MS Tied to 75% Increased Risk of Mortality in US Study
The overall risk of death is about 75% higher for people with multiple sclerosis (MS) than in the general population, according to a new study.
“The association was independent of demographic, socioeconomic variables, lifestyle factors, baseline diabetes, cardiovascular disease, chronic respiratory disease, and cancer status,” researchers wrote.
The study, “Association of multiple sclerosis with risk of mortality among a nationally representative sample of adults in the United States,” was published in Multiple Sclerosis Journal — Experimental, Translational and Clinical.
MS itself is not a deadly disease, but it can increase the risk of potentially life-limiting problems like pneumonia. A team of scientists in the U.S. and China conducted an analysis aiming to identify the association between MS and mortality risk, independent of other factors that can affect the risk of death.
“The objective of this study is to examine the association of MS with risk of mortality independent of demographic, socioeconomic, lifestyle factors, and several comorbidities [co-occurring health conditions] in a nationally representative sample of adults in the U.S.,” the team wrote.
For this study, the researchers assessed people who had participated in the National Health Interview Survey (NHIS) in 2002 and 2008. The NHIS is an annual effort to collect nationally representative healthcare data administered by the Centers for Disease Control and Prevention (CDC). The researchers noted that only the 2002 and 2008 cycles were included because these were the only years that the NHIS assessed MS.
“The major strength of this study was the nationally representative sampling with a large sample size in the NHIS. Therefore, our findings are expected to be generalizable to the general adult population in the United States,” the team wrote.
In total, the study included data for 23,053 adults, ages 45–79 years, just over half of whom were female. Among them, 120 had been diagnosed with MS at the time of the NHIS.
Compared with the general population, MS patients were more likely to be younger, female, non-Hispanic white, have chronic respiratory disease, have lower physical activity levels, and have reduced body mass index (BMI, a ratio of weight to height).
Over an average follow-up time of 9.4 years, 4,208 deaths were recorded. The average age of death was significantly younger for people with MS than for those without (65.2 vs. 67.6 years).
The researchers constructed statistical models to estimate the mortality risk for people with MS, adjusting for other factors. In an initial analysis, which adjusted for age, sex, race/ethnicity, socioeconomic factors, lifestyle factors, and BMI, the risk of death was significantly higher, by 80%, for people with MS.
An additional analysis that also included adjustments based on certain comorbidities — namely diabetes, cardiovascular disease, chronic lung disease, and cancer — the mortality risk was 75% higher for people with MS than those without.
“In a nationally representative sample of U.S. adults, we found a significant association of MS with a higher risk of all-cause mortality. This association persisted after adjustment for demographic, socioeconomic variables, lifestyle factors, BMI, and several comorbidities,” the researchers concluded.
The adjusted MS-related morality rate did not differ significantly between males and females, and the researchers were unable to compare ethnicity-based mortality rates because there were too few participants with MS of ethnicities other than non-Hispanic white.
The researchers noted that this study has some limitations; for example, the team did not have data on the severity of MS, causes of death, or patterns of MS treatment.
“Further investigation is warranted to determine whether and how severity and treatments will affect the association between MS and mortality,” the team wrote.