Overweight and obesity among rural schoolchildren of the Russian Arctic and North in 1994–2019

Full Text

INTRODUCTION

Overweight and obesity spread rapidly in rural areas worldwide [1, 2]. As many scholars show, populations of the northern (higher than 60°N) regions are also vulnerable to this process [3, 4]. For example, 64% of Canada’s Inuit were overweight or obese [5]. Among middle-aged Greenland Inuit, the proportion of obese individuals increased from 12.6% in 1993 to 27.3% in 2014 [6]. In 2010, 15.8% of all Greenlandic children were overweight and 6.8% were obese at school entry [7]. According to recent reports, the proportion of children with body mass index (BMI) above the norm in Greenland settlements, excluding Nuuk’s residents, is 28.8% [8].

Indigenous northerners of Russia also face widespread fat metabolism disorders [9]. Surveys conducted in the mid-2010s have reported excessive body weight (including obesity) in 62%–63% of the Nenets and Khanty people living in large settlements or a big city in Northwestern Siberia [10, 11].

The studies on the prevalence of obesity in the indigenous adult population of the northern regions of Russia are scarce, but since different authors use common criteria for excessive weight, they provide an integrated picture. In children, the situation is different.

Until the beginning of the 2000s, Russian practitioners used regional evaluation tables to assess the growth of children. Tables were constructed based on the average measurements of children’s body in every region. They also had updated data every 7–10 years, reflecting the change in the anthropometric characteristics of the population. It was only in 2017 that the Ministry of Health of the Russian Federation recommended using the child growth standards and references of the World Health Organization (WHO) for screening examinations. These circumstances make it difficult to estimate the change in obesity prevalence when a researcher has no access to primary data and should judge using published reports. We considered this issue elsewhere [12].

The outcome of the studies where the criteria for overweight and obesity were consistent with those of the WHO growth reference allows us to see the following picture. Between 1992 and 1998, the percentage of children with excessive weight in Russia fell from 15.6% to 9.0%, but it has slowly started to increase. In 1999–2001, the obesity rate was 5.6% in the rural and 8.4% in urban children aged 6–18 years [13], and in 2004, the prevalence of obesity among those aged 10–18 years reached 11.1% [14]. A study conducted in 2010 found that 19.9% of urban children were overweight and 5.6% were obese. That is, the proportion of children having BMI above the recommended values reached 22.5% [15].

These reports reflect the situation that has developed in large urban centers. Information on how childhood obesity spreads in rural settlements and small towns remained fragmented, making the assessment of the rate of change in remote northern regions difficult. Thus, our data collected for some years in the same settlements and processed by the common protocol enlightens the picture.

This study aimed to assess the prevalence of overweight and obesity in children aged 6–17 years living in rural areas of some northern regions of the Russian Federation from 1994 to 2019.

MATERIALS AND METHODS

The main data were collected during annual medical check-ups of children aged 6–17 years living in Murmansk Oblast, Khanty-Mansi Autonomous Okrug-Yugra (KMAO), Komi Republic, and Komi-Permyak Okrug (KPO) in Perm Krai. Additionally, in KPO and KMAO, information about schoolchildren in administrative centers of the districts of Kudymkar (population 30904 in 2019) and Berezovo (7050 inhabitants) were collected. From 1994 to 2019, data were collected subsequently in the same localities and schools in a region.

The map in the Fig. 1 shows the localization of the data collection sites. The ethnic composition of the study groups is shown in Table 1. The number of participants by the year of data collection is presented in Table 2. The total number of participants is 7548.

Рис. 1. Географическое положение мест сбора данных. Цифрами обозначены места сбора данных на территориях: 1 — Республика Коми; 2 — Коми-Пермяцкий округ (Пермский край); 3 — Ханты-Мансийский автономный округ — Югра.

Таблица 1. Этнический состав обследованных групп

Table 1. Ethnic composition of the study groups

Таблица 2. Размеры выборок по годам исследований (школьники 6–17 лет)

Table 2. Number of participants by year of data collection (schoolchildren aged 6–17 years)

No data are available on the ethnicity of schoolchildren in Lovozero (Murmansk region) for 2016, but in 1997, ethnic Sami accounted for 69%, and in 2005, they made up 60% of the study participants. Among those under examination in Komi Republic, >90% were Komi. Moreover, 82% of the study participants in the rural areas of KMAO belong to the indigenous peoples of the North (Mansi, 52%; Khanty, 30%); 18% are representatives of other ethnic groups, mainly Russians. The medical records on the schoolchildren of the Berezovo town (KMAO) did not contain information about ethnicity. However, according to an estimate based on data from Russian Statistical Agency [16], approximately 95% are of non-indigenous descent and approximately 5% are ethnic Mansi, Khanty, or Nenets. In Komi-Permyak Okrug, based on the school archive records, 85% of the students of rural schools were ethnic Komi-Permyaks, whereas in Kudymkar, it was 59% (we do not have data on the ethnicity of our study participants).

In those examinations where the ethnicities of the participants were known (Lovozero, 1997 and 2005; Komi-Permyak Okrug, 1994 and 2009; Khanty-Mansi AO, 2019), we did not reveal significant differences in body weight estimates between the representatives of the indigenous and non-indigenous populations [17, 18]. In this study, we disregard ethnicity and only consider the region of residence. However, we keep in mind that the rural groups in our study have ethnic specificity.

The data set was formed by total population sampling. The number of participants is shown in Table 2. Measurements were taken according to the WHO procedure [12, 19]. In the first half of the day, in school medical facilities, the participants, while wearing light clothes, underwent direct weight and height measurements using a calibrated medical scale (resolution 0.1 kg) and anthropometer (resolution, 0.1 cm).

The WHO-recommended method and reference BMI values for children aged 5–19 years [19] were used to estimate the individual weight status. According to this technique, each BMI value undergoes standardization, i.e., transformation into a Z-score, using the reference standard deviation (SD) and median (M) for the appropriate sex and age group:

Z=(BMI − M)/SD

Then, depending on the range in which the Z-score value fell, an estimate on the individual weight status is obtained according to the following rules:

−2 ≤ Z ≤ 1, normal;

1 < Z ≤ 2, overweight;

Z > 2, obesity.

Hereinafter, we use the term excessive body weight to refer to the combined weight class that includes overweight and obesity estimates.

As far as the individual estimates account for the sex and age of a participant, we can characterize a region- and time-specific study group by the percentage of participants falling into the mentioned weight ranges (classes).

The authors obtained body height and weight data by either measurements or copying from schoolchildren’s medical records. A comparison of the weight class frequency distributions in the measurement- and record-derived data study groups in the Murmansk region and the Komi Republic (2016 and 2018, respectively) did not reveal significant differences in the ranking results (in both cases, p >0.51). In our analysis, we combined data measured and extracted from medical records).

Statistical analysis consisted of group comparison using the Chi-square test adjusted for maximum likelihood. The significance level was set at 0.05.

RESULTS

The prevalence of overweight and obesity in children aged 6–17 years living in rural areas of the Murmansk region, Khanty-Mansi AO, Komi Republic, and Komi-Permyak Okrug of Perm Krai are presented in Table 3.

Таблица 3. Частота проявлений избыточной массы тела у школьников 6–17 лет в северных регионах Российской Федерации (в процентах, без учёта этнической принадлежности)

Table 3. Prevalence of excessive body weight among children aged 6–17 years in the northern regions of the Russian Federation (per cent, disregarding ethnic belonging)*

* Abbreviations: KMAO, Khanty-Mansi Autonomous Okrug; KPO, Komi-Permyak Okrug.

The proportion of children with excessive body weight has increased over time in all the locations. As shown in Table 4, in the 1990s, 4%–7% of schoolchildren had BMI above the norm; in the 2010s, the percentage increased substantially in all localities. By the end of the second decade of the 21st century, 23%–26% of the children aged 6–17 years living in the northern regions of the Russian Federation were overweight or obese.

The prevalence of excessive body weight and obesity by the year of data collection are presented in Table 4.

Таблица 4. Частота проявлений избыточной массы тела и ожирения у детей 6–17 лет по годам обследования

Table 4. Prevalence of excessive body weight and obesity in children aged 6–17-years by year of data collection

* Significance of the difference from the value in the previous line.

A comparison of data sets collected at a close time (less than a decade) revealed no considerable differences between the regions, except for the cases when the prevalence of obesity in 2005–2009 was lower in Lovozero settlement of the Murmansk region (0.9%) than in the Komi Republic (5%) and Komi–Permyak Okrug (3.3%, p <0.05 in both cases). In 2016–2019, it was virtually higher in Kudymkar town (KPO) than in Berezovo town of KMAO (10.2 and 7.9%, respectively, p=0.058).

The materials collected in Komi–Permyak Okrug and Berezovo districts of Khanty-Mansi AO allowed us to consider the differences between children living in settlements and administrative centers of the rural areas (Table 3).

In Komi-Permyak Okrug, there were no such differences in the percentage of either overweight or obese participants in all three consecutive data sets for 1994, 2009, and 2019 (p >0.1 in all cases).

In 2019, excessive weight was roughly equally prevalent among the children from settlements and Berezovo town of Khanty-Mansi AO (p=0.42), although the former had a higher rate of obesity cases than towners, with the level of significance close to the critical value (11.9 and 7.9%, respectively, p=0.055).

DISCUSSION

Our observations affirm that overweight and obesity in children spread rapidly in rural areas of northern parts of Russia (Tables 3 and 4). The changes were occurring simultaneously in various geographically remote areas such as Murmansk Oblast and the Komi Republic, which belong to the Barents region, Komi-Permyak Okrug in the northern Urals, and Khanty-Mansi AO in the north of Western Siberia. The prevalence of excessive body weight in 1994–1998 was 4%–7% (including obesity 0.6%–0.8%); in 2005–2009, it became 7.5%–18.7% (including obesity 0.9%–5.0%), and in 2016–2019, it further increased to 23.9%–26.6% (including obesity, 7.7%–11.9%).

Comparing our results with the conclusions of other researchers is difficult because of the lack of no uniform national criteria for children’s growth assessment in Russia until recently [12]. According to technically commensurable data, 16.40% of children towners in KMAO had BMI above the norm in 2009 [20]. Moreover, 18.5% of children living in rural settlements in the Arkhangelsk region had excessive body weight in 2010 [21]. Both of these estimates are close to the values obtained in the current study for the settlement residents of the Komi Republic in 2008 (18.7%, Table 4). Our findings are also in concert with the figures reported for children living in Nordic countries that are part of the Barents Region. In the NordChild 2011 cross-sectional survey, 16.5% of Finnish and 15.3% of Norwegian children aged 2–17 years were overweight or obese [22]. According to 2013 Global Burden of Disease Study, at least 20% of individuals aged <19 years in developed countries have bodyweights above normal [23]. Our data obtained in 2016–2019 comply with this assessment (Table 3).

In the present study, the prevalence of overweight and obesity are close in children living in rural settlements and neighboring small towns (Table 3). We previously reported on the similarity in the distribution of weight classes in schoolchildren living in rural settlements and large industrial centers in Perm Krai (2005–2009), Arkhangelsk (2010), and Murmansk (2012–2016) regions [21]. Data obtained in 2019 made it possible to compare the prevalence of overweight and obesity in school-age children in Moscow (largest city in Russia), Perm (main city of Perm Krai), the small town of Kudymkar, and small settlements of Kudymkar district of Perm Krai (Table 5). Pairwise comparisons revealed no significant differences in the prevalence of excess body weight (p >0.3 in all the cases). The obesity level in Kudymkar town (10.2%) was higher (p=0.012) than that in Perm City (6.9%). It was the only instance of significant difference.

Таблица 5. Частота проявлений избыточной массы и ожирения у школьников г. Москвы, г. Перми, г. Кудымкара и сёл Коми-Пермяцкого округа

Table 5. Prevalence of excessive body mass and obesity in schoolchildren of Moscow, Perm, Kudymkar (KPO small town), and rural settlements of KPO

1 — [24] (7-year-old, sexes combined, assessment made under condition of equal proportion of boys and girls.

2 — M. Otavina (2021), personal data

* — Difference between two values is significant, p=0.012

The study results not only enlighten the particular regional situation. Up to the beginning of the 2000s, some Russian scholars supposed that the indigenous people of the North were physiologically protected from fat metabolism disorders, including obesity [25]. Our observations over the last 20–25 years deflate this view. Excess weight among Russian children is almost equally prevalent in the populations of various geographic areas (Arctic, non-Arctic North, and Central Russia) irrespective of the type of residency (settlement, small town, large urban center, and metropolis).

Environmental specifics of the North even heighten the risk of obesity in children. Long winters, low temperatures, and harsh winds limit the time children spend outside, which lead to restricted physical activity [26]. The deficit in natural light during long northern winters may trigger seasonal affective disorder, which is associated with carbohydrate craving [27]. Concurrently, the consumption of carbohydrates in the northern regions of Russia has considerably increased, in amount and variety, over the past 30 years. The recent type of nutrition, contrasting to traditional diets, is a risk factor for the development of overweight and metabolic disorders [28]. From an evolutionary perspective, as sugars were scarce in the northern environment, the pressure of selection to support the activity of disaccharidase enzymes was weak. Consequently, the carriers of the alleles that determine a restricted production of lactase, trehalase, sucrase-isomaltase, and salivary and pancreatic amylase are in a high frequency in the northern populations. Given the high availability of dietary carbohydrates, such genotypes increase the risk of obesity, including in childhood [29, 30].

The environmental, nutritional, and genetic risks of metabolic disorders are at play simultaneously in modern indigenous northern populations. This supposition requires further investigation. The groups need closer attention from doctors, nutritionists, age physiologists, and healthcare providers.

CONCLUSION

A rapid spread of overweight and obesity among Russian children appertains to the second decade of the 21st century. The northern populations are subjected to this process to the same degree and extent as others. Geographic (the Arctic, non-Arctic North, and Central Russia) and socioeconomic (various levels of urbanization) factors do not play a major role in that negative dynamics.

ДОПОЛНИТЕЛЬНАЯ ИНФОРМАЦИЯ / ADDITIONAL INFORMATION

Вклад авторов. Оба автора совместно задумали исследование, организовали и провели сбор данных, статистическую обработку и анализ, обсудили полученные результаты. Статья написана А. Козловым при участии Г. Вершубской. Все авторы подтверждают, что их авторство соответствует международным критериям ICMJE (все авторы внесли значительный вклад в разработку концепции, исследование и подготовку статьи, прочитали и одобрили окончательный вариант перед публикацией).

Финансирование. Исследование проведено в рамках научной темы «Антропология населения Евразии» (АААА-А19- 119013090163-2) Научно-исследовательского института и музея антропологии Московского государственного университета имени М.В. Ломоносова. Публикация поддержана грантом, полученным от Научно-исследовательского центра адаптации человека в Арктике — филиала Федерального исследовательского центра «Кольский научный центр Российской академии наук» по теме «Влияние репродуктивного здоровья и качества арктической окружающей среды для состояние здоровья кольских саамов», финансируется через сквозные фонды Международного арктического научного комитета при участии Социальной и гуманитарной рабочей группы и Международной научной инициативы в русской Арктике.

Конфликт интересов. Авторы заявляют об отсутствии конфликта интересов.

Благодарности. Авторы выражают благодарность канд. биол. наук М.Л. Отавиной (Пермский государственный гуманитарно-педагогический университет) за разрешение использовать ее неопубликованные данные о школьниках г. Перми.

Authors contribution. In cooperation, A .Kozlov and G. Vershubskaya conceived the study, organized and performed data collection, statistical processing, and analysis, and discussed the results. A.Kozlov wrote the manuscript with input from G.Vershubskaya. All authors confirm that their authorship meets the international ICMJE criteria (all authors have made a significant contribution to the development of the concept, research and preparation of the article, read and approved the final version before publication).

Funding source. The study was conducted in the framework of Anthropology of Eurasian population research theme (АААА-А19-119013090163-2) of D. Anuchin Research Institute and Museum of Anthropology, Moscow State University. The publication was supported by a grant received by the Research Centre for Human Adaptation in the Arctic, Branch of the Federal Research Centre “Kola Science Centre of the Russian Academy of Science” on “The contribution of reproductive health and the quality of the Arctic environment to the Wellbeing of the Kola Sami” and is co-funded through the International Arctic Science Committee cross-cutting funds with contributions from the IASC Social & Human Working Group and the International Science Initiative in the Russian Arctic.

Competing interests. The authors declare no conflict of interests.

Acknowledgments. The authors are grateful to Dr. M.L. Otavina (Perm State Humanitarian-Pedagogical University) for the permission to use her unpublished data on schoolchildren of Perm City.

About the authors

Andrey I. Kozlov

Author for correspondence.
Email: dr.kozlov@gmail.com
ORCID iD: 0000-0002-6710-4862
SPIN-code: 2638-5395

Dr. Sci. (Biol.), Cand. of Sci. (Med.)

Galina G. Vershubskaya

Email: ggver@ya.ru
ORCID iD: 0000-0003-2452-1532
SPIN-code: 1172-4138
Russian Federation, Moscow

References

Supplementary files

Supplementary Files

Action

1. JATS XML

Download

2. Fig. 1. Geographic locations of data collection sites. Numbers depict data collecting localities: 1 — The Komi Republic; 2 — Komi-Permyak Okrug (Perm Krai); 3 — Khanty-Mansi Autonomous Okrug – Yugra.

Download (150KB)

Indexing metadata