Lactose Intolerance: Lack of Evidence for Short Stature or Vitamin D Deficiency in Prepubertal Children

Background: The health consequences of lactose intolerance (LI) are unclear. Aims: To investigate the effects of LI on stature and vitamin D status. Hypotheses: LI subjects will have similar heights and vitamin D status as controls. Subjects and Methods: Prepubertal children of ages 3-12 years with LI (n=38, age 8.61 +/- 3.08y, male/female 19/19) were compared to healthy, age-and gender-matched controls (n=49, age 7.95 +/- 2.64, male/female 28/21). Inclusion criteria: prepubertal status (boys: testicular volume <3cc; girls: Tanner 1 breasts), diagnosis of LI by hydrogen breath test, and no history of calcium or vitamin D supplementation. Vitamin D deficiency was defined as 25-hydroxyvitamin D [25(OH) D] <50 nmol/L. Gender-adjusted midparental target height (MPTH) z-score was calculated using NCHS data for 18 year-old adults. Data were expressed as mean +/- SD. Results: There was no significant difference in 25(OH) D between the LI and non-LI subjects (60.1 +/- 21.1, vs. 65.4 +/- 26.1 nmol/L, p = 0.29). Upon stratification into normal weight (BMI <85th percentile) vs. overweight/obese (BMI >= 85th percentile), the normal weight controls had significantly higher 25(OH) D level than both the normal weight LI children (78.3 +/- 32.6 vs. 62.9 +/- 23.2, p = 0.025), and the overweight/obese LI children (78.3 +/- 32.6 vs. 55.3 +/- 16.5, p = 0.004). Secondly, there was no overall difference in height z-score between the LI children and controls. The normal weight LI patients had similar height as normal controls (-0.46 +/- 0.89 vs. -0.71 +/- 1.67, p = 0.53), while the overweight/obese LI group was taller than the normal weight controls (0.36 +/- 1.41 vs. -0.71 +/- 1.67, p = 0.049), and of similar height as the overweight/obese controls (0.36 +/- 1.41 vs. 0.87 +/- 1.45, p = 0.28). MPTH z-score was similar between the groups. Conclusion: Short stature and vitamin D deficiency are not features of LI in prepubertal children.