Prevalence of Lactose Intolerance in Primary School Children in Qena Governorate, Egypt

Most people are born with the ability to digest lactose. Approximately 75% of the general population loses this ability, to some extent, going into adulthood (adult hypolactasia), while others retain such ability. The aim of the present study was to determine the prevalence of lactose intolerance, and its correlation with gastrointestinal symptoms, in primary school children aged 6-12 years in Qena Governorate, Egypt. A cross-sectional study was carried out on 300 school children with clinical suspicion of lactose intolerance. Biological and clinical data were obtained from children’s parents or guardians. The history of diarrheal attacks especially following ingestion of milk or dairy products, as well as the incidence of diabetes in the children or family history of such diseases was also obtained. The children were instructed to maintain a low fiber diet without lactose for 48 hours prior to the day of examination. After 12 hours of fasting lactose tolerance test was carried out. The data obtained revealed that 74% of the participants in the study were intolerant to lactose. However, only 56.8% of lactose-intolerant children had positive clinical history of abdominal pain, abdominal distension or diarrheal attacks following ingestion of milk or dairy products. The prevalence of lactose intolerance in the studied cohort increased with age. Such genetically determined intolerance was 58% at 6-7 years of age and increased to 90% by the age of 11-12.