BACKGROUND CONTEXT: Previous research has failed to identify strong consistent risk factors for low back pain (LBP). A plausible solution is to conduct hypothesis-generating studies such as twin case-control surveys. PURPOSE: To investigate twins' perceptions of the factors responsible for within-pair differences in LBP. STUDY DESIGN/SETTING: Case-control twin survey. PATIENT SAMPLE: Twenty four twin pairs that were generally and broadly discordant for LBP history. OUTCOME MEASURES: Participants' perceptions of factors that could explain within-pair differences in LBP history. METHODS: Twins were asked to identify factors responsible for within-pair differences in LBP. Closed-questioning collected information on known risk factors and open-ended questioning was used to reveal novel factors. Frequency of risk factors was presented to investigate the individual's perception of the contribution of factors in the development of their own and/or their twin's experience of LBP. The study did not have funding sources or potential conflict of interest. RESULTS: The most frequent factors reported in the closed questioning related to physical workload of the lumbar spine, specifically, the engagement in different types of work (n = 23/24 pairs, 96%). Types of work included those involving heavy loads, lifting, manual tasks, awkward postures and gardening. Single trauma or injury and vigorous physical activity participation were perceived as contributors by 79% (n=19/24 pairs) and 88% (n=21/24 pairs) of the pairs, respectively. Open-ended questioning did not reveal new risk factors for LBP. CONCLUSIONS: Twins attributed differences in LBP history to risk factors related to physical workload. Future studies investigating risk factors for LBP should include valid and comprehensive assessments of these factors.
a1878-1632 (Electronic)