From MedPage Today, March 10, 2016:
MS Diagnoses Linked to Other Health Problems
Is MS a 'lifestyle disease'?
by Sydney Lupkin
Reporter, VICE News/MedPage Today
Health records from the Canadian provinces of Quebec, Nova Scotia, Manitoba, and British Columbia indicated that those with MS were, at diagnosis, more likely to have every comorbidity examined except for hyperlipidemia, Ruth Ann Marrie, MD, PhD, of the University of Manitoba, and colleagues, reported in Neurology.
But the most common comorbidities among MS patients were fibromyalgia and depression, they found.
"The burden of psychiatric comorbidity for both sexes even at MS diagnosis was striking," the authors wrote. "While depression and anxiety are recognized to be common in established MS, our findings and those of prior studies collectively indicate that these conditions are the most or nearly the most common preexisting comorbidities at diagnosis, particularly among those aged 20-44 years."
Researchers looked at 23,382 MS cases and 116,638 age-, location-, and sex-matched controls, and found that people with MS were more likely to have the following, expressed as relative risks (all P<0.0001):
Hypertension: 1.17
Diabetes: 1.17
Ischemic heart disease: 1.30
Fibromyalgia: 2.87
Inflammatory bowel disease: 1.68
Epilepsy: 2.18
Depression: 2.04
Anxiety: 1.61
Bipolar disorder: 1.86
Schizophrenia: 1.32
For many of these conditions, dividing patients by gender produced even more pronounced results. For instance, women with MS had a 16% higher incidence of hypertension than women without MS. But men with MS had a 48% higher incidence of hypertension than those without MS. The researchers found similar results for several other comorbidities as well.
Although women with MS were expected to have higher rates of fibromyalgia and depression, the study authors did not anticipate that women with MS would have a 39% higher prevalence of chronic lung disease at MS diagnosis compared with non-MS women, or that men with MS would have only a 21% higher prevalence of chronic lung disease.
In an accompanying editorial questioning whether MS is a "lifestyle disease," William Grant, PhD, of the Sunlight Nutrition and Health Research Center, and Trond Riise, PhD, of the University of Bergen in Norway, wrote that the large number of cases and validated case definitions are both strengths of the study, but it lacks information on the extent of the comorbidities and other lifestyle issues, such as smoking.
They argued that many of the chronic diseases mentioned as comorbidities in the study could be tied to lifestyle risk factors, including low ultraviolet exposure, poor diet, and smoking.
"Nevertheless, the finding of a higher occurrence of a number of chronic diseases among patients with MS relative to the general population begs the question of whether there are shared risk factors for MS and these comorbid diseases," Grant and Riise wrote. "If so, recognizing them could lead to recommendations that would reduce the risk of both MS and the comorbid diseases."
Marrie said the idea for her series of MS comorbidity studies arose working with patients and wondering whether their other health problems were giving them more trouble than their MS. When she looked at the existing literature, she found mostly studies examining MS coupled with other immune-mediated diseases, but she wanted to know more.
"I worried about things like chronic bronchitis, shortness of breath walking across the room and fatigue," she told MedPage Today. "I decided I was going to try to figure this out."
Five years before patients were diagnosed with MS, the prevalence of all comorbidities was lower, records indicated. And as the patients with MS aged, they were more likely to have these comorbidities -- as is true of the general population with age.
Marrie and her team used administrative data collected in the four provinces. They excluded patients under 20 years old, which they say may have affected their results.
The investigators hypothesized that the comorbidities may be the result of shared genetic or environmental factors, but their presence before MS is diagnosed could actually increase the likelihood of an MS diagnosis because of increased surveillance by clinicians.
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The study was partially supported by the Canadian Institutes of Health Research, the Rx & D Health Research Foundation, a Don Paty Career Development award from the Multiple Sclerosis Society of Canada, a Manitoba Research Chair from Research Manitoba, and a Canada Research Chair in Neurological Health Services Research.
Grant reported relationships with Biotech Pharmacal, the Vitamin D Society, and the Vitamin D Council. Riise declared he had no competing interests.
The article can be seen
here.