Obesity in northern Canadian Indians: patterns ...

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Jul 10, 2011 - 64 y, oflndian ethnic origin, and usually resident in the community. Pregnant .... variable, normal was defined as a person with no past history.
Obesity in northern Canadian Indians: determinants, and consequences13 T Kue

Young

patterns,

and GustaafSevenhuysen ABSTRACT that

A survey

a large

aged 45-54 as gauged

alcohol the

use,

sum

age-adjusted

mean

both

and

and

poses

status,

and

thicknesses.

serum

diabetic

Indians

Cree

lipids,

Ojibwa

employment When

blood

hypertensive

was

were

three

pressures,

Obesity

for

future

associated

90%

with

of BMI and

were

found

of females

the

levels

of BMI

compared,

glycosylated

higher

hemoglobin

were

Calorie-adjusted and significant

is a significant chronic

Canada

Almost

was primarily ofthe central type analyses showed that age, sex,

categories glucose,

in northern obese.

energy was decreased. BMI was an independent

status. risks

Indians

groups

26. The obesity ratios. Multivariate

subjects whereas total in the obese subjects. particular

and

in all age-sex

public

diseases.

carbohypredictor

health

Am

J Clin

problem Nutr

1989;

49:786-93.

KEY WORDS

Obesity,

North

American

Indians,

Introduction

diseases,

Westernization

particularly

the

or modernization

demiologic

on

transition since

genetic

susceptibilities

as ischemic

brought

conditions

the end

diseases

of

heart

and diabetes (1), are relaIndians in terms of their burden (2). Such an epi-

has been

socioeconomic

so-called

such

disease, hypertension, stroke, tively new diseases for Canadian overall mortality and morbidity

ticularly

about and

of World

War

perhaps

by rapidly

lifestyles,

par-

II, superimposed peculiar

to

North

American Indians (3). Ethnographic observations, clinical impressions, and limited survey data support the conclusion that obesity is now very widespread in many groups oflndians. Yet, as recently as the 1940s two surveys in subarctic communities in the James Bay region and northeastern Manitoba revealed a native population hovering on the brink of starvation, with deficient energy and nutrient intakes (4, 5). By the l970s a nation-wide nutrition and anthropometric survey showed that Canadian Indians generally had much higher weight ans nationally (6).

This paper

reports

for age

on a study

compared

with

Canadi-

diseases

The study took place in six remote communities in northwestern Ontario and northeastern Manitoba, deep in the boreal forest of the central subarctic, inhabited by the culturally and linguistically closely related Cree and Ojibwa Indians.

To be eligible

on the prevalence

of obe-

Am J C/in Nuir

l989;49:786-93.

for inclusion

in the study,

subjects

must have

been between the ages of 20 and 64 y, oflndian ethnic origin, and usually resident in the community. Pregnant women were excluded from the study. The degree oflndian ancestry was not determined for the participants. In four of the communities all eligible adults were invited to participate, with an overall response rate of65%. In the two larger communities a 1 5% random sample was selected from the eligible list. People on the list but not in the random sample who wished to participate were also accepted; there were 1 27 such volunteers. The final cohort consisted of704 individuals (309 men and 395 women).

1 From the Department ofCommunity Health Sciences, Faculty of Medicine, and the Department ofFoods and Nutrition, Faculty of Human Ecology, University ofManitoba, Winnipeg, Manitoba, Canada. 2 Supported by the National Health Research Development Program of Health and Welfare Canada (6607-1383-53), the Manitoba Medical Services Foundation Inc (704-68), and the National Health

Research

sity, its determinants or risk factors, and its impact on the health ofthe population. It is part ofa larger, comprehensive study ofchronic diseases in Indians in the central subarctic region of Canada.

786

chronic

Methods

Chronic

changing

epidemiology,

Scholar

career

ada (6607-1377-48). 3 Address reprint nity

Health

Sciences,

award

requests

Printed

Health

and

Welfare

Department

ofManitoba,

750

Can-

of Commu-

Bannatyne

Avenue,

for Clinical

Nutrition

R3E 0W3. 1988.

for publication

in USA.

from

to TK Young,

University

Winnipeg, MB, Canada, Received March 25, Accepted

(TKY)

June

© 1989

15, 1988.

American

Society

Downloaded from www.ajcn.org by guest on July 10, 2011

for

adult

index (BMI) and girth

marital

of skinfold

observed in the obese drate intake was higher of

of 704

of individuals

y had a body mass by skinfold thickness

smoking, and/or

proportion

OBESITY

IN CANADIAN

A variety ofdata was collected, including sociodemographic, past health, cardiovascular symptoms, family history, lifestyle factors, anthropometric, physiologic, biochemical, electrocardiographic, and dietary history. (A research monograph detailing the design and methodology of the study is available from the first author.)

From

measurements

ofheight,

weight,

triceps

and subscapu-

lar skinfold thicknesses, and waist and hip circumferences, various indices of overall obesity and fat distribution were constructed. Lange calipers (Cambridge Scientific Industries, Cambridge, MD) were used to measure skinfold thickness. Subjects were requested to remove shoes, disrobe (except for underwear), and put on a disposable hospital gown for the anthropometry part of the examination. Waist girth was mea-. sured in the unclothed abdomen midway between the lower rib margin and the iliac crest and hip girth was measured posteriorly at the maximum protrusion ofthe gluteal area and anteriorly at the level ofthe symphysis pubis in accordance with the guide for anthropometric and nutritional assessment of Canadians published by the Department of National Health and Welfare (12).

For mercury

blood

pressure two sphygmomanometer

mc, Copiaque, computed

WHO

and

categories

NY) used

measurements were taken with a (Baumanometer#{174}, WA Baum, after 10 mm of rest. The means were as continuous variables in the analysis. The

of normal,

borderline,

and hypertensive

sure (DBP) 90 mm Hg. All others were considered hypertensive. Fasting blood samples were collected from all subjects and tested for glucose (FPG), glycosylated hemoglobin (HGB), total cholesterol (TCH), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TRG). A small subsamples of 143 subjects underwent a 2-h oral glucose-tolerance test. In the analysis diabetic status as a dichotomous variable was defined as a positive past history of physician-diagnosed diabetes (DM) or a current level of FPG 7.8 mmol/L in accordance with the WHO criteria(l4). A Hitachi 705 enzymatic analyzer (Hitachi, Tokyo, Japan) was used for the determination ofFPG, TRG, and TCH. HDL cholesterol was determined by a Chemetrics#{174} analyzer (Milliport Corp, Freehold, NJ) with the phototungstic acid precipitation method (15) and LDL cholesterol values were computed from TCH, HDL, and TRG values according to Friedewald’s formula (16). All data entry, management, and analyses were performed on a microcomputer with the software package STA TPAC (Walonick Associates, Minneapolis, MN). For certain statistical procedures, the SAS package ( 1 7) was used with a mainframe computer. This study was approved by the Faculty Committee on the Use ofHuman Subjects in Research ofthe University of Manitoba. Signed informed consent was obtained from all individual participants in the study. The Indian band councils in the communities surveyed also approved the study.

Results Obesity

Tables 1 and 2 show the correlation matrices of various anthropometric indices in this study for males and females, respectively. All the measures correlate poorly with height whereas body mass index (BMI) and the

girths in particular correlate strongly with weight and thus possess the desirable criteria for indices of overall obesity (1 8-20). BMI, also known as Quetelet index (wt/ ht2), is the preferred measure because existing standards for classifying individuals into obesity categories as well as Canadian

national

reference

data

are

available

from

the 198 1 Canada Fitness Survey and 1978 Canada Health Survey (2 1 22). BMI was shown in other studies to correlate with more direct measures ofbody fat such as skinfold thickness (23) and body densitometry (24, 25). However, the correlation between BMI and skinfold thickness was not strong in our sample. It was, however, ,

stronger thickness.

triceps sure may with

were

also used (1 3). When the category hypertensive was analyzed as a dichotomous variable, normal was defined as a person with no past history of physician-diagnosed hypertension or use of antihypertensive drugs, and with current systolic blood pressure (SBP) 140 mm Hg and fifth-phase diastolic blood pres-

indices

tio

with subscapular In the analysis

skinfold

the

thicknesses

than sum

with ofthe

is used as an alternative

of overall obesity to BMI well represent different different health risks.

because

fold thicknesses (STR) have centrality of fat distribution other.

measures As indices

were

only

offat

the

two

physiological

In the epidemiological literature both (WHR) and the ratio of subscapular

two

triceps skinfold subscapular and

meaindices

constructs

the waist-hip rato triceps skin-

been used as measures (26-28). In our sample

weakly distribution

correlated they

with should

one correlate

of the

an-

Downloaded from www.ajcn.org by guest on July 10, 2011

Procedures and questionnaires described in the World Health Organization (WHO) manual on cardiovascular survey methods were adopted whenever possible (7). A semiquantitative food frequency questionnaire was designed to assess usual diet (8). The food types and usual amounts consumed by each subject were recorded during the food frequency interview conducted by a dietitian. These data were transposed into estimates ofnutrient consumption per day based on the 3200-item Canadian Nutrient File prepared by the Department of National Health and Welfare, updated in 1986 (9). Calculations of nutrient content were carried out by use of the Nutrient Analysis Program (NAP) available in the University of Manitoba mainframe computer. To assess physical activity the Lipid Research Clinic instrument (two questions, three categories) was used ( 10). Those who did not engage in strenuous exercise or hard physical labor were classified as inactive. The active group could be further subdivided into very and moderately active depending on whether individuals exercised three times or more per week or less than three times per week, respectively. Caloric intake adjusted for body weight (1 1) could be used when physical activity was analyzed as a continuous variable. To reflect the episodic drinking pattern of the residents, the frequency of consumption over a l-y period rather than precise quantification was assessed. Three categories were recognized: not at all in the past year, a few times in the past year, and at least once a week. In analyses requiring a dichotomous variable, the last two were combined into a drinker category. The category bush living characterized subjects who spent a substantial portion of their time ( 1 mo continuously every year during the past 5 y) in traditional Native pursuits such as hunting, trapping, and fishing.

787

INDIANS

YOUNG

788 TABLE

AND

SEVENHUYSEN

1

Correlation

matrix

ofanthropometric

Ht Ht Wt BMI

indices

Wt

for males*

BMI

Tri

Sub

SUM

STR

Wai

0.93

Tri

0.05

0.43

0.44

Sub

0.04

0.63

0.65

SUM

0.05

0.58

0.59

0.92

0.89

STR

-0.03

0.05

0.06

-0.61

0.06

-0.33

Wai Hip

0.11 0.14

0.92 0.83

0.93 0.83

0.41 0.41

0.62 0.54

0.56 0.52

0.08 0.06

0.86

WHR

0.03

0.68

0.70

0.27

0.50

0.42

0.07

0.79

Ht, height; Wt, weight;

subscapular WHR, ratio

0.37

-

skinfold ofwaist

thicknesses; STR, to hip circumferences.

ratio

Tn,

triceps

of subscapular

skinfold to triceps

thickness; skinfold

thicknesses;

Wai,

skinfold waist

thickness;

SUM,

circumference;

Hip,

sum

oftriceps

and

hip circumference;

decreased from just over 3 in age group 25-34 y to 1.5 in the group aged 55-64 y. Similarly, if skinfold thicknesses are used for comparison with national standards from the Nutrition Canada Survey conducted in the early l970s (M Jette, unpublished observations, 1983), values for Indians generally exceeded those for Canadians, with the exception oftriceps skinfold thicknesses of older women (Fig 2). No comparable Canadian national data for centrality measures are available. The obesity of this population was predominantly of the central type. Table 3 shows that as BMI increased, the proportion of subjects with WHR and STR values above the top quartile ofthe total sample (males and females combined) also increased, with the exception of STR in men. Although the overall level of obesity was much higher in Indian women, a higher proportion of obese men were ofthe central type.

This feature is well in males, whereas BMI and weight in

‘-

ofobesity

The excessive level ofobesity in Indians in our sample compared with the Canadian national population according to the Canada Fitness Survey of 198 1 (2 1) is evident from Figure 1 In some age-sex groups, eg, women aged 45-54 y, almost 90% ofthe Indians had BMIs in the overweight or obese range. In both men and women and in all age groups the proportion ofthe population with a BMI 26 was higher than it was in Canadians. The ratio of BMI values for Indians to values for Canadians was ‘--2 for males in the youngest (20-24 y) age group and 5 for females. This ratio declined with increasing age. Above the age of 25 y the proportion of men with BMI 26 was only 20-30% higher for Indians when compared with Canadians nationally. For women the ratio .

TABLE

Sub, subscapular

Determinants of obesity Within the study sample sity

indices

between

various

there

were

differences

subgroups

in obe-

of subjects

cate-

2

Correlation

matrix

ofanthropometric

Ht

Ht

-

Wt

0.23

indices

for females*

BMI

Wt

Tri

BMI

-0.09

0.95

Tn Sub SUM ST! Wai Hip

0.01 0.00 0.01 -0.03 0.08 0.10

0.19

0.20

0.55

0.56

0.63

0.39 0.21 0.85 0.86

0.40 0.22 0.84 0.84

0.93 -0.61 0.06 0.23

WHR

-0.01

0.47

0.47

-0.21

Ht, height;

subscapular WHR, ratio

Wt, weight;

skinfold ofwaist

body

mass

thicknesses; STR, to hip circumferences.

BMI,

ratio

index;

Tri, triceps

of subscapular

Sub

SUM

STR

Wai

0.88 -0.01 0.50 0.56

-0.38 0.28 0.42

0.32 0.21

0.89

-0.03

0.32

0.73

0.20

skinfold to triceps

thickness; skinfold

Sub,

subscapular

thicknesses;

Wai,

skinfold waist

thickness;

circumference;

SUM, Hip,

Hip

WHR

0.34

-

sum oftriceps hip circumference;

and

Downloaded from www.ajcn.org by guest on July 10, 2011

Prevalence

0.64

BMI, body mass index;

only minimally with overall obesity. demonstrated by STR, particularly WHR correlated moderately with both males and females.

I

WHR

-

0.32 -0.04

I

Hip

OBESITY

IN CANADIAN

789

INDIANS

100

Subscapular

Skinfold

90

Female

Male

80 25

70 60 20

50

40

E E

30

Cl)

,

Indians

/

, /

15

-

-

Canada

-

-

Canada

(1)

20

a) C

10#{149}

10 C)

a)

-C

0

0.

Triceps

I-

a)

100

0 C

Indians

0

90

a)

Skinfold

V

C

>

80

a)

70

20 Cl) C

Indians

a)

15 Canada 10

2029

3039

4049

5059

6069

Age

2029

30-

40-

50-

60-

39

49

59

69

Group

FIG 2. Mean subscapular and triceps skinfold thicknesses and sex: comparison with Canadian national population.

Age

by age (y)

Group Indians

Canada

Dietary

correlates

::::::.:::

BMI

26-30

BMI>30

BMI

26-30

Total

BMI>30

energy

similarly FIG 1. Categories ison with Canadian

ofbody national

index(BMI)by population.

mass

age and sex: compar-

was decreased

lowered

observed

intake

in the obese

intercorrelation and with each

of other

To determine gorized by sex, age group, and other sociodemographic and lifestyle factors. Stepwise multiple-regression analyses were performed separately for males and females to determine significant predictors ofBMI and sum of skinfold

thicknesses

An increase BMI in both employed

men

(Tables

4 and

5).

in age was associated males and females. also

had

significantly

with an increase in Married women and higher

BMI

signifiNonthick-

nesses.

do not

inactive

men

and

women

who

subjects

(Table

most (29).

dietary

intake,

nutrient

justed

nutrient

scores

proposed

TABLE

3 ofbody

mass

index

STR

>

(BMI)

subjects.

nutrients

A

was also

6), reflecting

variables

the role ofindividual

of caloric

obese

with

nutrients

density

or the

by Willett

to centrality

and

the energy

indepencalorie-ad-

Stampfer

indices*

1.64

WHR

>

0.99

when

other variables were controlled for. Age was not cantly associated with sum ofskinfold thicknesses. smokers in both sexes had lower sums of skinfold Physically

major

dent

Relation

in the

ofmost

use alcohol regularly or are unemployed tended to have significantly higher sums of skinfold thicknesses. The discrepancy between predictors ofBMI and sum of skinfold thicknesses suggest that the two measures of obesity are not interchangeable. However, the r2 values for mdividual predictors were generally small and the overall variance explained in each of the regression models was only 10%.

BMI

Male

Female

Male

Female

%

30

28.0

35.2

75.0

18.2

Total

29.8

22.4

36.0

11.3

1.01 0.604

19.6 0.000

77.6 0.000

18.7 0.000

of subscapular

to triceps

x2 p I

ratio

STR, ratio ofwaist

to hip circumferences.

9.6

skinfold

1.6

thicknesses;

WHR,

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0

790

YOUNG

TABLE

4

Predictors

ofobesity

indices:

body

mass

Significant

Fe male

r2

predictors

/3

0.0776

0.3041

r2

3

0.0735

0.2485

status

(married

=

0, single

Employment (no=0,yes=

=

1)

-

1)

0.0 133

-

0.0243

0.1581

-

Totalr2

0.1020

0.0868

r SEM F

0.3193

0.2946

*

Other variables

hol use, and physical

tested

4.39

5.66

17.32

18.39

were education,

bush

-0. 1 174

-

living,

SEVENHUYSEN Because few coexisting ischemic heart disease cases have been discovered in the sample (based on medical history, Rose questionnaire [7], or electrocardiography), their association with obesity was not investigated. The survey also inquired into past history of clinical gallbladder disease (as detected by radiography and/or

index

M ale

Age Marital

AND

surgery)

tively) smoking,

alco-

although

those

without

past

disease

were

not

screened for current silent gallstones. Overall, 1 8.5% of women and 2.3% of men had previously detected gallbladder disease (GBD). Women with a past history of GBD had higher sum ofskinfold thicknesses, STR, BMI, and WHR. Of these, the differences in BMI and WHR were statistically significant (.p = 0.048 and 0.01 3, respecon one-way

analysis

of variance (p

WHR was statistically significant ANOVA, adjusting for the effect

(ANOVA). =

ofage

Only

0.04) on two-way groups.

activity.

Discussion

calorie-adjusted

measures

observed when absolute body weight were used. Metabolic

removed

intakes

the

sexual

or intake

difference

consequences

risks

BMI has an independent and significant effect on diabetic status, a dichotomous variable based on both past history and current FPG levels. When multiple logistic regression analysis is used to control for other sociodemographic, lifestyle, and metabolic factors, the odds ratio for diabetes was 1 .59 (95% confidence interval, 1.142.22) when the 75th percentile of BMI was compared with the 25th. Note that in a cross-sectional study the odds ratios (relative risks) refer to the risk of having the disease not ofdeveboping the disease. For hypertensive status (known past history or current SBP > 140 or DBP> 90), the odds ratio was 1.44(1.121 .83),

25th.

comparing

the

75th

percentile

of BMI

with

the

high

limited

level

of obesity

national

in this

survey

data

population

available

confirms on

Canadian

Indians. Considered to be relatively unacculturated until relatively recent times, ie, after the World War II, this group oflndians ofAlgonkian stock in the subarctic cubture area shares the same anthropometric characteristics as many other more southerly located tribes. The sociodemographic and lifestyle determinants of obesity

per kilogram

BMI categories also differed in terms of various metabolic and physiologic measures on univariate comparisons or when sex-specific, age-adjusted means are compared (Table 7). Obese subjects had unfavorable lipid profiles: decreased HDL and HDL:total cholesterol and increased TRG and LDL. Both SBP and DBP were increased in the high-BMI group (with the exception of SBP in men). Both FPG and HGB, the latter a more naturab measure ofusual glucose status (3 1), were higher for the obese subjects. Disease

The the

identified

in this

study

are compatible

with

find-

ings from surveys in other populations. In the Canada Health Survey (22), age, marital status, smoking, family income, and education were significant predictors of BMI in both sexes. Although there is no direct measure ofincome in this study, employment was positively associated with BMI for males but negatively associated with

TABLES Predictors

ofobesity

indices:

sum ofskinfold

thicknesses

M ale Significant

Fe male

r2

predictork

Alcohol use (no = 0, yes = 1) Physical activity (inactive = 0, active= 1) Employment (no = 0, yes = I) Smoking (smoker = 0, nonsmoker = 1)

fi

-

-

0.0261

-0.1618

-

-

0.0658

Totalr2

0.0919

r

0.3031

0.2475

r2

0.0762

0.022

0.0170

F

14.62

16.16

bush

living.

tested

were

1

-0.1430

0.1397

0.3396

17.20

variables

-

0.1153

12.74

Other

-0.1926

-

SEM

*

fi

age,

education,

marital

status,

and

Downloaded from www.ajcn.org by guest on July 10, 2011

(30) can be used. These measures generally change the direction ofthe association between obesity and absolute intake, or nutrient per kilogram. Subjects with a high BMI consumed significantly more carbohydrates independent oftotal caloric intake than did those with a low BMI. Fat intake was significantly decreased in obese subjects when nutrient density was used but not when cabrie-adjusted scores were used as the measure. The use of

OBESITY TABLE Mean

IN

CANADIAN

INDIANS

791

6 daily

nutrient

intake

by obesity

category

and sex Main

effect:

BMI

Main

effect:

sex Interaction

Variable

30

cholesterol

LDL cholesterol

31

p

31

p

(mmol/L)

1 .42

1 .26

1 . 16

0.000

1 .42

1 . 18

0.98

0.000

(mmol/L)

2.98

3.30

3.30

1.52 0.25

1.85 0.23

3.30 1.06 0.28

3.67 2.07 0.2 1

3.67 2.20 0. 18

0.003

I . 18 0.29

0.00 1 0.0 12 0.000

Triglycerides (mmol/L) HDL:total cholesterol Blood Pressure Systolic(mmHg) Diastolic(mmHg)

121.67 72.51

127.19 78.50

0.000 0.000

128.73 80.41

0.000 0.000

132.46 80.74

134.10 83.49

5.53 7.87

0.004

4.89

5.42

5.55

0.094

0.000

6.83

7.45

7.74

0.0 12

133.68 87.15

0.398 0.000

Glucose

Fasting glucose (mmol/L) Glycosylated hemoglobin

(%)

4.68 6.65

5. 13 7.31

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Fiber(g/kg)

Calorie-adjusted Proteins Fats Carbohydrates Cholesterol

26-30

792

YOUNG

AND

SEVENHUYSEN

Table 6, energy per kilogram body weight is lowest for people with a BMI > 30. However, physical activity as a dichotomous variable was a significant determinant of sum of skinfobd thicknesses in men but not of BMI in either sex (Tables 4 and 5). This study also provides cross-sectional evidence of the adverse health impact of obesity. Of particular concern

is that

the

predominant

pattern

of obesity

is of the

ger that

resulted

in the current

are

undergoing

ous.

There

promotion

is thus

some

studies

an

epidemiologic

strategies

urgency

and in this

transition

to conduct

intervention

and L Wilsack conducted

N Ling, and B Roche conducted all physical examinations.

base-line

trials

epi-

of health-

7. 8. 9. 10.

ity,

and assistance ofthe Chiefs and the staff and manageunits. Ms L Wadsworth, J

the dietary the remainder

treadmill

interviewsand

MsJ

of the interviews

Hovi,

and

13.

World

Health

WHO expert

test

performance

and

plasma

HDL

choles-

series

Organization.

Arterial

committee.

Geneva:

hypertension:

WHO,

report

of

1978. (Technical

a

report

628.)

14.

World

15.

study group. Geneva: WHO, 1985. (Technical report series 727). Calvert GD, Yeates RA, Mannik T. A comparison ofthe phosphotungstate magnesium precipitation and heparin-manganese pre-

Health

16.

Organization.

procedures

lesterol.

Diabetes

for estimating

Ann Clin Biochem

Friedewald

WT,

Levy

mellitus:

report

high-density

of a WHO

lipoprotein

cho-

1980; 17:105-8.

RI,

Fredrikson

centration ofbow-density out use of the preparative

DS.

Estimation

of the

con-

lipoprotein cholesterol in plasma, withultracentrifuge. Clin Chem 1972; 18:

499-502.

17. Statistical Analysis System Institute. SAS user’s guide: statistics. 5th ed. Cary, NC: SAS Institute, mc, 1985. 18. Keys A, Fidanza F, Karvonen MJ, et al. Indices ofrelative weight and obesity. J Chron Dis l972;25:329-43. 19. Khosla T, Lowe CR. Indices of obesity derived from body weight and height. Br J Prey Soc Med 1967;2 1:122-8. 20. Fborey C duV. The use and interpretation of ponderal index and other weight-height ratios in epidemiobogical studies. J Chron Dis 1970;23:93-103.

21.

Millar in

WJ,

Britain,

Stephen

T. The

Canada

and

prevalence

the

United

l987;77:38-4l. 22. Evers S. Economic and social factors adult Canadians. Nutr Res 1987;7:3-l3. 23.

Micozzi body

References 24. 1 . Trowell HC, Burkitt DP, eds. Western diseases: their emergence and prevention. Cambridge, MA: Harvard University Press, 1981. 2. Young TK. Are subarctic Indians undergoing an epidemiologic transition? Soc Sci Med l988;26:659-7 1. 3. Weiss KM, Ferrell RE, Hanis CL. A New World Syndrome of met-

exercise

terol: the Lipid Research Clinic’s Program Prevalence Study. Circulation l980;62(suppl 4):53-61. 1 1. Sopko G, Jacobs DR. Taylor HL. Dietary measures of physical activity. Am J Epidemiol 1984; 120:900-1 1. 12. Department of National Health and Welfare Canada. Guide for anthropometric classification of Canadian adults for use in nutritional assessment. Ottawa: Department of National Health and Welfare 1983.

#{163}3

population.

We wish to acknowledge the cooperation and Council of the six Indian communities ment of the local Indian Health Services

Britten,

6.

cipitation

and the increasing prominence ofchronic diseases in the near future can be expected (2). The conception that these diseases are diseases of affluence and thus would spare the economically disadvantaged Indians is erronedemiobogicab

5.

“epidemic.”

In a cross-sectional design where temporal sequence cannot be ascertained, the designation ofcertain factors as determinants and others as effects is often subject to debate. Long-term prospective studies are needed to elucidate cause-and-effect relationships. Indians in subarctic Canada

4.

MS. mass

Albanes

indices

D, with

Jones

weight,

of overweight States.

associated

V, Chumlea stature,

Am

WC.

and

J Public

with

obesity Health

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in

Correlation

of

composition in II. Am J Clin Nutr l986;44: and

body

men and women in NHANES I and 725-31. Revicki DA, Israel RG. Relationship between body mass indices and measures of body adiposity. Am J Public Health l986;76: 992-4.

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WC,

Webb P. Grading data. Am J Clin

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central, or centripetal, type. Increasingly, more epidemiobogic studies of a variety of populations have demonstrated that central fat distribution is an independent risk factor ofsuch chronic diseases as diabetes, hypertension, gallbladder disease, ischemic heart disease, and stroke (26, 27, 35-37). These observations are supported by metabolic studies ofregional adipose tissues (38, 39). There may well be a common underlying derangement in lipid and carbohydrate metabolism that beads to the development of these obesity-associated diseases. Insulin resistance has been suggested as the underlying derangement from the Pima, Israel glucose intolerance, obesity, and hypertension (GOH), and Texas Mexican studies (40-42). The high prevalence of obesity and its association with diabetes and gallbladder disease bed some population geneticists to postulate the existence of a New World Syndrome among Amerindians and the natural selection ofa genetic trait that conferred survival advantages during the early settlement of humans in North America (3). Rapid social change in the past half century, perhaps through decreased physical activity and/or dietary change, provided the environmental trig-

diseases with a genetic and evolutionary basis. Yearbk Phys Anthropol l984;27: 153-78. Vivian RP, McMillan C, Moore PE, et al. The nutrition and health oftheJames Bay Indian. Can Med AssocJ l948;59:505-l8. Moore PE, Kruse HD, Tisdall FF, Corrigan RSC. Medical survey ofnutrition among the northern Manitoba Indian. Can Med Assoc J l946;54:223-33. Department of National Health and Welfare. Nutrition Canada anthropometry report: height, weight and body dimensions. Ottawa: Department ofNational Health and Welfare, 1980. Rose GA, Blackburn H, Gillum FR, et al. Cardiovascular survey methods. 2nd ed. Geneva: World Health Organization, 1982. Sampson L. Food frequency questionnaires as a research instrument. Clin Nutr 1985;4:171-8. Department of National Health and Welfare. Canadian nutrient file. Ottawa: Department ofNational Health and Welfare, 1986. Haskell WL, Taylor HL, Wood PD, et al. Strenuous physical activabolic

OBESITY 26.

Hartz iU, surements 1984;

27.

Rupley DC, Rimm AA. The association with disease in 32,856 women. Am

IN

CANADIAN

of girth meaJ Epidemiol

119:71-80.

Lapidus

L, Bengtsson C, Larsson B, et al. Distribution of adipose and risk of cardiovascular disease and death: a 12-year foblow-up ofparticipants in the population study ofwomen in Gothenburg, Sweden. Br Med J l984;289: 127-61. 28. Haffner SM, Stern MP, Hazuda HP, et al. The role of behavioral variables and fat patterning in explaining ethnic differences in serum lipids and lipoproteins. Am J Epidemiol 1986; 123:830-9. 29. Gordon T, Fisher M, Rifkind BM. Some difficulties inherent in the interpretation of dietary data from free-living populations. Am J Clin Nutr 1984;39: 12-6. tissue

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Willett

WC,

Stampfer

M. Total

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intake:

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JAH,

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T, Kagan

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consumption,

in young

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adults.

to coronary

adipose

39.

and

its relation-

disease

and

death

in three

populations.

Cir-

40.

tissue

distribution.

insulin

resistance

Caucasians.

41.

42.

J Clin

Invest

1983;72:

1 150-62.

Kissebah AH, Vydelingum N, Murray R, et al. Relation of body fat distribution to metabolic complications ofobesity. J Clin Endocrinol Metab 1982; 54:254-60. Nagulesparan M, Savage PJ, Knowler WC, et al. Increased in vivo in

Diabetes

non-diabetic

Pima

Indians

compared

with

1982;3l:952-6.

Modan M, Halkin H, Almog S. et al. Hyperinsulinemia-a link between hypertension, obesity and glucose intolerance. J Clin Invest l985;75:809-17. Haffner SM, Stern MP, Hazuda HP, et al. Hyperinsulinemia in a population

et al. Diet

heart

N EnglJ

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1986;3l5:220-4.

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33.

ship

culation 1981;63:500-lS. 35. Szathmary EJE, Holt N. Hyperglycemia in Dogrib Indians of the NWT, Canada: association with age and a centripetal distribution ofbody fat. Hum Biol 1983;SS:493-SlS. 36. Welin L, Svardsudd K, Wilhelmsen L, et al. Analysis ofrisk factors forstrokeinacohortofmenbornin 1913. NEnglJ Med 1987;317: 52 1-6. 37. Blair D, Habicht J-P, Sims EAH, et al. Evidence for an increased risk for hypertension with centrally located body fat and the effect ofrace and sex on this risk. Am J Epidemiol 1984; 1 19:526-40. 38. Krotkiewski M, Bjorntorp P. Sjostrom L, Smith U. Impact of obesity on metabolism in men and women: importance of regional

for epi-

demiobogic analysis. Am J Epidemiol 1986; 124:17-27. 31. Duncan BB, Heiss G. Nonenzymatic glycosylation of proteins-a new tool for assessment ofcumulative hyperglycemia in epidemiologic studies, past and future. Am J Epidemiol 1984; 120:169-89. 32. Folsom AR, Caspersen CJ, Taylor HL, et al. Leisure time physical activity and its relationship to coronary risk factors in a population-based sample: the Minnesota Heart Survey. Am J Epidemiol 1985; 12 1:570-9.

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