Prevalence and influencing factors of anemia in children of 6 months to 18 years in Hainan Province

Abstract

Objective To investigate the prevalence and influencing factors of anemia among children aged 6 months to 18 years in Hainan Province, so as to provide evidence for region-specific prevention and control strategies. Methods A cross-sectional study was conducted from December 2020 to July 2021 using a multistage stratified cluster sampling method. A total of 58 649 children aged 6 months to 18 years were recruited from 18 municipalities/counties in Hainan Province (excluding Sansha City). Participants were stratified into two age groups: 6 months -<3 years old and 3 - 18 years old. Demographic characteristics and lifestyle behaviors were collected using standardized questionnaires. Hemoglobin concentration was measured by electrical impedance combined with photoelectric colorimetry, and anemia was diagnosed according to the WHO Guideline on Haemoglobin Cutoffs to Define Anaemia (2024). Rao-Scott χ² tests were used for group comparisons, and weighted binary logistic regression models were applied to identify influencing factors. Results The weighted prevalence of anemia among children aged 6 months to 18 years in Hainan Province was 6.92%, including 4.60% mild anemia, 2.26% moderate anemia, and 0.06% severe anemia. The prevalence was highest during infancy (10.81%), decreased during primary school age (4.88%), and increased again during adolescence. Adolescent girls had a significantly higher prevalence than boys (13.98% vs. 3.22%, P<0.001). Significant regional differences in anemia prevalence were observed across municipalities/counties (P<0.001), with Baoting Li and Miao Autonomous County showing the highest prevalence (17.62%). Multivariable logistic regression analysis indicated that ethnic minority status, non-only-child status, and insufficient meat intake were common risk factors in both age groups (P<0.05). In the 6 months -<3 years group, infancy, lower maternal educational level, and insufficient egg intake were additionally associated with increased anemia risk (P<0.05). In the 3 - 18 years group, adolescence (12 - 18 years old), female, rural residence, history of neonatal diseases, multiple births, non-nuclear family structure, non-parental caregiving, lower paternal educational level, annual household income <30 000 RMB, picky eating, and frequent iron supplementation were associated with higher anemia risk (P<0.05). Conclusions Although the overall prevalence of anemia among children aged 6 months to 18 years in Hainan Province is relatively low, infants, adolescent girls, ethnic minority children, and rural populations remain key target groups for intervention. Strengthening nutrition education, emphasizing early-life nutritional intervention and adolescent dietary guidance, and promoting parent-involved comprehensive intervention strategies may help reduce the burden of childhood anemia.

Keywords

anemia / prevalence / children / Hainan Province