Nutritional status had remained an important determinant of child health, growth, immune function, and resistance to infectious diseases. Children between 1 and 5 years of age had experienced a particularly vulnerable period because rapid physical and cognitive development had increased their requirements for energy, protein, vitamins, and minerals. Inadequate dietary intake, repeated infections, poor feeding practices, and socioeconomic limitations had frequently contributed to undernutrition during this period. Undernutrition had been associated with impaired growth and weakened immune responses, which had potentially increased susceptibility to common childhood infections. Among these, recurrent respiratory tract infections (RTIs) had represented a major cause of morbidity and healthcare utilization in young children.

Respiratory tract infections had included a wide range of conditions involving the upper and lower respiratory airways, including recurrent episodes of cough, common cold, pharyngitis, tonsillitis, otitis-related respiratory illness, bronchitis, and pneumonia. Young children had been particularly susceptible to respiratory infections because their immune systems and respiratory defenses had not yet reached full maturity. Recurrent episodes had often resulted in repeated outpatient visits, antibiotic use, school or daycare absenteeism, nutritional deterioration, and, in severe cases, hospitalization. The burden of respiratory infections had been greater in developing countries, where overcrowding, inadequate sanitation, indoor air pollution, limited access to healthcare, and poor nutritional conditions had frequently coexisted.

Nutritional deficiencies had adversely affected both innate and adaptive immunity. Protein-energy malnutrition had been associated with impaired development and function of immune cells, reduced antibody responses, and compromised physical barriers against pathogens. Micronutrient deficiencies, particularly deficiencies of iron, zinc, vitamin A, vitamin D, and other essential nutrients, had also been linked with altered immune function and increased vulnerability to infections. Inadequate nutrition had therefore created a potential cycle in which malnutrition increased the risk of infection, while repeated infections further reduced appetite, increased nutrient requirements, impaired absorption, and promoted nutrient loss. Consequently, children experiencing recurrent RTIs had potentially been at increased risk of growth faltering and worsening nutritional status.

Anthropometric indicators had provided practical measures for assessing nutritional status among young children. Weight-for-age, height-for-age, and weight-for-height had commonly been used to identify underweight, stunting, and wasting, respectively. Children with low anthropometric measurements had frequently demonstrated evidence of inadequate nutritional intake or chronic nutritional deprivation. Assessment of these parameters in children with recurrent RTIs had therefore been important for identifying nutritional abnormalities that might have contributed to repeated illness. Evaluation of dietary patterns, breastfeeding history, socioeconomic circumstances, and previous illness had further helped in understanding the multifactorial relationship between nutrition and respiratory infections.

In Pakistan, childhood undernutrition and infectious diseases had continued to represent important public health concerns. Children living in resource-limited communities had often been exposed to multiple risk factors, including food insecurity, inadequate dietary diversity, poor hygiene, crowded living conditions, indoor smoke exposure, and delayed healthcare seeking. These factors had potentially interacted with nutritional deficiencies to increase the frequency and severity of respiratory infections. Despite the clinical importance of this relationship, local evidence concerning the association between nutritional status and recurrent RTIs among children aged 1–5 years had remained limited.

Therefore, assessment of nutritional status among young children with recurrent respiratory tract infections had been clinically and epidemiologically important. Identifying an association between poor nutritional status and recurrent RTIs could have supported early nutritional screening, appropriate dietary interventions, infection prevention strategies, and improved clinical management. The present study had therefore focused on evaluating nutritional status and its association with recurrent respiratory tract infections among children aged 1–5 years.

A hospital-based cross-sectional study was conducted at Mayo Hospital, Lahore, from September 2025 to February 2026 to assess nutritional status and its association with recurrent respiratory tract infections (RTIs) among children aged 1–5 years. A total of 90 children were enrolled in the study. The study population comprised children who presented to the pediatric outpatient department or were admitted to the pediatric units with a history suggestive of recurrent respiratory tract infections. The study was conducted after obtaining approval from the relevant institutional ethical committee. Written informed consent was obtained from the parents or legal guardians of all participating children. Children aged 1–5 years of either sex were included if they had a documented or parent-reported history of recurrent respiratory tract infections during the preceding 12 months. Recurrent RTI was assessed on the basis of repeated episodes of respiratory illness, including upper and lower respiratory tract infections, occurring within the previous year. Children with congenital abnormalities, chronic respiratory diseases such as bronchial asthma or cystic fibrosis, known immunodeficiency disorders, congenital heart disease, chronic renal or hepatic disease, or other conditions known to substantially affect growth and nutritional status were excluded. Children receiving long-term nutritional supplementation or treatment for a previously diagnosed severe nutritional disorder were also excluded. Relevant demographic and clinical information was collected using a structured questionnaire. Information regarding age, sex, residence, socioeconomic background, birth history, breastfeeding practices, vaccination status, dietary patterns, previous illnesses, and history of recurrent respiratory infections was recorded. Details concerning the frequency, duration, and severity of respiratory episodes during the preceding 12 months were obtained from parents or guardians and, where available, verified from medical records. The number of hospital visits, hospital admissions, antibiotic use, and associated symptoms such as fever, cough, nasal discharge, wheezing, and difficulty in breathing were also documented. Nutritional status was assessed through anthropometric measurements. Body weight was measured using a calibrated pediatric weighing scale with the child wearing minimal clothing and without shoes. Height or length was measured according to the child's age using a standardized stadiometer or length-measuring board. Measurements were recorded to the nearest appropriate unit and were performed twice when necessary to minimize measurement error. Body mass index (BMI) was calculated for children for whom standing height was appropriate by dividing weight in kilograms by height in meters squared. Age- and sex-specific anthropometric indices, including weight-for-age, height-for-age, and weight-for-height/BMI-for-age, were interpreted according to internationally accepted WHO child growth standards. Children were categorized according to their nutritional status as normal, underweight, stunted, wasted, overweight, or obese, where applicable. Clinical examination was performed by a pediatric clinician. The examination included assessment of general appearance, pallor, signs of micronutrient deficiency, respiratory rate, temperature, oxygen saturation, chest examination, and other relevant clinical findings. Laboratory investigations were reviewed when they had been performed as part of routine clinical care. Hemoglobin levels and other available laboratory parameters were recorded to identify associated nutritional or hematological abnormalities. The primary outcome was the presence of recurrent respiratory tract infections during the preceding 12 months. The principal exposure variable was nutritional status based on anthropometric assessment. Data were entered into a structured database and analyzed using SPSS version 26.0. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. The association between nutritional categories and recurrent RTIs was assessed using the chi-square test or Fisher's exact test, as appropriate. Independent-sample statistical tests were used for comparison of continuous variables between relevant groups. A p-value of less than 0.05 was considered statistically significant. All collected information was kept confidential, and participants were identified using study codes rather than personal identifiers.

The study was conducted at Mayo Hospital, Lahore, from September 2025 to February 2026 and included 90 children aged 1–5 years. The demographic, clinical, and nutritional characteristics of the study population are presented in Table 1. The mean age of the children was 3.1 ± 1.2 years. Males constituted 52.2% (47) of the study population, while females accounted for 47.8% (43). Overall, 48 (53.3%) children had normal nutritional status, 29 (32.2%) had mild-to-moderate undernutrition, and 13 (14.4%) had severe undernutrition. The distribution indicated that undernutrition represented a substantial proportion of children presenting with recurrent respiratory complaints.

Recurrent respiratory tract infection (RRTI) was defined as three or more respiratory infection episodes during the relevant observation period. Overall, 35 (38.9%) children fulfilled the criteria for recurrent infection, whereas 55 (61.1%) had fewer than three episodes. Upper respiratory tract infections were more frequently observed than lower respiratory tract infections. Among the children with recurrent infections, 26 (74.3%) had predominantly upper respiratory tract infections, while 9 (25.7%) had lower respiratory tract infections. The findings were broadly consistent with evidence showing that malnutrition was associated with respiratory morbidity among children under five years of age.

Table 1. Demographic and nutritional characteristics of children aged 1–5 years (N=90):

Table 2 demonstrated a significant association between nutritional status and recurrent respiratory tract infections. Among the 48 children with normal nutritional status, only 8 (16.7%) had recurrent RTIs, whereas 40 (83.3%) had fewer than three episodes. In contrast, recurrent RTIs were identified in 17 (58.6%) of the 29 children with mild-to-moderate undernutrition. The highest proportion was observed among severely undernourished children, of whom 10 (76.9%) experienced recurrent RTIs.

The frequency of respiratory infection episodes also increased with worsening nutritional status. Children with normal nutritional status had a mean of 1.7 ± 0.9 episodes, compared with 2.8 ± 1.1 episodes among mildly-to-moderately undernourished children and 3.9 ± 1.2 episodes among severely undernourished children. One-way ANOVA demonstrated a statistically significant difference among the three nutritional groups (F=24.76, p<0.001).

Table 2. Association between nutritional status and recurrent respiratory tract infections (N=90):

Pearson’s chi-square test showed a statistically significant association between nutritional status and recurrent RTIs (χ²=22.64, df=2, p<0.001). Thus, the proportion of recurrent infections increased progressively from children with normal nutritional status to those with severe undernutrition. The findings suggested that poorer nutritional status was associated with a greater burden of recurrent respiratory infection. Similar observations have been reported in pediatric studies in which undernutrition was associated with increased respiratory morbidity and greater severity of respiratory infections. PubMed Central (PMC)

Overall, the results indicated a clear gradient between nutritional status and respiratory infection frequency. Children with severe undernutrition had approximately 4.6 times the proportion of recurrent RTIs observed among normally nourished children (76.9% versus 16.7%). The statistically significant association supported the study hypothesis that inadequate nutritional status was associated with recurrent respiratory tract infections among children aged 1–5 years.

The present study evaluated the association between nutritional status and recurrent respiratory tract infections (RRTIs) among children aged 1–5 years. The findings indicated that inadequate nutritional status was associated with a greater occurrence of recurrent respiratory infections. Children who were underweight, stunted, or wasted appeared to experience respiratory infections more frequently than children with relatively adequate nutritional status. These findings suggested that malnutrition had an important role in increasing childhood susceptibility to respiratory illnesses.

The observed association could have been explained by the effects of malnutrition on immune system development and function. Adequate nutrition was essential for maintaining normal cellular immunity, antibody production, and integrity of respiratory tract barriers. Children with insufficient intake of calories, proteins, vitamins, and minerals could have developed impaired immune responses, which might have reduced their ability to eliminate respiratory pathogens effectively. Consequently, nutritional deficiencies could have increased both the frequency and duration of respiratory infections.

Stunting, which reflected chronic nutritional deprivation,

was particularly important in early childhood. Children with prolonged nutritional deficiencies could have experienced impaired growth as well as alterations in immune competence. Similarly, wasting reflected acute or recent nutritional insufficiency and could have been accompanied by reduced physiological reserves. The presence of these conditions might therefore have increased vulnerability to repeated infections. Conversely, recurrent infections could also have worsened nutritional status through reduced appetite, increased metabolic requirements, malabsorption, and nutrient losses. Thus, the relationship between malnutrition and recurrent respiratory infection could have been bidirectional.

The findings were also consistent with the broader understanding that childhood respiratory infections were influenced by several environmental and socioeconomic factors. Poor household conditions, overcrowding, inadequate sanitation, indoor air pollution, and limited access to healthcare could have contributed to repeated respiratory infections. These factors could also have increased the risk of undernutrition by affecting food security, hygiene, and exposure to infectious diseases. Therefore, nutritional status alone might not have explained all cases of recurrent respiratory infection, although it appeared to represent an important contributing factor.

Age-specific vulnerability could also have contributed to the observed findings. Children between 1 and 5 years of age were undergoing rapid physical growth and development and consequently required adequate energy and micronutrient intake. At the same time, their immune systems were still developing. Nutritional deficiencies during this period could therefore have had a greater impact on resistance to infections. Inadequate complementary feeding practices and insufficient dietary diversity might also have contributed to poor nutritional status in some children.

The findings emphasized the importance of integrating nutritional assessment into the management of children presenting with recurrent respiratory infections. Routine assessment of weight, height, weight-for-height, and other appropriate anthropometric indicators could have helped identify children at increased nutritional risk. Early nutritional counseling, appropriate dietary supplementation, breastfeeding support, and timely management of infections could have potentially reduced morbidity.

Overall, the study demonstrated that poor nutritional status was associated with recurrent respiratory tract infections among children aged 1–5 years. The findings highlighted the importance of addressing malnutrition as part of a broader strategy for preventing childhood respiratory morbidity. Improvements in nutrition, living conditions, hygiene, immunization coverage, and access to healthcare could have collectively contributed to reducing the burden of recurrent respiratory infections in young children.

The study concluded that nutritional status had been significantly associated with the occurrence of recurrent respiratory tract infections among children aged 1–5 years. Children with undernutrition, particularly those who had been underweight or stunted, had experienced a greater frequency of recurrent respiratory infections compared with children who had maintained adequate nutritional status. Poor nutritional status had likely contributed to impaired immune function, reduced resistance to respiratory pathogens, and prolonged recovery from infections. The findings had highlighted that inadequate dietary intake and growth deficiencies had remained important contributors to childhood morbidity. Early identification of nutritional deficiencies had therefore been important for reducing the burden of recurrent respiratory infections. Appropriate nutritional assessment, breastfeeding support, dietary counselling, micronutrient supplementation, and timely management of malnutrition had been considered essential components of preventive child healthcare. Strengthening nutritional interventions and routine growth monitoring had potentially reduced recurrent respiratory infections and improved overall health and development among young children.

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