Molecularly defined adult-type hypolactasia among working age people with reference to milk consumption and gastrointestinal symptoms

AIM： To study milk consumption and subjective milk-related symptoms in adults genotyped for adult-type hypolactasia. METHODS： A total of 1900 Finnish adults were genotyped for the C/T-13910 variant of adult-type hypolactasia and filled in a structured questionnaire concerning milk consumption and gastrointestinal problems. RESULTS： The C/C-13910 genotype of adult-type hypolactasia was present in 18% of the study population. The prevalence of the C/C-13910 genotype was higher among subjects who were undergoing investigations because of abdominal symptoms （24%, P 〈 0.05）. Those with the C/C13910 genotype drank less milk than subjects with either the C/T-13910 or the T/T-13910 genotype of lactase persistence （18% vs 38%; 18% vs 36%, P 〈 0.01）. Subjects with the C/C-13910 genotype had experienced more gastrointestinal symptoms （84%） during the preceding three-month period than those with the C/T-13910 （79%, P 〈 0.05） or the T/T-13910 genotype （78 %, P 〈 0.05）. Only 9% （29/338） of the subjects with the C/C-13910 genotype consumed milk and reported no symptoms from it. CONCLUSION： Gastrointestinal symptoms are more common among adults with the C/C-13910 genotype of adult-type hypolactasia than in those with genotypes of lactase persistence.