Risk of myocardial infarction among subjects visiting a doctor because of back disorder. A case--control study in Finnish farmers.

STUDY DESIGN: A nested case-control study was made to analyze the correlation between back trouble and myocardial infarction. OBJECTIVES: The purpose of the present study was to determine whether individuals visiting a doctor because of back trouble have an increased risk for myocardial infarction. SUMMARY OF BACKGROUND DATA: According to previous results, back pain precedes myocardial infarction in young and middle-aged male farmers. There are no previous results concerning the risk of myocardial infarction among patients visiting a doctor because of back pain. METHODS: The basic cohort includes 3172 Finnish farmers. Those having myocardial infarction from February 1, 1980 through December 31, 1992 were considered case studies. Three matched control subjects were selected for every case subject. The final group had 83 case subjects and 249 matched control subjects. Case subjects and control subjects were compared according to doctor visits because of back complaint during the follow-up period, which began February 1, 1980 and ended on the date of myocardial infarction of each case subject. RESULTS: Fewer case subjects than control subjects visited a doctor because of back disorders during the follow-up period. This was especially true for nonspecific back pain (odds ratio = 0.51; confidence interval = 0.25-1.05). CONCLUSION: Atherosclerosis is not a probable cause of any kind of back pain among individuals visiting a general practitioner because of back complaint.