People who have trouble reading and comprehending basic health information are at greater risk of dying prematurely, suggests a new study.

British researchers studied the effect of poor literacy skills and limited health knowledge on mortality. They looked at the behaviours of 7,857 older adults (those aged 52 and over) enrolled in the English Longitudinal Study of Aging between 2004 and 2005. Deaths were tracked until October 2009.

Health literacy was assessed by how study participants understood medical instructions, and divided into three groups: high, medium and low,  Most people fell into the high literacy group (67.2 per cent), with 20.4 per cent in the medium group and 12.5 per cent in the lowest group. 

The researchers noted that the greatest percentage of deaths occurred in the group with the lowest literacy scores, followed by the group with medium scores and then highest scores. Those with low and medium health literacy had respectively a 75 per cent and 24 per cent increased risk of death.

"Poorer understanding is associated with higher mortality," reads the study. "Low health literacy may lead to particularly harmful consequences in older age, given the complexities of managing chronic disease and age-related cognitive decline."

The authors acknowledge that individuals in the low literacy group may be underrepresented, as "adults with low literacy levels may try to hide their reading difficulties and therefore be less likely to respond to surveys." Participants were surveyed about their health conditions, professions and physical capabilities.

The study was published Friday online in the British Medical Journal.