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/C(-13910) 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.