Development of trunk asymmetry in a cohort of children ages 11 to 22 years.

STUDY DESIGN: A cohort study with a follow-up period of 11 years. OBJECTIVES: To study the growth of the spine with a focus on the development of trunk asymmetry and scoliosis. SUMMARY OF BACKGROUND DATA: Trunk asymmetry, a common phenomenon at adolescence, can be considered the clinical expression of scoliosis. The importance of the pubertal growth spurt has been stressed in the natural history of scoliosis. However, no cohort studies have focused on the ascending and descending phase of the spine's peak growth and the development of trunk asymmetry. METHODS: The cohort consisted of all the fourth-grade school children in the Western school district of Helsinki, Finland, in the spring of 1986. These 1060 children (515 girls and 545 boys), from the average age of 11 to 14 years, were invited to undergo annual examinations. The 855 children (80.7%) who had participated in the study at the age of 14 years were invited to a reexamination at the age of 22 years. This invitation was accepted by 430 (208 women and 222 men; 54%) of those invited. The forward bending test, the spinal pantography, and the anthropometric measurements were carried out by the same author (M.N.) throughout this study. RESULTS: At 22 years of age, 30% of the adults were found to be symmetric, with a hump less than 4 mm in the forward bending test, whereas 51% had a hump of 4 to 9 mm, and 19% had a hump 10 mm or larger (major asymmetry). The directional asymmetry of trunk surface, a skew to the right at the thoracic level and to the left at the lumbar level at puberty, remained constant at adult age. The prevalence of major trunk asymmetry at adult age was the same in both women and men, in contrast to the female predominance at puberty in this cohort. There were close correlations in the degrees of thoracic and lumbar asymmetry between puberty and adult ages. CONCLUSIONS: The shape of the back develops mainly during the pubertal growth spurt at ages 12 to 14 years in girls and boys. Trunk asymmetry (and mild scoliosis) seems as prevalent in young adult women as in men, although at puberty idiopathic scoliosis was twice as prevalent among girls as among boys in this cohort.

Changes in capability in a sample of Finnish aging workers.

The purpose of the present study was to determine how capabilities changed during a 16-year follow-up, and the role of aging in the process. The study population consisted of those who filled out all four questionnaires (n = 3815). At the baseline, in 1981, all participants were active workers with a mean age of 50 years (range 45-58). In 1997, the respondents were mainly retired, only 5% were still at work. The total measure of capability was constructed by summing up the dimensions of cognitive, psychoemotional, physical, and motor capacity. The associations between capability and age, type of work, and occupational status were estimated by general linear models. The results indicate that there was a strong decrease of capability in the 50-year-old active workers from 1985 to 1992. After that, capability began to rise again. This suggests that more actions of promoting working ability should be directed to this age group.

Stress management, aging, and disease.

The association of stress management, work, and individual factors with the incidence of upper-back disorders and coronary heart disease was studied according to the House paradigm of stress research. The features of work concerned its organization and social environment. Stress management and individual factors covered coping styles, sense of coherence, family roles, gender, and age. These factors were measured by questionnaire studies in 1992 when the subjects (n = 1101, mean age 58 years) were active workers, and again in 1997. Manageability and withdrawal stress response prevented upper-back disorders, whereas dissatisfaction with the work schedule predicted these disorders. Male gender predicted coronary heart disease.

Finnish research project on aging workers in 1981-1992.

The objective of this follow-up study of aging workers was to determine changes in the work, life-style, health, functional capacity, and stress symptoms of Finnish municipal employees from 1981 to 1992. In addition, factors that predict improvement or decline in the ability to work were studied. With the use of this information, attempts were made to produce practical measures to decrease the work-related health risks of elderly workers and increase factors promoting work ability. Along with the stress-strain model applied in the study, the reference frame of the World Health Organization (WHO) was used. The WHO model emphasizes the interaction between work, life-style, aging, and health. Work, life-style, health, work ability, and stress symptoms were studied through the use of comprehensive questionnaire surveys in 1981, 1985 and 1992. Initially, all the subjects (N = 6257) were employed in municipal occupations. During the follow-up, the data were supplemented by information on disability to work and mortality. The changes in work, life-style, health, work ability, and stress symptoms were examined among employees who worked in the same job (N = 924) during the entire follow-up period.

Life-style, aging and work ability among active Finnish workers in 1981-1992.

OBJECTIVES: Life-style is an important factor in explaining the changes in health and well-being in old age. In this study life-style was defined according to Abel's definition as combining life chances and life conduct. The main question concerned the change in life-style components and work ability over a 11-year period. METHODS: The study population comprised workers who responded to a questionnaire in both 1981 and 1992 and were still working in 1992 (N = 924). The changes in the dimensions of life-style (hobbies, living habits, life satisfaction) were tested with Pearson's chi-square test. The associations between life-style, work ability, and health were analyzed by correspondence analysis. RESULTS: Physical activity was the life-style factor that showed a major change; it increased among both genders. All other leisure-time activities decreased during the follow-up. The women's satisfaction with their life situation increased, but the men were less satisfied at the end of the study. Work ability, as measured with the work ability index, was a crucial factor in these changes. If the work ability remained good, the respondents were also more active and more satisfied with their life. This effect of work ability was strong, especially with respect to the men's satisfaction with their life situation. CONCLUSIONS: Life-style, work ability, and perceived health are highly associated, and studying them separately may give a simplistic view of the interaction between aging and work. In the future, more comprehensive approaches should be applied.

Aging and changes in health.

OBJECTIVES: The study explored changes in the health of aging workers from 1981 to 1992. METHODS: Municipal workers [age 55 to 69 (mean 61.6) years in 1992] who filled out questionnaires in both 1981 and 1992 (N = 4534) were studied. The changes in disease prevalence and perceived health were tested with Pearson's chi-square independence test. Improvement and decline in perceived health were analyzed by logistic regression models. RESULTS: In 1992, significantly more diseases were reported than in 1981; the musculoskeletal disease rate rose from 38% in 1981 to 53% in 1992 for the women and from 35% to 49% for the men and the cardiovascular disease rate rose from 15% in 1981 to 28% in 1992 for the women and from 19% to 37% for the men. The age differences diminished during the follow-up. Self-assessed health improved in all the age groups among both those still working in 1992 and those retired. The association between illnesses and perceived health changed during the follow-up, 11% of those with no diseases experiencing their health as good in 1981 and over 40% in 1992. The most important factors explaining the improvement appeared to be a low number of physical illnesses and the absence of cardiovascular and musculoskeletal disease. Nonphysical work, frequent physical exercise, and satisfaction with life situation were also significant contributors to good perceived health. CONCLUSIONS: The improvement in perceived health during the follow-up may mean that older people have lower criteria for good perceived health than younger people do. The associations between self-assessed health and the presence of disease need further study.

Left handedness and risk of thoracic hyperkyphosis in prepubertal schoolchildren.

BACKGROUND: Hand dominance and spinal posture were studied for their prediction of the development of thoracic hyperkyphosis during the pubertal growth spurt. METHODS: The cohort consisted of all the fourth-grade school children of the Western School District of Helsinki, Finland, in the spring of 1986. They were examined annually from the mean age of 10.8 to 13.8 years. Handedness was determined at the baseline examination by observing the hand with which the child was writing. Anthropometric measurements, posture and growth were followed-up annually. A lateral standing radiograph was undertaken in those children who had pronounced thoracic kyphosis in spinal pantography. Kyphotic angles > or = 45 degrees were considered hyperkyphotic. RESULTS: In both girls and boys, left handedness was found to be a powerful determinant of hyperkyphosis. In left handed children the odds ratio (OR), adjusted for baseline spinal measurements, was 4.11 (95% confidence interval [CI]: 1.39-12.13). Hump size measured by the forward bending test also predicted significantly the development of thoracic hyperkyphosis (OR = 1.48; 95% CI: 1.23-1.76, per one degree). CONCLUSIONS: Left handedness may be a risk factor for thoracic hyperkyphosis during the pubertal growth spurt.

Anthropometric measurements and the incidence of low back pain in a cohort of pubertal children.

STUDY DESIGN: The authors studied the anthropometric measurements to predict low back pain (LBP) in a cohort of growing adolescents. SUMMARY OF BACKGROUND DATA: The cohort consisted of all the fourth-grade school children of the western school district of Helsinki, Finland, in the spring of 1986. They were examined annually from the mean age of 11.8 to 13.8 years. METHODS: The forward bending test, measurements of total arm length, pelvic equilibrium, and spinal pantographs were carried out by the same physiatrist. A standardized pain questionnaire presented at the final examination obtained the history of LBP. Of the original cohort of 1060 children, those 859 (408 girls and 451 boys) who participated in all the examinations and had not had LBP until the age of 12.8 years were included in this study. RESULTS: The 1-year (from 12.8 to 13.8 years) incidence of LBP was 18.4% in girls and 16.9% in boys. Trunk asymmetry measured by the forward bending test and sitting height were significant determinants of the incidence of LBP. In the whole cohort, the odds ratio (OR) of trunk asymmetry adjusted for all the other risk determinants was 1.19 and its confidence interval (CI) was 1.00-1.39 per one standard deviation increase of the trunk hump. In the multivariate analysis comprising both sexes, OR per one standard deviation increase of sitting height was 1.24, (95% CI 1.03-1.46). In boys, standing height (OR 1.40, 95% CI 1.13-1.65, per one standard deviation) and sitting height (OR 1.35, 95% CI 1.09-1.63, per one standard deviation) were positively associated with the risk of LBP. These associations were not significant in girls. CONCLUSIONS: Sitting height and trunk asymmetry may contribute to LBP in pubertal children. The role of anthropometric characteristics seems, however, modest.

Trunk asymmetry, posture, growth, and risk of scoliosis. A three-year follow-up of Finnish prepubertal school children.

Several anthropometric measurements were studied for their prediction of scoliosis in 896 children (430 girls and 466 boys) who were free from scoliosis at entry. The children were examined annually from the average age of 10.8 to 13.8 years to follow up their trunk asymmetry, posture, and growth. Scoliosis developed in 24 boys and 41 girls (Cobb angle > or = 10 degrees in a posteroanterior standing radiograph) during the 3 years. In both girls and boys, trunk asymmetry measured by the forward bending test was found to be the most powerful determinant of the incidence of scoliosis. In the whole cohort the adjusted odds ratio was 1.61 and its 95% confidence interval was 1.42-1.82 per one millimeter increase in trunk hump. Using spinal pantography the degree of thoracic kyphosis in girls (odds ratio = 1.05, 95% confidence interval = 1.01-1.09, per one degree) and the degree of lumbar lordosis in boys (odds ratio = 1.07, 95% confidence interval = 1.01-1.13, per one degree) were significant predictors of future scoliosis. In the children both sexes who eventually had scoliosis, body height, sitting height, and growth of sitting height were greater than in other children, but these factors carried no statistical significance in the logistic analyses. There were differences between the prescoliotic girls and other girls in both mean age (11.8 vs 12.1 years, P = 0.02) and value (5.5 cm vs 6.1 cm/yr, P = 0.08) of peak sitting height velocity.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnitude of misclassification bias when using a job-exposure matrix.

A job-exposure matrix constructed in Southampton, the United Kingdom, was assessed with the use of 1205 occupational histories collected for a case-referent study on primary liver cancer in Finland. The odds ratios calculated on the basis of the matrix and an assessment by occupational hygienists were compared. The ability of the matrix to detect excess risk was generally satisfactory for chemical and physical agents to which about 10% or more of the studied population was exposed. If only probable exposure at a high level was assigned to the category of the exposed, an excess risk was usually detectable also when the prevalence of exposure was below 10%. This assessment indicates that the British job-exposure matrix is an acceptably valid screening tool also outside the United Kingdom, provided that the misclassification characteristics of the matrix and the significant differences in exposure between the countries are taken into account.

Primary liver cancer and occupational exposure.

In a dynamic population-based case-referent study on primary liver cancer and occupational exposure, the work histories of 344 cases and 861 referents, derived from the follow-up of the whole Finnish population in 1976-1978 and 1981, were analyzed by industry, occupation, and agent. After adjustment for alcohol consumption, elevated odds ratios were found for the categories other agricultural workers (mainly milkmaids), clerical workers, persons exposed to welding fumes and those exposed to other inorganic dusts (mainly silica). One possible explanation for the excess among milkmaids was exposure to dust from cattle feed contaminated with aflatoxins. The excess among clerical workers was probably due to nonoccupational factors or chance because occupational exposure was generally rare. The excesses for welding fumes and inorganic dusts, although compatible with occupational etiology, contradict the results of many previous studies carried out among workers exposed to silica dust and welders.