Impact of Factors Related to Loose and Pouched Moist Smokeless Tobacco Product Use Behavior on Biomarkers of Exposure to Nicotine and <i>N</i>-Nitrosonornicotine

Summary Background Use behavior of loose or pouched moist smokeless tobacco (MST) products and its impact on biomarkers of exposure (BOE), specifically nicotine (nicotine equivalents; NE) and N -nitrosonornicotine (NNN), have not been well characterized. Methods We assessed ad libitum use behavior (pinch mass/number of pouches, number of use occasions, and time in mouth) of own-brand loose/pouched MST products among adults who used MST (N = 229) during 24-h clinical confinement. We also examined the relationship between use behavior and BOEs. Results Loose MST use behavior (mean ± SD) was 4.3 ± 2.19 g/pinch, 6.5 ± 2.24 occasions/day, 28.1 ± 18.22 g/day, with 74.0 ± 33.88 min/use; pouch use was 2.2 ± 0.99 pouches/use, 69.1 ± 32.49 min/use, 6.0 ± 2.64 occasions/day, and 13.3 ± 7.38 pouches/day. Average NE was significantly lower, and NNN, while lower, was not significantly different in pouch users (NE = 20.4 mg/24 h; NNN = 61.0 ng/24 h) compared to loose MST users (NE = 26.3 mg/24 h; NNN = 78.0 ng/24 h). For loose MST, number of use occasions, average duration in mouth, and average pinch mass were the most significant factors impacting NE exposure (r 2 = 0.4954); these factors and age were significant for NNN exposure (r 2 = 0.3328). Conclusions The amount and duration of loose and pouched MST use behavior parameters were higher than those in previously published reports. In addition, ~ 33–50% of the variability in daily exposure to nicotine and NNN can be explained by use behavior measured under the study conditions.