6th Nationwide Anthropological Survey of Children

and Adolescents 2001

Bláha P.*, Vignerová J.**

*Faculty of Science, Charles University, Prague

National Institute of Public Health

Czech Republic

• Apart from genetic determinants, growth of an individual is to a great extent influenced by external factors (familly backround, socio-economics conditions of the society, health care system, social system etc.).

FENOTYP OF AN INDIVIDUAL =FENOTYP OF AN INDIVIDUAL = GENETIC FACTORS + ENVIRONMENTAL FACTORS +

INTERACTION BETWEEN GENETIC AND ENVIRONMENTAL FACTORS

FAMILYFAMILYENVIRONMENTENVIRONMENT

HEALTH,HEALTH,GROWTHGROWTH

SESSES

PHYSICALPHYSICALENVIRONMENTENVIRONMENT STRESSSTRESS

Flinn M.V., England B.G., American Journal of Physical Anthropology, 1997

Material I.

• 1895: Measurements of 100.000 school children - Czech physician and anthropologist Matiegka (Matiegka J., 1927, Somatology of school children. Nakl. ČSAV a umění, Praha.) – He founded tradition of Nationwide Anthropological Surveys.

• 1800-1809: Mean heights and s.d. in military boarding-school children born between 1800-1809 (in Bohemia and Moravia), recorded in Vienna (Komlos J: Patterns of children’s growth in East-central Europe in the eighteenth century. Annals of Human Biology, 1986, Volume 13, No. 1, pp. 33 - 48.)

Material I: NATIONWIDE ANTHROPOLOGICAL

SURVEYS IN CR

• Every ten years - 1951, 1961, 1971, 1981, 1991, 2001

• Number of children per survey:

80.000 – 100.000 (3 to 5 % of the population of given age)

• Age: 0 to 19 years

Praha

NATIONWIDE ANTHROPOLOGICAL SURVEYS IN CR (1951 to 2001)

• Preschool children: in clinics, by instructed health professionals, mainly paeditricians.

• School children: teachers, provided with detailed written instructions.

• Anthropological measurements: height, body weight, circumferences of the head, arm, waist and hip – Martin Saller method.

• Questionnaires for children: dietary habits, sports activity, TV watching and PC games.

• Questionnaires for parents: parental height, weight, educational level, number of children in the family, breastfeeding and health status of their child.

METHODS

• Original data available from : 1951, 1981, 1991 and 2001.

• For other surveys: sample sizes for each age group, average values and standard deviations are available, for 1895 only average values.

• We have used only these summary values for the growth curves construction.

• Weighted polynomial smoothing spline of 3rd order was used for construction of the growth curves of the height.

• Weights were proportional to sample sizes at the particular time point.

• Its first derivative was then computed to obtain growth velocity.

-2

-1,5

-1

-0,5

0

0,5

1

1,5

2

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Age years

Z-score

195119711991WHO20011895

-2

-1,5

-1

-0,5

0

0,5

1

1,5

2

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Age years

Z-score

195119711991WHO20021895

BOYS GIRLS

Z-SCORE ACCORDING WHO REFERENCE VALUES

Height

Adult height: 1951 - 172.4 (s.d. 6.6)2001 - 180.4 (s.d. 7.0) dif. 8.0 cm

Adult height: 1951 - 161.0 (s.d. 5.6)2001 - 167.2 (s.d. 6.4) dif. 6.1 cm

BOYS GIRLS

-2

-1,5

-1

-0,5

0

0,5

1

1,5

2

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Age years

Z-score

195119711991WHO20011895

-2

-1,5

-1

-0,5

0

0,5

1

1,5

2

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Age years

Z-score

195119711991WHO20011895

Z-SCORE ACCORDING WHO REFERENCE VALUES

Weight

BIRTH WEIGHT- % in weight categories Boys

0%10%20%30%40%50%60%70%80%90%

100%

1955 1981 2001

Year

4500g <

3500-4499g

2500-3499g

1500-2499g

< 1500g

Czech Helath Statistics Yearbooks

BIRTH WEIGHT - % in weight categories Girls

0%

20%

40%

60%

80%

100%

1955 1981 2001

Year

4500g <

3500-4499g

2500-3499g

1500-2499g

< 1500g

Czech Helath Statistics Yearbooks

• 1951 – no data• Since 1975 no

changes• Boys: 50.5 cmBoys: 50.5 cm

3400 g3400 g• Girls: 49.7 cmGirls: 49.7 cm 3270 g3270 g

MEAN BIRTH LENGTH AND WEIGHT

The secular trend of height appears significant from the category of two years olds onwards.

SECULAR TREND OF HEIGHTGrowth curves

Boys

80

100

120

140

160

180

200

4 6 8 10 12 14 16 18Age years

cm

20011991198119711961195118951800-09

Girls

80

100

120

140

160

180

200

4 6 8 10 12 14 16 18Age years

cm

2001199119811971196119511895

3

1,5

0,8

0,2

0

0,5

1

1,5

2

2,5

3

3,5

41985 1951 1971 1991

Years

• In 1895 it was 3 years later3 years later (at 12 years) that boys and girls reached the same values of height and weight of today’s 9 year olds.

• 1951 – 1.51.5 years later

• 1971 – 0.80.8 years later

• 1991 – 0.2 0.2 years later

• The same applies to today’s 10 and 11 year old children

HEIGHT AND WEIGHT Comparison of age

Mean values of height and weight of boys and girls 9 year olds

- in 2001

6 8 10 12 14 16

34

56

7

boysgirls

11,15

Age years

13,327,16

7,87

cm • A comparison of a study from 90s with one from 70s shows shift of growth spurt towards younger age categories: 4 months4 months in girls and in girls and 3 months3 months in boysin boys

1975 1995

Girls 11.5 11.1

Boys 13.6 13.3

• The time shift between boys and girls in the onset of adolescent growth spurt is almost 2 years.

GROWTH VELOCITY OF THE HEIGHT(cm per year)

Longitudinal studies

00.10.20.30.40.50.60.70.80.9

1

10 11 12 13 14 15 16 17

Age years

Pro

bal

ity

Girls

Boys

Number: GIRLS: 12.837 BOYS: 9.645

Mean age of menarche:

(50 % YES, 50 % NO)1991: 13.00 years2001: 13.01 years

Mean age of voice-breaking:

1991: 14.50 years2001: 13.84 years

Corresponds with shifting of secular trend of height

AGE OF MENARCHE AND VOICE-BREAKING1991, 2001

Logistic regression

0.01 y.

0.66 y.

AGE OF ADIPOSITY REBOUNDMethod

• Age of adiposity rebound was defined as the local minimum position of the fitted BMI curve.

6.4

5.3 5.45.2

4

4.5

5

5.5

6

6.5

7

1951 1981 1991 2001

Age

yea

rs

AGE OF ADIPOSITY REBOUNDNationwide Anthropological Surveys

6.2

5.5 5.5

4.9

4

4.5

5

5.5

6

6.5

7

1951 1981 1991 2001

Age

yea

rs

BOYS GIRLS

Results for 50th centile, for higher centiles in the earlier age, for lower centiles later

1.3 1.2

BMI EMPIRICAL CENTILE CHARTS1951, 1991

10

12

14

16

18

20

22

24

26

28

30

2 4 6 8 10 12 14 16 18

Age years

kg/m2

97.perc.

90.perc.

50.perc.

10.perc.

3perc.

1951-97 p.

1951-90 p.

1951-50 p.

1951-10 p.

1951-3 p.

10

12

14

16

18

20

22

24

26

28

30

2 4 6 8 10 12 14 16 18

Age years

kg/m2

97. perc.

90. perc.

50. perc.

10. perc.

3. perc.

1951-97 p.

1951-90 p.

1951-50 p.

1951-10 p.

1951-3 p.

BOYS GIRLS

BMI EMPIRICAL CENTILE CHARTS1951, 1991

Adiposity rebound: in 1951 - 1.5 year later

0102030405060708090

100 110 120 130 140 150 160 170

cm

kg

97

75

50

25

3

BOYS

0102030405060708090

100 110 120 130 140 150 160 170

cm

kg

97

75

50

25

3

GIRLS

WEIGHT-HEIGHT RATIO Empirical centile charts

1951, 2001

PERCENTAGE OF OVERWEIGHT AND OBESE CHILDREN

Reference data: WHO and IOTF recommendationsAge 7 – 11 years

0

5

10

15

20

25

30

35

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Year

%

USAEuropeCzech Rep.

Report of the International Obesity Task Force, 2004

PERCENTAGE OF INHABITANTSBY EDUCATIONAL LEVEL

in the Czech Republic

0%

20%

40%

60%

80%

100%

1970 1980 1990 2000

University

High school

Apprentice

Basic

Czech Statistics Yearbooks

Socio-economic conditions in which the child grows up are to a considerabledegree affected by the level of education of his or her parents.

HEIGHT, WEIGHT-HEIGHT RATIOby parental educational level

Survey 2001, age 7.00 - 8.99 years (n = 3478) – before growth spurt

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Boys Girls

1

2

3

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

Boys Girls

1

2

3

Parents’ education:1. both lower level (basic and apprenticeship)2. one parent lower and one highter level3. both parents higher level (high school, university)

Height Weight-height ratioZ-scoreZ-score

Z-score: using WHO reference data

MEAN BODY HEIGHTBY SIZE OF THE COMMUNITY

AGE 7.00 YEARS

100

110

120

130

1 2 3 4

1951

2001

Statisticaly significant differences in 1951Not statisticaly significant differences in 2001

BOYS

100

110

120

130

1 2 3 4

1951

2001

GIRLScm cm

1 - village2 - small cities3 - large cities4 - Prague

Abstract: T. J. Cole: The secular trend in human physical T. J. Cole: The secular trend in human physical growth: a biological view. growth: a biological view. Economics &Human Biology, Vol. 1, Issue 2, June 2003, pp. 161-168

… In Northern Europe, adult height has In Northern Europe, adult height has largely stabilisedlargely stabilised, and the age of menarche has also settled at around 13 years, while weight continues to while weight continues to increase due to obesityincrease due to obesity. The increase in height from one generation to the next occurs mainly in the first 2 years of life, due to increases in leg length. …

CONCLUSION

• The development of physical characteristics, in particular height and weight of children and adolescents, is a sensitive indicator for socio-economic conditions in which the children grow up and mature.

• Throughout the period of the 20th century - in line with improvements in socio-economic conditions - the physical height was increasing in all age categories.

• A shift in onset and peak of the growth spurt occured towards lower age categories. The period of its cessation, however, remains the same since 1960.

• The shift in growth spurt is linked with shift in the timing of onset of the sexual maturity.

• A shift also occured in the adiposity rebound. • The proportion of children and adolescents with overweight

and obesity is also increasing, although to a lesser degree than in other developed countries.