The impact of non-response weighting in health surveys for estimates on primary health care utilization.

BACKGROUND: Low response rates in health surveys may affect the representativeness and generalizability of results if non-response is systematically related to the indicator of interest. To account for such potential bias, weighting procedures are widely used with an overall aim to obtain less biased estimates. The aim of this study was to assess the impact of applying calibrated weights on prevalence estimates of primary health care utilization among respondents compared to the entire sample of a representative Danish survey of adults aged ≥16 years. METHODS: Registry-based 1-year prevalence data on health care utilization of chiropractor/physiotherapist, dentist and psychologist in 2016 were linked to the entire sample (n = 312 349), including respondents (n = 183 372), from the Danish National Health Survey in 2017. Calibrated weights, which applied information on e.g. sex, age, ethnic background, education and overall health service use were used to assess their impact on prevalence estimates among respondents. RESULTS: Across all included types of health care, weighting for non-response decreased prevalence estimates among respondents, which resulted in less biased estimates. For example, the overall 1-year prevalence of chiropractor/physiotherapist, dentist and psychologist utilization decreased from 19.1% to 16.9%, 68.4% to 62.5% and 1.9% to 1.8%, respectively. The corresponding prevalence in the entire sample was 16.5%, 59.4% and 1.7%. CONCLUSIONS: Applying calibrated weights to survey data to account for non-response reduces bias in primary health care utilization estimates. Future studies are needed to explore the possible impact of weighting on other health estimates.

Sickness absence associated with shared and open-plan offices--a national cross sectional questionnaire survey.

OBJECTIVE: The aim of this study was to examine whether shared and open-plan offices are associated with more days of sickness absence than cellular offices. METHODS: The analysis was based on a national survey of Danish inhabitants between 18-59 years of age (response rate 62%), and the study population consisted of the 2403 employees that reported working in offices. The different types of offices were characterized according to self-reported number of occupants in the space. The log-linear Poisson model was used to model the number of self-reported sickness absence days depending on the type of office; the analysis was adjusted for age, gender, socioeconomic status, body mass index, alcohol consumption, smoking habits, and physical activity during leisure time. RESULTS: Sickness absence was significantly related to having a greater number of occupants in the office (P<0.001) when adjusting for confounders. Compared to cellular offices, occupants in 2-person offices had 50% more days of sickness absence [rate ratio (RR) 1.50, 95% confidence interval (95% CI) 1.13-1.98], occupants in 3-6-person offices had 36% more days of sickness absence (RR 1.36, 95% CI 1.08-1.73), and occupants in open-plan offices (>6 persons) had 62% more days of sickness absence (RR 1.62, 95% CI 1.30-2.02). CONCLUSION: Occupants sharing an office and occupants in open-plan offices (>6 occupants) had significantly more days of sickness absence than occupants in cellular offices.

The attribution of work environment in explaining gender differences in long-term sickness absence: results from the prospective DREAM study.

OBJECTIVES: To identify differences in risk of long-term sickness absence between female and male employees in Denmark and to examine to what extent differences could be explained by work environment factors. METHODS: A cohort of 5026 employees (49.1% women, mean age 40.4years; 50.9% men, mean age 40.2years) was interviewed in 2000 regarding gender, age, family status, socio-economic position and psychosocial and physical work environment factors. The participants were followed for 18months in order to assess their incidence of long-term sickness absence exceeding 8 consecutive weeks. RESULTS: 298 workers (5.9%) received sickness absence compensation for 8weeks or more. Women had an excess risk of 37% compared to men, when adjusting for age, family status and socio-economic position. Physical work environment exposures could not explain this difference, whereas differences in psychosocial work environment exposures explained 32% of the differences in risk of long-term sickness absence between men and women, causing the effect of gender to become statistically insignificant. The combined effect of physical and psychosocial factors was similar, explaining 30% of the gender difference. CONCLUSION: Differences in psychosocial work environments in terms of emotional demands, reward at work, management quality and role conflicts, explained roughly 30% of women's excess long-term sickness absence risk. Assuming women and men had identical working conditions would leave the larger part of the gender difference in long-term sickness absence from work unexplained.

Industrial differences in female fertility treatment rates--a new approach to assess differences related to occupation?

AIMS: Infertility is highly prevalent and 16-26% of women trying to achieve a pregnancy experience infertility in one or more periods. Several exposures in the work environment have been hypothesized to affect female reproduction. This study aimed to estimate relative rates (RR) of female fertility treatment in the 57 industrial groups in Denmark. METHODS: The closed cohort of all 20-39 year old economically active women in Denmark by January 2001 (n = 567,816) were followed-up for hospital contacts due to infertility from 2001 to 2005 as registered in the Danish Occupational Hospital Register. Age-standardized relative rates for being diagnosed as infertile were estimated by industry. Further standardization with respect to socioeconomic status was also performed. RESULTS: In total, 12,575 women were diagnosed with infertility during the follow-up period. Three industries presented with statistically significant elevations in age-standardized RRs: hospitals (RR = 1.27, 95% confidence interval (CI): 1.20-1.35), general and dental practice (RR = 1.17, 95% CI: 1.02-1.35) and other health care (RR = 1.24, 95% CI: 1.09-1.41). Standardization for socioeconomic status rendered two industries that were statistically significantly elevated: manufacture of wood and wood products (RR = 1.20, 95% CI: 1.02-1.42) and hospitals (RR = 1.17, 95% CI: 1.10-1.24). CONCLUSIONS: Interpretation of the results is complex, since the relative contributions to the observed inequalities of the work environment and, for example, differences in inclination to start a family or in proneness to seek treatment are difficult to resolve. Withstanding shortcomings and limitations, register data of fertility treatment offers a possibility to suggest industries for further investigation of reproductive health.

Protocol for work place adjusted intelligent physical exercise reducing musculoskeletal pain in shoulder and neck (VIMS): a cluster randomized controlled trial.

BACKGROUND: Neck and shoulder complaints are common among employees in sedentary occupations characterized by intensive computer use. Specific strength training is a promising type of physical exercise for relieving neck and shoulder pain in office workers. However, the optimal combination of frequency and exercise duration, as well as the importance of exercise supervision, is unknown. The VIMS study investigates in a cluster randomized controlled design the effectiveness of different time wise combinations of specific strength training with identical accumulated volume, and the relevance of training supervision for safe and effective training. METHODS/DESIGN: A cluster randomized controlled trial of 20 weeks duration where employed office workers are randomized to 1 x 60 min, 3 x 20 min, 9 x 7 min per week of specific strength training with training supervision, to 3 x 20 min per week of specific strength training with a minimal amount of training supervision, or to a reference group without training. A questionnaire will be sent to 2000 employees in jobs characterized by intensive computer work. Employees with cardiovascular disease, trauma, hypertension, or serious chronic disease will be excluded. The main outcome measure is pain in the neck and shoulders at week 20. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov, number NCT01027390.

The impact of self-reported exposure to whole-body-vibrations on the risk of disability pension among men: a 15 year prospective study.

BACKGROUND: Whole-body-vibrations are often associated with adverse health effect but the long term effects are less known. This study investigates the association between occupational exposures to whole-body vibrations, and subsequent transition to disability pension. METHODS: A total of 4215 male employees were followed up for subsequent disability pension retirement. Exposure to whole-body-vibration was self-reported while new cases of disability pension were retrieved from a national register. RESULTS: The hazard ratio (HR) for disability pension retirement among men exposed to whole-body-vibrations was 1.61 (95% confidence interval (CI) 1.07-2.40) after adjustment for age, smoking habits, BMI, physical job demands and awkward work postures. In our model, with the available explanatory variables, 5.6% of the male disability pension cases were attributable to whole-body-vibrations. CONCLUSIONS: Exposure to whole-body-vibrations predicts subsequent disability pension retirement. Continued reduction of whole-body-vibrations may reduce the number of new cases of disability pension.

The impact of ergonomic work environment exposures on the risk of disability pension: Prospective results from DWECS/DREAM.

The objectives were to identify the impact of ergonomic work environment exposures on the risk of disability pension. A representative sample of 8475 employees of the total working population in Denmark were interviewed regarding work environment exposures and followed in a national register with data on granted disability pension. For women, approximately 34% of the disability pension cases were attributable to ergonomic work environment exposures. For men, 21% of the disability pension cases were attributable to ergonomic work environment. Ergonomic work environment, especially physically demanding work, working with hands lifted and repetitive work, are areas of intervention at the workplace that can facilitate and prolong labour market participation. The study provides estimates for the association between ergonomic exposures at work and administrative, cost-related measures of work disability in a large population-based longitudinal cohort study over 14 years. Approximately 21% for men and 34% for women of the disability pension cases were attributable to ergonomic work environment exposures.

The impact of job satisfaction on the risk of disability pension. A 15-year prospective study.

OBJECTIVES: To identify the impact of job satisfaction on the risk of disability pension. METHODS: A total of 8,338 employees were sampled from the total working population in Denmark. They were interviewed regarding age, gender, job satisfaction and health behaviour. Interview data were merged with national register data on granted disability pension for up to 15 years after baseline data collection. RESULTS: The study found a statistically significant association between low job satisfaction and disability pension for women when adjusted for age, smoking status and BMI. CONCLUSIONS: Based on the results, investing in giving workers a satisfying work environment could be a low-cost way of improving employee health and prolonging labour market participation.

Increased incidence of infertility treatment among women working in the plastics industry.

Several plastic chemicals adversely affect reproductive ability. This study examined the possible association between employment in the plastics industry and infertility. Dynamic cohorts of economically active women and men were followed for hospital contacts due to infertility in the Danish Occupational Hospitalisation Register, from 1995 to 2005. A person was considered to be at increased risk in a particular year if plastic work was the main occupation in the previous year. Analyses were standardized according to county, socio-economic group, year and age. 107 cases of treatment for female infertility were observed among female plastic workers, as opposed to an expected 87.15 cases, i.e. relative risk was 1.23 (95% CI: 1.01-1.48). For male workers the numbers were 41 respectively 49.9 cases, with relative risk being 0.82 (95% CI: 0.59-1.11). The increased incidence of infertility treatment in female plastics workers motivates more specific studies of reproductive occupational health in the plastics industry.

Self-reported occupational skin contact with cleaning agents and the risk of disability pension.

BACKGROUND: Occupational skin diseases often affect the hands and can lead to consequences at both the individual and the social level. OBJECTIVES: To investigate and quantify the association between self-reported occupational skin contact with cleaning agents and subsequent transition to disability pension. METHODS: A sample of 8337 employees between 18 and 59 years of age participated in the Danish Work Environment Cohort Study in 1990, 1995, or 2000. They were followed up regarding disability pension until 2006 using the DREAM register on social transfer payments for all inhabitants in Denmark. The Cox proportional hazards model was used to estimate the impact of occupational exposure to cleaning agents on subsequent disability pension. RESULTS: Among women, 11% of the disability pension cases were attributable to exposure to cleaning agents and/or disinfectants. CONCLUSIONS: The study suggests a potential for prevention of work-related disabilities among job groups exposed to cleaning agents.

Work injuries and disability.

PROBLEM: This study estimated the hazard ratio for disability pension retirement (DPR) for persons who have experienced a work injury causing absence lasting at least one day after the accidental injury occurred and to estimate the fraction of DPR attributable to work injuries. METHODS: A total of 4,217 male and 4,105 female employees from a national survey were followed up for subsequent DPR. RESULTS AND IMPACT ON INDUSTRY AND GOVERNMENT: Having had a work injury was a strong predictor of DPR among men. After control for age, smoking, body mass index, body postures, and physical demands, the hazard ratio (HR) among those employees who had ever experienced a work injury was 1.80 (95% confidence interval (CI): 1.20-2.68). No association was found among women. SUMMARY: Having had a reportable work injury is a strong predictor of subsequent DPR for men.

Infertility among women working in horticulture. A follow-up study in the Danish Occupational Hospitalization Register.

The possible association between employment in horticulture with potential exposure to pesticides and female infertility was examined by identification of women with hospital contact due to infertility and working in horticulture through the Danish Occupational Hospitalization Register. This follow-up study gave a standardized incidence ratio of 1.06 (95% confidence interval: 0.84-1.32) for treatment of infertility in women working in horticulture compared with the standard population and did not confirm that women working in the horticultural industry are at increased risk for infertility.

Prevalence of workplace bullying and risk groups: a representative population study.

OBJECTIVES: To estimate the prevalence of bullying and to identify risk groups in a representative population sample. METHODS: The data for this study was taken from the second Danish Psychosocial Work Environment Study (DPWES). The sample consisted of 3,429 employees between 20 and 59-years. The response rate for the study was 60.4%. RESULTS: The study showed that 8.3% of the respondents had been bullied within the past year, 1.6% of the sample reported daily to weekly bullying. Co-workers (71.5%) and managers/supervisors (32.4%) were most often reported as perpetrators of bullying, but bullying from subordinates (6%) was also reported. We found significant differences in the prevalence of bullying for both occupational status and work process, a variable characterizing the employees main task in their job. Unskilled workers reported the highest prevalence of bullying, while managers/supervisors the lowest prevalence. People working with things (male-dominated occupations) and people working with clients/patients (female-dominated occupations) reported higher prevalence of bullying than people working with symbols or customers. No significant gender or age differences were found. CONCLUSIONS: These findings suggest that types of work and gender ratio are risk factors in the onset of workplace bullying. Future studies should take into account the type of work and the gender ratio of the organization.

The impact of psychosocial work environment factors on the risk of disability pension in Denmark.

This study quantifies the impact of psychosocial work environment factors on the risk of disability pension. Differences in risk of disability pension were estimated in a representative sample of Danish employees followed for a total of 118 117 person-years of risk time. After control for smoking, BMI and ergonomic work environment, low decision authority and low variation in work showed a statistically significant association with disability pension. Adverse psychosocial work environment factors accounted for 10-15% of disability pension cases.

A randomized trial of mailed questionnaires versus telephone interviews: response patterns in a survey.

BACKGROUND: Data for health surveys are often collected using either mailed questionnaires, telephone interviews or a combination. Mode of data collection can affect the propensity to refuse to respond and result in different patterns of responses. The objective of this paper is to examine and quantify effects of mode of data collection in health surveys. METHODS: A stratified sample of 4,000 adults residing in Denmark was randomised to mailed questionnaires or computer-assisted telephone interviews. 45 health-related items were analyzed; four concerning behaviour and 41 concerning self assessment. Odds ratios for more positive answers and more frequent use of extreme response categories (both positive and negative) among telephone respondents compared to questionnaire respondents were estimated. Tests were Bonferroni corrected. RESULTS: For the four health behaviour items there were no significant differences in the response patterns. For 32 of the 41 health self assessment items the response pattern was statistically significantly different and extreme response categories were used more frequently among telephone respondents (Median estimated odds ratio: 1.67). For a majority of these mode sensitive items (26/32), a more positive reporting was observed among telephone respondents (Median estimated odds ratio: 1.73). The overall response rate was similar among persons randomly assigned to questionnaires (58.1%) and to telephone interviews (56.2%). A differential nonresponse bias for age and gender was observed. The rate of missing responses was higher for questionnaires (0.73-6.00%) than for telephone interviews (0-0.51%). The "don't know" option was used more often by mail respondents (10-24%) than by telephone respondents (2-4%). CONCLUSION: The mode of data collection affects the reporting of self assessed health items substantially. In epidemiological studies, the method effect may be as large as the effects under investigation. Caution is needed when comparing prevalences across surveys or when studying time trends.

Quantifying inequality in health in the absence of a natural reference group.

When quantifying inequality in health, the excess fraction (i.e. the proportional reduction in the outcome in question that would occur if all groups had the same, lowest, risk rate) is an appealing measure. If the population contains a natural, healthiest reference group, the excess fraction is straightforward to estimate. In the absence of an a priori reference group, calculating the excess fraction requires reflection, since using the group with the lowest observed risk rate as reference can lead to erroneous conclusions. This paper proposes a simple simulation procedure for calculating the excess fraction, without fixing a reference group.

Risk factors for neck-shoulder and wrist-hand symptoms in a 5-year follow-up study of 3,990 employees in Denmark.

OBJECTIVES: A prospective follow-up study of employees in Denmark was analyzed in order to investigate the association between physical and psychosocial exposures and musculoskeletal symptoms in the neck-shoulder and wrist-hand regions. METHODS: Data were derived from a 5-year follow-up questionnaire study of a sample of employees in Denmark, aged between 18 and 59 years. Occupational and individual background factors were assessed in 1990, and the associations with symptoms in 1995 were analyzed using logistic regression. The analysis was restricted to comprise employees free of symptoms in 1990. The neck-shoulder and wrist-hand analyses included 1,895 and 3,179 employees, respectively. RESULTS: Among men, neck-shoulder symptoms were predicted by twisting or bending (odds ratio (OR) 1.5, 95% confidence interval (CI) 1.01-2.26) and social support at work (OR 1.8, CI 1.24-2.50 for low versus rather high social support, OR 1.4, CI 1.00-2.09 for high versus rather high social support). Furthermore, an interacting effect of heavy lifting and sedentary work was indicated. Symptoms in the wrist-hand region were predicted by stress symptoms (OR 1.7, CI 1.12-2.71) and twisting or bending (OR 1.7, CI 1.18-2.57). For women, smoking habits predicted neck-shoulder symptoms (OR 1.8, CI 1.14-2.82, former versus never smokers). Symptoms in the wrist-hand region were predicted by stress symptoms (OR 1.7, CI 1.16-2.41) and twisting or bending (OR 1.9, CI 1.34-2.80). CONCLUSION: The results confirm that physical exposures at work influence the development of musculoskeletal symptoms in the neck-shoulder and wrist-hand regions. However, the results also suggest that a psychosocial exposure (social support) and perceived stress symptoms influence musculoskeletal symptoms.