Came across a research study about helmets on snow done in Canada and reported in a medical journal. Sounds like back then some people were thinking a helmet would cause injuries to the neck and spine. Just as some people believe that not wearing a seatbelt and being ejected during a car crash is "safer" although any statistical analysis easily disproves that urban myth.
March 2010, The Canadian Medical Association Journal (CMAJ is a peer-reviewed general medical journal)
The effect of helmets on the risk of head and neck injuries among skiers and snowboarders: a meta-analysis
[numbers in the last two paragraphs are links to references in the original article online]
Abstract
Background: The prevention of head injuries in alpine activities has focused on helmets. However, no systematic review has examined the effect of helmets on head and neck injuries among skiers and snowboarders.
Methods: We searched electronic databases, conference proceedings and reference lists using a combination of the key words “head injury or head trauma,” “helmet” and “skiing or snowboarding.” We included studies that used a control group; compared skiers or snowboarders with and without helmets; and measured at least one objectively quantified outcome (e.g., head injury, and neck or cervical injury).
Results: We included 10 case–control, 1 case–control/case-crossover and 1 cohort study in our analysis. The pooled odds ratio (OR) indicated that skiers and snowboarders with a helmet were significantly less likely than those without a helmet to have a head injury (OR 0.65, 95% confidence interval [CI] 0.55–0.79). The result was similar for studies that used controls without an injury (OR 0.61, 95% CI 0.36–0.92), those that used controls with an injury other than a head or neck injury (OR 0.63, 95% CI 0.52–0.80) and studies that included children under the age of 13 years (OR 0.41, 95% CI 0.27–0.59). Helmets were not associated with an increased risk of neck injury (OR 0.89, 95% CI 0.72–1.09).
Interpretation: Our findings show that helmets reduce the risk of head injury among skiers and snowboarders with no evidence of an increased risk of neck injury.
Skiing and snowboarding are popular winter activities. 1 Estimates from numerous countries indicate that head injuries account for 9% to 19%, and neck injuries for 1% to 4%, of all injuries reported by ski patrols and emergency departments. 2–11 Rates of head and neck injuries have been reported between 0.09 and 0.46 per 1000 outings. 12 Head and neck injuries are disproportionately represented in cases of severe trauma, and traumatic brain injury is the leading cause of death and serious injury among skiers and snow-boarders. 13 As far back as 1983, Oh and Schmid recommended mandatory helmet use for children while skiing. 14
Many studies of the relation between helmet use and head injuries among skiers and snowboarders have found a protective effect. 15–24 It has been suggested that the use of helmets may increase the risk of neck injury in a crash or fall. 25 This may be more evident among children because they have a greater head:body ratio than adults, and the additional size and weight of the helmet may increase the risk of neck injury in an otherwise routine fall. 26 We conducted a systematic review of the effect of helmets on head and neck injuries among skiers and snowboarders."