The overall prevalence of anemia in children aged 6 to 59 months in Tanzania, according to the 2022 TDHS-MIS data, was 70.16%, a significant increase from previous studies, which reported 53.6% [18] and 57.80% [19]. In some regions of Tanzania, the prevalence of anemia in children aged 6 to 59 months was alarmingly high, reaching up to 84.6% [20]. However, in other regions, the rates were lower, such as 37.9% in the northeast district of Rondo [21], and in Zanzibar, with rates of 76.1%, 70.2%, and 65.4% [7]. Compared to other African countries, such as Nigeria (68.1%) [14], Togo (70.9%) [8], and Mozambique (80.3%) [22], Tanzania showed converging rates, although lower than those of Ghana [16, 23], Ethiopia [15, 24], Zimbabwe [25], and Namibia [26]. Among these affected children, 40.8% had mild anemia, 56.4% moderate anemia, and 2.8% severe anemia. These numbers reflect similar trends in Ghana [16] and Togo [8], while lower rates were found in Ghana [27] and in the South and Southeast Asian regions [28]. In Mozambique, the severe anemia in this age group was about twice as high (7.0%) [22]. While the WHO considers a prevalence of anemia above 40% as a serious public health problem [1, 2], most African countries, including the context of this study, face rates well above this threshold. It is crucial to improve existing policies and implement specific interventions, such as geographic, behavioral, community, and individual strategies, to drastically reduce these rates [23].
In this study, several factors were identified as predictors of anemia in children aged 6 to 59 months, after adjustments for potential confounding variables. An important contribution of this study in relation to previous research [10, 18, 29] is the evidence that maternal anemia and communities with a high prevalence of anemic women have adverse effects on the occurrence of anemia in children in this age group. It was observed that children whose mothers had mild, moderate, and severe anemia showed, respectively, increases of (AOR = 1.48; 95% CI: 1.18; 1.87), (AOR = 1.71; 95% CI: 1.32; 2.21), and (AOR = 2.14; 95% CI: 1.08; 4.26) in the odds of developing anemia. A compelling explanation is that anemic mothers often reside in unfavorable socioeconomic environments, where they face challenges in securing adequate nutrition for both them and their children. This lack of vital nutrients, such as iron, can trigger anemia [30]. Additionally, in the first months after birth, mothers and children share the same social environment, which directly influences their dietary patterns and lifestyle [10]. Furthermore, low levels of essential minerals, such as iron, zinc, and folate, along with vitamins A and B12 in the breast milk of anemic mothers, can significantly impact the hemoglobin levels in breastfeeding children.
Additionally, children aged between 6 and 23 months (AOR = 1.72; 95% CI: 1.43; 2.07) had a higher chance of developing anemia compared to children over 23 months of age. This finding is in line with several previous studies [21, 23, 24, 26]. After six months of age, children begin to introduce complementary foods into their diet. However, up to two years of age, there may be difficulty in the intake of these foods, especially due to the lack of socioeconomic conditions to acquire them, which can result in nutrient deficiency and increase the likelihood of anemia [31]. Moreover, infections caused by contaminated food and water can result in gastrointestinal symptoms, such as diarrhea, vomiting, and mouth ulcers, impairing the ability to ingest and absorb iron and other essential nutrients, which can contribute to anemia.
Male children in this study had a higher probability of developing anemia compared to female children (AOR = 1.27; 95% CI: 1.06; 1.51). This trend is consistent with several other findings in previous studies [10, 23, 26]. This might be explained by the fact that male children tend to have a higher growth rate, which results in an increased demand for iron in the body [32]. However, this increased need for iron may not be fully met by the diet, leading to a higher prevalence of anemia in boys [33].
Consistent with previous studies [31, 34, 35], a recent history of diarrhea (AOR = 1.43; 95% CI: 1.06; 1.92) emerged as a predictor of anemia in this age group. This association can be explained by the fact that diarrhea leads to a decrease in body fluids, resulting in the loss of important nutrients, such as iron, due to poor absorption in the gastrointestinal tract.
In this study, it was observed that children born to mothers aged between 20 and 29 years (AOR = 1.48; 95% CI: 1.03; 2.12) and those belonging to families with three or more children per household (AOR = 1.31; 95% CI: 1.02; 1.67) had a higher risk of anemia. This finding is in line with previous studies [31, 36]. This may be explained by the fact that younger mothers may have less experience in care and proper feeding practices, while families with many children may face additional challenges in providing a balanced and nutritionally adequate diet for each member [31]. Younger mothers may also be in a phase of anatomical and physiological formation, which can result in a lower reserve of nutrients. These mothers face the challenge of sharing these nutrients with their children.
Treatment for parasitic infections in children in the last 6 months was shown to be a significant protective factor (AOR = 0.82; 95% CI: 0.69; 0.99). Similar associations were found in some previous studies [37, 38]. These findings highlight the importance of addressing the presence of intestinal parasites in child health. Intestinal parasites can impair iron levels by feeding on the blood from the intestinal wall, causing bleeding and reducing the absorption of essential nutrients [39]. Furthermore, they cause gastrointestinal disorders, such as diarrhea or dysentery. This can lead to anemia in children due to loss of appetite, competition for micronutrients, and interference in the absorption of vitamin A, which is essential for hemoglobin synthesis.
The limitations of this study include the cross-sectional nature of the data, which precludes establishing causal relationships between exposures and child anemia. Additionally, self-reported DHS data may introduce recall bias. Despite these limitations, the results still offer valuable insights for the planning and monitoring of child anemia at the national level, given the representativeness of the study data, which used nationally representative survey data. These results are consistent with previous studies that investigated the prevalence and risk factors of anemia in children aged 6 to 59 months.