What have we found in HuLARS so far?

• Persons who have had angina, myocardial infarction or stroke are at an increased risk of developing rheumatoid arthritis: Cardiovascular disease is associated with increased risk of rheumatoid arthritis (blog NTNUhealth 11.06.14)
• HUNT-data contributes to new insights on ankylosing spondylitis: ​​​​​​​New risk genes for ankylosing spondylitis are identified – HUNT data contribute to new insights (blog NTNUhealth 31.07.13)
• Smoking doubles the risk of ankylosing spondylitis

We are performing further analysis of the HuLARS data and new results will be posted as they become available.

How HuLARS is conducted

HuLARS has been ongoing since 2009, and is based on data from the Trøndelag Health Study (HUNT). We have identified those who had rheumatoid arthritis or ankylosing spondylitis in HUNT2 (1995-1997) and HUNT3 (2006-2008). Some of these persons participated in both survey, permitting studies of changes in risk factors by time. We are planning further participant inclusion in HuLARS based on the future HUNT4 survey.

In addition to answers from questionnaires and data from the clinical examination at HUNT, we have results from typing of genetic risk variants. We have also collected information about myocardial infarctions from the Myocardial Infarction Registry in the North-Trøndelag Health Trust and about deaths from the National Causes of Death Registry. Data regarding drug treatment are available from the Norwegian Prescription Database, allowing investigation of whether arthritis medication may also reduce the risk of cardiovascular disease. The findings are compared with results from HUNT participants without arthritis.

HuLARS is very well suited to identify new associations because we have good data on lifestyle factors as well genetic information from several thousand individuals. HuLARS is approved by the Regional Committee for Medical and Health Research Ethics (REK Midt) and the Norwegian Data Inspectorate. HuLARS has received funding from the Liaison Committee between the Central Norway Regional Health Authority and the Norwegian University of Science and Technology and the Research Council of Norway.

Arthritis and ankylosing spondylitis

Rheumatoid arthritis and ankylosing spondylitis are two common forms of chronic autoimmune inflammatory arthritis.

They are not caused by infections in the joints, but by activation of the immune system in ways that are not completely understood. Both diseases run in families and have so-called complex heritability, i.e. they are caused by environmental factors interacting with a strong genetic predisposition. It is well-known that arthritis patients have an increased risk of cardiovascular disease. This is partly related to unfavorable classical risk factors (e.g. smoking, hypertension and blood lipids), and partly related to an increased level of inflammation in the body due to their joint disease.

Rheumatoid arthritis

Rheumatoid arthritis (RA) affects 0.5-1% of the population, especially in older age groups. The disease is 2-3 times more common in women than in men. Both small and large joints are affected. RA may also involve other organs such as the lungs and kidneys. Without appropriate treatment joint destruction and severe functional disability may ensue. The prognosis is improved with intensive modern treatment.

Ankylosing spondylitis

Ankylosing spondylitis (AS) affects 0.2-0.8% of the population. Young men are at an increased risk. A prominent characteristic of AS is enthesitis, i.e. inflammation where tendons attach to bone, typically affecting the joints of the pelvis and vertebral column. Pain and stiffness ensue and the joints may develop so-called ankylosis with total loss of movement. Patients with AS are also at an increased risk of uveitis (inflammation of the eyes) and inflammatory bowel disease. Diagnosis of AS may be difficult before the joint changes are relatively advanced.

Smoking is harmful to the joints

Smoking increases the risk of rheumatoid arthritis (RA) at least two-fold. Smoking is especially harmful in persons who are genetically predisposed to RA. In RA patients who continue to smoke, the rate of joint damage increases and treatment is less effective. Patients with ankylosing spondylitis (AS) lose joint movement more rapidly if they smoke. Our data from HuLARS also indicate that smokers are at a higher risk of developing AS. If you have relatives with RA or AS, avoiding smoking is something you can do to reduce your own risk of getting arthritis.