Asia Pac J Clin Nutr 2011;20 (2):180-189

180

Original Article

Secular changes in growth among Japanese children
over 100 years (1900-2000)
Masaharu Kagawa PhD1,2, Yasuaki Tahara PhD3, Kazuhiko Moji PhD4, Rieko Nakao EdM5,
Kiyoshi Aoyagi PhD6, Andrew P Hills PhD7
1

Institute of Nutrition Sciences, Kagawa Nutrition University, Saitama, Japan
National Institute of Public Health, Saitama, Japan
3
Faculty of Education, Nagasaki University, Nagasaki, Japan
4
Research Institute for Humanity and Nature, Kyoto, Japan
5
Department of Health Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki,Japan
6
Department of Public Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki,Japan
7
ATN Centre for Metabolic Fitness, School of Human Movement Studies, Institute of Health and Biomedical
Innovation, Queensland University of Technology, Brisbane, Australia
2

Human growth is associated with complex interactions between genetic and environmental factors. While research has reported increased body size and body mass index (BMI) of Japanese children, few studies have compared the magnitude of increments in growth before and after World War II (WW II) and also considered othersocial and economical events that may have influenced the growth of children. The current study assessed thesecular change in growth in Japanese children and adolescents aged between 6 and 17 years using data from the
School Health Statistics Survey conducted between 1900 and 2000 with consideration of key social changes during the 20th Century. Over the 100-year period, Japanese boys had height and weight increments of 1.0-2.0 cm
per decade and 0.4-1.7 kg per decade whereas girls had rates of 1.1-1.9 cm and 0.4-1.5 kg per decade, respectively. The rates of height increment were significantly (p<0.05) different between pre-, during and post-WW II
periods. While Japanese children were considerably larger in 2000 compared to 1900, increments between 1950
and 1960 reflected catch-up growth to restore physical size seen in children prior to WW II. The increments inbody size continued after 1960 with greatest changes seen across the pubertal years. While increments in BMI
were evident in most age groups, the BMI of 17-year-old girls was consistent over the 100 years. Results clarified secular changes in growth in Japanese school children across the 20th Century and possible factors contributing to these changes.

Key Words: secular change, Japan, children, height, BMI

INTRODUCTION
Human growth is governed by a complex set of interactions between genetic and environmental factors.1 Genes
are responsible for biochemical and hormonal regulations
governing optimum height, and mechanisms of puberty
including the tempo of growth, changes in body composition2,3 and regulation of body weight. A previous study hassuggested that genetic factors explain as much as 90% of
individual variability in body mass index (BMI).4 However, environmental factors interact with genetic influences on growth; for example, insufficient nutritional
intake restricts growth and the onset of puberty. At thesame time, being obese during childhood is an importantrisk factor for the development of adult obesity regardlessof having obese parents.5 Prenatal nutritional status also
contributes to physical growth and the onset of puberty.6-8
Other studies have reported that environmental factors areassociated with both maternal nutritional status as well as
the growth of offspring.9 Since low birth weight infants
have higher risk of developing chronic diseases at laterstage of life,10 it is important to consider social and environmental factors when discussing growth and healthstatus of children.
Earlier growth studies reported that Japanese children
showed the greatest height increment amongst 17 nations
compared11 and others reported increases in body size (ie,height) and leg length.12,13 On the other hand, a limited
number of studies have examined secular changes before
World War II (WW II). Previous studies that compareddifferences in growth between pre- and post-WW II suggested greater rates of height and weight increments in

Corresponding Author: Dr Masaharu Kagawa, Institute of
Nutrition Sciences, Kagawa Nutrition University, 3-9-21 Chiyoda, Sakado, Saitama, Japan 350-0288.
Tel: +81-49-281-7743; Fax: +81-49-284-3679
Email: mskagawa@eiyo.ac.jp; masaharuk@hotmail.com
Manuscript received 30 September 2010. Initial review completed 5 January 2010. Revision accepted 8 February 2011.

M Kagawa, Y Tahara, K Moji, R Nakao, K Aoyagi and AP Hills

the post-WW II period and concluded a significant effectof the war on the growth pattern of children and adolescents.14,15 On the other hand, these studies utilized a selected set of pre- and post-war data, insufficient to take
into account the influence of other social and economic
events during the last century. Apart from WW II, theJapanese also experienced WW I (1914-1918), the Showafinancial crisis (1927), and the subsequent crisis stemming from the Great Depression in the US in 1929. Eachmay have also influenced food availability and therefore
the nutritional status of the population (Figure 1). In addition to the abovementioned social events, the growth ofJapanese children may have been influenced by the nation-wide school lunch program which was commenced
from 1932. Although the program was interrupted during
WW II and until 1947 (resumed in Tokyo and the surrounding area from 1946 and in complete form from1950), it is likely to have influenced nutritional status andthereby growth of Japanese children. Accordingly, it isimportant to compare secular changes in growth observedin both the pre- and post-WW II periods, as well as considering major social/financial events which occurred inJapan. The aim of the current study was to observe thesecular change in growth in Japanese children and adolescents aged 6 to 17 years using data from the School
Health Statistics Survey (SHSS) from 1900 to 2000.
MATERIALS AND METHODS
The current study utilized the SHSS conducted under the
auspices of the Ministry of Education (presently, the Ministry of Education, Science, Culture and Sports; MEXT),
Japan. The Survey was first conducted in the 1890’s toestablish growth standards and a growth monitoring system in Japan. By law, the annual health survey measures
all kindergarten and schoolchildren in the country aged 5
to 17 years. Measurements of height and weight are taken
by school nurses between April and June every year. Data
were randomly extracted to analyze health status and thegrowth trends of Japanese children and adolescents. In
2008, data from 3,322,441 children and adolescents from7,755 schools (22.6% of the students measured) was used
to determine health status and of these, data from 695,600
children (4.7% of the total) was used to assess growthtrends.16
The 1900-2000 datasets were extracted from the SHSS
archive, and gender- and age-specific mean height andweight for 6 to 17-year-old groups at every decade weregenerated.17 Since the SHSS was not published during the
1940-1947 period due to WW II, the 1939 dataset (thelast dataset prior to the WW II) was utilized in the current
study. In addition, because regular measurements of fiveyear-old children did not commence until 1948, the current study excluded this age group.
The datasets were divided into before WW II (preWW II: 1900-1939), during (1939-1950), and after WW
II (post-WW II: 1950-2000) to determine the impact of
the war on the growth of children as well as differences insecular growth change before and after the event. In addition, based on key social events which occurred in Japan
during this period (Figure 1), time points were grouped
into the following periods to examine the impact of key
events: 1) the period of stable economy (1900-1920); 2)
the period during the depression (1920-1930); 3) the pe-

181

riod after commencement of the school lunch program(1930-1939); 4) the wartime period (1939-1950); 5) the
period after the resumption of the school lunch program(1950-1960); 6) the period of economic growth (19601990); 7) the period during the lost decade after the “bubble economy” (1990-2000). Dots in Figure 1 indicate key
time points for the abovementioned periods. Values wereexpressed in absolute and percentage (%) terms as well asa rate per decade using following equations:Difference(X1 – X2 period)=(value in X2) – (value in X1)%difference(X1 – X2 period)=(value in X2 – value in X1)/
(value in X1) x 100
Rate per decade(X1 – X2 period)=(value in X2 – value in
X1)/number of decades
In addition, BMI (kg/m2) for each age group was calculated from the population mean height and weight values reported each year and gender differences in secularchanges in BMI were observed. Although BMI values
calculated from the population mean height and weightcannot reflect individual variability in health status or
growth, observation of the population BMI is still usefulin understanding the secular changes in growth andchanges in physique of this population.
All statistical analyses were conducted using SPSS for
Windows (version 17.0.0, SPSS Inc., Chicago, IL, 2008).
Differences in rates of increment for height, weight and
BMI between the tested periods were assessed using
ANOVA with Bonferonni post hoc test for each gender.
In addition, influences of age, gender and the sub-periods
on the rates of increment were examined using stepwise
regression analyses. A significant level of 0.05 was used
unless otherwise stated.
RESULTS
Figures 2 and 3 show secular changes in height and weightfor Japanese children over the 100–year period. Using the1900 data as a reference, both genders showed an increment in height and weight in 2000 in all age groups. The
figures also illustrate consistent secular changes in bothgenders with gradual increments in height and weightfrom 1900 until 1939, followed by a significant (p<0.05)
decline in 1950 and dramatic and continuous incrementfrom 1960 onwards. Using the rate of increment during
the 1900-1910 period as a reference (0.2 cm per decadefor boys and 0.8 cm per decade for girls), boys showed a

Figure 1. Time line of Japan with social and health events related
to nutrition and growth in Japanese children.

Secular changes in growth in Japan

182a) Boys
170
160

1900
1910
1920
1930
1939
1950
1960
1970
1980
1990
2000

Height (cm)

150
140
130
120
110
100
6

7

8

9

10

11
12
13
Age (years)

14

15

16

17

b) Girls
170
160

1900
1910
1920
1930
1939
1950
1960
1970
1980
1990
2000

Height (cm)

150
140
130
120
110
100
6

7

8

9

10

11
12
13
Age (years)

14

15

16

17

Figure 2. Pseudo distance curves for height for Japanese a) boys and b) girls between the 1900-2000 sub-periodsa) Boys
65

Weight (kg)

55

1900
1910
1920
1930
1939
1950
1960
1970
1980
1990
2000

45

35

25

15
6

7

8

9

10

11
12
13
Age (years)

14

15

16

17

b) Girls

55
1900
1910
1920
1930
1939
1950
1960
1970
1980
1990
2000

Weight (kg)

45

35

25

15
6

7

8

9

10

11
12
Age (years)

13

14

15

16

17

Figure 3. Pseudo distance curves for weight for Japanese a) boys and b) girls between the 1900-2000 sub-periods

M Kagawa, Y Tahara, K Moji, R Nakao, K Aoyagi and AP Hills

significant increment in height during 1920-1930 (1.7 cm
per decade) as well as 1950-1980 periods (ranging from
2.1-4.8 cm per decade). Girls showed significant heightincrements during 1950-1960 and 1960-1970 (3.9 and 3.4
cm per decade, respectively). For weight, increments observed from 1900-1910 for boys (0.51 kg per decade) andgirls (0.18 kg per decade) were significantly (p<0.05)
different from the 1950-1980 periods (ranging from 2.02.7 kg per decade) in boys and 1950-1970 periods in girls(2.4 kg per decade), respectively.
Height and weight increments between 1900 and 2000
are presented in Tables 1 and 2. Increments in height during the pre-WW II period ranged from 2.1 cm to 6.0 cm
in boys and 2.9 cm to 6.1 cm in girls, depending on age.
This is equivalent to an increment per decade in boys
from 0.5 to 1.5 cm, and 0.7 to 1.6 cm in girls. This secularchange was reversed during WW II. Using the 1939 data
as a reference, boys showed greater reduction in height in1950 (ranging from -0.3 cm to -4.8 cm or from -0.3% to 3.2%) compared to girls (ranging from -0.1 cm to -2.1 cm
or from -0.1% to -1.4%). Height was restored after WW
II and the rate of increment over the following five decades (1950-2000) was greater in boys (1.6 cm to 3.8 cm
per decade) compared to girls (1.1 cm to 3.1 cm per decade). Over the 100-year period, Japanese boys and girls
experienced height increments of 9.7 to 20.0 cm (1.0-2.0
cm per decade) and 11.0 to 19.2 cm (1.1-1.9 cm per decade) respectively, depending on age. The rates of heightincrement were significantly (p<0.05) different between

183

pre-, during and post-WW II periods.
A similar pattern was observed for weight. Both boys
and girls showed comparable rates of increment during
the pre-WW II period (0.1-1.4 kg per decade in boys and
0.1-1.3 kg per decade in girls) followed by a decrease inweight gain during wartime. While boys experienced agreater decrease in weight than girls (as much as 3.9 kg or
8.9% in boys compared to 2.1 kg or 4.8% in girls), boys
also recovered considerably during the post-WW II period (rate of increment: 0.7-3.1 kg per decade in boys and
0.7-2.5 kg per decade in girls). Over the 100 years,
weight increments were 4.4-17.4 kg or 0.4-1.7 kg per
decade in boys and 4.3-15.3 kg or 0.4-1.5 kg per decadein girls. As observed for height, the rates of weight increment were significantly (p<0.05) different between
pre-, during and post-WW II periods.
In addition to an assessment of secular changes ingrowth between pre-, during and post WW II, the impactof other social and economic events were examined. As
shown in Figures 4 and 5, both genders experienced
greatest increments in height and weight during the 19501960 period (boys: 4.8 cm per decade and 2.7 kg per decade; girls: 3.9 cm per decade and 2.4 kg per decade),which was significant compared to the 1900-1920 subperiod (p<0.05) in both genders. In contrast, a deceleration in growth was observed during the 1939-1950 period(boys: -1.8 cm per decade and -1.2 kg per decade; girls: 0.8 cm per decade and -0.4 kg per decade) which wassignificant in boys for both height and weight and only

Table 1. Secular change in height in Japanese children and adolescents (6-17 years) between 1900 and 2000
Age (yrs)
Boys
Difference, cm

Rate (/decade)Girls
Difference, cm

Rate (/decade)

6

7

8

9

10

11

12

13

14

15

16

17

1900-1910
1910-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1970
1970-1980
1980-1990
1990-2000
1900-2000
Pre-WW II
DuringPost-WW II
1900-2000

0.0
0.0
1.1
1.0
-0.5
3.1
2.8
1.3
1.0
-0.1
9.7
0.5
-0.5
1.6
1.0

0.3
0.9
1.1
0.7
-0.3
3.4
3.2
1.2
1.1
0.0
11.6
0.8
-0.3
1.8
1.2

-0.3
0.6
1.6
1.3
-0.9
3.5
3.6
1.4
1.2
0.0
12.0
0.8
-0.8
1.9
1.2

0.3
0.6
1.7
2.4
-2.1
3.9
3.6
1.6
1.2
0.4
13.6
1.3
-1.9
2.1
1.4

0.6
1.0
1.5
1.2
-1.1
4.5
3.7
2.0
1.3
0.5
15.2
1.1
-1.0
2.4
1.5

0.6
0.9
2.0
1.5
-1.8
5.1
4.3
2.4
1.5
0.9
17.4
1.3
-1.6
2.8
1.7

-0.3
1.2
2.3
0.7
-1.8
5.9
5.2
2.7
1.6
1.5
19.0
1.0
-1.6
3.4
1.9

-0.9
1.5
2.7
0.7
-2.8
6.9
5.9
2.9
1.9
1.2
20.0
1.0
-2.5
3.8
2.0

-0.6
1.8
2.5
1.4
-4.8
7.8
5.4
3.1
0.9
1.0
18.5
1.3
-4.4
3.6
1.9

0.6
1.5
2.0
1.9
-3.3
6.4
3.1
2.7
0.9
0.7
16.5
1.5
-3.0
2.8
1.7

1.2
0.9
1.3
1.4
-1.6
4.3
3.0
2.3
0.6
0.6
14.0
1.2
-1.5
2.2
1.4

1.2
0.9
1.0
1.5
-0.7
3.2
2.8
1.9
0.7
0.4
12.9
1.2
-0.6
1.8
1.3

1900-1910
1910-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1970
1970-1980
1980-1990
1900-2000
Pre-WW II
DuringPost-WW II
1900-2000

1.0
0.0
1.1
1.2
-0.3
2.8
3.0
1.3
1.1
11.0
0.8
-0.3
1.6
1.1

0.0
0.3
1.6
1.0
-0.1
3.1
3.4
1.3
1.2
11.7
0.7
-0.1
1.8
1.2

0.6
0.7
1.5
1.0
-0.1
3.5
3.5
1.6
1.2
13.6
1.0
-0.1
2.0
1.4

-0.3
0.9
1.6
1.8
-1.0
4.2
3.8
1.8
1.2
14.4
1.0
-0.9
2.3
1.4

-0.3
0.6
1.8
1.7
-1.1
5.4
4.2
2.1
1.2
16.4
1.0
-1.0
2.7
1.6

0.6
1.2
1.6
1.4
-1.0
6.4
4.8
2.0
1.4
19.2
1.2
-0.9
3.1
1.9

0.6
2.5
2.3
0.4
-1.5
6.7
4.4
2.2
0.9
19.1
1.5
-1.4
3.0
1.9

1.2
2.4
2.0
0.5
-1.5
5.6
4.0
1.9
0.7
17.2
1.6
-1.4
2.5
1.7

0.6
2.8
1.3
1.0
-2.1
4.1
3.5
1.8
0.4
13.8
1.5
-1.9
2.0
1.4

2.2
1.2
1.4
1.1
-0.5
2.5
2.4
1.5
0.6
12.5
1.5
-0.5
1.4
1.3

2.1
0.9
1.5
1.5
-0.3
1.5
2.1
1.5
0.7
11.6
1.5
-0.3
1.2
1.2

1.8
0.9
1.0
1.8
0.2
1.0
1.9
1.4
0.9
11.1
1.4
0.2
1.1
1.1

Secular changes in growth in Japan

184

Table 2. Secular change in weight in Japanese children and adolescents (6-17 years) between 1900 and 2000
Age (yrs)
Boys
Difference, kg

Rate (/decade)Girls
Difference, kg

Rate (/decade)

6

7

8

9

10

11

12

13

14

15

16

17

1900-1910
1910-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1970
1970-1980
1980-1990
1990-2000
1900-2000
Pre-WW II
DuringPost-WW II
1900-2000

0.5
0.1
0.3
0.6
0.0
0.6
1.0
0.7
0.7
0.3
4.8
0.4
0.0
0.7
0.5

-0.8
0.2
0.4
0.5
0.1
0.6
1.4
0.8
0.8
0.4
4.4
0.1
0.1
0.8
0.4

0.1
0.1
0.6
0.7
-0.1
0.8
1.8
1.0
1.2
0.5
6.7
0.4
-0.1
1.1
0.7

-0.1
0.3
0.6
0.8
-0.2
1.1
2.1
1.3
1.4
0.9
8.2
0.4
-0.2
1.4
0.8

-0.1
0.4
0.6
1.0
-0.5
1.6
2.5
1.9
1.5
1.2
10.1
0.5
-0.5
1.7
1.0

0.1
0.4
0.9
0.9
-0.6
2.0
3.1
2.4
1.8
1.4
12.4
0.6
-0.5
2.1
1.2

0.8
0.7
1.3
0.7
-1.0
3.1
3.9
2.9
2.1
1.9
16.4
0.9
-0.9
2.8
1.6

0.5
1.1
1.6
0.7
-1.8
4.2
4.4
3.0
2.3
1.4
17.4
1.0
-1.6
3.1
1.7

0.6
1.3
2.1
1.6
-3.9
5.6
4.3
2.8
1.8
1.2
17.4
1.4
-3.5
3.1
1.7

1.6
0.6
1.9
1.5
-2.9
5.3
2.7
3.2
2.1
0.7
16.7
1.4
-2.6
2.8
1.7

1.5
0.6
1.5
1.2
-1.9
4.2
2.6
2.5
1.5
0.5
14.2
1.2
-1.7
2.3
1.4

1.4
0.4
1.2
0.9
-1.3
3.5
2.6
1.9
1.4
0.6
12.6
1.0
-1.2
2.0
1.3

1900-1910
1910-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1970
1970-1980
1980-1990
1900-2000
Pre-WW II
DuringPost-WW II
1900-2000

0.0
0.0
0.3
0.4
0.2
0.6
1.0
0.8
0.8
4.3
0.2
0.2
0.7
0.4

-0.6
0.2
0.4
0.4
0.4
0.7
1.3
0.8
1.0
4.8
0.1
0.4
0.8
0.5

0.3
-0.3
0.9
0.8
0.1
0.9
1.7
1.1
1.1
7.0
0.4
0.1
1.0
0.7

0.2
0.2
0.6
0.7
0.1
1.4
2.0
1.3
1.4
8.7
0.4
0.1
1.4
0.9

-0.7
0.3
0.8
1.1
-0.5
2.2
2.8
1.6
1.4
9.9
0.4
-0.5
1.8
1.0

0.0
0.4
1.1
1.0
-0.7
3.5
3.4
1.6
1.6
13.1
0.6
-0.6
2.3
1.3

1.2
0.1
1.9
0.5
-1.1
4.3
3.7
2.0
1.3
15.0
0.9
-1.0
2.5
1.5

1.2
1.5
2.0
0.5
-1.3
4.6
3.4
1.6
1.0
15.3
1.3
-1.2
2.3
1.5

-0.2
1.3
2.0
1.2
-2.1
4.1
3.0
1.3
0.6
11.7
1.1
-1.9
1.9
1.2

0.9
0.5
1.6
0.0
0.2
2.9
2.4
0.9
0.7
10.1
0.8
0.2
1.4
1.0

0.1
0.7
0.9
0.8
0.2
1.9
2.1
0.5
0.4
8.0
0.6
0.2
1.1
0.8

-0.2
0.6
0.7
0.7
0.3
1.3
1.7
0.0
0.7
6.1
0.5
0.3
0.8
0.6

a) Boys
Rate of height increment (per decade)108
6
1900-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1990
1990-2000

4
2
0
-2
-4
-6
6

7

8

9

10

11 12
Age

13

14

15

16

17

b) Girls
Rate of height increment (per decade)

8
7
6
5

1900-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1990
1990-2000

4
3
2
1
0
-1
-2
-3
6

7

8

9

10

11 12
Age

13

14

15

16

17

Figure 4. Rate of increment in height (per decade) for Japanese a) boys and b) girls between the 1900-2000 sub-periods

M Kagawa, Y Tahara, K Moji, R Nakao, K Aoyagi and AP Hills

185a) Boys
Rate of weight increment (per decade)8
6
4

1900-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1990
1990-2000

2
0
-2
-4
-6
6

7

8

9

10

11
12
Age

13

14

15

16

17

b) Girls
Rate of weight increment (per decade)5
4
3
1900-1920
1920-1930
1930-1939
1939-1950
1950-1960
1960-1990
1990-2000

2
1
0
-1
-2
-3
6

7

8

9

10

11 12
Age

13

14

15

16

17

Figure 5. Rate of increment in weight (per decade) for Japanese a) boys and b) girls between the 1900-2000 sub-periods

height in girls (p<0.05). The rates of increment varied
between age groups. While boys showed greatest variability for both height and weight in the 14-year-old
group, greatest deceleration in growth during wartime wasobserved around the age of 14 but the greatest recovery
was observed in the 12-year-old group. There were no
significant differences in the average rate of increment
between the 1900-1920 period (boys: 0.6 cm per decadefor height and 0.5 kg per decade for weight; girls: 1.0 cm
per decade for height and 0.3 kg per decade for weight)
and other pre-WW II sub-periods (i.e. 1920-1930 and
1930-1939). In addition, the rate in the 1900-1920 period
was comparable to that of the 1990-2000 period for bothheight and weight regardless of gender. Figures also show
a deceleration of growth rate to the 1900-1939 level in thelater years of the 20th Century (i.e., 1960 onwards). The
regression analyses also confirmed significant differencesin the rate of increment between sub-periods. Using age,gender and sub-periods as covariates, rates of increment
for height and weight were described as follows:
Rate of height increment = 0.731 + 0.179 x (subperiods), (Radj = 0.043, SEE = 1.71)
Rate of weight increment = -0.601 + 0.201 x (subperiods) + 0.073 x (age), (Radj = 0.146, SEE = 1.17)
where the variable (sub-periods) is the 1900-1920 =1, 1920-1930 = 2, 1930-1939 = 3, 1939-1950 = 4,
1950-1960 = 5, 1960-1990 = 6, 1990-2000 =7.
The secular change in BMI from 1900 to 2000 is presented in Figure 6. Based on pseudo distance curves, BMI

in Japanese boys increased gradually from 1900 until
1950. While both boys and girls showed a slight decline
in BMI in 1950 compared to 1939, boys restored their
BMI back to 1939 level by 1960 and continued to increase in all age groups until 2000. In girls, on the other
hand, a greater recovery in their BMI was seen in 1960
compared to their 1939 values with a continued increase
until 2000. However, after the 1970’s, the distance curvestarted to plateau at around 15-years and as a result,unlike boys, 17-year-old girls showed a consistent BMI
score across the century.
DISCUSSION
The current study examined secular changes in growthamong Japanese children and adolescents across the 20th
Century to better understand the impact of social events
including WW II, and other economic as well as healthpromotion strategies. The study confirmed that the bodysize of Japanese children and adolescents changed dramatically over this period.
In comparison with data collected in 1900, absolutebody size (height and weight) of Japanese children andadolescents has increased considerably over the last century regardless of gender. However, the present study
clarified a difference in the rate of increment in height
and weight between pre-, during, and post-WW II periods.
From 1900 until 1939, the body size of Japanese children
and adolescents increased gradually. The growth rate declined in the wartime (1939-1950) but recovered by 1960

Secular changes in growth in Japan

186a) Boys
22

1900
1910
1920
1930
1939
1950
1960
1970
1980
1990
2000

BMI (kg/m 2 )

20

18

16

14
6

7

8

9

10

11
12
13
Age (years)

14

15

16

17

b) Girls
22

1900
1910
1920
1930
1939
1950
1960
1970
1980
1990
2000

BMI (kg/m 2 )

20

18

16

14
6

7

8

9

10

11
12
13
Age (years)

14

15

16

17

Figure 6. Pseudo distance curves for BMI for Japanese a) boys and b) girls between the 1900-2000 sub-periods

then increased continuously until 2000. This observationof complete recovery by 1960 was consistent to a previous study that reported complete recovery of height andweight in both genders of all ages by 1956 for height and1957 for weight.14
Apart from WW II, Japan experienced a number of national and international events that might have influenced
food availability and indirectly, the growth of children
and adolescents. The current study grouped datasets into
seven sub-periods – three during the pre-WW II period(1900-1920, 1920-1930, 1930-1939), the WW II period(1939-1950), and three during the post-WW II period(1950-1960, 1960-1990, 1990-2000). Due to a natural
disaster (Great Kanto earthquake) in 1923 and financial
crises (Showa financial crisis and Great depression) in thelate 1920s to early 1930s, it was hypothesized that thegrowth of children may have been affected during thisperiod. However, comparable increment rates of height
and weight were see compared to the 1900-1920 subperiod indicating the minimum impact of these events on
growth. In addition, there was no significant difference inthe rates of increment in 1930-1939, even though previous literature reported an annual economic growth of
4.5% between 1930-1940, with a 9% industrial production rate and also the commencement of the school lunch
program in 1932.18,19 This may reflect that the Japanese
economy was sufficient to provide a constant food supply
compared to 1900 with a lack of severe health conditions

that may have caused deterioration in growth with catchup growth at a later stage.
A deceleration in growth observed in 1939-1950 islikely related to food shortages during WW II. In addition,
malnutrition and poor growth may also be attributed topoor hygiene and increased risk of infections. A previous
study reported that the rate of parasite infection increased
to 73.1% in 1949 from 58.1% in 1945.20 The recovery ingrowth observed in the 1950-1960 sub-period is likely areflection of catch-up growth from an improvement in
nutritional status and dietary pattern as reported in previous studies.21, 22 From the end of 1946, the Japanese government resumed the school lunch program at selectedsites (i.e., Tokyo and nearby regions) and with food supplied from General Headquarters (GHQ) and the United
Nations Children’s Fund (UNICEF), the program resumed at major cities in January 1947. The program provided lunch in a complete form (including bread, milk
and a side dish) in 1950, and by February 1951, approximately four million school children across the country
had access to the program.19 As this lunch provided adequate energy for growth as well as essential nutrients,
particularly calcium, it is likely that the nationwide program contributed to the rapid recovery of children’
growth. In addition, the year 1960 in Japan was within adramatic economic growth period known as the “Japanesepost-war economic miracle.” The current study clarified
that adolescent age groups (14-year-old boys and 12-14year-old girls) were most affected during the 1940-1950

M Kagawa, Y Tahara, K Moji, R Nakao, K Aoyagi and AP Hills

period and showed the greatest recovery during the 19501960 period. Puberty is the time of greatest growth aswell as physiological change that requires appropriate
interactions between biological and environmental factors.23 Although the current study did not observe strong
evidence in support of a direct influence of the economy
on the growth of children, it might have assisted indirectly in the achievement of an optimum catch-up growthrate in children and adolescents. Rates of increment for
both height and weight started to drop after 1960 regardless of gender and the rate in the 1990-2000 sub-period
was comparable to that of the 1900-1920. This pattern ofsecular change in growth provides additional support for
the theory that the rapid growth Japanese children andadolescents experienced during the 1950-1960 sub-period
was, at least until late 1950’s,14 a reflection of catch-up
growth rather than an increase in body size per se.
Consistent with the changes in physical size, the current study also confirmed an increase in BMI over the last
100 years. The increase in BMI appears minimal until
1939 and after a slight decrease in 1950, it started to increase again, particularly after 1960 (ie, during the postWW II period). This rapid increase in BMI after WW II isconsistent with the global trend in the second half of the20th century.24-26 A number of studies have reported thatthe onset of puberty and physical development in Japanese school children is about two years earlier.15,21,27
Since the level of body fat is associated with the early
onset of puberty,28,29 it can be suggested that an improvement in nutritional status plus an increase in adipose
tissue deposition caused the early onset of puberty. This
allowed Japanese children an extended period in which toincrease their height, mainly due to increases absolute andrelative leg lengths.12,13 As others have suggested in relation to BMI,30 body proportion is related to body weight.
While an increment in absolute height and subsequent
increase in frame size will increase weight, an increment
in relative leg length will decrease weight compared tothose with shorter relative leg length. Therefore, it may besuggested that the observed BMI secular change in the
post-WW II period is a result of a balance between 1) therate of weight increment relative to height (due to an increase in fat-free mass [FFM] and fat mass [FM]), and 2)
the rate of leg length increment relative to height.
During the post-WW II period, particularly after 1960,
both genders showed a considerable increase in BMI
from 6 years of age and except for 17-year-old girls, values were greater than the previous sub-periods of thesame age groups. This may partially reflect a previous
study that found an increase in the proportion of overweight and obese children in Japan (based on age- andgender-specific 95th percentile cut-off points).31 As theJapanese are likely to develop obesity-related metabolic
problems at a lower BMI compared to Caucasians regardless of their age,32,33 the increasing trend of BMI is considered a health concerns in Japan. While there report of
reduced levels of physical activity between 1981 and
1992,21 it is also true that, based on the adult data, theaverage total energy consumption among Japanese has
been declining in the past several years.34 In addition, aprevious study reported that Japanese children and adolescents underwent a change in body proportion until

187

1980’s and those with comparable body proportion
showed minimum increment in their upper body mass.35
Therefore, despite the fact that a number of Japanesechildren are overweight or obese, it may be inappropriate
to conclude that an increase in BMI in this population
over the last 100 years is solely due to an energy imbalance.
Unlike boys, girls aged 15 to 17 years showed consistent BMI values across the century. This finding suggests
a small increment rate of weight relative to height which
is likely to be due to increased awareness of the “ideal”
thin female body image and prevalence of weight management practices after 1960. In support of this hypothesis, Takimoto et al.36 reported that the proportion ofyoung females whose BMI was below 18.5 kg/m2 as wellas those with BMI below 17 kg/m2 has been increasingover the last 30 years (1976-2000). In addition, girls may
require further health promotion strategies to prevent
health problems associated with a distorted body image(e.g. disordered eating behaviour, eating disorders, osteoporosis, and anaemia) as well as to prevent them becoming thin and malnourished mothers and subsequently delivering low birth weight infants.
CONCLUSION
The current study confirmed secular changes in height
and weight among Japanese school children over the last
100 years. Compared to during and post-WW II, the rateof growth during the pre-WW II was constant and was
not affected by social events, including a natural disasterand financial crisis. Despite a deterioration in growth during wartime, Japanese children and adolescents experienced rapid catch-up in growth during the post-WW II
period. The rate of growth varies between age groups andthe pubertal years were most affected by environmental
factors.
The current observation indicated that the secularchanges among Japanese children and adolescents occurred
predominantly due to catch-up growth. However, after
complete recovery, improved nutritional status led to increased adipose tissue deposition. This may accelerate theonset of puberty and affect both absolute size and body
proportions. It is difficult to clarify the exact cause of
BMI increment during the post-WW II period due to thepotential for combined effects of weight increment relative to height and leg length increment relative to heightand growth. As BMI is only a crude measure of heaviness
relative to height, it may be inappropriate to conclude thatan ‘observed’ increase in BMI over the last 100 years was
solely due to energy imbalance. However, a limitation of
the current study was that BMI values were calculatedusing population means rather than individual values.
Further studies are warranted to better understand theprevalence of overweight/obesity as well as metabolic
health problems with consideration of both lifestyle andbiological factors in order to develop/implement healthpromotion strategies appropriate for each gender.
AUTHOR DISCLOSURES
There were no conflict of interest among the authors and nofinancial grant or other funding was obtained for the study.

188

Secular changes in growth in Japan

REFERENCES
1. Delemarre-van de Waal HA. Environmental factors influencing growth and pubertal development. Environ Health
Perspect. 1993;101:39-44.
2. Veldhuis JD, Roemmich JN, Richmond EJ, Rogol AD,
Lovejoy JC, Sheffield-Moore M et al. Endocrine control ofbody composition in infancy, childhood, and puberty. Endocr Rev. 2005;26:114-46.
3. Banerjee I, Clayton P. The genetic basis for the timing of
human puberty. J Neuroendocrinol. 2007;19:831-8.
4. Maes HHM, Neale MC, Eaves LJ. Genetic and environmental factors in relative body weight and human adiposity.
Behav Genet. 1997;27:325-51.
5. Whitaker RC, Wright JA, Pepe MS, Seidel KD, Dietz WH.
Predicting obesity in young adulthood from childhood andparental obesity. N Engl J Med. 1997;337:869-73.
6. Ibáñez L, de Zegher F. Puberty and prenatal growth. Mol
Cell Endocrinol. 2006;25:22-5.
7. Ong KK, Ahmed ML, Dunger DB. Lessons from large
population studies on timing and tempo of puberty (seculartrends and relation to body size): the European trend. Mol
Cell Endocrinol. 2006;254-255:8-12.
8. Eriksson JG. Epidemiology, genes and the environment:
lessons learned from the Helsinki Birth Cohort Study. J Intern Med. 2007;261:418-25.
9. Gitau R, Makasa M, Kasonka L, Sinkala M, Chintu C,
Tomkins A et al. Maternal micronutrient status and decreased growth of Zambian infants born during and after themaize price increases resulting from the southern African
drought of 2001-2002. Public Health Nutr. 2005;8:837-43.
10. Barker DJ, Clark PM. Fetal undernutrition and disease inlater life. Rev Reprod. 1997;2:105-12.
11. Takaishi M. Growth standards for Japanese children -- an
overview with special reference to secular changes ingrowth. In: Hauspie R, Lindgren G, Falkner F, editors. Essays on Auxology. Welwyn Garden City, UK: Castlemead;
1995. pp. 302-11.
12. Tanner JM, Hayashi T, Preece MA, Cameron N. Increase inlength of leg relative to trunk in Japanese children andadults from 1957 to 1977: comparison with British and withJapanese Americans. Ann Hum Biol. 1982;9:411-23.
13. Ali MA, Uetake T, Ohtsuki F. Secular changes in relative
leg length in post-war Japan. Am J Hum Biol. 2000;12:40516.
14. Hayase T, Muramatsu T, Fujita O, Okada A, Muramatsu S.
The influence of the war experience upon the physical development among children and young adults. Iris Health.
2003;3:17-21. (In Japanese)
15. Kawahata A. The acceleration of growth and developmentof Japanese school students. Part XXII Before and afterWorld War II. Gakkou Hoken Kenkyu. 1979;21:497-500.
(In Japanese)
16. Ministry of Education Science Culture and Sports (MEXT).
Announcement on 2008 School Health Statistical Survey.
[cited 2009/01/09]; Available from: http://www.mext.go.
jp/b_menu/toukei/001/h20.htm
17. Ministry of Education Culture Sports Science and Technology (MEXT). The Statistical Report of the School Health
Survey. [cited 2011/01/07]; Available from: http://www.estat.go.jp/SG1/estat/List.do?bid=000001014499&cycode=0

18. Takagi S. Wartime Japanese economy and a floating exchange rate. Kinyu Kenkyu. 1989;8:109-40. (In Japanese)
19. Ministry of Education Culture Sports Science and Technology (MEXT). Promotion of the school lunch program.
[cited 2009/04/18]; Available from: http://www.mext.go.jp/
b_menu/hakusho/html/hpbz198101/hpbz198101_2_185.html
20. Tada I. Parasite controls in Japan with emphasis on special
characteristics. Trop Med Health. 2008;36:49-68. (In Japanese)
21. Murata M. Secular trends in growth and changes in eating
patterns of Japanese children. Am J Clin Nutr. 2000;72:
1379S-83.
22. Takahashi M. Secular trend in milk consumption andgrowth in Japan. Hum Biol. 1984;56:427-37.
23. Pinyerd B, Zipf WB. Puberty-timing is everything! J Pediatr
Nurs. 2005;20:75-82.
24. Chrzanowska M, Koziel S, Ulijaszek SJ. Changes in BMI
and the prevalence of overweight and obesity in children
and adolescents in Cracow, Poland, 1971-2000. Econ Hum
Biol. 2007;5:370-8.
25. Zhang YX, Wang SR. Distribution of body mass index andthe prevalence changes of overweight and obesity among
adolescents in Shandong, China from 1985 to 2005. Ann
Hum Biol. 2008;35:547-55.
26. Ji CY, Chen TJ. Secular changes in stature and body massindex for Chinese youth in sixteen major cities, 1950s-2005.
Am J Hum Biol. 2008;20:530-7.
27. Hermanussen M, Molinari L, Satake T. BMI in Japanesechildren since 1948: no evidence of a major rise in theprevalence of obesity in Japan. Anthropol Anz. 2007;65:275-83.
28. Wang Y. Is obesity associated with early sexual maturation?
A comparison of the association in American boys versus
girls. Pediatrics. 2002;110:903-10.
29. Kaplowitz PB. Link between body fat and the timing ofpuberty. Pediatrics. 2008;121:S208-17.
30. Deurenberg P, Deurenberg-Yap M, Guricci S. Asians aredifferent from Caucasians and from each other in their bodymass index/body fat per cent relationship. Obes Rev. 2002;
3:141-6.
31. Yoshinaga M, Shimago A, Koriyama C, Nomura Y, Miyata
K, Hashiguchi J et al. Rapid increase in the prevalence ofobesity in elementary school children. Int J Obes. 2004;28:
494-9.
32. Matsuzawa Y, Inoue S, Ikeda Y, Sakata T, Saito Y, Satou Y
et al. Atarashii himan no hantei to himanshou no shindan kijun. J Jap Soc Study Obes. 2000;6:18-28. (In Japanese)
33. Yoshinaga M, Tanaka S, Shimago A, Sameshima K, Nishi J,
Nomura Y et al. Metabolic syndrome in overweight andobese Japanese children. Obes Res. 2005;13:1135-40.
34. Ministry of Health Labour and Welfare. Overview of the
National Nutrition Survey in Japan, 2000. Tokyo; 2000. (InJapanese)
35. Kagawa M, Hills AP. Secular changes in BMI and obesity
risk in Japanese children: Considerations from a morphologic perspective. Open Obes J. 2011;3:9-16.
36. Takimoto H, Yoshiike N, Kaneda F, Yoshita K. Thinness
among young Japanese women. Am J Public Health. 2004;
94:1592-5.

M Kagawa, Y Tahara, K Moji, R Nakao, K Aoyagi and AP Hills

189

Original Article

Secular changes in growth among Japanese children over
100 years (1900-2000)
Masaharu Kagawa PhD1,2, Yasuaki Tahara PhD3, Kazuhiko Moji PhD4, Rieko Nakao EdM5,
Kiyoshi Aoyagi PhD6, Andrew P Hills PhD7
1

Institute of Nutrition Sciences, Kagawa Nutrition University, Saitama, Japan
National Institute of Public Health, Saitama, Japan
3
Faculty of Education, Nagasaki University, Nagasaki, Japan
4
Research Institute for Humanity and Nature, Kyoto, Japan
5
Department of Health Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki,Japan
6
Department of Public Health, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
7
ATN Centre for Metabolic Fitness, School of Human Movement Studies, Institute of Health and Biomedical
Innovation, Queensland University of Technology, Brisbane, Australia
2日本兒童在 20 世紀期間生長情況之變化
基因與環境因子複雜的交互作用與人類生長息息相關。過去研究曾報告日本兒童體型與身體質量指數的增加，然而較少的研究比較二次世界大戰前後兒童之生長，並且較少考慮其他社會及經濟因子對日本兒童生長之衝擊。本研究使用
1900 至 2000 年所進行的學童健康統計調查(School Health Statistics Survey)資料，
以 6 至 17 歲之日本兒童與青少年為目標族群，同時考慮主要的社會變遷，評估
在 20 世紀間目標族群之生長變化。在 20 世紀的 100 年間，男生平均每 10 年身高增加 1.0-2.0 公分，體重增加 0.4-1.7 公斤；而女生平均每 10 年身高增加 1.11.9 公分，體重增加 0.4-1.5 公斤。在二次世界大戰前、戰爭期間及戰後，身高增
加的速率有顯著差異。雖然 2000 年的日本孩童比上 1900 年的孩童，體型明顯較大，但是在 1950 至 1960 年間，增加的幅度可能只是補長，回復至二次大戰前的體型大小。在 1960 年後，體型仍繼續增長，以青春期學生的體型增加最大。雖
然身體質量指數在大部分年齡層都增加，但 17 歲的女生在那 100 年間都維持一
致的身體質量指數。本篇結果釐清 20 世紀日本學童生長情況的長期變化，以及可能造成影響之因素。
關鍵字：長期性變化、日本、兒童、身高、身體質量指數