Risk factors for lactose intolerance include the following:
Lactase production decreases with age, resulting in a greater chance of developing lactose intolerance as you grow older. Lactose intolerance usually appears in late childhood or early adulthood, and is uncommon in infants and young children.
Lactose intolerance is more common in certain ethnic and cultural groups. It’s most common in African, Asian, Hispanic and American Indian populations.
Infants born prematurely (between 28 and 32 weeks of gestation) have low levels of lactase, because the small intestines don’t develop lactase-producing cells until the third trimester.
Diseases affecting the small intestine
Diseases of the small intestine, such as celiac disease and Crohn’s disease, can cause lactose intolerance. These diseases cause inflammation and atrophy of the villi in the small intestines, thereby affecting the production of lactase.
Radiation therapy for cancer in the abdomen, or intestinal complications from chemotherapy, also affect the lining of the small intestine and may result in lactose intolerance.
Reviewed by Kim Hofmann, registered dietitian, BSc Medical (Honours) Nutrition and Dietetics, BSc (Honours) Psychology. August 2018.