|Mortality on Mount Everest, 1921-2006: descriptive study
By Paul G Firth, Hui Zheng, Jeremy S Windsor, Andrew I Sutherland, Christopher H Imray,
G W K Moore, John L Semple, Robert C Roach, Richard A Salisbury
British Medical Journal, 11 December 2008
Objective: To examine patterns of mortality among climbers on Mount Everest over an 86 year period.
Design: Descriptive study.
Setting: Climbing expeditions to Mount Everest, 1921-2006.
Participants: 14,138 mountaineers; 8030 climbers and 6108 Sherpas.
Main outcome measure: Circumstances of deaths.
Results: The mortality rate among mountaineers above base camp was 1.3%. Deaths could
be classified as involving trauma (objective hazards or falls, n=113), as non-traumatic
(high altitude illness, hypothermia, or sudden death, n=52), or as a disappearance (body
never found, n=27). During the spring climbing seasons from 1982 to 2006, 82.3% of
deaths of climbers occurred during an attempt at reaching the summit. The death rate
during all descents via standard routes was higher for climbers than for Sherpas (2.7%
(43/1585) v 0.4% (5/1231), P<0.001; all mountaineers 1.9%). Of 94 mountaineers who
died after climbing above 8000m, 53 (56%) died during descent from the summit, 16
(17%) after turning back, 9 (10%) during the ascent, 4 (5%) before leaving the final
camp, and for 12 (13%) the stage of the summit bid was unknown. The median time to
reach the summit via standard routes was earlier for survivors than for non-survivors
(0900-0959 v 1300-1359, P<0.001). Profound fatigue (n=34), cognitive changes (n=21),
and ataxia (n=12) were the commonest symptoms reported in non-survivors, whereas
respiratory distress (n=5), headache (n=0), and nausea or vomiting (n=3) were rarely described.
Conclusions: Debilitating symptoms consistent with high altitude cerebral oedema
commonly present during descent from the summit of Mount Everest. Profound fatigue
and late times in reaching the summit are early features associated with subsequent death.
The study may be accessed at Everest-BMJ-Dec2008 [0.3kb Pdf].
Reference: Firth PG, Zheng H, Windsor JS, Sutherland AS, Imray CH, Moore GWK,
Semple JL, Roach RC, Salisbury RA.
Mortality on Mount Everest, 1921-2006: descriptive study. BMJ 2008; 337:a2654
Additional data relating to this study is given in
Mortality on Mount Everest Supplemental Data.