Multiple Sclerosis and Coexisting Health Conditions

By Ruth Ann Marrie, MD, MS–Mellen Center for MS Treatment and Research, Cleveland Clinic Foundation–CMSC/NARCOMS Research Fellow



Introduction

Multiple sclerosis (MS) is a chronic disease affecting more than 300,000 Americans (Anderson et al., 1992). Having one chronic disease or health problem does not mean that patients with MS cannot have other health problems, such as diabetes or high blood pressure. We do not know enough about how often these other health problems occur, or how they affect MS. This article discusses what is known about other health problems in MS, and upcoming research planned by NARCOMS on this topic.



Other Autoimmune Diseases

We know that patients with MS are more likely to have other autoimmune diseases than persons in the general population (Somer, Muller, & Kinnunen, 1989; Seyfert, Klapps, Meisel, Fischer, & Junghan, 1990; Midgard, Gronning, Riise, Kvale, & Nyland, 1996; Biousse, Trichet, Bloch-Michel, & Roullet, 1999; Karni & Abramsky, 1999; Frese, Bethke, Ludemann, & Stogbauer, 2000; Kimura, Hunter, Thollander, Loftus, Melton et al., 2000; Isbister, Mackenzie, Anderson, Wade, & Oger, 2003; Dionisiotis, Zoukos, & Thomaides, 2004; Edwards & Constantinescu, 2004). When you have an autoimmune disease, the immune system makes a mistake and reacts to the body’s own tissues, causing damage. In MS the damage occurs in the brain, optic nerves, and spinal cord. In other autoimmune diseases, different tissues, such as the eyes or skin may be affected. Autoimmune diseases that are reported to occur more frequently than expected in patients with MS include:



inflammatory bowel disease (Crohn’s disease or ulcerative colitis)

type 1 diabetes mellitus

pernicious anemia (vitamin B12 deficiency)

thyroid disease (Graves disease or Hashimoto’s thyroiditis)

uveitis (inflammation of the eye)

seronegative spondyloarthropathies (diseases that cause inflammation in specific areas of the body, particularly in parts of the spine and at other joints where tendons attach to bones)

myasthenia gravis (disorder of neuromuscular transmission)

rheumatoid arthritis



Other Chronic Diseases

Most patients with MS are diagnosed between the ages of 20 and 40 years (Koch-Henriksen, Bronnum-Hansen, & Hyllested, 1992). The risk of conditions such as type 2 diabetes, high blood pressure, and high cholesterol is relatively low in this age group (Mokdad, Ford, Bowman, Nelson, & Engelgau, 2000; Carroll et al., 2005; National Center for Health Statistics, 2005). In general, as we age our risk of chronic diseases such as diabetes, and high blood pressure, increases (Hoffman, Rice, & Sung, 1996; National Center for Health Statistics, 2005). The risk of having more than one chronic condition also rises (Hoffman et al., 1996). The presence of more than one health condition in a single person is referred to as comorbidity. Thus it is reasonable to expect that patients with MS will acquire more chronic health conditions (comorbidities) as they age, but we do not know if the ages at which these conditions develop or the type of conditions that develop, differ from the general population.





Heart Disease and Cancer

Studies show conflicting results as to whether patients with MS have a decreased risk of heart disease or cancer as compared to persons without MS (Koch-Henriksen, Bronnum-Hansne, & Stenager, 1998; Sumelahti, Tienari, Wikstrom, Salminen, & Hakama, 2002). A Finnish study of 1,614 patients with MS reported that death due to heart disease was less common than in the general population, and that death due to cancer was more common (Sumelahti et al., 2002). A Danish study of 6,068 patients with MS reported opposite findings; death due to heart disease was more common than in the general population, and death due to cancer was less common (Koch-Henriksen et al., 1998). Another Danish study looked at all diagnoses of cancer, and not simply deaths due to cancer; this study did not find any overall change in the risk of cancer in patients with MS, but suggested a very slight increase in the risk of breast cancer in female patients with MS (Nielsen, Rostgaard, Rasmussen, Koch-Henriksen, & Storm, 2006). We need more studies to determine whether patients with MS have different risks of having other chronic conditions than the general population.



Lifestyle Factors

Lifestyle factors, such as smoking, alcohol intake and exercise, also deserve more attention. In 2005, Nortvedt et al. conducted a study of more than 20,000 persons born between 1953 and 1957, and living in Norway in 1997 (Nortvedt, Riise, & Maeland, 2005). This group included 87 people with MS. As compared to people from the study group with asthma and diabetes, people with MS had less strenuous leisure physical activity. A combined analysis of several studies (meta-analysis) also concluded that patients with MS are less active than the general population (Motl, McAuley, & Snook, 2005). Patients with MS may become less physically active and have reduced exercise capacity for several reasons. These reasons include fatigue, depression and physical problems such as weakness, poor balance or difficulty walking (Slawta et al., 2003; Romberg et al., 2004). Lower levels of exercise are associated with increased risks of coronary heart disease in MS (Slawta et al., 2002) and increased body fat (Slawta et al., 2003).



Norwegian patients with MS were also more likely to smoke than patients without MS, with 40% of participants reporting that they currently smoked (Nortvedt et al., 2005). The importance of smoking in MS is another area where existing studies do not agree (D’hooghe & Nagels, 2005; Hernan et al., 2005). Hernan et al. used a British database to study the effects of smoking on the risk of developing secondary progressive MS (Hernan et al., 2005). They reported that smokers with relapsing-remitting MS at diagnosis had more than three times the risk of developing secondary progressive MS as non-smokers (Hernan et al., 2005). D’hooghe and colleagues, however, reported that smoking was not associated with disability progression (D’hooghe et al., 2005). Both studies were relatively small and larger studies are needed to determine if smoking really influences MS-associated disability.



Summary

There is a need for additional research to investigate lifestyle factors and the presence of other chronic health conditions in patients with MS. There are many questions to answer. These include finding out whether the risk of having another chronic condition is greater in patients with MS, whether MS behaves differently in the presence of another chronic condition, whether treatment responses differ and whether different treatments should be used? This is an area of particular current interest to the NARCOMS Patient Registry.