MS is not a terminal condition and long-term studies suggest that multiple sclerosis only has a small impact on life expectancy.
A study in Canada examined this area in terms of level of disability and found that life expectancy for those people whose experience of MS ranged from no symptoms to full time use of a manual wheelchair (less than or equal to 7.0 on the Expanded Disability Status Scale (EDSS)) was only slightly reduced.
The research found that people with more complex disability (EDSS greater than or equal to 7.5) were more at risk of potentially life threatening complications - such as respiratory or cardiovascular problems which tend to result from reduced mobility. Co-morbidities like stroke and vascular issues affected the overall life expectancy figures. Even with this group included, overall life expectancy for people with MS was only about six to seven years less than that for the general population.
This effect has been seen in other studies of health insurance records - for instance an American study of data collected between 1996 and 2009 and a Canadian study with records from 1984 to 2012 both found that life expectancy was on average six years less for people with multiple sclerosis.
A Norwegian study in 2017 found that life expectancy in people with MS is increasing at the same rate as that seen in the general population. Overall, life expectancy was seven years less than people who didn't have MS (74.7 years vs 81.8 years). The life expectancy for people with relapsing remitting MS was longer than for those with primary progressive MS (77.8 years vs 71.5 years).
The disease modifying drugs (DMDs) for relapsing MS began to appear in the mid 1990s, so many of the people in the studies would not have had access to these treatments for part of their time with the condition. Future long term studies might show an extended life expectancy since the arrival of effective drugs for people with MS.