RT Journal Article SR Electronic T1 Impacts of helmet law on the changes in potential years of life lost due to traffic injury: a multiple-province evaluation in Vietnam JF Injury Prevention JO Inj Prev FD BMJ Publishing Group Ltd SP 109 OP 115 DO 10.1136/injuryprev-2018-043088 VO 26 IS 2 A1 Dung Phung A1 Ha Trong Nguyen A1 Cordia Chu A1 Ross Sadler A1 Anh Mai Luong A1 Huyen Thi Nguyen A1 Tuan Cong Pham A1 Cunrui Huang YR 2020 UL http://injuryprevention.bmj.com/content/26/2/109.abstract AB Introduction This study aimed to evaluate the impact of the helmet law on the changes in potential years of life lost (PYLL) due to traffic mortality and to examine modification effects of socioeconomic factors on the impacts in Vietnam.Methods We applied an interrupted time series design using the Bayesian framework to estimate the impact of the law at the provincial level. Then, we used random effects meta-analysis to estimate the impact of the law at the country level and to examine the modification effects of socioeconomic factors.Results The results indicate that the impacts varied among the provinces. These impacts could be classified by four main groups comprising positive impact, and positive impact without sustainability, possible positive impact, negative or inconsistent impact. For the country-level impact, the results reveal a significantly consistent change in monthly PYLLs at the level of 18 per 100 000 persons, and the post-trend was stable without significant change. The results of meta-regression show that 1 unit increase in the population density (persons/km2), migration rate (%) and income (×1000 dong) are non-significantly associated with increases of PYLLs at 1.3, 27 and 27 per 100 000 person-months, respectively, whereas 1% increase in literacy associated with a decrease of PYLL at 44 per 100 000 person-months.Discussion Further studies should be warranted to provide a comprehensive evaluation of the law implementation, including its acceptability, adoption, appropriateness, feasibility, cost-effectiveness and sustainability.