Document Type : Original article
1 Department of Neonatology, Shariati Hospital, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
2 Department of Pediatrics, Islamic Azad University of Medical Sciences, Yazd, Iran
Background: Kidney stones are one of several serious health problems in childhood that cause nutritional and growth disorders, and may finally lead to chronic kidney failure in this group.
Methods: In this analytical study conducted through a case-control design, 30 children under the age of two with kidney stones, and 125 children of the same age and sex without stones were studied. Patient information including personal profile and the results of some necessary tests were extracted from patient records and listed in a checklist. The data was analyzed using SPSS (Version 17.0). Statistical significance was considered when p-value was <0.05.
Results: In terms of duration of breastfeeding, a significant difference was observed between the patients with stones and patients without stones; the duration of breastfeeding was longer in the control group (p=0.003). In addition, the duration of feeding with formula milk and cow milk was longer in the case group (p=0.038 and p=0.012, respectively).
Conclusion: Breastfeeding can serve as a nutritional factor that plays a preventive and protective role against the formation of kidney stones in infants.
Keywords: Animals, Breast feeding, Child, Infant, Kidney stone, Milk
Kidney stones are a serious health problem in children that causes nutritional, cardiovascular and growth disorders, and may finally lead to chronic renal failure in this group (1). The formation of these stones follows a process, which begins with the crystallization of dissolved materials and subsequently the growth and accumulation of crystals (2). These stones are made of different compounds with calcium oxalate being the most frequent type, followed by calcium phosphate (3). The stones are formed when the equilibrium between solutes, stimulants and inhibitors of deposition is disrupted (1). In general, the incidence rate of kidney stones in children is 2 to 3%; however, the incidence, composition, site of formation and clinical characteristics vary from region to region and from time to time. The variation may be due to differences in climate, diet, economic and social factors (4,5). In Iran, the western and northern parts of the country have the highest incidence of kidney stones (6,7).
Breastfeeding is one of the goals of the World Health Organization (WHO) that emphasizes breastfeeding in the early hours after delivery and for at least 6 months postpartum (8). This emphasis is backed by health experts who consider breastfeeding as the best choice for infant nutrition (9). In terms of quality and quantity, the human milk satisfies the growth requirement of infants, provides energy and is easily digested; no other method can replace breastfeeding. More than 400 beneficial substances, including white blood cells and immunoglobulins are found in human milk, which protect the baby from diseases, and cannot be synthesized in laboratories (10). Human milk reduces the incidence of hospitalization due to respiratory diseases and protects the infant from diarrhea caused by enterococci, otitis media, allergies, and type 2 diabetes (11). Given the benefits of breastfeeding, it is believed to be one of the protective factors against the formation of kidney stones in infants. A study in Iran reported that milk consumption acts as a protective factor while the male gender, family history of urolithiasis and increased body mass index are the risk factors for urinary stones (12). A study conducted in Kuwait also found that lithogenic metabolic factors were the most important predisposing factors for stone formation among Kuwaiti children, while diet and environmental factors played an insignificant role (13). Limited studies have been conducted in Iran in the field of urolithiasis, and the effects of different fluids and the fluid intake pattern on the development of kidney stones have not been determined appropriately. Given the increasing incidence of urolithiasis in children, there is a need for further studies in this field. Therefore, an attempt was made to investigate the relationship between the type of the milk consumed and formation of kidney stones in children under two years of age.
Materials and Methods
In this analytical study conducted through case-control design, 30 children under the age of two with kidney stones, and 125 children of the same age and sex with kidney stones were evaluated. Patient information including personal profile and the results of some necessary tests were extracted from patient records and listed in a checklist.
All children under two years of age with kidney stones were included in the study.
Patients over two years or under 2 months old, patients with hereditary renal stones such as cystinuria and hyperoxaluria and patients dissatisfied with their inclusion in the study were excluded from the research.