Nutritional improvement status of primary and secondary school students in the pilot nutrition improvement areas of Hainan, China from 2014 to 2021
Authors: Liu Diyue , Zhang Fan , Zhang Yanming , Wu Yuting , Lu Jingjing , Dong Chunbo , Xiao Yingchen , Xiao Xiaoyu , Zhang Jiaqing , Feng Qiqin 
Published: July 2024

Abstract
Objective
By meticulously tracking the evolving growth, development, and nutritional status of primary and secondary school students in Qiongzhong County from 2014 to 2021 post-implementation of the “Nutrition Improvement Program for Rural Compulsory Education Students”(NIPRCES, This project provides a supplementary food allowance of at least ￥4 per person per day for primary and secondary school students. The project area undergoes annual routine monitoring.), this study aims to offer a scientific basis for enhancing and promoting the project. Through thorough monitoring of students’ nutritional status changes influenced by this program, we strive to establish a comprehensive and evidence-based framework for its future advancement.

Methods
From 2014 to 2021, this study employed a multi-stage sampling method utilizing cluster sampling to select six primary and six secondary schools in Qiongzhong County, Hainan Province. Data on the growth and development of respondents were collected. This cohort was a dynamic cohort with a total of 18,762 final data recovered. The prevalence of malnutrition was evaluated using the Cochran Armitage Trend Test (CATT) to assess year-to-year changes. Furthermore, height/weight and the prevalence of malnutrition between groups were compared using the t-test, χ2 test, and Bonferroni’s corrected analysis.

Results
The average height of both boys and girls has increased. In 2021, boys and girls of all ages showed an average height increase of 2.31 cm and 1.98 cm, respectively, compared to 2014. Nevertheless, the growth and development levels, and rate of improvement of these students remain comparatively lower than their rural counterparts across China, who are of the same age. From 2014 to 2021, the prevalence of undernutrition (mainly wasting) showed a significant downward trend (P < 0.05) from 29.30% to 22.19%, and the prevalence of overnutrition showed an upward trend (both P < 0.05). The prevalence of undernutrition was higher among boys, students in grades 1–3 and those of Li nationality. Meanwhile, the prevalence of overnutrition was higher among boys, students in grades 1–3 and those of Han nationality.

Conclusions
Over the 8-year period of NIPRCES, there has been progress in the growth and development of students, yet levels still lag behind the national average for rural students of the same age. While malnutrition prevalence have decreased, they remain high, with a concerning rise in overnutrition prevalence. Undernutrition and overweight/obesity are more prevalent among boys and younger students. Li students show higher prevalence of undernutrition, while overnutrition is a growing issue among Han students. Simultaneously, local education and health care departments must acknowledge the disparities in growth and nutritional status among primary and secondary school students residing in rural areas within the tropics and those in rural areas across the entire nation. Nutritional improvement measures should be tailored to local conditions.