Table 3. Effect of Diet on NDMA and DMA 24-Hour Urinary Excretion and Plasma Measurements (Exploratory Outcomes).
| Study drug | Cured-meats diet, median (IQR) | Noncured-meats diet, median (IQR) | Paired differences, median (IQR)a | P valueb | |
|---|---|---|---|---|---|
| No. | 17 | ||||
| NDMA 24-h urinary excretion, ng | Ranitidine | 11.9 (5.6-48.6) | 0.6 (0-29.7) | 9.3 (3.8 to 25.0) | .005 |
| Placebo | 23.4 (8.6-36.7) | 10.5 (0-17.8) | 6.4 (0 to 23.4) | .007 | |
| Maximum NDMA plasma concentration, pg/mL | Ranitidine | 29.0 (0-34.5) | 18.9 (0-25.7) | 0.4 (−5.1 to 32.6) | .15 |
| Placebo | 16.2 (0-27.4) | 20.3 (0-33.5) | 0 (−18.8 to 8.1) | .74 | |
| Cured-meats diet, geometric mean (CV %) | Noncured-meats diet, geometric mean (CV %) | Geometric mean ratio (95% CI) | |||
| DMA 24-h urinary excretion, mg | Ranitidine | 40.7 (52) | 38.8 (38) | 1.05 (0.90 to 1.23) | .52 |
| Placebo | 43.1 (34) | 41.1 (33) | 1.05 (0.93 to 1.19) | .42 | |
| Maximum DMA plasma concentration, μg/mL | Ranitidine | 1.36 (27) | 1.51 (25) | 0.90 (0.84 to 0.97) | .009 |
| Placebo | 1.41 (26) | 1.48 (27) | 0.95 (0.86 to 1.06) | .33 | |
| 24-h plasma DMA area under the curve, h∙μg/mL | Ranitidine | 20.9 (53) | 26.3 (34) | 0.80 (0.67 to 0.95) | .02 |
| Placebo | 20.9 (46) | 26.2 (35) | 0.80 (0.65 to 0.98) | .03 |
Abbreviations: CV, coefficient of variation; DMA, dimethylamine; IQR, interquartile range; NDMA, N-nitrosodimethylamine.
a
Calculated by first determining the difference between the 2 treatments for each individual participant and then determining the median of those values. The Wilcoxon signed-rank test used for NDMA analyses is also based on first determining the difference between the treatment groups for each individual participant.
b
Exploratory analyses on the effect of diet used a 1-sided lower P value <.05 for NDMA, as the cured-meats diet was designed to have higher NDMA but used P < .05 (2-sided) for DMA, as the effect of diet on these outcomes was not known.