White matter hyperintensities and cognitive performance in adult patients with bipolar I, bipolar II, and major depressive disorders.

PURPOSE: We evaluate for the first time the associations of brain white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) with neuropsychological variables among middle-aged bipolar I (BPI), II (BPII) and major depressive disorder (MDD) patients and controls using a path model. METHODS: Thirteen BPI, 15 BPII, 16 MDD patients, and 21 controls underwent brain MRI and a neuropsychological examination. Two experienced neuroradiologists evaluated WMHs on the MRI scans. We constructed structural equation models to test the strength of the associations between deep WMH (DWMH) grade, neuropsychological performance and diagnostic group. RESULTS: Belonging in the BPI group as opposed to the control group predicted higher DWMH grade (coefficient estimate 1.13, P=0.012). The DWMH grade independently predicted worse performance on the Visual Span Forward test (coefficient estimate -0.48, P=0.002). Group effects of BPI and MDD were significant in predicting poorer performance on the Digit Symbol test (coefficient estimate -5.57, P=0.016 and coefficient estimate -5.66, P=0.034, respectively). LIMITATIONS: Because of the small number of study subjects in groups, the negative results must be considered with caution. CONCLUSIONS: Only BPI patients had an increased risk for DWMHs. DWMHs were independently associated with deficits in visual attention.

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.

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.

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.

Anticardiolipin and antinuclear antibodies in epilepsy--a population-based cross-sectional study.

Increased prevalence of autoantibodies has been suggested in patients with epilepsy. This study determined the presence of autoantibodies in a representative cohort of 960 patients with epilepsy. The frequency of antinuclear antibodies (ANA), immunoglobulin G class anticardiolipin antibodies (aCL) and anti-B2-glycoprotein I antibodies were studied in 960 consenting adult patients with epilepsy and in 580 population-based reference subjects identified from the Finnish Population Registry. Overall the frequencies of the autoantibodies studied did not differ between patients with epilepsy and reference subjects. aCL were present in 4.5% of the patients and in 5.0% of the reference subjects and 17% of both the patients and the reference subjects had antinuclear antibodies. However, patients with partial epilepsy for > or =30 years were three times more likely to have aCL than patients with partial epilepsy for <10 years. Patients with partial epilepsy and > or=1 seizure per month were 2.2 times more likely to have aCL than patients with partial epilepsy with <1 seizure per month. Moreover, ANA tended to be more frequent among patients with > or =1 seizure per month. No association was found between the major antiepileptic drugs and autoantibodies. Overall the frequencies of the autoantobodies studied were similar in the large epilepsy cohort and in matched reference subjects from the general population. However, a long duration of epilepsy and poor seizure control were associated with an increased presence of aCL in patients with partial epilepsy.

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.

Low back pain in relation to lumbar disc degeneration.

STUDY DESIGN: Cross-sectional magnetic resonance imaging (MRI) study. OBJECTIVES: To study the relation of low back pain (LBP) to disc degeneration in the lumbar spine. BACKGROUND DATA: Controversy still prevails about the relationship between disc degeneration and LBP. Classification of disc degeneration and symptoms varies, hampering comparison of study results. METHODS: Subjects comprised 164 men aged 40-45 years-53 machine drivers, 51 construction carpenters, and 60 office workers. The data of different types of LBP, individual characteristics, and lifestyle factors were obtained from a questionnaire and a structured interview. Degeneration of discs L2/L3-L5/S1 (dark nucleus pulposus and posterior and anterior bulge) was assessed with MRI. RESULTS: An increased risk of LBP (including all types) was found in relation to all signs of disc degeneration. An increased risk of sciatic pain was found in relation to posterior bulges, but local LBP was not related to disc degeneration. The risks of LBP and sciatic pain were strongly affected by occupation. CONCLUSIONS: Low back pain is associated with signs of disc degeneration and sciatic pain with posterior disc bulges. Low back pain is strongly associated with occupation.

Lumbar disc degeneration in relation to occupation.

OBJECTIVES: The aim was to study risk factors of lumbar disc degeneration demonstrable with magnetic resonance imaging (MRI) with special emphasis on occupational load and back accidents. METHODS: The subjects in this cross-sectional study were 53 machine drivers, 51 construction carpenters, and 60 municipal office workers aged 40-45 years. Data on possible risk factors were available from current structured questionnaires and for 4 and 7 years in retrospect. The prevalence of lumbar disc degeneration L2/L3-L5/S1 was determined with MRI. RESULTS: An increased risk was found for posterior disc bulges among the carpenters and for anterior disc bulges among the machine drivers, but decreased signal intensity was not related to occupation. Car driving was also associated with anterior disc bulges. All signs of disc degeneration were related to a history of back accidents. Disc degeneration was not related to body height, overweight, smoking, or the frequency of physical exercise. CONCLUSIONS: Occupational load affects the risk of disc degeneration of the lumbar spine. Accidental back injuries and motor vehicle driving are associated with an increased risk of disc degeneration. Anterior and posterior disc bulges seem to be related to different types of physical loads.

Financial incentives and productive efficiency in Finnish health centres.

This paper examines the productive efficiency of Finnish health centres by applying data envelopment analysis (DEA) and econometric methods. The Tobit model was used in an attempt to find out how various economic, structural and demographic factors affect efficiency. The dependent variable of the model, the coefficient of inefficiency, was obtained by deducting the DEA efficiency score from one. According to the results, a high percentage of funding coming from central government matching grants and high taxable income per inhabitant are significant predictors of inefficiency. The results suggest that more generous resources tend to increase inefficiency since they may lessen incentives for tight cost and performance control. A high share of doctors and a low share of administrative, maintenance and support personnel promote efficiency. A low population share of the elderly and a long distance to the nearest hospital are positively associated with inefficiency.

Determinants of expenditure variation in health care and care of the elderly among Finnish municipalities.

In Finland, municipal health care expenditure varies from FIM 3 800 per capita to FIM 7 800 per capita. The objective of this study was to estimate the impact of different economic, structural and demographic factors on the per capita costs of health services and care of the elderly. Using regression analysis we attempted to explain observed differences in expenditure by determining separately the effects of allocative and productive inefficiency and the effects of factors influencing the demand for services. We found income level of local population, generosity of central government matching grant, allocative efficiency (the mix of care between institutional and non-institutional care), productive efficiency of service providers, and factors associated with the need of services (age structure, morbidity) to be the most important determinants of health care expenditure. Our results reveal that municipalities have the means at their disposal (by shifting resources to outpatient care and increasing productivity) to significantly reduce expenditure on health services and care of the elderly.

Is the signal intensity of cerebrospinal fluid constant? Intensity measurements with high and low field magnetic resonance imagers.

The signal intensity of cerebrospinal fluid (CSF) was studied by measuring the intensity of nine samples of CSF using various routine pulse sequences with 1.0 T and 0.1 T magnetic resonance imagers. The observed signal intensity differences between the CSF samples were small, as were the differences between the CSF samples and distilled water, although two of the samples were pathological with an elevated protein content. Signal intensity did not correlate with the protein content, and the location of the sample in the coil (head coils were used) caused more variation in the results than did the composition of the sample. The same results were obtained with both imagers. Our results suggest that CSF may be suitable for an intensity reference in routine patient studies in regions where the flow and pulsatile movement of CSF are slow enough not to affect the signal intensity, but further studies are needed to determine such regions in the CSF system.

Congenital malformations and maternal occupation in Finland: multivariate analysis.

The Finnish Register of Congenital Malformations was used in a multivariate analysis to explore the associations between maternal occupation in industry and children born with central nervous system (CNS) or musculoskeletal or oral cleft malformations. Possible confounding factors were selected in preliminary screening of risk indicators for malformations. These factors included characteristics of the mother, the child, and the family; maternal illnesses; an maternal medication at the time of pregnancy. Tobacco smoking was a confounding factor for all type of malformations; number of children born to the mother, maternal age, malformations in the family, number of rooms occupied by the family, sex of the child, threatened abortion, and continuous medication of the mother during the first trimester confounded the association for certain type of malformations. After adjusting for confounding factors, maternal occupation in industrial trades significantly correlated with CNS, oral cleft, and musculoskeletal malformation in the offspring. Maternal occupation in industry and construction only was significantly associated with CNS malformations in the offspring but the associations with oral cleft and musculoskeletal malformations were not significant.

Transplacental carcinogens and mutagens: childhood cancer, malformations, and abortions as risk indicators.

Childhood cancer, malformations, and spontaneous abortions in Finland were analyzed according to the parents' occupations. Children of women working in the food industry and farming and of men working in motor vehicle driving and farming appeared to have an elevated risk of cancer. Women in industrial and construction occupations had an increased risk of having malformed children and spontaneous abortions.

Angina pectoris, ECG findings and blood pressure of foundry workers in relation to carbon monoxide exposure.

A prevalence study on angina pectoris, ECG changes, and blood pressure was carried out with those 1,000 workers (response rate 93.1%) with the longest exposure time (minimum 4.2 years) from a statistical sample of 20 foundries. The history of angina was obtained from a questionnaire recommended by the World Health Organization, and the ECGs were coded according to the Minnesota code. On the basis of measurements of the concentration of carbon monoxide (CO) in the air, the workers were divided into three occupational exposure groups, one with definite CO exposure, one with slight or occasional CO exposure, and one without CO exposure. Allowance was also made for present and past smoking habits. All comparisons were made on an intrastudy basis between the different subcategories. The prevalence of angina showed a clear dose-response relationship with regard to CO exposure from either occupation, smoking, or both, but no such trend was found for ECG findings suggestive of CHD. These results may suggest a greater sensitivity in detecting CHD on the part of the angina questionnaire. The systolic and diastolic blood pressures of CO exposed workers were slightly higher than those of other workers when age and smoking habits were taken into consideration. However, exposure to heat was intermixed with exposure to CO. It could be shown that selection based on health had operated in the foundries. Hence, the prevalence found can be considered to be underestimates of the "true" occurrence of cardiac disorders. Nevertheless both angina and "coronary" ECG findings were more prevalent than in other methodologically comparable studies on the general population or industrial workers without toxic exposure.

Prevalence of pneumoconiosis and chronic bronchitis in foundry workers.

The prevalence of pneumoconiosis, chronic bronchitis, and impaired lung function was studied among those 1,000 foundry workers (response rate 93.1%) with the longest exposure time (minimum 4.2, mean 17, SD 9 years) from a representative sample of 20 foundries. Pneumoconiosis was diagnosed from 100 x 100 mm radiographs, and the false positives and false negatives were evaluated from normal-size radiographs from all those with a positive finding and a sample of those with a negative finding. Chronic bronchitis was studied by means of a translation of the MRC Short Questionnarie on Respiratory Symptoms. Forced vital capacity and forced expiratory volume in 1 s were measured with a Vitalograph Single Breath Wedge Spirometer, and the FEV % was calculated from these variables. The subjects were grouped according to smoking habits and dust exposure, which could be fairly well evaluated from measurements performed in connection with the health survey. All comparisons were made between different subcategories. The overall prevalence of pneumoconiosis was 3.8%, when allowance had been made for false positive and false negative findings. Most cases were mild. Chronic bronchitis occurred more frequently among those occupied in jobs classified as dusty. Smoking also strongly increased its prevalence; a combination of both exposures produced the strongest effect. The effect of smoking was also evident as an impairment of lung function; however, no such effect of dust exposure could be shown in this material. Since this was a prevalence study, the selective removal of workers from dusty jobs probably led to underestimates of all the health effects studied. In spite of the effect of selection excess bronchitis could be demonstrated in workers from dusty environments. Therefore effective dust control must be initiated not only with regard to silica dust but also with respect to total dust.

Turnover and health selection among foundry workers.

The quantity, reasons, and health selection involved in labor turnover were studied with the use of questionnaires and employers' records. The basic material was the personnel of 20 representative foundries. The turnover in 1950--1972 was estimated from a sample of 588 workers. The causes and health selection were studied with questionnaires put to the 1,789 current employees (91% response), the 493 foundrymen who had left after at least 5 years of exposure (the 5-year-plus men, 71% response) and 424 of those who had left after less than 1 year of exposure (the 1-year-minus men, 55% response). The men were asked to describe their present and earlier work at the foundry, the nature and duration of their exposure, diagnosed lung and heart diseases, and chronic bronchitis and angina pectoris and to assess their present and former state of health and work capacity. The disability analysis was based on a sample of 2,834 men whose data were taken from the Social Insurance Register. The disability findings were compared to expected values based on the Finnish male population. Turnover proved to be rapid; short periods of employment predominated. The major reasons for leaving were poor work conditions, physically demanding work, low pay, and poor health. The turnover was fastest in dusty occupations. Relatively more exfoundrymen, both 5-year-plus and 1-year-minus, than current employees felt their health and/or work capacity to be poor. More of the older men in the 5-year-plus group than men of the same age in the current group had chronic bronchitis and diagnosed lung disorders. Both the 5-year-plus and the 1-year-minus exfoundrymen had relatively more diagnosed heart disorders than did the current employees. The disability prevalences of the foundrymen in any category of diseases did not exceed the expected values based on the male population. The overall findings indicate early health selection prior to pensionable disability and/or death.