Undernutrition is still a significant health challenge globally, especially in low- and middle-income countries (1). Undernutrition comprises four forms: stunting (low height-for-age), wasting (low weight for height), underweight (low weight-for-age), and micronutrient deficiencies. Globally in 2020, 149 million children were stunted, 45 million were estimated to be wasted, and approximately 45% of deaths among children below the age of 5 years were associated with undernutrition (2). A recently conducted National Family Health Survey-5 in India during 2019–2020 estimated that 35%, 19.3%, and 32.1% of children younger than 5 years were stunted, wasted, and underweight, respectively (3). Despite several large-scale flagship programs such as the Mid-Day Meal Scheme, Integrated Child Development Services (ICDS), and Prime Minister's Overarching Scheme for Holistic Nutrition (POSHAN), the persistence of undernutrition in India is impeding the efforts to achieve the targets set by the National Nutrition Mission in which the aim is to reduce the stunting in children (0–6 years of age) from 38.4% to 25% by 2022 (Mission 25 by 2022) in India (4, 5).

Undernourished children have a high risk of infection due to immune dysfunction (6, 7), growth flattering (8), neurocognitive impairment, decreased physical capacity, poor academic performance, increased absenteeism, and early school dropout (7, 9–11). While monitoring the nutritional indicators among children younger than 5 years has always been key in the Millennium Development Goals, the Sustainable Development Goals, and the NFHS-5 survey in India (3, 12, 13), it has inadvertently led to overlooking nutritional status among school-age children. Older children and adolescents are mainly at risk of undernutrition because they experience a growth spurt, requiring all essential macronutrients and micronutrients to supplement the body's increased demand for attaining puberty and development. Many studies have also documented that undernutrition is associated with delayed sexual maturation, which is required to achieve an adult's developmental potential (14, 15).

Globally, most nutritional surveys primarily focus on children of < 5 years and adolescents (11–15), neglecting school-going children, which have been highlighted in a few studies conducted in India and African countries (7, 10, 16). A nutritional survey of school-going children is essential in understanding their transition from childhood to adolescence and adulthood (14–17). The preschool years are the first crucial time for intervention when a child's overall growth is compromised. However, some studies have shown evidence of catch-up growth beyond the preschool age. With the right nutritional interventions, school-going children who are undernourished have a significantly high chance of catching up during the pubertal period (the second crucial time) (15, 18, 19). The World Health Organization (WHO) added growth standards for children aged 5 to 19 years in 2007 by using the prevalence of stunting, underweight, and thinness as undernutrition indicators rather than wasting in recognition of the importance of the age group and to close the gap (20). Despite that, nutritional data on school-aged children are globally scarce, including in India (21, 22).

India is a large nation with a diverse geography, climatic conditions, socioeconomic distribution, religion, culture, and food habits. Thus, the prevalence of undernutrition differs substantially between the states and districts. NITI Aayog of the Government of India introduced the Aspirational Districts Programme in 2018 to catalyze development in the 112 most backward districts of the country (23, 24). In Karnataka, Raichur and Yadgir are the only two districts in the Aspirational Districts Programme. The program aims to rapidly and sustainably transform the backward districts to catch up with the rest of the country in terms of key development indicators. The Aspirational Districts Programme is a holistic effort to address all aspects of development, including health and nutrition. The introduction of the Aspirational Districts Programme recognizes that despite decades of action, there are still significant disparities in the development across India. The program will go a long way in ensuring that the fruits of development reach all sections of society, especially the most vulnerable and marginalized (24). Raichur district has a low literacy rate of 59.56%, indicating limited educational attainment (25). The NITI Aayog report highlights that 32.19% of the population in Raichur experiences multidimensional poverty, emphasizing the prevalence of socioeconomic challenges in the region (26).

The prevalence of stunting, wasting, and being underweight among children aged < 5 years was 39.8, 23.2, and 40.7%, respectively, in the Raichur district (27). The prevalence of thinness among adolescents was 26.5% in the state of Karnataka (28). There is a need to bridge the data gap regarding the growth and nutritional status between children of age < 5 years and adolescents. Hence, the present study was designed to evaluate the nutritional status among school-age children in one of the aspirational districts of India.

The study included 2,700 rural school students from 30 different schools in the Raichur district of Karnataka. After data cleaning, measurements for weight and height were available for 2,602 (96.4%) and 2,688 (99.5%) students, respectively. The age of children ranged from 72 to 155 months. There was an even distribution of male (1,349; 49.9%) and female (1,351; 50.1%) school children for the study. The mean weight and height of the study sample were 22.2 kg (+5.8) and 124.9 cm (+11.6), respectively (Table 1). Figure 2 illustrates the prevalence of underweight, stunting, and thinness categorized by age and gender. The kernel density plots for WAZ, HAZ, and BAZ portrayed skewness toward the left side when compared with the WHO growth standard graph (Figure 3).

The NFHS-5 (2019–2020) findings from the Raichur district have highlighted a high prevalence of stunting (39.8%), wasting (23.2%), and underweight (40.7%) in the under-5 age group (28). The lack of nutritional data in school-age children from one of the most backward districts of Karnataka stressed the immediate need to bridge the gap. Thus, the current study aimed at generating evidence to devise holistic interventions in future. The results of the present study illustrated the perpetuation of undernutrition in school-going children.

The present study found an overall high prevalence of underweight (45.3%), with 17.8% of the children being severely underweight, with no significant difference between the genders. The findings of this study suggest that the prevalence of underweight in the study area was higher compared with the overall prevalence of Karnataka reported in the Comprehensive National Nutritional Survey (CNNS) 2019. According to CNNS data for the age group of 5–9 years, the distribution of WAZ less than−2SD was 35.2% and 39.5% in India and Karnataka, respectively, whereas this study showed that in the Raichur district, it was 45.3%. Similarly, the percentage below−3SD was 10.0% at the national level, 11.3% at the state level (27), and 17.8% at the study district. One of the studies conducted in the Mandya district of Karnataka reported the underweight to be 30.3%, which was significantly less compared with this study's results (30). A study conducted in Telangana, a neighboring state of Karnataka, had reported 30.85% underweight (31), and a study conducted in Punjab found that 58.8% of children (5–9 years) were severely underweight (10). This study showed a higher prevalence of underweight than studies conducted in Sri Lanka, Nigeria, and Nepal (7, 32, 33) and a lower prevalence than a study conducted in Ethiopia, where the prevalence was 59.7% (34). The underweight results of this study mirror the results of the study in Ghana, where the prevalence was 45.8% (35). The studies conducted by Isanaka et al. (36) in Colombia and Ieiri et al. (37) in the Philippines have established a relationship between the underweight and food insecurity, utilizing underweight as a nutritional indicator to assess recent weight loss or taking into consideration people who are unable to gain weight because of a lack of food supply or intake due to episodes of disease (38, 39). The findings of this study make way to explore the challenges associated with food insecurity in the Raichur district, where most of the children mainly depend on mid-day meals to cover most of their daily calorie requirements. The Mid-Day Meal Scheme is a government-sponsored program in India that aims to improve the nutritional status among primary and upper primary school children by providing free mid-day meals, meeting the minimum nutritional standard of 450–700 kCal and 12–20 g of protein (40).

Another notable finding of this study was the left-side skewness of the HAZ kernel density plots compared with the WHO growth standard graph, indicating the high prevalence of stunting. The distribution of stunting in the study area was more when compared with that of Karnataka (27). The study results align with the findings of the studies conducted in the south Indian districts of Mandya and Karimnagar (30, 31); however, higher compared with the study in Sri Lanka (32) and Nigeria (7) and much lower compared with the study undertaken in Ethiopia by Herrador et al. (41). According to the report of NFHS-5 data and the Raichur district nutrition profile carried out in 2020 by the International Food Policy Research Institute (IFPRI), the prevalence of stunting was approximately 40% among < 5-year-old children (28, 42), indicating that the interventions to address undernutrition have not yielded the expected results in the aspiration district. In this study, the distribution of stunting was found more in female children compared with male children; a similar trend was observed in the study conducted by Nowsin et al. (43) in Bangladesh; in contrast, the study in Srilanka by Naotunna et al. (32) found a higher distribution of stunting in male children than female children. Another study from Abakaliki metropolis of Nigeria found no difference in the stunting proportion between the genders (7). Stunting was most prevalent in the age group of 144–155 months, with a significantly high occurrence among female children compared with male children. The study conducted by Bongale Y T et al. observed that children aged 10–12 years had a 70% higher likelihood of experiencing stunting compared with children aged 6–7 years. One of the reasons could be prolonged exposure to chronic food shortages (44). The finding of higher prevalence among female children could be linked to the factors such as household dynamics, gender bias, and parental preferences, favoring male children (45). Several studies have found that mothers' educational status, poor dietary diversity, household income, and size were significantly associated with stunting (5, 46, 47). Since Raichur is one of the most socioeconomically underdeveloped districts, it is important to identify the causes of stunting, especially in female children because the effects of stunting tend to be passed down from generation to generation and have an impact on pregnancy outcomes such as small for gestational age and preterm birth (48).

The high prevalence of thinness indicates acute undernutrition, perhaps due to an acute shortage in the supply or intake of food (7). This study found a significantly higher prevalence of thinness (43%) than the overall prevalence in India (23.0%) and Karnataka (28.2%) (27). The distribution of thinness was more in male children when compared with female children. One reason could be gender disparities in physical activity levels, contributing to differences in energy expenditure between male and female children. According to a longitudinal study, male children demonstrated a daily increase in local energy expenditure from the age of 5 to 10 years. In contrast, female children experienced a significant 50% decline in physical activity between the age of 6 and 9 years (49, 50). There may be various sociocultural and psychosocial factors that influence the socialization of girls toward physical activity, necessitating further exploration. Similar findings were observed in the study conducted in Sudan, Nigeria, Sri Lanka, and Myanmar (7, 32, 51, 52). One of the interesting findings of the study was the geographical variation in the distribution of BMI for age Z-scores, particularly with the Sindhanur sub-district/taluka, where the prevalence of > +1SD and > +2SD was high compared with that of other talukas in the district as well as that of Karnataka state (27). Sindhanur as a major taluka with thriving commercial and industrial activities (53) may have better socioeconomic conditions, explaining the variation compared with other talukas. This finding implies that the interventions should be segmented and much more comprehensive to tackle both thinness and overweight in the target talukas facing the double burden of malnutrition.

Considering this study among some of the limited studies conducted in India regarding malnutrition in school-age children, the authors acknowledge some limitations in this study. The study results should be interpreted after careful contemplation of the methodology. As the study mainly focused on the children of rural areas, the study's findings are valid, particularly for rural settings. Even though adequately trained doctors from RIMS did the anthropometric measurements, some anthropometric measurement errors attributed to inter-observer and intra-observer bias cannot be denied in the study.

In conclusion, the Raichur district, which is working to catch up with the rest of the country in terms of key development indicators, has a serious problem with undernutrition among school-going children (6–12 years). Additionally, exploratory studies are advised in this age group to break the intergenerational cycle of undernutrition and plan an evidence-based intervention by identifying the factors linked to undernutrition.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by Institutional Ethics Committee of Raichur Institute of Medical Sciences (RIMS), with approval number RIMS/IEC/Approval/02/22-23. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.

PV: project implementation, management, data collection, anthropometry, BMI analysis, and the first draft of the manuscript. SN: project implementation, management, data collection, and the first draft of the manuscript. UP: project implementation, management, data collection, anthropometry, data entry, and the first draft of the manuscript. RK: project implementation, fieldwork management, and finalization of the draft. NC and MB: data review, analysis, drafting, and finalizing the manuscript. SH and SS: project implementation, fieldwork management, and finalization of the draft. SR: conceptualization, overall project management, drafting, and finalization of the manuscript. All authors contributed to the article and approved the submitted version.