The findings identify groups with higher observed odds of iron deficiency anaemia, but the study design cannot establish that these factors caused the condition. Preterm infants are particularly vulnerable to iron deficiency because they generally have limited iron stores at birth, may lose blood through clinical procedures and undergo rapid growth when iron requirements are high. The study notes that iron deficiency anaemia can adversely affect neurodevelopment, immunity, growth and general health, with some consequences potentially becoming irreversible.

This makes early assessment of iron status relevant for infants born before 37 completed weeks of gestation, although the new findings concern a defined group of clinic attendees rather than all preterm births in Tanzania. Participants were recruited sequentially using convenience sampling until the required sample size of 190 was reached. The investigators initially assessed 202 preterm infants for eligibility.

Twelve were excluded because they had fever or had received a blood transfusion within the previous three months. The protocol also excluded infants with specified congenital anomalies, including cleft lip and palate, hydrocephalus and congenital heart disease with oxygen saturation below 90% and cyanosis, as well as infants who were acutely unwell, had tachycardia, tachypnoea or fever. Of the final sample, 139 infants came from Dodoma Regional Referral Hospital and 51 from Makole Health Centre.

Their mean age was 4.01 months, with a standard deviation of 0.99 months, and 109 of 190 were female. Information on the infants’ demographic characteristics, birth history, feeding practices, phlebotomy history, iron supplementation, clinical condition and maternal factors was gathered with a structured, pre-tested questionnaire, Reproductive and Child Health records, physical examinations and blood tests. The questionnaire was adapted from WHO STEPS instruments and relevant literature.

Its content validity was assessed by 10 experts, producing a scale-level content validity index of 0.90. Pretesting with 10% of the required sample produced a Cronbach’s alpha of 0.91, which the investigators described as excellent internal consistency. Data were entered in Microsoft Excel 2019 and analysed in IBM SPSS Statistics version 26 using descriptive statistics, chi-square tests and univariable and multivariable binary logistic regression.

Iron deficiency anaemia was identified through laboratory measures alone. Participants needed to meet at least three of five predefined criteria: haemoglobin below 10 g/dL, mean corpuscular volume below 80 fL, mean corpuscular haemoglobin concentration below 32 g/dL, serum ferritin below 12 micrograms per litre and C-reactive protein below 5 mg/L. Serum ferritin was used as the indicator of iron stores, while C-reactive protein was measured to account for the effect of inflammation on ferritin concentrations because ferritin is an acute-phase reactant. This operational definition is important when interpreting the prevalence because estimates can vary according to the criteria used to classify iron deficiency and anaemia, as well as the population, age at assessment, birth characteristics and supplementation practices.

The sample covered a range of preterm and low-birth-weight infants. Sixty-seven infants, or 35.26% of the sample, weighed less than 1.5 kg at birth, while 123 weighed between 1.5 kg and no more than 2.5 kg. Seventy-six infants were born before 32 weeks, 40 at 32–33 weeks and 74 at 34–36 weeks.

A total of 146 infants, or 76.84%, were exclusively breastfed, while 44 received mixed feeding with formula milk. Most infants received iron supplementation: 175 of 190, or 92.11%. Multiple gestation was reported for 33 mothers, and 22 infants had mothers whose haemoglobin before delivery was below 7 g/dL, which the study classified as severe anaemia.

In unadjusted comparisons, iron deficiency anaemia occurred in 19.4% of infants with a birth weight below 1.5 kg, compared with 7.3% among those weighing at least 1.5 kg. It was present in 60.0% of the 15 infants who had not received iron supplementation, compared with 7.4% of the 175 supplemented infants. Prevalence was 30.3% among infants born after multiple gestation and 7.6% among those born after singleton delivery.

Among infants whose mothers had haemoglobin below 7 g/dL before delivery, 50.0% had iron deficiency anaemia, compared with 6.6% when maternal haemoglobin was at least 7 g/dL. The bivariate analysis also found associations with gestational age and the duration of maternal iron supplementation. Infant age, phlebotomy history, feeding practices and maternal illness during pregnancy did not reach statistical significance in that analysis.

Multivariable analysis produced the strongest adjusted association for maternal severe anaemia. Infants whose mothers had haemoglobin below 7 g/dL before delivery had 12.00 times the adjusted odds of iron deficiency anaemia compared with infants whose mothers had haemoglobin of at least 7 g/dL, although the estimate was imprecise, with a 95% confidence interval of 2.70–53.34. Very low birth weight was associated with 6.91 times the adjusted odds of the condition, with a 95% confidence interval of 1.47–32.36.

Multiple gestation carried an adjusted odds ratio of 6.85, with a 95% confidence interval of 1.69–27.71, while absence of infant iron supplementation was associated with an adjusted odds ratio of 6.28, with a 95% confidence interval of 1.05–37.76. All four associations met the study’s statistical threshold of p below 0.05, but the wide confidence intervals indicate substantial uncertainty around the estimates. The 11.58% prevalence was similar to figures reported in other settings, including 9.9% in Sweden and 14.5% in Kenya, although the authors cautioned that comparisons are affected by differences in gestational age, birth weight, age at assessment, supplementation practices and eligibility criteria.

The Dodoma estimate was lower than reports from Turkey, at 42.8%, and Brazil, at 26.5%, and higher than a figure of 6% from Indonesia. The Indonesian study included infants born at 32–36 weeks, whereas the Dodoma study also included infants born before 32 weeks. The relatively high proportion of supplemented infants in the Dodoma sample may partly explain its lower prevalence compared with some studies, but the cross-sectional design does not allow the effect of supplementation to be isolated.

The comparison figures also come from different populations and definitions, so they do not establish a geographic trend. Several limitations constrain how far the findings can be generalised. Convenience sampling may have introduced selection bias because infants attending the two clinics may differ from other preterm infants, including those who did not attend these facilities.

Restricting recruitment to two health facilities in Dodoma also limits the applicability of the results to other regions and healthcare settings in Tanzania. In addition, some exposure categories contained relatively few participants, contributing to wide confidence intervals and reduced precision. The cross-sectional design prevents establishment of temporal or causal relationships between the identified factors and iron deficiency anaemia.

Within those boundaries, the measurements show that the condition occurred in a notable minority of these clinic attendees and that several maternal and infant characteristics were markers of higher observed odds. The authors identified strengthening iron supplementation, early recognition of high-risk infants and attention to maternal anaemia as priorities that may help reduce the burden, while noting that the study itself did not test an intervention or establish clinical effectiveness.

Subject of Research: Prevalence and associated factors of iron deficiency anaemia among preterm infants in Dodoma, Tanzania

Article Title: Prevalence of iron deficiency anaemia and associated factors among preterm infants aged 3–6 months attending clinics in Dodoma, Tanzania: a facility-based cross-sectional study

Article References: Mchwampaka, C., Mahamba, D., Jumanne, S., Msuya, M. A., & Matovelo, S. (2026). Prevalence of iron deficiency anaemia and associated factors among preterm infants aged 3–6 months attending clinics in Dodoma, Tanzania: a facility-based cross-sectional study. Frontiers in Pediatrics, 14, Article 1913886. https://doi.org/10.3389/fped.2026.1913886

Image Credits: AI Generated

DOI: 10.3389/fped.2026.1913886

Keywords: iron deficiency anaemia, preterm infants, Tanzania, Dodoma, birth weight, iron supplementation, maternal anaemia, multiple gestation, cross-sectional study, prevalence, iron, deficiency