October 29 (HealthDay News) -- The diagnosis of multiple sclerosis (MS) may be delayed in people if they have other medical conditions, a new Canadian study suggests.

Obesity, diabetes, high blood pressure and high cholesterol appeared to mask early MS symptoms and lead doctors to delay its treatment, concluded the study, published in the Oct. 29 online issue of Neurology. As a result, MS often worsens significantly before it is addressed by doctors.

"Our study suggests that doctors who treat people with chronic diseases should not attribute new neurological symptoms such as numbness and tingling to existing conditions without careful consideration," study author Dr. Ruth Ann Marrie, of the University of Manitoba in Winnipeg, said in a news release from the journal.

The study, which analyzed the medical records of almost 9,000 people with MS, revealed that it took one to 10 years longer for the diagnosis to be reached in people who were obese, smokers, or who had other physical or mental health conditions. Also, the more preexisting conditions the MS patient had, the more severe the disease was by its diagnosis.

"People with vascular problems or who were obese were about one-and-a-half times more likely to be moderately disabled at the time of diagnosis compared with those who had MS but did not have any heart or weight problems," Marrie said. "We also 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 at the time of diagnosis."

SOURCE: American Academy of Neurology, news release, Oct. 29, 2008