Exposure to a Motor Vehicle Collision and the Risk of Future Neck Pain: A Systematic Review and Meta-Analysis.

The studies were observational, so they show association rather than proof that a collision caused neck pain. The pooled analysis had substantial heterogeneity, with I2 = 75.5%, so the 2.3-times estimate did not apply equally across studies. Exposure definitions varied widely, including self-reported injury, emergency room diagnosis, police records, and insurance records. Neck pain was measured differently across studies, with some using a single yes or no question and others using questionnaires. Follow-up time varied from unknown to 1, 5, 7, and 17 years, and meta-regression did not explain heterogeneity by follow-up time. Some studies had moderate or high risk of bias in participation, attrition, neck pain measurement, confounding, or reporting. Control groups were not always unexposed; one general population control group included people with prior motor vehicle collision exposure. The 57% attributable risk was calculated from the pooled relative risk, not measured directly in a single patient. The search was limited to English-language studies published from 1998 onward.

Do not conclude that any motor vehicle collision causes future neck pain. The increased risk was found only in studies where participants had a neck injury in a collision. Studies of collisions without reported neck injury or with unknown injury status found no increased risk.