LONDON, Jan 14 (BBC)--Women may suffer more from rheumatoid arthritis than men, findings suggest.
Female patients say they experience more symptoms like aches, pains and tiredness even when they appear to have the same level of disease as men.
The Finnish researchers believe their findings may be down to physical strength - women are naturally weaker than men and thus feel the strain more.
Details of their study of over 6,000 patients from 25 countries is published in Arthritis Research and Therapy.
It is already known that the disease is more common in women than in men - more than 70% of those with rheumatoid arthritis are female.
In the latest study, the men and women were asked to complete questionnaires about their disease and underwent x-rays and blood tests to gauge how advanced their arthritis was.
Lead researcher Dr Tuulikki Sokka, a consultant in rheumatology at the Jyvaskyla Central Hospital, said: "The level of rheumatoid arthritis appears to be pretty much the same in both sexes but the symptoms of joint tenderness and things like that appear to be worse in women.
"The problem is that the only real measure we have for rheumatoid arthritis is the X-ray, which only measures damage.
"This is not a very valuable tool in the everyday clinic and so we need to rely on what patients tell us. We found that women tell us they have more severe symptoms."
Dr Sokka believes this relates to women being physically weaker than men.
"Our findings were particularly obvious in older women, who are losing their muscle mass little by little every year.
"Given that woman is the 'weaker vessel' concerning musculoskeletal size and strength and her baseline values are lower than men's, the same burden of a musculoskeletal disease may appear to be more harmful to a woman than to a man."