Is Obesity a Risk Factor for Acute Mountain Sickness? A Systematic Review

An ascent to high altitude exposes the human body to a reduction in the partial pressure of inspired oxygen. In order to maintain oxygen delivery to the tissues, a series of physiological adaptations must take place. However, in many cases this process is incomplete and high-altitude illnesses develop. The commonest form of high-altitude illness is acute mountain sickness (AMS). The aim of this systematic review is to summarise the relevant research and determine whether obesity is a risk factor for AMS.

From a systematic search of the medical literature, a total of 25 publications were included for analysis.

Ten studies sought to determine whether participants with AMS had a higher BMI than those who did not. Four studies reported a statistically significant difference. One study reported a statistically non-significant difference. The remaining five studies reported no difference. Fifteen studies sought to determine whether AMS was commoner in those with obesity.Nine studies reported a statistically significant difference. Four studies reported a statistically non-significant difference. The remaining two studies reported no difference. Seven studies presented the odds ratios and 95% confidence intervals of AMS incidence in obese compared to non-obese populations. Five of the seven studies showed a statistically significant difference in AMS incidence with odds ratios ranging between 1.2 and 3.8.

Whilst a small number of studies failed to show a statistically significant difference in AMS between obese and non-obese individuals, the majority supported the assertion that obesity is a potential risk factor for AMS. Further research is required to support this conclusion and identify the wider challenges faced by obese individuals heading to high altitude.