A study of whether occupational physical load predicted subsequent chronic shoulder disorders.
A comprehensive national survey was carried out among a representative sample (n = 7217) of the Finnish adult population in 1977-80. Twenty years later, 1286 participants from the previous survey were invited to be re-examined, and 909 (71%) participated. After excluding those with diagnosed shoulder disorders at baseline, 883 subjects were available for the analyses.
At follow-up, a physician diagnosed chronic shoulder disorders in 63 subjects (7%) using a standardised protocol. Work exposure to repetitive movements and vibration at baseline increased the risk of shoulder disorder: adjusted ORs 2.3 (95% CI 1.3 to 4.1) and 2.5 (1.2 to 5.2), respectively. Exposure to several physical factors increased the risk further, the adjusted OR was nearly 4 for at least three exposures. The adverse effects of physical work were seen even among those older than 75 years at follow-up. The statistically significant risk factors differed between genders: for men vibration and repetitive movements, and for women lifting heavy loads and working in awkward postures. Age and body mass index modified the effects of the physical exposures. The results remained similar after excluding those with any shoulder pain at baseline.
This is the first prospective study in a general population showing that occupational physical loading increases the risk of a subsequent clinical shoulder disorder and the effects seem to be long-term. Early preventive measures at the workplace may have long-lasting health benefits for the shoulder.