TABLE 1.
Demographic variables
| Demographic |
Genetic variant at position 13910 of the lactase structural gene |
|
|---|---|---|
| Lactase nonpersistent (C/C) (n=30) | Lactase persistent (C/T or T/T) (n=27) | |
| Categorical variables | ||
| Women | 63 (9) | 56 (10) |
| Race | ||
| African | 27 (8) | 7 (5) |
| Asian | 30 (8) | 0 (0) |
| Caucasian | 43 (9) | 93 (5) |
| Positive hydrogen breath test | 97 (3) | 7 (5) |
| C/T genetic status | NA | 59 (10) |
| Continuous variables | ||
| Age, years | 32.1±8.7 | 26.3±6.5 |
| Lactose intake, mL | 12.2 (31) | 15 (29.6) |
| Lactose consumption ≤10 g/day, % | 47 (9) | 44 (10) |
| Total breath hydrogen, ppm | 424.5±377.5 | 36±79 |
| Total symptom score | 10±15 | 0±5.5 |
Categorical variables are presented as % (SE). Continuous variables are presented as mean ± SD if normally distributed and as median (interquartile range) if there is a skewed distribution. Total breath hydrogen was calculated by subtracting the baseline breath hydrogen from each of the breath hydrogen scores at 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 240 min and 270 min, and then adding them together. Total symptom score was calculated by summing the symptom score for each time point at 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 240 min and 270 min. For symptoms of bloating, gas and cramps, the following scores were used: 0 = absent, 1 = mild, 2 = moderate, 3 = severe. For diarrhea, a score of 0 = none and 1 = present. The theoretical maximum total symptom score is 90. C Cytosine; NA Not available; ppm Parts per million; T Thymine