Genetically defined adult-type hypolactasia and self-reported lactose intolerance as risk factors of osteoporosis in Finnish postmenopausal women

Eur J Clin Nutr. 2005 Oct;59(10):1105-11. doi: 10.1038/sj.ejcn.1602219.


Objective: To study the relationships of molecularly defined lactose malabsorption (LM) and self-reported lactose intolerance (LI) to bone mineral density (BMD) and fractures among Finnish postmenopausal women.

Design: A cross-sectional study of two cohorts.

Setting: Helsinki University Central Hospital.

Subjects: One cohort was population-based and comprised 453 women, aged 62-78 (mean 69) y. Another comprised 52 women, aged 69-85 (mean 75) y, with osteoporotic fractures and 59 control women, aged 69-83 (mean 74) y, without osteoporosis.

Methods: A single nucleotide polymorphism of the lactase (LCT) gene at chromosome 2q21-22 was studied. It shows complete association with intestinal disaccharidase activity, with the genotype CC(-13 910) meaning adult-type hypolactasia (primary LM) and the genotypes CT(-13 910) and TT(-13 910) lactose absorption. BMD of the heel was measured by dual-energy X-ray absorptiometry (DXA).

Results: In the population-based cohort, 16.0% of women had self-reported LI but only 15.3% of them had the CC(-13 910) genotype. Calcium intake from dairy products (P = 0.10) and BMD, adjusted for age, weight, height, exercise, smoking, and estrogen use (P = 0.71) were similar for the genotypes. Women with self-reported LI had reduced calcium intake from dairy products (P < 0.0001) but they were more frequent users of calcium supplements than lactose-tolerants (P < 0.0001). Adjusted BMD was similar for lactose intolerant and tolerant women (P = 0.60). Of 104 women with previous fracture in the population-based cohort, 13.5% had the CC(-13 910) genotype, which did not differ from the prevalence of 19.3% among 347 women without fractures (P = 0.29). The frequency of the CC(-13 910) genotype (23.1%) for 52 women with established osteoporosis was similar as for 59 control women (15.3%) (P = 0.19).

Conclusion: Molecularly defined LM and self-reported LI are not risk factors for osteoporosis, if calcium intake from diet and/or supplements remains sufficient. Our study confirms the poor correlation between self-reported LI and LM established by different techniques.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Calcium, Dietary / administration & dosage
  • Calcium, Dietary / metabolism
  • Case-Control Studies
  • Cohort Studies
  • Cross-Sectional Studies
  • Dairy Products
  • Female
  • Finland / epidemiology
  • Fractures, Bone / epidemiology
  • Fractures, Bone / etiology
  • Genetic Predisposition to Disease
  • Genotype
  • Humans
  • Lactase* / deficiency
  • Lactase* / genetics
  • Lactose / metabolism*
  • Lactose Intolerance / complications
  • Lactose Intolerance / epidemiology
  • Lactose Intolerance / genetics*
  • Middle Aged
  • Osteoporosis, Postmenopausal / epidemiology*
  • Osteoporosis, Postmenopausal / etiology
  • Polymorphism, Single Nucleotide*
  • Risk Factors


  • Calcium, Dietary
  • Lactase
  • Lactose