease.

In This Issue of Archives of Internal Medicine

Arch Intern Med. 2005 Oct 10;165(18):2052.

Cardiorespiratory Fitness and BMI as Predictors of CVD Mortality Among Men With

Diabetes

Questions remain as to whether higher levels of cardiorespiratory fitness are

associated with lower risk of cardiovascular disease (CVD) mortality in

overweight

and obese individuals with diabetes. In this prospective epidemiological study

of

2316 men with diabetes, Church et al sought to quantify the independent and

joint

relations of cardiorespiratory fitness and body mass index with CVD mortality.

They

found that low cardiorespiratory fitness was associated with increased risk of

CVD

mortality within normal weight, overweight, and class 1 obese weight categories.

These results further reinforce that health care providers should give increased

attention to counseling for increasing activity and improving fitness in

patients

with diabetes for the intrinsic benefits associated with increased fitness and

for

the critical role regular physical activity plays in long-term weight loss and

maintenance.

Church TS, Lamonte MJ, Barlow CE, Blair SN.

Cardiorespiratory fitness and body mass index as predictors of cardiovascular

disease mortality among men with diabetes.

Arch Intern Med. 2005 Oct 10;165(18):2114-20.

PMID: 16217001

ABSTRACT

Background Questions remain as to whether higher levels of cardiorespiratory

fitness, a measure of regular physical activity, are associated with lower risk

of

cardiovascular disease (CVD) mortality in overweight and obese individuals with

diabetes. Our objective was to quantify the independent and joint relations of

cardiorespiratory fitness (hereafter, fitness) and body mass index (BMI;

calculated

as weight in kilograms divided by the square of height in meters) with CVD

mortality

in men with diabetes.

Methods This study was conducted using prospective observational data from the

Aerobics Center Longitudinal Study. Study participants comprised 2316 men with

no

history of stroke or myocardial infarction and who were diagnosed as having

diabetes

(mean [sD] age, 50 [10] years); had a medical examination, including a maximal

exercise test during 1970 to 1997 with mortality surveillance to December 31,

1998;

and had a BMI of 18.5 or greater and less than 35.0. The main outcome measure

was

CVD mortality across levels of fitness with stratification by BMI.

Results We identified 179 CVD deaths during a mean (SD) follow-up of 15.9 (7.9)

years and 36 710 man-years of exposure. In a model containing age, examination

year,

fasting glucose level, systolic blood pressure, parental history of premature

CVD,

total cholesterol level, cigarette smoking, abnormal resting, and exercise

electrocardiograms, a significantly higher adjusted risk of mortality was

observed

in men with a low fitness level who were normal weight (hazard ratio, 2.7 [95%

confidence interval, 1.3-5.7]), overweight (hazard ratio, 2.7 [95% confidence

interval, 1.4-5.1]), and class 1 obese (hazard ratio, 2.8 [95% confidence

interval,

1.4-5.1]) compared with normal weight men with a high fitness level.

Conclusion In this cohort of men with diabetes, low fitness level was

associated

with increased risk of CVD mortality within normal weight, overweight, and class

1

obese weight categories.

.... Table 1. Baseline Characteristics of 2316 Men With Diabetes Grouped by

Survival

Status (Aerobics Center Longitudinal Study, 1970-1997)*

==============

----Participants----

Characteristic----Survivors (n = 2137) CVD mortality (n = 179)----P

==============

Man-years of observation 34,487 2222

Age, y 49.6 (9.9) 56.0 (9.8) <.001

Body mass index 26.9 (3.4) 27.0 (3.2) .70

Maximal METs obtained, METs 10.4 (2.1) 8.9 (2.0) <.001

Cholesterol level, mg/dL 225.1 (43.7) 233.4 (48.2) .02

Fasting glucose level, mg/dL 134.4 (48.9) 146.3 (60.1) .002

Systolic BP, mm Hg 126.5 (15.6) 133.4 (16.8) <.001

Diastolic BP, mm Hg 83.5 (9.9) 85.6 (11.1) .01

Cigarette smoking, % – – – .01

Never 35.8 28.0

Past 44.0 48.6

Current 20.2 23.4

Hypertension, % 30.4 49.1 <.001

Parental history of premature CVD, % 14.1 21.0 .003

Abnormal resting ECG, % 8.0 22.9 <.001

Abnormal exercise ECG, % 11.8 36.9 <.001

=============

Abbreviations: BMI, body mass index; BP, blood pressure; CVD, cardiovascular

disease; ECG, electrocardiogram; MET, metabolic equivalent.

SI conversion factors: To convert cholesterol to millimoles per liter, multiply

by

0.0259; to convert glucose to millimoles per liter, multiply by 0.0555.

*Unless otherwise indicated, values are presented as mean (SD).

.... Table 2. Age- and Examination Year–Adjusted Hazard Ratios (HRs) of CVD Death

(n

= 179) According to Exercise Capacity, BMI, and Other Clinical, Health Status,

and

Lifestyle Variables for 2316 Men With Diabetes, Aerobics Center Longitudinal

Study,

1970-1997

==============

Variable HR (95% CI) P

==============

Maximal METs obtained (per 1-MET increment) 1.20 (1.10-1.32) <.001

BMI (per 1-unit increment) 1.00 (0.95-1.05) .90

Fasting glucose (per 10-mg/dL increment) 1.04 (1.02-1.06) <.001

Systolic BP (per 10-mm Hg increment) 1.10 (1.01-1.19) .04

Parental history of premature CVD 1.72 (1.20-2.50) .004

Total cholesterol level (per 10-mg/dL increment) 1.02 (0.98-1.05) .33

Cigarette smoking

Past 1.05 (0.73-1.49) .80

Current 1.26 (0.82-1.95) .29

Abnormal resting ECG 1.32 (0.90-1.92) .16

Abnormal exercise ECG 2.2 (1.55-3.09) <.001

===============

Abbreviations: BMI, body mass index; BP, blood pressure; CI, confidence

interval;

CVD, cardiovascular disease; ECG, electrocardiogram; HR, hazard ratio from

proportional hazard models; METs, metabolic equivalents (1 MET = 3.5 mL of

oxygen

uptake/kg -1 per minute -1 ).

.... Table 3. Rates and Hazard Ratios of Cardiovascular Disease Death by Body

Mass

Index and Cardiorespiratory Fitness Level

===============

Cardiorespiratory fitness No. Man-years deaths Rate* HR† (95% CI) Ptrend HR‡

(95%

CI) Ptrend

===============

BMI, 18.5-24.9 – – – <.001 – – – <.001

Low 116 2111.7 17 79.0 4.2 (2.0-8.6) 2.7 (1.3-5.7)

Moderate 279 5319.4 27 51.3 2.7 (1.4-5.3) 2.3 (1.2-4.6)

High 354 6143.4 13 18.9 1.0 (Reference) 1.0 (Reference)

BMI, 25.0-29.9 – – – <.001 – – – .07

Low 339 5730.5 44 80.7 4.3 (2.3-7.9) 2.7 (1.4-5.1)

Moderate 519 8068.3 31 34.9 1.9 (0.9-3.6) 1.6 (0.9-3.2)

High 247 3408.8 12 32.5 1.7 (0.8-3.8) 1.5 (0.7-3.4)

BMI, 30.0-34.9 – – – <.001 – – – .02

Low 256 3622.4 27 84.2 4.5 (2.3-8.7) <.001 2.8 (1.4-5.6)

Moderate/high 206 2305.7 8 32.2 1.7 (0.7-4.1) 1.5 (0.6-3.6)

===============

Abbreviations: BMI, body mass index (calculated as weight in kilograms divided

by

the square of height in meters); CI, confidence interval; HR, hazard ratio from

proportional hazard models.

*Per 10,000 man-years with adjustment for age and examination year.

†Adjusted for age and examination year.

‡Adjusted for age, examination year, fasting glucose level, systolic blood

pressure,

parental history of premature CVD, total cholesterol level, cigarette smoking,

abnormal resting, and exercise electrocardiograms.

.... Table 4. Rates and Hazard Ratios of Cardiovascular Disease Death by

Cardiorespiratory Fitness Level Quantified in 1-MET Increments Obtained During a

Maximal Treadmill Test

=============

METs No. Man-Yyars No. of deaths Rate* HR (95% CI)† HR (95% CI)‡

=============

<7.0 126 1602 31 142.8 2.8 (1.6-4.7) 1.6 (0.9-2.8)

7.0-7.9 205 3117 35 110.8 2.1 (1.3-3.5) 1.7 (1.0-2.8)

8.0-8.9 293 4159 35 91.7 1.8 (1.1-2.9) 1.6 (0.9-2.6)

9.0-9.9 415 6450 27 51.8 1.0 (Reference) 1.0 (Reference)

10.0-10.9 486 8078 26 41.8 0.8 (0.5-1.4) 0.9 (0.5-1.5)

11.0-11.9 299 5014 14 40.6 0.8 (0.4-1.5) 0.9 (0.5-1.8)

12.0-12.9 242 4168 5 17.1 0.3 (0.1-0.9) 0.3 (0.1-0.9)

=/>13.0 250 4118 6 23.1 0.4 (0.2-1.1) 0.6 (0.3-1.4)

==============

Abbreviations: CI, confidence interval; HR, hazard ratio from proportional

hazard models; METs, metabolic equivalents (1 MET = 3.5 mL of oxygen uptake/kg

-1

per minute -1 ).

*Per 10,000 man-years with adjustment for age and examination year.

†Adjusted for age and examination year (P value for trend, <.001).

‡Adjusted for age, examination year, fasting glucose level, systolic blood

pressure,

parental history of premature cardiovascular disease, total cholesterol level,

cigarette smoking, abnormal resting, and exercise electrocardiograms (P value

for

trend, <.001).

Al Pater, PhD; email: old542000@...

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