Costs and benefits of multifactorial falls prevention in nursing homes in the Netherlands.

OBJECTIVES: To investigate whether the implementation of a multifactorial falls intervention in nursing homes is cost-beneficial and alleviates the professional workload. DESIGN: A comprehensive quantitative model was developed to calculate the impact of investments in multifactorial falls prevention in nursing homes in the Netherlands, comparing the fall incidence using intervention strategies in 1000 nursing home residents with the conditions of usual care over a five-year timeline. SETTING AND PARTICIPANTS: We built a model combining several data sources regarding falls and injury prevalence in nursing home residents, health care costs, intervention costs and effectiveness, and demographic statistics. MEASURES: The primary outcomes were number of falls and injuries, treatment hours and cost. RESULTS: In the nursing home setting, a baseline scenario was calculated with 1471 falls incidents resulting in 345 injuries per year. The mean cost of injury related treatment and care was calculated 860 thousand euro per year and €4.63 million in five years. Implementing multifactorial intervention over five years, costing 702 thousand euro, resulted in savings in health care costs of €2.0 million, of which €1.6 million was saved in nursing home injury care. The benefits outweighed the costs: each euro invested was compensated by 2.86 euro benefit in total care, 2.31 benefit in nursing home care. Yearly 3050 nursing hours, 3100 paramedical care hours and 760 h of physician care were saved. CONCLUSION AND IMPLICATIONS: Implementation of customized multifactorial interventions provided by multidisciplinary teams is cost-beneficial in reduction of falls in nursing homes. The CBA model gives valuable information about the advantageous consequences (i.e. health benefits, financial benefits and reduced workload of staff) of falls prevention in nursing homes and can provide guidance to the management in structural implementation of multifactorial falls prevention.

Prevention program at construction worksites aimed at improving health and work ability is cost-saving to the employer: results from an RCT.

BACKGROUND: To prolong sustainable healthy working lives of construction workers, a prevention program was developed which aimed to improve the health and work ability of construction workers. The objective of this study was to analyze the cost-effectiveness and financial return from the employers' perspective of this program. METHODS: A total of 293 workers in 15 departments were randomized to the intervention (n = 8 departments) or control group (n = 7). Data on work ability and health were collected using questionnaires. Sick leave data were obtained from the companies. Both the cost-effectiveness analyses and return on investment analyses were performed. RESULTS: After 12 months, the absenteeism costs were significantly lower in the intervention group than in the control group. At 12-month follow-up, no significant differences were found with respect to the primary outcomes (work ability, mental and physical health status) and secondary outcomes (musculoskeletal symptoms), meaning that the intervention was not cost-effective in comparison with the control group. The net-benefit was €641 per worker, and the intervention generated a positive financial return to the employer. CONCLUSION: The intervention in the present study was cost-saving to the employer due to reduced sickness absenteeism costs in the intervention group compared with the control group. However, the intervention cannot be regarded as cost-effective as no significant effects were found for work ability and health.

The effects of workplace stressors on muscle activity in the neck-shoulder and forearm muscles during computer work: a systematic review and meta-analysis.

Workplace stressors have been indicated to play a role in the development of neck and upper extremity pain possibly through an increase of sustained (low-level) muscle activity. The aim of this review was to study the effects of workplace stressors on muscle activity in the neck-shoulder and forearm muscles. An additional aim was to find out whether the muscles of the neck-shoulder and the forearm are affected differently by different types of workplace stressors. A systematic literature search was conducted on studies investigating the relation between simulated or realistic workplace stressors and neck-shoulder and forearm muscle activity. For studies meeting the inclusion criteria, a risk of bias assessment was performed and data were extracted for synthesis. Results were pooled when possible and otherwise described. Twenty-eight articles met the inclusion criteria, reporting data of 25 different studies. Except for one field study, all included studies were laboratory studies. Data of 19 articles could be included in the meta-analysis and revealed a statistically significant, medium increase in neck-shoulder and forearm muscle activity as a result of workplace stressors. In subgroup analyses, we found an equal effect of different stressor types (i.e. cognitive/emotional stress, work pace, and precision) on muscle activity in both body regions. In conclusion, simulated workplace stressors result in an increase in neck-shoulder and forearm muscle activity. No indications were found that different types of stressors affect these body regions differently. These conclusions are fully based on laboratory studies, since field studies on this topic are currently lacking.

Observed differences in upper extremity forces, muscle efforts, postures, velocities and accelerations across computer activities in a field study of office workers.

This study, a part of the PRedicting Occupational biomechanics in OFfice workers (PROOF) study, investigated whether there are differences in field-measured forces, muscle efforts, postures, velocities and accelerations across computer activities. These parameters were measured continuously for 120 office workers performing their own work for two hours each. There were differences in nearly all forces, muscle efforts, postures, velocities and accelerations across keyboard, mouse and idle activities. Keyboard activities showed a 50% increase in the median right trapezius muscle effort when compared to mouse activities. Median shoulder rotation changed from 25 degrees internal rotation during keyboard use to 15 degrees external rotation during mouse use. Only keyboard use was associated with median ulnar deviations greater than 5 degrees. Idle activities led to the greatest variability observed in all muscle efforts and postures measured. In future studies, measurements of computer activities could be used to provide information on the physical exposures experienced during computer use. Practitioner Summary: Computer users may develop musculoskeletal disorders due to their force, muscle effort, posture and wrist velocity and acceleration exposures during computer use. We report that many physical exposures are different across computer activities. This information may be used to estimate physical exposures based on patterns of computer activities over time.

Developing a framework for assessing muscle effort and postures during computer work in the field: the effect of computer activities on neck/shoulder muscle effort and postures.

The present study, a part of the PROOF (PRedicting Occupational biomechanics in OFfice workers) study, aimed to determine whether trapezius muscle effort was different across computer activities in a field study of computer workers, and also investigated whether head and shoulder postures were different across computer activities. One hundred twenty participants were measured continuously for two hours each while performing their own computer work. Keyboard activities were associated with the highest intensity of left and right trapezius muscle efforts, and mouse activities were associated with the smallest variability in left and right trapezius muscle efforts. Corresponding trends in head and shoulder postures included that the greatest head flexion and left and right shoulder internal rotation was observed during keyboard activities, and that the smallest variability in head flexion, head lateral tilt, and right shoulder internal rotation was observed during mouse activities. Identifying which muscle efforts and postures are different across computer activities is the first essential step for developing prediction rules for muscle efforts and postures, which can be used to link muscle efforts and postures to musculoskeletal symptoms in epidemiological studies.

Prognostic factors for disability claim duration due to musculoskeletal symptoms among self-employed persons.

BACKGROUND: Employees and self-employed persons have, among others, different personal characteristics and different working conditions, which may influence the prognosis of sick leave and the duration of a disability claim. The purpose of the current study is to identify prognostic factors for the duration of a disability claim due to non-specific musculoskeletal disorders (MSD) among self-employed persons in the Netherlands. METHODS: The study population consisted of 276 self-employed persons, who all had a disability claim episode due to MSD with at least 75% work disability. The study was a cohort study with a follow-up period of 12 months. At baseline, participants filled in a questionnaire with possible individual, work-related and disease-related prognostic factors. RESULTS: The following prognostic factors significantly increased claim duration: age > 40 years (Hazard Ratio 0.54), no similar symptoms in the past (HR 0.46), having long-lasting symptoms of more than six months (HR 0.60), self-predicted return to work within more than one month or never (HR 0.24) and job dissatisfaction (HR 0.54). CONCLUSIONS: The prognostic factors we found indicate that for self-employed persons, the duration of a disability claim not only depends on the (history of) impairment of the insured, but also on age, self-predicted return to work and job satisfaction.

Internal consistency, test-retest reliability and concurrent validity of a questionnaire on work-related exposure related to arm, shoulder and neck symptoms in computer workers.

The aim of this study was to determine the internal consistency, test-retest reliability and concurrent validity of the RSI QuickScan, a newly developed questionnaire that aims to identify the presumed risk factors for neck, shoulder and arm symptoms in a population of computer workers. The internal consistency was calculated using item analysis. The test-retest reliability and concurrent validity were analysed by calculating the percentage of agreement, Cohen's Kappa and the Ppositive and Pnegative. The concurrent validity was also tested by comparing the results from the new questionnaire with those from the original questionnaires that the current questionnaire was based on, on-site expert observations and direct measurements. The results indicate that the RSI QuickScan is a measurement tool with acceptable internal consistency, reliability and concurrent validity. The questionnaire can be used as a means to rapidly collect data on a large population of office workers and at low cost.

Should office workers spend fewer hours at their computer? A systematic review of the literature.

Worldwide, millions of office workers use a computer. Reports of adverse health effects due to computer use have received considerable media attention. This systematic review summarises the evidence for a relationship between the duration of work time spent using the computer and the incidence of hand-arm and neck-shoulder symptoms and disorders. Several databases were systematically searched up to 6 November 2005. Two reviewers independently selected articles that presented a risk estimate for the duration of computer use, included an outcome measure related to hand-arm or neck-shoulder symptoms or disorders, and had a longitudinal study design. The strength of the evidence was based on methodological quality and consistency of the results. Nine relevant articles were identified, of which six were rated as high quality. Moderate evidence was concluded for a positive association between the duration of mouse use and hand-arm symptoms. For this association, indications for a dose-response relationship were found. Risk estimates were in general stronger for the hand-arm region than for the neck-shoulder region, and stronger for mouse use than for total computer use and keyboard use. A pathophysiological model focusing on the overuse of muscles during computer use supports these differences. Future studies are needed to improve our understanding of safe levels of computer use by measuring the duration of computer use in a more objective way, differentiating between total computer use, mouse use and keyboard use, attaining sufficient exposure contrast, and collecting data on disability caused by symptoms.

Epidemiology of work related neck and upper limb problems: psychosocial and personal risk factors (part I) and effective interventions from a bio behavioural perspective (part II).

Work related neck and upper limb symptoms have a multi-factorial origin. Possible risk factors are of a physical, psychosocial or personal origin. These factors can reinforce each other and their influence can also be mediated by cultural or societal factors. Initially, most research on neck and upper limb symptoms focused on work-related physical exposure. Nowadays, psychosocial work characteristics are recognized as important risk factors. Various models have been developed to offer frameworks for possible pathways, but their empirical support is still not conclusive. In part I of this paper an overview is presented of the results of recent epidemiological studies on work related psychosocial and personal risk factors for neck and upper limb symptoms. In addition, the interplay between these factors and the possible intermediate role of an individuals work style in this process is explored. In contrast to previous reviews, it is now possible to base the conclusions on the effect of work related psychosocial factors on neck and upper limb symptoms on quite a few longitudinal studies. These studies show that high work demands or little control at work are often related to these symptoms. However, this relationship is neither very strong nor very specific. Perceived stress is studied in not as many studies but more consistently related to neck and upper limb symptoms. This also applies to general distress or other pain (co-morbidity). Job dissatisfaction does not contribute to neck and upper limb symptoms. Too little research on personal characteristics is available to draw any conclusions. It is plausible that behavioural aspects, such as work style, are of importance in the etiology of work related upper limb symptoms. However, studies concerning these factors are promising but too scarce to draw conclusions. Future studies should address these behavioural aspects. In part II, the recent studies on the effectiveness of preventive measures for work related neck and upper limb problems are discussed. Few randomised or non randomised controlled trials have been carried out to evaluate the effectiveness of individual or organisational interventions to improve work related psychosocial factors. Very few have reported on the preventive effect for work related neck and upper limb symptoms. Therefore, there is a great need for additional high quality trials before any conclusions on effectiveness of bio-behavioural interventions for reduction of neck and upper limb problems and return to work after these symptoms can be made. From the low back pain intervention research can be learned that interventions should best be targeted to both the worker and the organisation and that interventions will only be successful when all stakeholders are involved.

Do work-related physical factors predict neck and upper limb symptoms in office workers?

OBJECTIVES: The objective of this study was to examine the influence of physical exposure at work on neck and upper limb symptoms in office workers. METHODS: Data were used from a prospective cohort study with a follow-up period of 3 years. Independent variables were physical exposure at work, observed and self-reported. Outcome measures were neck-shoulder symptoms and elbow-wrist-hand symptoms. Data were analyzed with the generalized estimating equation (GEE) method, with adjustment for age, gender, psychosocial work characteristics and the outcome at baseline. RESULTS: Neck rotation was associated with neck-shoulder symptoms in the analyses with observed data (OR: 1.57; CI: 0.99-2.50) as well as those with self-reported data (OR: 1.43; CI: 1.02-2.01). Neck extension was also statistically significantly associated with neck-shoulder symptoms (OR: 2.42; CI: 1.22-4.80), but only self-reported data were available. Neck flexion, self-reported wrist pronation, self-reported arm elevation and self-reported duration of computer work, were not associated with symptoms. An indication was found of an adverse effect on neck-shoulder symptoms of long working days and on elbow-wrist-hand symptoms of self-reported wrist flexion and full-time work or longer compared to part-time work. CONCLUSIONS: Only a limited number of work-related physical factors were related to neck and upper limb symptoms in office workers. Only neck rotation and self-reported neck extension were identified as risk factors for neck-shoulder symptoms.

Physical capacity in relation to low back, neck, or shoulder pain in a working population.

AIMS: To investigate the longitudinal relation between physical capacity (isokinetic lifting strength, static endurance of the back, neck, and shoulder muscles, and mobility of the spine) and low back, neck, and shoulder pain. METHODS: In this prospective cohort study, 1789 Dutch workers participated. At baseline, isokinetic lifting strength, static endurance of the back, neck, and shoulder muscles, and mobility of the spine were measured in the pain free workers, as well as potential confounders, including physical workload. Low back, neck, and shoulder pain were self-reported annually at baseline and three times during follow up. RESULTS: After adjustment for confounders, Poisson generalised estimation equations showed an increased risk of low back pain among workers in the lowest sex specific tertile of performance in the static back endurance tests compared to workers in the reference category (RR = 1.42; 95% CI 1.19 to 1.71), but this was not found for isokinetic trunk lifting strength or mobility of the spine. An increased risk of neck pain was shown for workers with low performance in tests of isokinetic neck/shoulder lifting strength (RR = 1.31; 95% CI 1.03 to 1.67) and static neck endurance (RR = 1.22; 95% CI 1.00 to 1.49). Among workers in the lowest tertiles of isokinetic neck/shoulder lifting strength or endurance of the shoulder muscles, no increased risk of shoulder pain was found. CONCLUSIONS: The findings of this study suggest that low back or neck endurance were independent predictors of low back or neck pain, respectively, and that low lifting neck/shoulder strength was an independent predictor of neck pain. No association was found between lifting trunk strength, or mobility of the spine and the risk of low back pain, nor between lifting neck/shoulder strength or endurance of the shoulder muscles and the risk of shoulder pain.

Effect of sporting activity on absenteeism in a working population.

OBJECTIVES: To determine the effects of sporting activity on absenteeism in a working population. METHODS: Data were used from a prospective cohort study in a working population with a follow up period of 3 years and were collected with yearly questionnaires or collected from company records. Complete data on absenteeism, sporting activity, and potential confounders were collected for 1228 workers. ANOVA was used to test differences in frequency and duration of absenteeism, correlations were computed to measure the association between number of sporting years (divided by age) and frequency and duration of absenteeism, and survival analysis, according to the Cox proportional hazards model, was used to test differences in relative risk at absenteeism and recovery. All analyses were adjusted for age, gender, smoking, and alcohol consumption, and were stratified for employees with sedentary and with more active jobs. RESULTS: ANOVA showed a statistically significant higher mean duration of absenteeism among employees not practicing sports, of approximately 20 days over a period of 4 years. The survival analysis showed an increased relative risk at absenteeism (relative risk (RR) 1.09; confidence interval (CI) 1.01 to 1.18) and a decreased relative risk at recovery (RR 0.90; CI 0.85 to 0.95) for employees not practicing sports. The effect of sporting activity is larger in employees with sedentary work. No associations were found between number of sporting years and absenteeism. CONCLUSION: Employees practicing sports take sick leave significantly less often than their colleagues not practicing sports, while their periods of sick leave are shorter, especially when their work is sedentary.

A comparison of methods for the assessment of postural load and duration of computer use.

AIM: To compare two different methods for assessment of postural load and duration of computer use in office workers. METHODS: The study population existed of 87 computer workers. Questionnaire data about exposure were compared with exposures measured by a standardised or objective method. Measuring true exposure to postural load consisted of an observation of the workstation design and posture by a trained observer. A software program was used to record individual computer use. RESULTS: Comparing the answers for each item of postural load, six of eleven items showed low agreement (kappa <0.20). For six items the sensitivity was below 50%, while for eight items the specificity was 80% or higher. Computer workers were unable to identify risk factors in their workplace and work posture. On average, computer workers overestimated their total computer use by 1.6 hours. The agreement among employees who reported a maximum of three hours of computer use per day was higher than the agreement among employees with a high duration of computer use. CONCLUSIONS: Self-report by means of this questionnaire is not a very reliable method to measure postural load and duration of computer use. This study emphasises that the challenge to develop quick and inexpensive techniques for assessing exposure to postural load and duration of computer use is still open.

[Repetitive strain injury (RSI): occurrence, etiology, therapy and prevention]. / RSI: vóórkomen, ontstaan, therapie en preventie.

In the Netherlands, work related upper-limb disorders are called Repetitive Strain Injuries (RSI). RSI is not a diagnosis but a catch-all term for symptoms and signs located in the neck, upper back, shoulder, arm, elbow, hand, wrist and fingers. These symptoms may include pain, stiffness, tingling, clumsiness, loss of co-ordination, loss of strength, skin discoloration and temperature differences. Each year, 8% of working Dutch citizens take time off work due to RSI symptoms. Although the number of people claiming disability benefit due to RSI is limited, this figure has risen consecutively over the last three years. There is consensus that repetitive work at a high frequency and possibly accompanied by exertion of force is accompanied by RSI symptoms. There are indications of a relation between visual display unit use and these symptoms. However, these relations have not been established in a longitudinal study of adequate quality. High perceived job stress and a high workload are thought to be related to RSI, and women report more symptoms than men. There is insufficient information available on the role of different coping styles, perfectionism and dealing with symptoms. There is little information on the underlying mechanisms in the development of RSI, the diagnostics, therapy and prevention. In view of the lack of clear diagnostic criteria, suggestions have been made for a standardised description of the symptoms involved in the syndrome. A multidisciplinary treatment is likely to have the most effect. In terms of prevention, an integrated approach aimed at improving the working posture, reduction of static load and job stress and at individual factors is assumed to be the most effective.

Spina bifida and parental occupation: results from three malformation monitoring programs in Europe.

As the evidence for an association between spina bifida and parental agricultural occupations is inconclusive, we evaluated this association and the potential associations between spina bifida and other parental occupations. Three register-based case-referent studies were conducted in Sweden, Spain, and Hungary. From the registries of congenital malformations in each country, 482, 478, and 1119 cases with spina bifida were identified, respectively. Identified as referents were 964, 434, and 1489 children without abnormalities. Information on parental occupation was available in the registries from questionnaires or interviews conducted among the parents. Occupations with a potential for physical or chemical exposure were compared to non-exposed occupations. Increased odds ratios (ORs) were observed for women in agricultural occupations in Sweden (OR: 1.8, 95% CI: 0.8-4.2) and in Spain (OR: 2.2, 95% CI: 0.8-5.9), but not in Hungary (OR: 1.1, 95% CI: 0.7-1.7). Several other parental occupations were analysed, but the associations with spina bifida were inconsistent. Concluding, the results are not totally consistent but point to an increased risk of spina bifida among women in agricultural occupations.

Paternal occupational exposure around conception and spina bifida in offspring.

A multi-center case-referent study was conducted on the relation between paternal occupational exposure and spina bifida in offspring. Cases were born between 1980 and 1992 in The Netherlands. Referents were recruited from hospitals and from the general population. Postal questionnaires were used to gather information on occupation and potential confounders. Through job-specific telephone interviews with 122 case fathers and 411 referent fathers, detailed exposure information was collected on specific tasks, the use of chemical or physical agents, frequency of exposure, and use of protective equipment. The study yielded statistically significant associations between spina bifida and low exposure to welding fumes (OR = 1.6, 95% CI: 1.0-2.6) and low exposure to UV radiation during welding (OR = 2.6, 95% CI: 1.2-5.6), and suggestive findings of an association between spina bifida and moderate or high exposure to cleaning agents, moderate or high pesticide exposure (OR = 1.7, 95% CI: 0.7-4.0), and stainless steel dust (OR = 2.0, 95% CI: 0.8-5.2). No associations were identified for other paternal occupational exposures, such as organic solvents.

Heterogeneity of spina bifida.

Splitting birth defects into dysmorphologically homogeneous groups might improve the ability to detect a genetic risk factor or teratogenic exposure. With regard to spina bifida, recent studies suggest that etiologic heterogeneity exists within the group of spina bifida, although exogenous risk factors have been sparsely evaluated for subgroups. In the present study, 210 spina bifida patients were classified into relatively homogeneous groups, based on retrospective information on appearance and functional aspects of the lesion abstracted from medical records of the patients. We compared high with low spina bifida, and open with closed spina bifida, and investigated whether risk factors for spina bifida such as maternal age, antiepileptic drug use, parental occupation, and genetic factors were specifically associated with these homogeneous subclasses. For these comparisons, a referent group of 671 children was used. Although classifying spina bifida into homogeneous subclasses presented some difficulties and numbers were small, this study provides some evidence for different risk profiles for subclasses of spina bifida. The sex ratio, the proportion of miscarriages of siblings, and maternal age did not differ among the different subclasses of spina bifida. However, children with a positive family history of neural tube defects (NTDs) had a higher risk of high spina bifida [odds ratio (OR) = 6.3, 95% confidence interval (CI): 1.7-19.2] than of low spina bifida (OR = 2.1, 95% CI: 1.0-4.2). Siblings with NTDs were more common in cases with high spina bifida and cases with open spina bifida. A strongly increased risk of high spina bifida was found for male welders (OR = 12.1, 95% CI: 1.5-64.2), whereas the risk of low spina bifida was much lower (OR = 1.6, 95% CI: 0.2-7.9). For mothers with agricultural occupations, a strongly increased risk was observed for open spina bifida (OR = 14.3, 95% CI: 2.9-77.7), whereas none of 107 cases with closed spina bifida had a mother with an occupation in agriculture. Due to small numbers, the results must be interpreted with caution.

Assessment of occupational exposure in a population based case-control study: comparing postal questionnaires with personal interviews.

BACKGROUND: In case-control studies, data collection on occupational exposures by means of personal interviews is usually costly and time consuming. As detailed semiquantitative information on exposure from these interviews often has to be dichotomised in the analyses due to the small numbers of exposed subjects, the question is raised whether simple postal questionnaires yield the same results for occupational exposure in epidemiological studies as job specific personal interviews. METHODS: Data on occupational exposures during pregnancy were compared from 121 women who both completed a checklist with 17 occupational exposure categories in a postal questionnaire and were personally interviewed with specific questions on exposure with details of job and task. kappa Coefficients were calculated as measures of agreement corrected for chance, and sensitivity and positive predictive values as measures of validity and usefulness, with the exposure assessment based on information from the interview as the gold standard. RESULTS: Values of kappa varied from 0.09 for domestic cleaning agents to 0.70 for pesticides, indicating only low to moderate agreement between the questionnaire and the interview. Sensitivity ranged from 38% to 100%, with the highest values for agents used by healthcare workers. Positive predictive values were lower, between 9% and 63%, which indicates that overreporting was more common than underreporting in the questionnaire. CONCLUSIONS: These results underline the high potential for misclassification of occupational exposure in studies based on questionnaires. Therefore, postal questionnaires are not considered an alternative to job and task specific personal interviews in epidemiological studies.

Spina bifida and parental occupation in a Swedish register-based study.

OBJECTIVES: To gather more evidence on a possible relation between spina bifida and agricultural and other occupations of parents, a register-based linkage study was conducted in Sweden. METHODS: Four hundred and eighty-two cases of spina bifida in infants born between 1976 and 1991 were identified from the Swedish Register of Congenital Malformations. Nine hundred and sixty-four referents without spina bifida were selected from the Medical Birth Register and matched for year of birth of the child, maternal age, and parity. Information on occupation was obtained from the Medical Birth Register from 1983 on, and from the census, which is performed every fifth year. RESULTS: A slightly increased odds ratio (OR) was observed for women in agricultural occupations [OR 1.8, 95% confidence interval (95% CI) 0.8-4.2]. For all women who had an agricultural occupation or lived on a farm, the OR was 2.2 (95% CI 1.3-3.8). The OR values of most of the other occupational groups were close to unity. CONCLUSIONS: The results suggest an increased risk of spina bifida for the infants of women in agricultural occupations, but they do not provide insight into any specific occupational risk factors.

Spina bifida and parental occupation.

To examine the association between parental occupation and spina bifida in offspring, we conducted a multicenter case-referent study in the Netherlands. Cases were children with spina bifida aperta from nine different hospitals throughout the country; the referent group comprised population-based referents who were randomly drawn from municipal birth registries. All children were born between 1980 and 1992. We collected data using postal questionnaires for both parents with questions about occupational title, industry, daily occupational activities, and a number of potential confounders. We were able to include 353 cases and 1,329 referents in the analyses. We found increased risks for maternal agricultural occupations [odds ratio (OR) = 5.6; 95% confidence interval (CI) = 1.8-17.8] and for cleaning women (OR = 1.9; 95% CI = 0.9-3.9). For the fathers, we saw increased odds ratios for welders (OR = 2.1; 95% CI = 0.6-7.0) and transport workers (OR = 1.4; 95% CI = 0.9-2.1).