Declining Growth Status of Indigenous Siberian Children in Post-Soviet Russia

13 Pages·2002·0.19 MB·English

Declining Growth Status of Indigenous Siberian Children
in Post-Soviet Russia
WILLIAM R. LEONARD,1GARYJ. SPENCER,2VICTORIAA. GALLOWAY,3AND
LUDMILLAOSIPOVA4
Abstract Human health status in Russia has declined sharply over the last
decade. The massive social changes that have taken place since the fall of the
Soviet Union have resulted in increasing morbidity and mortality rates. How-
ever, relatively little information is available on the changes in health and dis-
ease patterns of Russia’s many indigenous populations. The present study ex-
amines anthropometric indices of growth status of young children (< 6 years;
n= 155), a sensitive index of population health, in three indigenous Evenki
communities of Central Siberia between 1991 and 1995. Children of the 1995
sample are significantly shorter, lighter, and leaner than those measured in
1991 and 1992. In 1995, 61% of Evenki children were growth stunted (height-
for-age zscore < –2.0), as compared to 34% in 1991 and 1992 (p< 0.001).
Similarly, the prevalence of low weight-for-age (weight-for-age z score <
–2.0) children in the 1995 sample was more than double that of the 1991/92
sample (43% vs. 18%; p< 0.001), and the prevalence of low weight-for-height
(weight-for-height zscore < –2.0; “wasting”) increased from 2% to 17% (p<
0.001). The levels of growth retardation observed in 1995 are comparable to
those seen among impoverished third-world populations. Additionally, the de-
clines in linear growth appear to be particularly pronounced in girls, raising
the question of whether there may be differential treatment of boys and girls
under these conditions of stress. Overall, these results indicate that increased
economic marginalization is having a profound effect on the health and well-
being of indigenous Siberian groups. Further work is necessary to determine
the proximate causes of the disturbing trends, and the potential solutions and
interventions.
Much recent evidence indicates that human health status in Russia is declining
sharply. The massive social and economic changes that have taken place since the
fall of the Soviet Union in 1991 have resulted in increasing morbidity and mor-
1Department of Anthropology, Northwestern University, Evanston, IL60208.
2Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
N1G 2W1.
3Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
4Institute of Cytology and Genetics, Russian Academy of Sciences, Novosibirsk, Russia.
Human Biology,April 2002, v. 74, no. 2, pp. 197–209.
Copyright ©2001 Wayne State University Press, Detroit, Michigan 48201-1309
KEYWORDS: GROWTH, NUTRITIONALSTATUS, ANTHROPOMETRY, ECONOMIC CHANGE,
EVENKI
198/ leonard et al.
tality rates and unparalleled declines in life expectancy (Notzon et al. 1998; Kon-
torovich 2001; Shkolnikov et al. 2001). Such changes are the consequence of
many factors, including widespread alcoholism, and more limited access to med-
ical care. Consequently, it appears that in many parts of Russia mortality rates are
approaching those seen in the developing world.
Although much of the research on health declines in Russia has focused on
changes in the larger urban centers, the changes for indigenous Siberian popula-
tions appear to have been profound as well (Leonard et al. 1997; Sorensen et al.
2000; Spencer 1998). Most striking has been the dismantling of the state-run col-
lectives that had been instituted during the Stalinist era (Uvachan 1975; Forsyth
1992; Fondahl 1995, 1998). Among the Evenki herders with whom we have
worked, this shift has resulted in the return of reindeer herds to individual extend-
ed families rather than control by the state-run collectives. This transition has
contributed to greater isolation of the Evenki from the larger towns and urban
centers in Central Siberia. The increased isolation is the result of the great reduc-
tion in airplane and helicopter flights into the Evenki villages and herding units in
the absence of financial support from the collectives. Hence, the transport of food
and medical supplies, as well as travel in the region, has been greatly constricted.
These changes are having important demographic consequences for the
Evenki. In particular, it appears that the wealthier and nonindigenous segments of
the populations living in the rural Evenki villages have largely migrated out to
larger towns and urban centers with access to regular air transport. Additionally,
as has been seen in the urban areas of Russia, the post-Soviet period has seen a
marked increase in death rates (Leonard et al. 1997).
Given that so many measures of adult health status have declined in Siberia
over the last decade, it is reasonable to expect that childhood health and well-be-
ing have been influenced as well. This study addresses this question by examining
anthropometric indices of growth and nutritional status of young children under 6
years of age, a sensitive index of population health, in indigenous Evenki com-
munities of Central Siberia between 1991 and 1995. Specifically, we will exam-
ine the changes in standard indices of growth status (height-for-age, weight-for-
age, and skinfold measures) and explore the nature and potential causes of the
observed changes.
Methods
Anthropometric data on the Evenki children were collected from two vil-
lages and their associated herding brigades in the Baykit District of Central
Siberia. These data were collected during the summers of 1991and 1992, when
the herding collectives were in operation, and in the summer of 1995, after the col-
lectives had been dissolved. Atotal of 155 children under the age of 6 years were
measured (see Table 1 for sample composition). Measurements included stature
(cm), weight (kg), and the sum of the triceps and subcscapular skinfolds (mm).
Declining Growth Status of Evenki Children/ 199
Table 1. Sample Sizes of Evenki children (< 6 years of age) from the Baykit District of
Central Siberia, Measured in 1991/92 and 1995
Males Females
Age (Years) 1991/92 1995 1991/92 1995
0.0–0.9 2 4 5 4
1.0–1.9 1 4 4 6
2.0–2.9 3 3 11 3
3.0–3.9 8 3 11 9
4.0–4.9 16 3 7 9
5.0–5.9 16 4 17 2
Total 46 21 55 33
All measurements were taken by a single observer (WRL) using standard
techniques as outlined by Lohman et al. (1988). Linear (length/stature) measure-
ments were recorded to the nearest mm. Recumbent length was measured for
children under 2 years of age, whereas stature (standing height) was measured for
children over 2 years. Body mass was measured to the nearest 0.2 kg with a hang-
ing scale for children under 2 years, and a standing floor scale for children over 2
years. Skinfold thicknesses were measured to the nearest 0.5 mm using Lange
calipers.
Height-for-age, weight-for-age, and weight-for-height measures were stan-
dardized as z scores relative to the US National Center for Health Statistics
(NCHS) norms (Hamill et al. 1979) using the ANTHRO software program (Sulli-
van and Gorstein 1990). The sum of triceps and subscapular skinfold measures
were compared to the US norms compiled by Frisancho (1990).
Results
Patterns of Growth. Figures 1a and b show statural growth of Evenki boys
and girls, respectively, compared to the US 5th and 50th centiles. Among the
boys, differences between the two cohorts are evident under age 2 years, with
those of the 1995 cohort being shorter than those measured in 1991/92. Above
age 2 years, average stature in the two cohorts is similar, tracking at about the US
5th centile. The pattern is comparable for girls. Those of the 1995 cohort are sys-
tematically shorter than their peers from 1991/92, with the differences being most
pronounced under 2 years of age.
Figures 2a and b present growth patterns in body weight for Evenki boys
and girls, respectively, relative to the US norms. In both sexes, children of the
1991/92 cohort are systematically heavier than those of the 1995 cohort. Children
of the 1991/92 cohort tend to track between the 5th and 50th US centiles, where-
as those of the 1995 groups track at or below the 5th centile.
Figures 3aand b present the sum of triceps and subscapular skinfold mea-
200/ leonard et al.
m-
o
c
e
ar
a
at
d
ki
n
e
v
E
5.
9
9
1
n
d i
n
a
2
9
1/
9
9
1
n
d i
e
ur
s
a
e
m
s
e
pl
m
a
s
m
o
s fr
ar
e
y
6
of
e
nder the agal. (1979).
males umill et
b) fem Ha
males and (centiles fro
Evenki (a) h and 50th
h of US 5t
wte
oh
gro t
ar d t
Linepare
1.
e
r
u
g
Fi
Declining Growth Status of Evenki Children/ 201
m-
o
c
e
ar
a
at
d
ki
n
e
v
E
5.
9
9
1
n
d i
n
a
2
9
1/
9
9
1
n
d i
e
ur
s
a
e
m
s
e
pl
m
a
s
m
o
s fr
ar
e
y
6
of
e
g
a
e
h
er t9).
d7
n9
b) females umill et al. (1
d (Ha
anm
males es fro
nki (a) h centil
ve0t
E5
of nd
ght growth he US 5th a
weio t
y d t
de
Bopar
2.
e
r
u
g
Fi
202/ leonard et al.
5.
9
9
1
n
d i
n
a
2
9
1/
9
9
1
n
d i
e
ur
s
a
e
m
s
e
pl
m
a
s
m
o
s fr
ar
e
y
6
of
e
g
a
e
h
er t
d
un0).
es 99
malo (1
nd (b) feFrisanch
s am
eo
mals fr
enki (a) h centile
ds for Evh and 50t
ol5t
nfS
kiU
ular so the
apd t
bscare
up
sm
d o
nc
ps aare
of triceki data
m en
uv
SE
3.
e
r
u
g
Fi
Declining Growth Status of Evenki Children/ 203
sures for Evenki boys and girls compared to the US norms of Frisancho (1990).
As with body weight, children of the 1991/92 cohort show systematically higher
levels of subcutaneous fatness over all ages. Among males, those of the 1991/92
cohort have average skinfold measures that approximate the US median, whereas
those of the 1995 cohort tend to fall closer to the 15th centile. Similarly, among
females, the skinfold measures for the 1991/92 cohort are close to the US median,
whereas those of the 1995 group approximate the 25th centile.
This pattern of skinfold (fatness) measures comparing more favorably to
US norms than either weight or height measures is one that has been observed
among children of other “growth stunted” populations. For example, research
among Andean populations has consistently found high levels of statural growth
retardation associated with near-normal levels of subcutaneous fatness (e.g., Fri-
sancho and Baker 1970; Leonard 1991). It appears that among young children of
these populations, subcutaneous fatness tends to be preserved except under con-
ditions of very severe, acute nutritional stress (see Kuzawa 1998). Additionally, in
environments such as the Arctic and the high Andes where cold stress is persis-
tent, preserving subcutaneous fatness may also be critical for the survival of chil-
dren who are very susceptible to heat loss due to their high surface-area-to-mass
ratios (Frisancho 1993; Leonard et al. 1994).
Differences in Growth and Nutritional Status between Cohorts. Table 2
compares the standardized measures of growth and nutritional status—height-for-
age z scores (HAZ), weight-for-age z scores (WAZ), weight-for-height z scores
(WHZ), and sum of triceps and subscapular skin folds (Sumskin)—between the
two cohorts for both Evenki boys and girls. In all the comparisons, we adjusted
for differences in age between the samples by using analysis of covariance (AN-
COVA).
In both sexes, children of the 1995 cohort have significantly lower HAZ
measures than those of the 1991/92 cohort. Mean HAZ values for boys and girls
Table 2. Comparison of Measures of Growth and Nutritional Status (HAZ, WAZ, WHZ,
and Sumskin) between Evenki Children Measured in 1991/92 and 1995a
Males Females
Measures 1991/92 1995 1991/92 1995
HAZ –1.49 ±0.18 –2.10 ±0.26* –1.21 ±0.19 –2.35 ±0.24***
WAZ –1.06 ±0.16 –2.09 ±0.24*** –0.90 ±0.13 –1.92 ±0.17***
WHZ –0.14 ±0.17 –1.07 ±0.26** –0.11 ±0.16 –0.56 ±0.21
Sumskin 14.5 ±0.4 12.1 ±0.6** 16.5 ±0.4 14.5 ±0.5**
a. All values are mean ±SEM, adjusting for differences in age using ANCOVA. Measures include:
height-for-age zscores (HAZ), weight-for-age z scores (WAZ), weight-for-height z scores (WHZ),
and sum of triceps and subscapular skinfolds (Sumskin).
Note:Differences between the 1991/92 and 1995 cohorts are statistically significant at:
*p< 0.05; **p< 0.01; ***p< 0.001.
204/ leonard et al.
of the 1995 sample fall below –2.0, suggesting substantial statural growth retar-
dation. Additionally, we find that the magnitude of the between-cohort differ-
ences is substantially greater in girls than in boys (girls: HAZ = –1.21 vs. –2.35;
p< 0.001; boys: HAZ = –1.50 vs. –2.05; p< 0.05), perhaps suggesting differen-
tial impact on girls.
Children of the 1995 cohort also have significantly poorer WAZ measures,
with the between-cohort differences being larger than for HAZ. The differences
in WAZ between the cohorts are similar in both boys and girls (boys: WAZ =
–1.06 vs. –2.09; p < 0.001; girls: WAZ = –0.90 vs. –1.92; p < 0.001). As with
HAZ, the mean values for WAZ in the 1995 cohorts approximate –2.0.
Weight-for-height z scores, a measure of acute nutritional stress, are also
worse in the 1995 cohort. Among boys, the 1995 cohort is almost a full standard
deviation below the 1991/92 cohort (WHZ = –0.14 vs. –1.07; p< 0.01), whereas
the differences are more modest among the girls (WHZ = –0.11 vs. –0.56; p =
0.08).
Body fat reserves, as reflected in the sum of skinfolds, are also lower in the
1995 cohorts for both sexes. As with WAZ, the magnitude of the between cohort
differences are similar for boys and girls (boys: Sumskin = 14.5 vs. 12.1 mm; p<
0.01; girls: Sumskin = 16.5 vs. 14.5 mm; p< 0.01).
The proportion of Evenki children showing evidence of growth failure is
also much greater in the 1995 sample. Table 3shows the percentages of each co-
hort having HAZ, WAZ, or WHZ measures of less than –2.0, the standard thresh-
old for characterizing a child as nutritionally at risk (Frisancho 1990; Waterlow et
al. 1977; WHO 1983). We see that the proportion of children with severe statural
growth stunting (HAZ < –2.0) almost doubled between 1991/92 and 1995, in-
creasing from 34% in the 1991/92 cohort to 61% in the 1995 group (p< 0.001).
At 60%, these levels of stunting are comparable to those seen in rural areas of the
developing world (see, for example, Allen et al. 1992; Beaton 1992; Berti et al.
1998; Martorell and Habicht 1986). The increased prevalence of stunting is evi-
dent in both sexes; however the magnitude of the increase is greater in girls (64%
[1995] vs. 29% [1991/91]; p< 0.01) than in boys (57% [1995] vs. 39% [1991/91];
p= 0.17).
Table 3. Comparison of the Prevalence (% of Sample) of Low Height-for-Age (“Stunt-
ing”), Low Weight-for-Age, and Low Weight-for-Height (“Wasting”) in Evenki Children
Measured in 1991/92 and 1995
Males Females Total
Measures 1991/92 (%) 1995 (%) 1991/92 (%) 1995 (%) 1991/92 (%) 1995 (%)
Low height-for-age 39 57 29 64** 34 61***
Low weight-for-age 22 43 15 42** 18 43***
Low weight-for-height 2 24** 2 12* 2 17***
Note:Differences between the 1991/92 and 1995 cohorts are statistically significant at:
*p< 0.05; **p < 0.01; ***p< 0.001.
Declining Growth Status of Evenki Children/ 205
Similar patterns are evident for body weight. The proportion of children
who are severely underweight (WAZ < –2.0) has more than doubled, increasing
from 18% of the 1991/92 sample to 43% of the 1995 group (p< 0.001). As with
stature, the increased prevalence of low weight-for-age is more pronounced in
girls (42% [1995] vs. 15% [1991/91]; p< 0.01) than in boys (43% [1995] vs. 22%
[1991/91]; p=0.08).
Low weight-for-height (or “wasting”) is also more common in the 1995 co-
hort. Indeed, the proportion of children who are acutely undernourished accord-
ing to this measure (WHZ < –2.0) has increased almost tenfold between 1992 and
1995 (2% in 1991/92 vs. 17% in 1995; p< 0.001). Unlike height- and weight-for-
age, the increases are more dramatic in boys (24% [1995] vs. 2% [1991/92]; p<
0.01) than girls (12% [1995] vs. 2% [1991/92]; p< 0.05).
Overall, the differences between the two cohorts in allthe anthropometric
dimensions clearly indicate sharp declines in growth and nutritional status among
young Evenki children during the early period of post-Soviet transition in Central
Siberia. These changes parallel the changes in migration patterns, demographic
structure, and mortality rates previously documented in this region (Leonard et al.
1997). We will now explore the potential causes of disturbing trends in childhood
health and well-being.
Discussion
This study has demonstrated dramatic declines in growth and nutritional
status among young Evenki children of Central Siberia between 1991 and 1995.
These changes are likely the consequence of the massive social and economic
transformations occurring in Siberia and throughout Russia. Looking at the pat-
terns of change in growth status, we find that all the key anthropometric indices
considered—height-for-age, weight-for-age, weight-for-height, and sum of skin-
folds—have significantly declined during the post-Soviet period. The magnitude
of decline, however, appears to be greatest and most uniform across ages for
weight and the sum of skin folds. This pattern is consistent with expectations of
recent changes in “environmental quality” associated with the social and eco-
nomic collapse in Russia. Indeed, of the anthropometric indices considered,
weight and body fatness are more ecosensitive than statural (linear) measures, re-
sponding more quickly to changes in the environment (Waterlow et al. 1977).
In contrast, stature is more reflective of long-term, cumulative nutritional
health. Consequently, it is not surprising that the differences in height-for-age be-
tween the cohorts, although significant, are most evident in the youngest age
groups (under 2–3 years). These are precisely the ages in which we should expect
the largest differences. Children under the age of ∼3 years from the 1995 cohort
would have lived their entire postnatal growth period in poorer, post-Soviet con-
ditions. In contrast, children who were over age 3 in 1995 spent at least a portion
of their earliest childhood growing up under what appear to have been better eco-
nomic and nutritional circumstances.
Although both boys and girls show declines in growth status, the magnitude
206/ leonard et al.
of the changes appears to be greater for girls. This is particularly evident from the
differences in mean HAZs and the prevalence of low height-for-age and low
weight-for-age. This pattern is remarkable because there is considerable evidence
to suggest that males are generally more vulnerable to environmental insults dur-
ing development (e.g., Stini 1975; Stinson 1985; Dettwyler 1991; Leonard 1991).
The greater impact on Evenki females may reflect gender bias in parental atten-
tion and/or resource allocation, as has been documented in parts of South Asia
(e.g., Chen et al. 1981).
The reasons for the marked overall declines in growth status and nutrition-
al health of the Evenki children are likely a consequence of the greater isolation
and return to a more “traditional” lifestyle among the Evenki. The shift away
from a collectivized herding system and the general economic decline throughout
Russia have resulted in greater isolation for the populations of this region. Indeed,
during the early 1990s, helicopters typically visited even the most remote herding
units on a biweekly basis. In contrast, by the mid-1990s, most of the herding
brigades were visited by helicopter only once or twice during the summer
months. Thus, access to market foods, medical supplies, and even basic medical
care was much more constrained by the middle 1990s.
Limitations on food availability may have particularly important conse-
quences for the nutritional status of young children. Typical weaning foods for
Evenki children during the collective period were condensed milk and various ce-
reals (wheat, rice). By 1995, these foods were much less available and consider-
ably more expensive than they were in the early 1990s. Consequently, the diver-
sity of weaning foods appears to have markedly declined for Evenki mothers.
In contrast to most nonlocal food items, alcohol has remained widely avail-
able for the Evenki in the post-Soviet period. As is the case throughout Russia, al-
coholism is common among both Evenki men and women. From survey data col-
lected in 1995, we found that equally high proportions of adult Evenki men and
women regularly consumed alcohol (94% of men and 89% of women). Further,
we estimate per capita alcohol consumption among Evenki adults to be 20–30
liters/year, comparable to the national average of 22.7 liter/person/year for Russia
(White 1996), and some two to three times higher than recent US consumption
levels (9.6 liters/year; US Statistical Abstracts 1996). Given the direct conse-
quences that maternal alcohol consumption has on fetal development, and the im-
pact that alcoholism has on social dynamics and child neglect, it is likely that the
high rates of alcohol use among the Evenki adults have contributed to the declin-
ing health status of their children.
Further work is necessary to determine if these trends of declining growth
status are continuing among the Evenki. Recent analyses of the health changes in
Russia after 1995 have yielded contradictory results. Shkolnikov and colleagues
(2001), for example, have found that mortality rates in Russia improved during
the second half of the 1990s, whereas the work of Kontorovich (2001) indicates
that mortality rates have not changed. If the levels of childhood growth stunting
continue to remain at or near 1995 levels, the Evenki will likely experience a re-