Evidence of gender differences in esophageal pain threshold.

OBJECTIVE: To compare esophageal sensation thresholds between healthy males and females.
METHODS: We used esophageal balloon distention to compare sensory thresholds between nine male and 10 female volunteers with a latex balloon (length 3 cm) positioned 5 cm proximal to the lower esophageal sphincter. Subjects indicated feeling: 0 (no sensation), 1 (aware of balloon but no discomfort), 2 (pain or discomfort) during rapid (170 cc/s) or slow (0.7 cc/s) balloon inflation rates as the balloon was inflated with increasing volumes of 2 cc. Females were studied on two separate occasions, days 5-7 and days 20-22 of their menstrual cycles, with day 1 being the first day of menses.
RESULTS: Females had a significantly lower pain threshold and a trend toward lower awareness level. No significant differences in sensory perception were found between the two phases of the female cycle. Poor correlation (r = 0.35 in rapid, r = 0.4 in slow inflation) was found between subject height and balloon volume at perception of pain.
CONCLUSION: Healthy females demonstrate a lower threshold to esophageal pain induced by balloon distention than healthy males. This difference is not explained by hormonal changes during normal menstrual cycle or by body size. This observation may explain in part the observed preponderance of females with unexplained chest pain of possible esophageal origin.