COMMUNITY HEALTH STUDIES VOLUME VIL NUMBER 3. 1983

PREVALENCE OF SOME RISK FACTORS FOR CARDIOVASCULAR DISEASE IN RURAL WESTERN AUSTRALIAN CHILDREN Barrie Margetts*, Bruce Armstrong*, Colin Binnst, John Masarei+, and Michael McCall**

NH & MRC Research Unit in Epidemiology and Preventive Medicine, Department of Medicine, University of Western Australia, 6009.

t School of Community Health, Western Australian Institute of Technology. + Department of Clinical Biochemistry and,

** Department of Medicine, University of Western Australia.

Abstract Sitting and standing blood pressures, pulse

rate, body height and weight, triceps skinfold thickness and mid-upper arm circumference were measured in 285 girls and 304 boys of caucasian origin aged 12 or 13 years in six Western Australian country towns. Means, standard deviations and 5th and 95th centiles of these variables and Quetelet's index (weight / height2) are presented in each sex for 12 and 13 year-olds separately. The mean heights and weights of children in this survey were generally greater than have bexn recorded in previous surveys of Australian children of the same age. Mean blood pressures, however, were appreciably lower. They were lower also than levels measured in recent surveys in the United States of America, Norway, Greece and Italy. Compared with these four populations, Western Australian children were taller than most, and intermediate with respect to body weight and obesity. Levels of these variables were not noticeably correlated with mortality from ischaemic heart disease (IHD) in adults in the same populations. There was some evidence, however, of a relationship between IHD mortality and mean plasma cholesterol levels in children. Introduction

Chron ic diseases and par t icu lar ly cardiovascular disease may have their origin in lifestyle and its effects on risk factors in childhood.I.2.3 An understanding of the relevant factors and their modification in early life may hold the key to the later prevention of chronic diseases. Comparison of the prevalence of risk factors in children in populations experiencing differing rates of disease may add to an understanding of the causal factors.

Recently, Wynder et a1 reported the results of screening for cardiovascular risk factors in children from fifteen countries (not including Australia).' We present here data from children in rural Western Australia and compare them with

MARGETTS ET AL 256

data from other Australian and non-Australian populations. Methods

All children in their first year of high school (year 8) in each of six towns in the South-West of Western Australia were considered for inclusion in the study. Towns were initially selected on the basis of proximity to Perth (within 350km), the availability of 100 or more students attending year 8 at the local high school and the level of sodium in the water supply. Two schools were selected from each of three water sodium level areas. They covered 4 of the 9 rural statistical divisions of the State. The towns selected were rural centres, except for one which in addition to servicing surrounding rural areas, housed part of the workforce of a nearby mining operation.

Surveys were conducted over three days in each school, within the period 20 March to 2 May, 1979. The data recorded were collected as part of a study assessing the relationship between water sodium and blood pressure.5

Height, weight, triceps skinfold thickness, mid-upper-arm circumference (MUAC), pulse rate and blood pressure were measured in each child. Blood pressures were measured by the same two trained observers throughout. Inter- and intra- observer variation was minimized by initial use of a standard training tape and timer.6

To check for inter-observer variation in blood pressure measurement, mean blood pressure levels at one school were calculated for each observer separately. There were no significant differences between the means so calculated and the standard deviations were similar.

Two London School of Hygiene and Tropical Medicine Sphygmomanometers were used and pressures were recorded after five minutes rest with the subjects seated (two readings taken and subsequently averaged) and then, once only, immediately after standing. Large cuffs (22.9 cm by 12.7 cm) were used following the

COMMUNITY HEALTH STUDIES

recommendation of Long et al.7 Diastolic blood pressure was recorded a t the point of disappearance of sound (Korotkoff phase 5). Children recording diastolic pressure below 20 mmHg have been excluded from calculations of all mean blood pressure levels in accordance with the recommendation of Voors et a1.8

Duplicate measurements of triceps skinfold thickness (Harpenden calipers) and MUAC were made by one dietitian throughout, who was experienced in these techniques and used the methods of Zerfas et al.9 Height and weight were recorded by a single observer using the same equipment throughout (beam scales and stadiometer) and a standardized technique.10

Results Of a total of 792 children eligible for inclusion

in the survey, 635 participated (80.2 percent - 309 girls and 326 boys). Participation rates were high in all but one school, where about half the boys living in the school hostel refused to join the survey. In the remaining schools no specific selective factors were known t o be responsible for non- participation, although data on non-participants was limited to sex and name.

There were only minor differences between the occupation distributions of the parents of children in the study and all persons of similar age in the towns in the study, the Statistical Divisions in which these towns lay and in all rural Western Australia, as recorded at the 1976 census. There were also few appreciable differences between the country-of-birth distribution of the parents of children in the study and those of persons of similar age in the same Statistical Divisions and all of rural Western Australia. In two of the study towns, however, there was a relative excess of parents born in Italy (4 percent and 7 percent compared with 1 percent in the corresponding Statistical Divisions). The vast majority of the children themselves (about 90 percent in 5 of the 6 towns) were born in Australia. The corresponding percentages born in Australia and aged 10-14years a t the 1976 census ranged from 87 percent to 94 percent in the six towns. The Statistical Divisions represented by the towns in the study showed similar age and marital status distributions to those of the rest of rural Western Australia.

The analyses reported here are restricted to those children of Caucasian origin born in Australia, New Zealand or Britain (285 girls and 304 boys), on whom measurements were made and who were aged either 12 or 13 years. Data from all six towns have been combined.

MARGETTS ET AL 257

Mean levels of the measurements recorded are presented in Tables 1 and 2 by age and sex; 5th and 95th centile values are also given to indicate the distribution of values about the mean. Girls were consistently taller, heavier and had greater triceps skinfolds and higher pulse rates than boys. Height increased by a n average of 4 cm from 12 to I3 years in both boys and girls, while 13 year olds of both sexes were about 3 kg heavier than 12 year olds. From values of Quetelet’s index (weight/ height*), it appeared that 13 year olds were also more obese than 12year olds. While MUAC increased with age in both sexes, there was a slight rise in mean triceps skinfold thickness in boys and a slight fall in girls. The 5th and 95th centile values for triceps skinfold thickness indicated that, for each sex and age group, there was considerable variation.

For all blood pressure measurements, except sitting diastolic in boys, there was no apparent increase with age. Sitting systolic blood pressure was, on average, 2mm higher in 13 year old boys and 2.5mm higher in 13 year old girls than in 12 year olds. Mean sitting blood pressures were higher in girls than boys, whereas the reverse was the case for standing blood pressures; that is, there was a more marked increase in blood pressures among boys upon standing. The range of diastolic blood pressure measurements was generally greater than for systolic blood pressure.

It has been suggested that the cut-off for “high-risk” should be around 135/85 for 13 year olds.4 No boys and only 3 girls (3.6 percent) recorded ’high risk” systolic blood pressures a t this level, while no children recorded diastolic blood pressure above 85mmHg. It has also been suggested that there may be an optimal blood pressure of 100/604; in our study 58 percent of 13 year old girls and 62 percent of 13 year old boys recorded systolic blood pressure at or below this level.

The heights and weights recorded in this study were generally higher than those of other 12 year old children in Australia (Table 3), the major exception being that 12 year old girls from Sydney were taller and heavier than I2 year old girls in this study. When Sydney and Perth urban children were pooled and compared with rural children from Busselton and this study, urban children of both sexes were significantly taller ( I .O cm boys, 2.0 cm girls; 60 .05 ) and urban girls were also significantly heavier (1.3 kg; p<0.05). In comparison to perceived weights and heights reported recently from Tasmania (not presented here), 12 year olds were of similar height but slightly heavier, while 13 year olds were both

COMMUNITY HEALTH STUDIES

TABLE

1

Mea

sure

men

ts in

12

year

old

boy

s and

girl

s

Boy

s (2

04)*

Girls

(193

)*

Cen

tiles

C

entil

es

Mea

n (S

.D.)

5th

95th

M

ean

(S.D

.) 5t

h 95

th

Hei

ght (cm)

Wei

ght (

kg)

Que

tele

t’s In

dex

(gm

/cm

2)

Tric

eps

Skin

fold

(m

m)

MU

AC

(cm)

Puls

e (b

eats

/min

)

152.0

(7.0)

139.8

163.9

153.6

(6.8)

141.4

163.3

42.8

(8.6)

32.0

56.9

44.0

(7.1)

32.7

56.1

1.84

(0.26)

1.55

2.32

1.86

(0.24)

1.55

2.32

-8.8

(3.6)

5.2

17.1

11.6

(3.8)

6.8

18.7

22.1

(2.6)

18.4

26.5

22.7

(2.2)

19.2

26.6

79.1

(1 2.4)

60.4

99.7

79.4

(12.5)

59.2

99.8

( I83)#

Sitti

ng B

lood

Pre

ssur

es

Syst

olic

(mm

Hg)

97.2

(9.3)

82.5

114.0

97.9

(10.4)

80.0

114.5

Dia

stol

ic (m

mH

g)

47.7

(10.8)

28.0

65.0

49.9

(10.7)

33.5

69.5

Syst

olic

(mm

Hg)

107.5

(11.7)

91.5

126.2

105.9

(16.9)

82.1

127.6

Dia

stol

ic (m

mH

g)

66.9

(1 1.0)

47.5

85.2

65.4

(12.5)

44.1

83.6

Stan

ding

Blo

od P

ress

ures

% c 5 T

* N

umbe

r of

res

pond

ents

for

hei

ght t

hrou

gh p

ulse

mea

sure

men

ts

# N

umbe

r of

res

pond

ents

for

blo

od p

ress

ures

; chi

ldre

n w

ith p

hase

5 b

elow

20

mm

wer

e ex

clud

ed, n

o ph

ase 4

subs

titut

ion.

E 2 3 Q 8 tr

Ql

TA

BL

E 2

Mea

sure

men

ts in

13 year o

ld boys

and

girl

s

F

Hei

ght (

cm)

Wei

ght (kg)

Que

tele

t's I

ndex

(gm

/cm

2)

Tric

eps

Skin

fold

(mm)

MU

AC

(cm

) Pu

lse

(bea

ts/ m

in)

Boys (

loo)

* G

irls

(92)

*

Cen

tiles

C

entil

es

Mea

n (S

.D.1

5t

h 95

th

Mea

n (S

.D.)

5t

h 95

th

Sitti

ng B

lood

Pre

ssur

es

Syst

olic

(m

mH

g)

Dia

stol

ic I

mm

Ha)

156.

1 (7

.5)

145.

5 16

9.8

157.

2 (5

.8)

147.

6 16

6.1

45.5

(8

.6)

33.6

61

.7

47.1

(8

.3)

35.0

61

.3

1.86

(0

.26)

1.

49

2.36

1.

90

(0.2

7)

1.52

2.

35

9.0

(4.2

) 4.

5 16

.8

11.1

(3

.7)

6.4

17.6

22

.5

(2.5

) 19

.1

27.1

23

.1

(2.6

) 18

.9

21.3

76

.2

(10.

9)

59.6

98

.2

80.2

(1

3.0)

57

.8

101.

2

99.2

(1

0.9)

80

.0

114.

0 10

0.4

(12.

8)

83.5

12

5.5

41.4

(1

0.6)

29

.5

63.5

50

.3

(11.

6)

27.0

68

.0

Stan

ding

io

od

Fre

ssur

es

Syst

olic

(m

mH

g)

110.

4 (1

2.3)

89

.8

126.

2 10

7.6

(13.

8)

83.6

13

3.6

Dia

stol

ic (

mm

Hg)

67

.1

(1 1.

0)

49.8

84

.1

66.8

(1

1.6)

45

.6

85.9

* #

Num

ber

of r

espo

nden

ts f

or h

eigh

t th

roug

h pu

lse

mea

sure

men

ts

Num

ber

of r

espo

nden

ts f

or b

lood

pre

ssur

es;

child

ren

with

pha

se 5

bel

ow 2

0 mm w

ere

excl

uded

, no

phas

e 4

subs

titut

ion.

TABLE 3

Comparison of height and weight in 12 year old children in Australia*

New South Wales Queensland Western Australia Western Australia Western Australi8

Sydney Busaelton Perth This study Nature of sample Urban Urban k Rural Rural Urban Rural Year of measurement 1970 1976 1975 1971 1979

BOYS Number in sample 1082 220 77 448 204 Height (cm) 150.6 (7.5)+ 149.1 (N.A.) 147.2 (7.4) 149.1 (7.3) 150.0 (7.0) Weight (kg) 41.4 (7.6) 39.6 (N.A.) 38.8 (6.8) 39.7 (7.0) 42.8 (8.6)

Girls

Height (cm) 156.1 (8.2) 150.8 (N.A.) 150.0 (7.5) 150.9 (7.5) 153.6 (6.8) Number in sample 1010 200 68 364 193

Weight (kg) 45.8 (8.1) 43.4 (N.A.) 41.8 (8.6) 41.8 (8.3) 44.0 (7.1)

* Derived from: Sydney;20 Queensland;21 Busselton;22 Perth23

+ Mean with standard deviation in parentheses; N.A. indicates not available.

lighter and shorter in this study.” These differences could have been due to small differences in the age structures of the samples.

Mean blood pressure levels recorded in this study were considerably lower than those published for children of similar age in Busselton12 and Adelaide” (Table 4). Blood pressures in the Adelaide children were recorded by use of the same type of sphygmomanometer as in this study, while the Busselton study used a standard mercury sphygmomanometer. Other details were not stated

for the Adelaide study; in Busselton children were rested and lying down.

A comparison of data from 12 year old boys and girls in six countries from which all the listed data were available (except serum cholesterol in France) are presented in Tables 5 and 6. Mean systolic and diastolic blood pressures in the Western Australian study fell well below all others, even allowing for the fact that other studies recorded diastolic blood pressure at phase 4. With respect to this latter point, several major United

TABLE 4

Cornpubon of blood pressures in 13 year old children in Australia*+ Western AustraU8 South Austrdia Western Australia

Nature of sample Year of Mwurement

Bussclton Rural 1977

Adelaide Urban

Uncertsin

This study Rural 1979

Boys Girls Sexes combined BOYS Girls

Number in sample 61 56 Uncertain 100 84 Systolic BP (mmHg) 108 (8.6)# 109 (9.0) 113 (N.A.) 99.2 (10.9) 100.4 (12.8) Diastolic BP

at phase 4 (mmHg) 64 (9.4) 63 (9.0) 70 (N.A.) at phase 5 (mmHg) - - 68 (N.A.) 47.4 (10.6) 50.3 (11.6)

Derivedfrom: Busselton;’2 Adelaide;l3

+ Blood pressure measurements in the present study and the Adelaide study were made using the London School of Hygiene Sphygmomanometers.

# Mean with standard deviation in parentheses; N.A. indicates not available.

MARGETTS ET AL 260 COMMUNITY HEALTH STUDIES

States studies have presented mean phase 5 blood pressures and these were still higher than those recorded in this study (for example, Tecumsehl4 boys 71 mm and girls 72mm), although within the United States there has been considerable variation in mean phase 5 levels (for example, boys in the United States Health Examination Survey, 63 mm;” Morrison et al, 60.8 mm;16 Tecumseh, 71 mm14). The pulse rates recorded in this study were also lower than those from Tecumseh17 where mean levels of 87.6 in pre-menarcheal girls, 9 I . I in post-menarcheal girls and 89.3 in boys were recorded.

Twelve year old rural Western Australian boys and girls were taller than those in the other countries except Norway, they were lighter than Greek and United States, about the same or heavier than Norwegian children and heavier than French and Italian children. With respect to Quetelet’s index, the Western Australian boys and girls were, on average, less obese than Italians, Greeks and United States children, and as or more obese than Norwegian and French children. Mean cholesterol levels were exceeded only by those in Norway. It should be noted that the cholesterol levels given for Australian children in Tables 5 and 6 were not measured in this study but were those measured in Busselton, another rural Western Australian town, in 1973, on plasma by the direct Liebermann-Burchard method on a Technicon SMA 12/60 Autoanalyser.

Discussion The most notable difference between

coronary risk factors in these Western Australian children and those recorded elsewhere is the apparently lower blood pressures. This difference may be due, a t least party, to methodological factors. It has been shown recently that when compared with the Hawksley random zero sphygmomanometer, the London School of Hygiene (LSH) sphygmomanometer (which we used) read on average, in a population of (presumably adult) hospital patients, 7.1 mm lower for systolic blood pressure and 3.6 mm lower for diastolic blood pressure.18 These differences were thought to be due to observer delay in registering the systolic and diastolic pressures when using the LSH machine. If they represent appropriate corrections to our mean blood pressure levels, the corrected means would still remain the lowest of any of those listed in tables 4, 5 and 6.

Similar problems may also affect comparison of plasma or serum cholesterol levels. The mean concentrations from Western Australia given in

MARGETTS ET AL 26 1

tables 5 and 6 were measured in plasma by the direct Liebermann-Burchard method. A variety of methods were used on serum in the other countries, although all were standardized with the United States Center for Disease Control or the WHO Regional Lipid Reference Center in Prague.4 The Western Australian laboratory was not standardized to either of these reference centres when the cholesterols presented here were measured and it is not known how these results compare with them.

Differences in degree of sexual maturation may also influence comparisons between populations of children aged 12 and 13 years. This would be particularly true of comparisons of height, weight and Quetelet’s index. Age at menarche is reportedly six months earlier in Italians (at 12.5 years) than other populations included in table 6.” The smaller differences in height between Italian girls and others, compared with Italian boys and others, may be explained partly by their earlier menarche. Post-menarcheal girls in Tecumseh are considerably taller than pre- menarcheal girls a t either 12 or 13 years, although blood pressure levels were not markedly different, especially after adjustment for adip0sity.1~ We did not record age at menarche in this study.

Rural, as compared to urban, residence may also be important; Tanner reported several studies which showed a tendency for urban children to be several centimeters taller than their rural counter- parts.19 In the present comparisons (tables 5 and 6) the Italian, French and Australian populations were rural whereas the United States, Norwegian and Greek populations were urban. When children from urban centres in Australia were pooled and compared with children from rural centres, urban children of either sex were taller and girls were heavier. There were, however, appreciable differences within the urban, and rural samples, considered separately: this makes even more problematic the use of a pooled urban-rural sample comparison.

The above considerations suggest that any conclusions on the relationship between coronary risk factor levels, as brought together in this paper, and ischaemic heart disease (IHD) incidence or mortality in later life should be drawn with caution. There is, however, no clear relationship between the risk factors detailed in tables 5 and 6 and IHD mortality in adults in the countries concerned. IHD mortality rates in the United States and Australia (ages 35 to 64 years, table 7) were nearly twice those in Norway and some three or more times higher than in Greece, Italy and France. In contrast, mean blood pressure levels in

COMMUNITY HEA L TH STUDIES

TA

BL

E 5

E

Com

pari

son

of s

ome

card

iova

scul

ar risk

fact

ors in

12 y

ear

old bo

ys fr

om s

ix c

ount

ries

* > P VY

syst

olic

D

iast

olic

Pl

asm

a or

m

pr

essu

re#

pres

sure

# H

eigh

t W

eight

In

dex

Cho

lest

erol

-I F

Boys

No.

(m

mH

g)

(mm

Hg)

N

o.

(cm

) 0%

) (g

m/c

m2)

N

o.

(mmo 1 / 1)

seru

m

bloo

d bl

ood

Que

tele

t !

U.S

.A.

347

100.

1(10

.4)+

71

.3 (

7.1)

34

7 15

1.0

(7.8

) 44

.2 (

8.8)

1.

93 (0

.28)

30

2 4.

13 (

0.60

) A

ustr

alia

19

0 97

.2 (

9.3)

47

.7(1

0.8)

20

4 15

2.0

(7.0

) 42

.8 (

8.6)

1.

84 (0

.26)

78

8 4.

91 (

0.88

) N

orw

ay

87

107.

0(10

.7)*

63

.0 (

9.3)

12

0 15

3.1

(6.9

) 42

.7 (

6.9)

1.

82 (

0.20

) 10

8 5.23 (

0.88

) G

reec

e 14

8 10

9.8(

10.8

) 72

.3 (

8.1)

14

8 15

1.2

(7.9

) 44

.7(1

0.7)

1.

92 (

0.34

) 12

6 3.

91 (

0.78

) It

aly

75

105.

0 (9

) 70

.0 (

9)

75

144.

0 (7)

41.0

(9)

2.

00 (

0.20

) 50

3.

82 (

0.60

) Fr

ance

13

11

8.1(

13.9

) 71

.2 (

9.6)

75

14

7.1

(8.2

) 39

.3 (

7.8)

1.

82(N

.A.)

N.A

. ~

~ ~~

*Ref

eren

ces

U.S

.A.:2

4 N

orw

ay;2

5 G

reec

e;26

Ita

ly;2

7 Fr

ance

;2*

Aus

tral

ia (

this

stu

dy)

+ #Mea

sure

d at

pha

se 4

for

all

cou

ntri

es e

xcep

t Aus

tral

ia, w

here

pha

se 5

was

rec

orde

d 0

From

Ste

nhou

se22

Mea

ns w

ith s

tand

ard

devi

atio

ns in

par

enth

eses

; N

.A.

indi

cate

s no

t ava

ilabl

e

h) m

N

TABL

E 6

Com

pari

son

of so

me

card

iova

scul

ar risk

fact

ors i

n 12

yea

r ol

d girls

from

six

cou

ntri

es,

Plas

ma

or

Syst

olic

D

iast

olic

pres

sure

pr

essu

re+

Hei

ght

Weig

ht

Inde

x C

hole

ster

ol

Girls

No.

(m

mH

g)#

(mm

Hg)

N

o.

(em

) (k

b)

(gm

/cm

2)

No.

(m

mol

/ 1)

0

bloo

d bl

ood

Que

tele

t se

rum

k 8 ~

U.S

.A.

404

109.

1 (1

0.8)

+ 72

.0 (

8.0)

40

3 15

1.5

(7.4

) 44

.9 (

9.0)

1.

95 (

0.28

) 32

7 4.

21 (

0.61

) A

ustr

alia

18

3 97

.q10

.4)

49.9

(10.

7)

193

153.

6 (6

.8)

44.0

(7.

1)

1.86

(0.

24)

688

4.99

(0.

85)

Nor

way

10

1 11

0.0(

12.6

) 67

.q10

.3)

146

156.

6 (7

.1)

45.9

(8.

8)

1.86

(0.

27)

129

5.26

(0.

74)

Y

Gre

ece

144

111.

7(10

.4)

74.1

(8.

0)

144

152.

3 (6

.5)

46.0

(9.

0)

1.98

(0.

32)

113

3.92

(0.

70)

Q e

Ital

y 56

10

8.0(

10)

71.0

(8)

56

14

7.0 (7)

43.0

(10)

2.

00 (

0.20

) 37

4.

03 (

0.81

) Fr

ance

15

11

2.3(

11.2

) 67

.7 (

6.2)

82

14

6.9

(8.4

) 38

.4 (

6.8)

1.

78(N

.A.)

N.A

. b

~

t,

*Ref

eren

ces U

.S.A

.?

Nor

way

;25

Gre

ece;

26

Italy

;27

Fran

ce;*

* A

ustr

alia

(th

is s

tudy

) cy !? z

8 Fr

om S

tenh

ouse

22

+ M

eans

with

sta

ndar

d de

viat

ions

in

pare

nthe

ses;

N.A

. in

dica

tes

not a

vaila

ble

#Mea

sure

d at

pha

se 4

for

all

coun

trie

s ex

cept

Aus

tral

ia, w

here

pha

se 5

was

rec

orde

d

TA

BL

E 7

Age

and

sex

spe

cific

Isch

aem

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12 year olds in Greece and France were nearly the same as in the United States and apparently greater than in Australia and Norway; Greek and Italian children were as obese as United States children and more obese than Australian and Norwegian children.

Only the pasma cholesterol concentrations bore some relationship to IHD mortality in these countries. The mean levels were higher in United States, Australian and Norwegian children than in Greek and Italian children. Among United States, Australian and Norwegian children, however, the r ank ing of mean p lasma choles te ro l concentrations in both sexes was the inverse of the mortality rates. Apart from possible differences in standardization or analytical methods for cholesterol, this anomaly could be due to the samples of children being so small or so selected as not to represent all children in the countries concerned; to recent lifestyle changes in these countries affecting cholesterol concentrations in children but not IHD mortality in adults (at least,

not yet or not to the same extent) or to the predominance of some factor other than early elevation of plasma cholesterol in determining differences in IHD mortality in these countries.

The data reported here may be useful for purposes other than international comparison. Tables I and 2 have been presented to permit comparison with other local populations and to give an indication of "normal" values against which the results of measurements of individuals may be compared. There are surprisingly few such data available for children of this age in Australia (those which could be compared are shown in tables 3 and 4) and most are not very recent. 20-23 As with international comparisons, however, differences in methods of measurement must be taken into account 'when using these data as "normal" values. This is particularly important for blood pressure. Again, provided comparable methods are used in the future, these data may serve as baselines against which the effects of efforts to alter coronary risk factors in children may be measured.

References

1.

2.

3.

4.

5.

6.

7.

Lauer RM, Connor WE, Leaverton PE, Reiter MA, Clarke WR. Coronary heart disease risk factors in school children: The Muscatine Study. J. Pediatr 1975; 86: 697- 706. Frerichs RR, Webber S, Voors AW, Berenson GS. Cardiovascular disease risk factor variables in children at two successive years - the Bogalusa Heart Study. J. Chron Dis 1979;

Wilmore JH, McNamara JJ. Prevalence of coronary heart disease risk factors in boys 8 to 12 years of age. J Pediatr 1974; 8 4 527-533. Wynder EL, Williams CL, Laakso K et al. Screening for risk factors for chronic disease in children from fifteen countries. Prev Med

Armstrong BK, Margetts BM, Binns CW, Campbell NA, Masarei JRL, McCall MG. Water sodium and blood pressure in rural school children. Arch Environ Health 1982; 37: 236-245. Prineas RJ. Blood pressure sounds: Their measurement and meaning. Gamma'Medical Products Corporation, 1976. Long M, Dunlop JR, Holland WW. Blood pressure recording in children. Arch Dis Child

32: 251-262.

1981; 10: 121-132.

1971; 46: 253-272.

MARGETTS ET AL

8.

9.

10.

11.

12.

13.

14.

264

Voors AW, Webber LS, Berenson GS. A choice of diastolic Korotkoff phases in mercury sphygmomanometry of children. Prev Med 1979; 8: 492-499. Zerfas AJ, Shoor IJ, Neumann CG. Office assessment of nutritional status. Pediatr Clin North Am 1977; 2 4 253-272. National Health and Medical Research Council. Charts and tables of heights, masses and head circumferences of infants and c h i l d r e n f o r u s e in A u s t r a l i a . Canber ra : Aus t ra l ian Government Publishing Service, 1975. Woodward DR, Lynch PP, Waters MJ et al. Dietary studies on Tasmanian High School students: Intakes of energy and nutrients. Aust Paediatr J 1981; 17: 196-201. Gracey M, Hitchcock NE, Wearne KL, Garcia-Webb P. Lewis R. The 1977 Busselton children's survey. Med J Aust 1979; 2: 265- 267. Jureidini KF, Adams APS, Burnell RH, Goldblatt E, Roberts ME, Vimpani G. Blood pressure in school children aged between seven and thirteen years. Aust NZJ Med 1980; 1 0 479-480. Johnson BC, Epstein FH, Kjelsberg MO. Distributions and familial studies of blood

COMMUNITY HEALTH STUDIES

pressure and serum cholesterol levels in a total community - Tecumech, Michigan. J Chron Dis 1965; 18: 147-160.

15. Cornoni-Huntley J, Harlan WR, Leaverton PE. Blood pressure in adolescence. The United S t a t e s Heal th E x a m i n a t i o n Survey. Hypertension 1979; 1: 566-571.

16. Morrison JA, Khoury P, Kelly K et al. Studies of blood pressure in school children (ages 6- 19) and their parents in an integrated suburban school district. Am J Epidemiol 1980; 111: 156-165.

17. Higgins M, Keller J, Moore F, Ostrander L, Metzner M, Stock L. Studies of blood pressure in Tecumseh, Michigan. I. Blood pressure in young people and its relationship to personal and familial characteristics and complications of pregnancy in mothers. Am J Epidemiol 1980; I 1 I: 142-155.

28. Fitzgerald DJ, O’Malley K, OBrien ET. Inaccuracy of London School of Hygiene sphygmomanometer. Br Med J 1982; i: 18-19.

19. Tanner JM. Foetus into man: physical growth from conception to maturity. London: Open Books, 1978.

20. Jones DL, Hemphill W, Meyers ESA. Height, weight and other physical characteristics of New South Wales children. Part I . Children agedfive years and over. New South Wales: Government Printer, 1973.

21. May GMS, O’Hara VM, Dugdale AE. Patterns of growth in Queensland school children, 191 1 to 1976. Med J Aust 1979; 2: 610-614. .

22. Stenhouse NS. Busselton Norms. Perth; University of Western Australia, 1979.

23. Blanksby BA, Freedman L, Barrett P, Blomfield J. Secular changes in the heights and weights of Western Australian primary

MARGETTS ET AL 265

school children. Ann Hum Biol 1974; 1: 301- 309.

24. Williams CL, Carter BJ, Wynder EL. Prevalence of selected cardiovascular and cancer risk fac tors i n a pedia t r ic population: The “Know Your Body” project, New York; USA. Prev Med 1981; 10:

25. Tell GS, Vellar OD, Monrad-Hansen HP. Risk factors for chronic diseases in Norwegian School children: Preliminary findings of a baseline survey as part of an intervention study (The Oslo Youth Study). Prev Med 1981; 10: 21 1-225.

26. Kafatos AG, Panagiotakopoulos G, Bastikas N, Trakas D, Stoikidou M, Pantelakis S. Cardiovascular risk factor status of Greek adolescents in Athens. Prev Med 1981; 10:

27. Farinaro E, Panico S, Mancini M. The Know Your Body Program in Italy. Prev Med 1981;

28. Choay P, Morla S. The Know Your Body Program in France. Prev Med 1981; 10:149- 158.

29. World Health Organisation. World Heolth Statistics Annual. Vital Statistics and Cause of Death. Geneve: WHO, 1979.

30. World Health Organization. World Heolth Statistics Annual Vital Statistics ond Cause of Death. Geneve: WHO, 1980.

31. Doll R. Comparisons between registries: Age standardized rate$. In: Waterhouse J, Correa P, Muir C. Powell J, eds. Cuncer Incidence in Five Continents Volume III - 1976. Lyon: International Agency for Research on Cancer, 1976 (IARC Scientific Publications No. 15).

235-250.

173-186.

10: 187-194.

COMMUNITY HEALTH STUDIES