Helmet use among motorcycle riders in Ho Chi Minh City, Vietnam: results of a five-year repeated cross-sectional study.

OBJECTIVE

In Vietnam, motorcycle riders comprise about three-quarters of road traffic fatalities, the most common cause of which is head injuries that can be prevented by wearing a helmet. This study aims to assess helmet-wearing behaviors in Ho Chi Minh City, the largest city in Vietnam.

METHODS

Eight rounds of observational studies were conducted in six randomly selected locations between July 2015 and April 2019. Given the multinomial nature of the outcome measure (not wearing a helmet; wearing a substandard helmet; wearing an unstrapped standard helmet; wearing a strapped standard helmet), a multinomial model was developed to estimate the level and trend of helmet use and identify the related individual and environmental factors.

FINDINGS: A total of 479,892 motorcycle riders were observed, over 90 % of whom were wearing helmets (range over the eight rounds: 92.5 %-96.0 %). However, the prevalence of correct helmet use (defined as wearing a strapped standard helmet) gradually declined from 80.8 % in round 1-55.6 % in round 8. Results from a multinomial model showed the probability of wearing a strapped standard helmet had declined by 22.4 percentage points from round 3 to round 8 while holding other factors constant (95 % CI: 21.8-23.0). The prevalence of correct use is 11.3 percentage points higher for adults than for children (95 % CI: 10.5-12.1). During the same period, unstrapped standard helmet use increased by 24.5 percentage points (95 % CI: 24.1-24.9); substandard helmet use declined but remained high.

CONCLUSION

The upward trend of incorrect helmet wearing behaviors and wearing substandard helmets sends a rallying call for multisectoral interventions.