Lactose intolerance: a risk factor for reduced bone mineral density and vertebral fractures?

BACKGROUND: The purpose of the present study was to determine differences, if any, in bone mineral density, the risk of fracture, and clinical behavior in patients with lactose intolerance investigated by hydrogen breath test.

METHODS: The study population (n = 218; age, mean +/- SD, 58.2 +/- 11.5 years) consisted of 103 healthy individuals negative hydrogen breath test (Delta H2 0-20 ppm; group I), and 115 individuals with evidence of lactose intolerance according to the hydrogen breath test (Delta H2 > 20 ppm), of whom 40 individuals had test results of 20 ppm < Delta H2 < 59 ppm (group II). The remaining 75 individuals were strongly positive on the hydrogen breath test (Delta H2 > 60 ppm; group III). The entire study population was measured for bone mineral density in the nondominant forearm and in the vertebra (quantitative computed tomography [qCT]). Radiographs of the spine were studied for fractures.

RESULTS: In healthy individuals, bone mineral density in the vertebra assessed by qCT (mean +/- SD, 111.2 +/- 31 mg/cc) did not significantly differ between those with mild (qCT, mean +/- SD, 109.8 +/- 35 mg/cc) and those with severe (qCT, mean +/- SD, 107.7 +/- 36 mg/cc) lactose intolerance. Lactose-intolerant individuals had more vertebral fractures per patient when compared with those with mild lactose intolerance or controls ( P < 0.05). Considering vertebral and self-reported non-vertebral fractures, no statistically significant differences were found. In the entire group, the overall occurrences of fracture in the presence of lactose intolerance and in controls were comparable after correction for age and body mass index (BMI).

CONCLUSIONS: Individuals with lactose intolerance verified by the hydrogen breath test appear not to be at risk for accelerated bone loss. Nevertheless, a relationship between vertebral fractures and an apparent lactose intolerance cannot be excluded, as a few individuals with severe lactose intolerance had a large number of vertebral fractures.