Validity of self-reported physical work load in epidemiologic studies on musculoskeletal disorders.

OBJECTIVES: This study assessed the validity of self-reported physical work load by questionnaire and logbook against task analysis and observation. It also investigated factors (job type and low-back or neck pain) affecting the self-assessment of physical work load and compared the assessments between the questionnaire and the logbook. METHODS: A self-administered questionnaire including 10 questions (ordinal scales) on physical work load and musculoskeletal symptoms was filled out by 2756 men in the forest industry. From this population, 36 men were selected for task analysis and observation. Logbooks including 10 continuous variables were analyzed for 386 men. RESULTS: The Spearman rank correlation coefficients between the self-assessments and observations for the frequency of manual handling, duration of trunk flexion, neck rotation, hand above shoulder level, and squatting or kneeling ranged between 0.42 and 0.55. The correlation coefficients for the questionnaire items were higher in general, and the accuracy better, for those with no low-back pain than for those with pain. The duration of trunk flexion, neck flexion and hand above shoulder level was overestimated in the questionnaires and less so in the logbooks. CONCLUSIONS: Self-administered questionnaires may help to classify groups with heterogeneous occupational tasks according to some work-load factors. The accuracy of the assessments is not good for studying quantitative exposure-effect relationships, however. The logbook method might give more valid information. The perception of musculoskeletal pain may bias the self-assessment of work load.

Seasonal variation in neck and shoulder symptoms.

The objective of the investigation was to study the course of neck and shoulder symptoms and the predictors for these symptoms among women in light sedentary work. Postal surveys were conducted among 351 tellers (age 20-50 years) of a bank company in September, December, March, and May. The response rates were 74-90%. The outcome was the frequency of the symptoms during the previous three months. In the analysis, univariate explorations and random-effects logistic binomial regression for distinguishable responses were used. A change in the frequency of neck and shoulder symptoms was seen in 40.5% of the subjects during the follow-up period from autumn to spring. The frequency of the symptoms decreased from autumn and winter towards spring. The stability of the frequency of the symptoms was positively associated with age. Seasonal variation in symptoms should be considered when preventive programs against neck and shoulder disorders are planned and evaluated.

Class specific antibody response to gonococcal infection.

An enzyme immunoassay was used to determine IgM, IgG, and IgA antibodies to gonococcal pili in 68 patients with uncomplicated gonorrhoea, 35 women with pelvic inflammatory disease, and in 115 normal controls. A clear difference in response rate in all three antibody classes between patients with gonorrhoea and healthy controls was evident. Among women with gonorrhoea, the magnitude of antibody response was higher than among men with gonorrhoea, especially in the IgM class. No major differences were found in the overall distribution of serological findings between women with uncomplicated gonorrhoea and those with gonococcal pelvic inflammatory disease. Among this last group, however, high IgM antibody levels in acute phase sera were significantly associated with the isolation of Neisseria gonorrhoeae in the upper genital tract.