Prospective study on shoulder symptoms among kitchen workers in relation to self-perceived and observed work load.

OBJECTIVES: To study the occurrence of shoulder symptoms among professional kitchen workers, and whether reduction in self-perceived and observed physical work load decreases future symptoms. METHODS: In this prospective study conducted in 2002-2005 in municipal kitchens in Finland, changes during a 1-year follow-up in the physical strenuousness of work tasks were self-assessed by 376 female workers (substudy I). Changes in exposure to manual lifting and awkward upper arm posture during the follow-up were also observed by experts in 69 kitchens with 183 workers (substudy II). Information on shoulder symptoms was collected with questionnaires at baseline and at follow-up. The risk of shoulder symptoms at follow-up related to changes in exposure was estimated with logistic regression. RESULTS: The 3-month prevalence of shoulder pain was 34% at baseline and 41% at follow-up. Reduction during follow-up in work tasks perceived as the most strenuous physically (ie, receiving and storing raw food) led to a significantly reduced risk of future shoulder pain with an adjusted odds ratio (OR) of 0.41 (95% CI 0.17 to 0.98) and trouble caused by the pain with an OR of 0.34 (0.14 to 0.83). The observed reduction in lifting was also associated with a lower risk for future shoulder symptoms. CONCLUSIONS: Reduction in lifting showed beneficial protective effects on the shoulder. Although more risk factor and intervention studies are needed to estimate the health impacts of kitchen work, special attention should be paid to work tasks that include lifting when assessing risk and designing preventive measures.

COL2A1 gene polymorphisms and susceptibility to osteoarthritis of the hand in Finnish women.

OBJECTIVES: To study the role of two COL2A1 single nucleotide polymorphisms (rs3737548 and rs2276455) and their haplotypes in individual susceptibility to osteoarthritis (OA) of the hand in Finnish women. METHODS: Bilateral hand radiographs of 543 Finnish female dentists and teachers aged 45-63 years were examined and classified for the presence of OA by using reference images. The COL2A1 genotypes were determined by PCR-based methods. Data regarding other risk factors were collected by questionnaire. The haplotypes were statistically reconstructed from the genotype data by the PHASE program. Associations between the genotypes/diplotypes and hand OA were studied by logistic regression. RESULTS: Allowing for age and occupation, the carriage of at least one COL2A1 intron 33 minor allele was associated with an increased risk of hand OA (odds ratio (OR) 1.58, 95% CI 1.05 to 2.36) and the number of affected joints. When stratified by occupation, the increased risk associated with the intron 33 minor allele carriage appeared to be mainly attributable to the dentists (OR 2.18, 95% CI 1.18 to 4.06). The 2-1 haplotype (exon 5B minor allele-intron 33 major allele) posed a significantly higher risk of hand OA (OR 3.21, 95% CI 1.08 to 9.55) compared with non-carriers. Moreover, an interaction was observed between intron 33 minor allele carriage and low task variation history in dental work (OR 2.87, 95% CI 1.05 to 7.89 for their joint effect). CONCLUSIONS: The results suggest that the studied COL2A1 gene polymorphisms may play a role in the aetiology of hand OA and that this effect may be enhanced by repetitive loading work tasks.

A randomised controlled trial on whether a participatory ergonomics intervention could prevent musculoskeletal disorders.

OBJECTIVES: To examine the efficacy of a participatory ergonomics intervention in preventing musculoskeletal disorders among kitchen workers. Participatory ergonomics is commonly recommended to reduce musculoskeletal disorders, but evidence for its effectiveness is sparse. METHODS: A cluster randomised controlled trial among the 504 workers of 119 kitchens in Finland was conducted during 2002-2005. Kitchens were randomised to an intervention (n = 59) and control (n = 60) group. The duration of the intervention that guided the workers to identify strenuous work tasks and to seek solutions for decreasing physical and mental workload, was 11 to 14 months. In total, 402 ergonomic changes were implemented. The main outcome measures were the occurrence of and trouble caused by musculoskeletal pain in seven anatomical sites, local fatigue after work, and sick leave due to musculoskeletal disorders. Individual level data were collected by a questionnaire at baseline and every 3 months during the intervention and 1-year follow-up period. All response rates exceeded 92%. RESULTS: No systematic differences in any outcome variable were found between the intervention and control groups during the intervention or during the 1-year follow-up. CONCLUSIONS: The intervention did not reduce perceived physical work load and no evidence was found for the efficacy of the intervention in preventing musculoskeletal disorders among kitchen workers. It may be that a more comprehensive redesign of work organisation and processes is needed, taking more account of workers' physical and mental resources.

Finger joint pain in relation to radiographic osteoarthritis and joint location--a study of middle-aged female dentists and teachers.

OBJECTIVES: To investigate the associations of radiographic finger joint osteoarthritis (ROA), hand laterality (right/left) and anatomical location within the hand, with finger joint pain. METHODS: Radiographs of both hands of 295 female dentists and 248 female teachers were examined for the presence of osteoarthritis in each finger joint, using grades 0 = no OA, 1 = doubtful OA, 2 = mild OA, 3 = moderate OA, 4 = severe OA. Information on the occurrence of pain in each finger joint during the past 30 days and hand laterality was obtained by questionnaire. RESULTS: Compared with subjects with no ROA, the prevalence ratio (PR) of finger joint pain was 1.92 [95% confidence interval (CI) 1.61-2.34] among those with mild ROA and 5.34 (4.51-6.54) among those with at least moderate ROA, based on a multivariate log-binomial regression model. Pain was slightly more common in the right than in the left hand (1.27; 1.15-1.40). Compared with the little finger, more pain occurred in the thumb (2.67; 2.25-3.16), the index finger (1.76; 1.50-2.07) and the middle finger (1.47; 1.24-1.74). Further, pain was more common in the proximal interphalangeal (1.77; 1.56-2.00) and the distal interphalangeal (1.51; 1.29-1.76) joints than in the metacarpophalangeal joints. The strength of the association between ROA and finger joint pain increased with the severity of pain. CONCLUSIONS: Our findings suggest that ROA, anatomic localization within the hand, and hand laterality have independent effects on finger joint pain.

Aggrecan core protein of a certain length is protective against hand osteoarthritis.

OBJECTIVE: To study the contribution of aggrecan VNTR (variable number of tandem repeats) polymorphism to clinically differing manifestations of hand osteoarthritis (OA). DESIGN: Five hundred thirty Finnish females representing two academically similar occupations with completely diverse exposure to hand load were included. Radiographs of hands were analysed, the OA findings were graded and the subjects were divided into categories. Aggrecan VNTR alleles were identified by Southern hybridization. Statistical analyses were used to compare joint involvement and pathological findings with the prevalences of the alleles and genotypes. RESULTS: Subjects homozygous for the most common aggrecan VNTR allele, A27 with 27 repeats, had a significantly lower risk of hand OA, with OR 0.46 (95% CI 0.27-0.78) for OA of grade 2 or more. Our results suggest that carrying two copies of the alleles with less than 27 repeats could predispose a subject to a severe hand OA (OR 2.45, 95% CI 1.17-5.12) and carrying two copies of the alleles with more than 27 repeats also increases the risk of the disease (OR 1.73, 95% CI 1.03-2.89). CONCLUSIONS: These findings indicate that allele A27 provides protection from hand OA and that alleles shorter or longer than this may predispose subjects to the disease. Furthermore, they suggest that a certain number of tandem repeats provide for optimal functioning of the aggrecan molecule and that the contribution of genetic factors to the development of hand OA may be even more important than that of environmental factors.

How consistently distributed are the socioeconomic differences in severe back morbidity by age and gender? A population based study of hospitalisation among Finnish employees.

AIMS: To study the socioeconomic distribution of severe back morbidity by age and gender, and to examine to what extent the differences in back morbidity between socioeconomic groups are particularly related to manual work in different age groups. METHODS: Hospital admissions in 1996 for back disorders of 25-64 year old men (3123 of a total 743,961) and women (3043 of 773,936) from the Finnish Hospital Discharge Register were linked with demographic and socioeconomic data from the 1995 population census. Poisson regression analysis was used to calculate the rate ratios for back related hospitalisation by occupational class and education. The distribution of cases according to occupational status and education was presented in relation to the whole occupationally active workforce by age and gender. RESULTS: Blue-collar (manual) workers had a higher risk of being hospitalised because of back disorders compared with white-collar employees (non-manual) in all age groups among both genders. Manual work versus non-manual work was associated with a 1.3 to 1.4-fold risk (95% CI 1.0 to 1.8) among women and a 1.3 to 1.6-fold risk (95% CI 1.1 to 2.2) among men. The risk of hospitalisation was further inversely associated with educational level within manual and non-manual work in all other age groups except in those aged 55-64 years. Gender related differences were much smaller compared with the socioeconomic ones. CONCLUSIONS: Socioeconomic differences in back morbidity leading to hospitalisation were consistent by age and gender. The results suggest that not only the physical strenuousness of work, but also other causes of severe back disorders are clustered around a subject's socioeconomic status, indicated by formal education. This may have implications for prevention and the planning of rehabilitation.

Finger osteoarthritis and differences in dental work tasks.

Mechanical load has been proposed as a risk factor for hand osteoarthritis. Dentists produce high manual forces in their work tasks. We studied whether the pattern of dental work tasks was associated with finger osteoarthritis. Radiographs of both hands of 291 middle-aged female dentists were examined for the presence of osteoarthritis. Patterns of dental work tasks during work history were empirically defined by cluster analysis. Three patterns emerged reflecting high, moderate, and mild task variation. Age, specialization, years in clinical work, various activities requiring hand use, family history of Heberden's nodes, body mass index, and smoking were accounted for in logistic regression analyses. The dentists with a history of low task variation had a greater prevalence of osteoarthritis in the thumb, index, and middle fingers compared with dentists with high variation (OR 2.22; 95%CI 1.04-4.91). The pattern of dental work task history is associated with the localization of osteoarthritis in the fingers.

Disc degeneration of the lumbar spine in relation to overweight.

OBJECTIVE: To study the association between overweight and lumbar disc degeneration. DESIGN: Population-based 4-y follow-up magnetic resonance imaging (MRI) study. SUBJECTS: The subjects were 129 working middle-aged men selected to the baseline magnetic resonance imaging (MRI) study from a cohort of 1832 men representing three occupations: machine drivers, construction carpenters, and office workers. The selection was based on the paticipants' age (40-45 y) and place of residence. MR images of the lumbar spines were obtained at baseline and at 4-y follow-up. MEASUREMENTS: Signal intensity of the nucleus pulposus of the discs L2/L3-L4/L5 was visually assessed by two readers using the adjacent cerebrospinal fluid as an intensity reference. The weight (at age 25 and 40-45 y) and height of the subjects, history of car driving, smoking, and back injuries were assessed by questionnaire. RESULTS: Multiple regression analyses allowing for occupation, history of car driving, smoking, and back injuries showed that persistent overweight (body mass index (BMI) > or =25 kg/m(2) at both ages) associated strongly with an increased risk of the number of lumbar discs with decreased signal intensity of nucleus pulposus at follow-up, adjusted odds ratio (OR) being 4.3 (95% confidence intervals (95% CIs) 1.3-14.3). Overweight at young age (risk ratio (RR) 3.8; 95% CI 1.4-10.4) was a stronger predictor of an increase in the number of degenerated discs during follow-up than overweight in middle age (RR 1.3; 95% CI 0.7-2.7). CONCLUSIONS: The study provides evidence that the BMI above 25 kg/m(2) increases the risk of lumbar disc degeneration. Overweight at young age seems to be particularly detrimental.

Hand use and patterns of joint involvement in osteoarthritis. A comparison of female dentists and teachers.

OBJECTIVES: To investigate the effect of mechanical stress on finger osteoarthritis (OA) by comparing women from two occupations with different hand load but the same socio-economic grade, and to investigate whether hand load may affect the pattern of joint involvement in OA. METHODS: Radiographs of both hands of 295 dentists and 248 teachers were examined. Each interphalangeal (distal, proximal and thumb interphalangeal) and the metacarpophalangeal joints were graded (0 = no OA, 4 = severe OA) separately by using reference images. The co-involvement of different hand joints was analysed by logistic regression. RESULTS: The distal interphalangeal joints were the most frequently involved joints. The non-dominant hand was more frequently affected by OA of grade 2 or more than the dominant hand. The prevalence of OA of grade 2 or more in any finger joint and also in any distal interphalangeal joint was higher among the teachers compared with the dentists (59 vs 48%, P = 0.020 and 58 vs 47%, P < 0.010 respectively). Finger OA showed more clustering in the ring and little fingers and more row clustering and symmetry in the teachers than in the dentists [age-adjusted odds ratio (OR) = 1.57, 95% confidence interval (CI) 1.10-2.23, OR = 1.84, 95% CI 1.28-2.64, and OR = 1.98, 95% CI 1.38-2.86 respectively]. The OR of more severe OA (grade 3 or more) in the right-hand thumb and the index and middle fingers was significantly elevated among the dentists compared with the teachers (OR 2.61, 95% CI 1.03-6.59). CONCLUSION: Our findings indicate that finger OA in middle-aged women is highly prevalent and often polyarticular. Hand use may have a protective effect on finger joint OA, whereas continuing joint overload may lead to joint impairment.

Leisure time physical activity and strenuousness of work as predictors of physical functioning: a 28 year follow up of a cohort of industrial employees.

AIMS: To examine associations of leisure time physical activity and physical strenuousness of work with physical functioning 28 years later. METHODS: A cohort (n = 902) of metal industry employees was studied for exercise and housework activity in 1973 and 1978, and for BMI, current smoking, strenuousness of work, grip strength, and chronic diseases in 1973. Of the 670 survivors in 2000, 529 (79%) responded to all studied items in a follow up questionnaire including the SF-36 Physical Functioning (PF) scale. Belonging to the lower quartile of the PF scale denoted poor functioning. RESULTS: Vigorous exercise and housework activity were inversely associated with poor PF 28 years later in both white-collar and blue-collar workers. Engaging in activities of any intensity was similarly associated among the blue-collar workers. In a multiple logistic regression model including as independent variables age, sex, occupational class, the number of chronic diseases, vigorous leisure time physical activity, BMI, physical work strenuousness, and smoking (all measured at baseline), the risk of poor PF at follow up was decreased by vigorous leisure time physical activity and increased by high physical strenuousness of work, high BMI, and smoking. The effect of work strenuousness was mainly due to that among the blue-collar group. Allowing for baseline grip strength did not materially alter the results. CONCLUSION: Vigorous leisure time physical activity decreased the risk of poor physical functioning as perceived considerably later in life, while high work strenuousness, smoking, and overweight increased it. Among blue-collar workers a beneficial association was observed with all leisure time activity, including that of lower intensity.

Weight changes and the risk of knee osteoarthritis requiring arthroplasty.

OBJECTIVE: To examine the effect of weight changes between 20 and 50 years of age on the risk of severe knee osteoarthritis (OA) requiring arthroplasty. SUBJECTS AND METHODS: Cases were 55-75 year old men and women (n = 220) having had knee arthroplasty for primary osteoarthritis at the Kuopio University Hospital in 1992-93. Controls (n = 415) were randomly selected from the population of Kuopio Province. Weight at the age of 20, 30, 40, and 50 years was collected retrospectively with a postal questionnaire. RESULTS: After adjustment for age, sex, history of physical workload, recreational physical activity, and previous knee injury, weight gain resulting to a shift from normal body mass index (BMI < or =25 kg/m(2)) to overweight (BMI >25 kg/m(2)) was associated with a higher relative risk of knee OA requiring arthroplasty than persistent overweight from 20-50 years of age, compared with those with normal relative weight during the corresponding age period. The odds ratios (OR) were 3.07 (95% confidence interval 1.87 to 5.05) for those with normal weight at the age of 20 years and overweight at two or three of the ages 30, 40 or 50 years, 3.15 (1.85 to 5.36) for those with overweight from the age of 30 years, and 2.37 (1.21 to 4.62) for those with overweight from the age of 20 years, respectively. CONCLUSION: In adult life, a shift from normal to overweight may carry a higher risk for knee OA requiring arthroplasty than does constant overweight.

Possible association of interleukin 1 gene locus polymorphisms with low back pain.

Based on a hypothesis that interleukin 1 (IL-1) activity is associated with low back pain (LBP), we investigated relationships between previously described functional IL-1 gene polymorphisms and LBP. The subjects were a subgroup of a Finnish study cohort. The IL-1alpha(C(889)-T), IL-1beta(C(3954)-T) and IL-1 receptor antagonist (IL-1RN)(G(1812)-A, G(1887)-C and T(11100)-C) polymorphisms were genotyped in 131 middle-aged men from three occupational groups (machine drivers, carpenters and office workers). A questionnaire inquired about individual and lifestyle characteristics and the occurrence of LBP, the number of days with pain and days with limitation of daily activities because of pain, and pain intensity, during the past 12 months. Lumbar disc degeneration was determined with magnetic resonance imaging. Carriers of the IL-1RNA(1812) allele had an increased risk of LBP (OR 2.5, 95% CI 1.0-6.0) and carriers of this allele in combination with the IL-1alphaT(889) or IL-1betaT(3954) allele had a higher risk of and more days with LBP than non-carriers. Pain intensity was associated with the simultaneous carriage of the IL-1alphaT(889) and IL-1RNA(1812) alleles (OR 3.7, 95% CI 1.2-11.9). Multiple regression analyses allowing for occupation and disc degeneration showed that carriage of the IL-1RNA(1812) allele was associated with the occurrence of pain, the number of days with pain and days with limitations of daily activities. Carriage of the IL-1betaT(3954) allele was associated with the number of days with pain. The results suggest a possible contribution of the IL-1 gene locus polymorphisms to the pathogenesis of LBP. The possibility of chance findings cannot be excluded due to the small sample size.

A prospective study on knee pain and its risk factors.

OBJECTIVES: To evaluate the effects of work-related and individual factors as well as physical activity and sports on the incidence and persistence of knee pain among a working population. DESIGN: Employees of a large Finnish forestry company replied to a questionnaire (a modified version of the Nordic Questionnaire) on musculoskeletal pain and its possible risk factors at the baseline of this study. A cohort of 2122 workers free of knee pain and another cohort of 333 workers with severe knee pain were followed up for one year. The effects of the risk factors on the incidence and persistence of knee pain were studied using multivariable logistic regression models. RESULTS: A total of 214 (10%) workers developed knee pain during the follow-up. Significant predictors of incident knee pain in the multivariable model were higher age, overweight, smoking, and previous knee injuries. Also, working with the trunk forward flexed in kneeling or standing position and physically strenuous work were non-significant predictors of incident knee pain. Of those 333 workers with severe knee pain at baseline, 220 (66%) still reported severe knee pain after one year. Higher age and job dissatisfaction increased the risk of persistent symptoms. General physical exercise and different sports activities did not predict the incidence or persistence of knee pain. CONCLUSIONS: In this large prospective study, the risk factors for self-reported knee pain seemed to be highly similar to the risk factors for knee osteoarthritis (OA) reported in other papers. Age, previous knee injuries, overweight, and knee-straining work were those risk factors, which contributed to the incidence of knee pain. Psychosocial elements of work were more involved in the persistence of the symptoms in the knee.

A prospective study of work related factors and physical exercise as predictors of shoulder pain.

OBJECTIVES: To evaluate the effects of work related and individual factors as well as physical activity and sports on the incidence and persistence of shoulder pain among forestry workers. METHODS: Workers in a large Finnish forestry company replied to a questionnaire (a modified version of the Nordic questionnaire) on musculoskeletal pain and its possible risk factors for 4 consecutive years 1992-5. This 1 year follow up study covers the time 1994-5. Year 1994 was chosen as baseline because in that year the questionnaire contained for the first time more detailed questions about different sports. The response rate in 1995 was 90%. The effects of the predictors on 1 year incidence and persistence of shoulder pain were studied with multivariate logistic regression modelling. RESULTS: At baseline, 2094 subjects had been free of shoulder pain during the preceding 12 months. After 1 year, 14% (n=285) reported having mild or severe shoulder pain. Higher age, obesity, and mental stress as well as physically strenuous work and working with trunk forward flexed or with a hand above shoulder level increased the risk of incident shoulder pain. Of the different sports activities, dancing increased the risk of incident pain whereas jogging decreased the risk significantly. Of those 419 workers who had severe shoulder pain at baseline, 55% (n=230) still had severe pain 1 year later. Higher age, overload at work, and working with a hand above shoulder level increased the risk of persistent severe shoulder pain whereas cross country skiing and general sports activity decreased the risk. CONCLUSION: Our results support the current view that shoulder pain is the result of many factors, including occupational and individual factors. In this longitudinal study, physical work with a heavy load, awkward work postures, mental stress, and obesity were the risk factors at which preventive measures could be aimed. As a new finding, physical exercise had more protective than impairing effects on the shoulders.

Physical exercise and musculoskeletal pain among forest industry workers.

The study investigated the relations between physical exercise and musculoskeletal pain among forest industry workers. We studied a population of 3312 Finnish forest industry workers, who replied to a questionnaire survey in 1994 (response rate 77%). The outcome variables in this cross-sectional study were the number of days with pain in the low back, neck, shoulder and knee during the preceding 12 months. Multivariable logistic regression models were used in statistical analyses. Active walkers had more sciatic pain, active volleyball players had more shoulder pain and those who practiced trekking actively had more knee pain than those who practiced these activities less. The risk of shoulder pain was more than three times higher for those who played volleyball actively compared to those who played less. In addition, age, mental stress and work-related physical loading were strongly associated with musculoskeletal pain. When studying the relations between physical exercise and musculoskeletal pain in a working population, it is important to not only detect the general physical activity but also to specify the different modes of exercise. In addition, the other factors which are strongly related to pain (such as mental stress and work-related physical loading) should be taken into account.

Association between pleural plaques and coronary heart disease.

OBJECTIVE: The aim of this study was to verify a clinical impression that patients with coronary heart disease disproportionately frequently have calcified pleural plaques. METHODS: Chest X-rays were collected from 148 patients referred consecutively to the Helsinki University Central Hospital for coronary angiography and from 100 consecutive lung cancer patients seen at the same hospital. The radiographs were analyzed for the presence of calcified pleural plaques according to the classification the International Labour Office. A generalized linear model with binomial distribution and log link was used to estimate the relative risks and their 95% confidence intervals (95% CI). RESULTS: The prevalence of calcified pleural plaques was 35% for the coronary patients and 19% for the lung cancer patients. Calcified pleural plaques were more common among the men than the women, and the risk increased with age. The relative risk of calcified pleural plaques, adjusted for age and gender, was 2.19 (95% CI 1.44-3.32) for the coronary patients as compared with the lung cancer patients. CONCLUSIONS: Further studies with better information on past exposure to asbestos and other potential risk factors are warranted to confirm the observations and to examine whether the association between coronary heart disease and calcified pleural plaques is related to an etiologic or an individual susceptibility factor common to both of these conditions.

Physical exercise and risk of severe knee osteoarthritis requiring arthroplasty.

OBJECTIVES: To examine the association between physical exercise and the risk of severe knee osteoarthritis requiring arthroplasty. SUBJECTS AND METHODS: A case-control study was carried out in which the cases were men (n=55) and women aged 55-75 yr (n=226) receiving knee arthroplasty for primary osteoarthritis at the Kuopio University Hospital. Controls (n=524) were selected randomly from the population of Kuopio province. Lifetime physical exercise was assessed retrospectively. Cumulative exercise hours were calculated and divided into two classes by mean (low/high). RESULTS: The risk of knee osteoarthritis requiring arthroplasty decreased with increasing cumulative hours of recreational physical exercise. After adjustment for age, body mass index, physical work stress, knee injury and smoking, the odds ratios (with 95% confidence intervals) of knee arthroplasty were 0.91 (0.31-2.63) in men with a low number of cumulative exercise hours and 0.35 (0.12-0.95) in those with a high number of cumulative exercise hours, with a history of no regular physical exercise as the reference. For the women, the corresponding odds ratios were 0.56 (0.3-0.93) and 0.56 (0.32-0.98). CONCLUSION: Moderate recreational physical exercise is associated with a decrease in the risk of knee osteoarthritis.

Longitudinal study on work related and individual risk factors affecting radiating neck pain.

OBJECTIVES: To study the effects of work related and individual factors affecting radiating neck pain. METHODS: A longitudinal study was carried out with repeated measurements. A total of 5180 Finnish forest industry workers replied to a questionnaire survey in 1992 (response rate 75%). Response rates to follow up questionnaires in 1993, 1994, and 1995 were 83%, 77%, and 90%, respectively. The outcome variable was the number of days with radiating neck pain during the preceding 12 months with three levels (<8, 8-30, >30 days). The generalised estimating equations method was used to fit a marginal model and a transition model was used in a predictive analysis. RESULTS: Items showing associations with radiating neck pain in both analyses were sex, age, body mass index, smoking, duration of work with a hand above shoulder level, mental stress, and other musculoskeletal pains. In the transition model, radiating neck pain in a previous questionnaire was included in the model. Although it was a strong predictor, the variables already mentioned retained their significance. CONCLUSION: Programmes targeted to reduce physical load at work, mental stress, being overweight, and smoking could potentially prevent radiating neck pain.

Disc height and signal intensity of the nucleus pulposus on magnetic resonance imaging as indicators of lumbar disc degeneration.

STUDY DESIGN: A cross-sectional magnetic resonance imaging (MRI) study of degeneration of the lumbar spine. OBJECTIVES: To compare the usefulness of disc height and that of T2-weighted signal intensity as indicators of disc degeneration. SUMMARY OF BACKGROUND DATA: Disc height and signal intensity have been used as indicators for disc degeneration. Their relation to each other and to early degeneration has not been well documented. There is evidence that physical load can affect disc height. METHODS: Forty-one machine operators, 41 construction carpenters, and 46 office workers, aged 40-45 years, and 22 students aged 18-20 years were examined with sagittal magnetic resonance imaging. All study participants were men. The mean value of the anterior and posterior disc height and the relative T2-weighted signal intensity of the nucleus pulposus of discs L2-L3 to L5-S1 were measured. RESULTS: Young men showed the lowest disc height but the highest relative signal intensity. Disc height showed an increasing trend from the office workers (sedentary) to blue-collar workers (more physical work) at all disc levels but L5-S1. Relative signal intensity showed a decreasing trend for these same worker types at all levels. In generalized linear modeling, signal intensity and the occupations, in reference to the young students, showed a significant effect on disc height. CONCLUSIONS: Relative signal intensity was lower in the middle-aged men than in the young men, indicating age-related disc degeneration. Despite the general positive association between disc narrowing and decreased relative signal intensity, disc narrowing may behave unexpectedly in relation to signal intensity and age. Signal intensity may be a more sensitive measure of disc degeneration. The validity of disc height as an indicator of early degeneration seems questionable.