The Place: Finland. The Time: Between 1978 and 1980. The People: 8,000 Finns, age 30 or older.
Doctors offered each person in this pool of 8000 subjects a complete physical exam. Then everyone was followed for up to 17 years. Researchers use studies like this to look at many health issues. This study measured the number of cases of thumb arthritis and looked for risk factors.
Subjects with a history or symptoms of muscle or bone disease were given a special X-ray of the hand. A test of function was given to assess overall disability. The authors found that women who smoked were more likely to have arthritis of the carpometacarpal joint (CMC). The CMC joint is at the base of the thumb. Obesity was directly linked to thumb OA in both men and women. In fact, overweight subjects were twice as likely to have thumb OA compared to people the same age with normal weight.
The authors conclude that OA of the CMC joint is common in Finland. Obesity is the number one risk factor. It affects the body as a whole and the thumb joint in particular.