Purpose
To test the hypothesis that an important step in a causative mechanism for carpal tunnel syndrome (CTS) is sleeping in a lateral position (sleeping on the side), we designed a cross-sectional survey to measure the association between sleep position, age, gender, and body mass index (BMI).
Methods and Findings
We surveyed 247 patients in a primary care setting. Fifty percent of men and 73% of women prefer to sleep on their side (p < .001; unadjusted odds ratio, 2.7). In addition, the proportion of women who prefer to sleep on their side increased with increasing age (p < .001). There was no association between BMI and sleeping in a lateral position.
Conclusions
This study supports the hypothesis that sleeping on the side is an important step in a causal pathway for CTS.