In a study it was found that it took one to 10 years longer for people who were obese, smoked, or had physical or mental health conditions to be diagnosed with MS, compared with people without such conditions.
The more medical problems someone with MS had, the more severe the disease became by the time they were diagnosed, the researchers found.
People who had a mental disorder or any muscle or joint problem along with MS were nearly two times more likely to be severely disabled when diagnosed compared with those with a mild disability, according to the study.
Those with vascular problems such as diabetes, high blood pressure or high cholesterol, were about 1.5 times more likely to be moderately disabled when diagnosed compared with people who had MS but no heart or weight problems.
The findings of the study undertaken in Manitoba, Canada were reported in Wednesday's issue of the journal Neurology.
"...for some diseases, such as cancer, patients may run to their doctor sooner than average. But in other cases, patients may chalk up new symptoms such as numbness and tingling to an existing condition, potentially leading to delays in an MS diagnosis. Delays on the order of months are not a problem, but years could be," study author Dr. Ruth Ann Marrie of the University of Manitoba in Winnipeg Marrie told CBC.
Comorbidity is common in the general population and is associated with adverse health outcomes. In multiple sclerosis (MS), it is unknown whether preexisting comorbidity affects the delay between initial symptom onset and diagnosis ("diagnostic delay") or the severiy of disability at MS diagnosis.
Using the North American Research Committee on Multiple Sclerosis Registry, the Manitoba researchers assessed the association between comorbidity and both the diagnostic delay and severity of disability at diagnosis.
The study included 8,983 participants. After multivariable adjustment for demographic and clinical characteristics, the diagnostic delay increased if obesity, smoking, or physical or mental comorbidities were present.
Both diagnostic delay and disability at diagnosis are influenced by comorbidity, they concluded and said the mechanisms underlying those associations required further investigation.
"People with multiple medical problems on top of MS may need more health-care resources or might respond differently to medication," Marrie said. "This needs more study."
This study was supported by the National Institutes of Health and the National Institute of Child Health and Human Development and Consortium of MS Centers.