Separable and controlled direct effects for competing events: Estimation of component specific effects on sickness absence.

In many settings, it is reasonable to think of treatment as consisting of a number of components, either because this is the case in practice or because it is conceptually possible to decompose treatment into separate components due to the way in which it exerts effects on the outcome of interest. For competing events, the treatment decomposition idea has recently been suggested to separate effects of treatments on the outcome of interest from effects mediated through competing events using so-called separable effects. Like the idea of separating effects of exposure, it has been pointed out that ideas from mediation analysis generally may help to clarify the interpretation of existing estimands used in competing events settings. One example is the use of the controlled direct effect, to conceptualize the effects of interventions preventing the competing event from occurring. In this article, we identify the controlled direct effect as a component specific effect and discuss the merits of this estimand when the prevented event is non terminal and other methods of effects separation are problematic. Our motivating example is the study of a policy initiative, introduced in 2001, aimed at reducing long term sickness absence (SA) in Norway. The initiative consists of different components, one being to encourage use of graded SA, which is considered a key tool in the Nordic countries to reduce long term SA. The analysis makes use of longitudinal registry data for 113 808 individuals, followed from the time of first SA.

Hearing Loss and Annual Earnings Over a 20-Year Period: The HUNT Cohort Study.

OBJECTIVES: The association between hearing loss and income has only been examined in cross-sectional studies. We aim to study annual increase in earnings over 20 years, comparing people with and without hearing loss. DESIGN: We used data from a population-based hearing study in Norway (The Trøndelag Health Study, 1996-1998), including 14,825 persons (46.2% men, mean age at baseline 30.6 years, age range 20 to 40 years). Hearing loss was defined as the pure-tone average threshold of 0.5 to 4 kHz in the better hearing ear ≥20 dB HL (n = 230). Annual earnings were assessed from 1997 to 2017. Longitudinal analyses were performed with linear mixed models adjusted for age, sex, and education. RESULTS: People without hearing loss at baseline (before age 40) had a greater annual increase in earnings over a 20-year follow-up period compared with people with hearing loss. For people with normal hearing, annual earnings over 20 years increased by 453 Euro (EUR) (95% confidence interval [CI] = 384 to 522) or 13.2% more per year than for people with hearing loss, adjusted for age and sex. The difference in annual earnings over 20 year was greater among women (462 EUR, 95% CI = 376 to 547) than men (424 EUR, 95% CI = 315 to 533), greater among younger than older adults, and greater among lower than higher educated persons. When including adjustment for education in the model, in addition to age and sex, the difference in annual earnings over 20 years between persons with and without hearing loss was reduced (337 EUR, 95% CI = 269 to 405). CONCLUSIONS: The results from this large population-based study indicates that people with hearing loss experience lower long-term earnings growth compared with people with normal hearing. The findings highlight the need for increased interventions in the workplace for people with hearing loss.

Does country of resettlement influence the risk of labor market marginalization among refugees? A cohort study in Sweden and Norway.

OBJECTIVES: This study aimed to compare the risk of labor market marginalization among refugees across different host countries of resettlement and examine the moderating role of birth country and length of stay on these associations. METHODS: Cohorts of refugees and native-born individuals aged 19-60 in Sweden (N=3 605 949, 3.5% refugees) and Norway (N=1 784 861, 1.7% refugees) were followed during 2010-2016. Rates (per 1000 person-years) of long-term unemployment, long-term sickness absence, and disability pension were estimated for refugees and the host populations. Cox regression models estimated crude and adjusted (for sex, age, educational level, and civil status) hazard ratio (HRadj) for refugees compared to their respective host population, with 95% confidence intervals (CI). Analyses were also stratified by birth country and length of stay. RESULTS: Refugees in Norway and Sweden had a higher incidence of labor market marginalization compared to their host population. Refugees in Sweden had a comparatively lower relative risk of long-term unemployment but higher risk of disability pension (HRadj 3.44, 95% CI, 3.38-3.50 and HRadj 2.45, 2.35-2.56, respectively) than refugees in Norway (HRadj 3.70, 3.58-3.82 and HRadj 1.57, 1.49-1.66, respectively). These relative risks varied when stratifying by birth country. A shorter length of stay was associated with a higher risk of long-term unemployment and a lower risk of disability pension, with a stronger gradient in Sweden than in Norway. CONCLUSIONS: The relative risk of labor market marginalization varied by the refugees' birth country but followed similar trends in Sweden and Norway. Although speculative, these findings may hint at non-structural factors related to the refugee experience playing a more important role than host country structural factors for the risk of labor market marginalization among refugees. Future research, including host countries with more variability in structural factors, is required to further investigate these associations. The higher risk of long-term unemployment among refugees with shorter length of stay indicates a need for more efficient labor market integration policies for newly-arrived refugees.

Gender and educational differences in work participation and working years lost in Norway.

OBJECTIVES: This study aimed to quantify the duration of work participation and reasons for working years lost, according to gender and educational attainment, among a Norwegian population. METHODS: Register data on labor market attachment between 2000-2015 were obtained from Statistics Norway. We included five cohorts: individuals turning 20 (N=323 333), 30 (N=386 006), 40 (N=388 962), 50 (N=358 745), and 60 years (N=284 425) between 1 January 2000 and 31 December 2005. Individuals were followed for ten years. Data completeness allowed calculation of the average time spent in work and years lost to health-related absences and non-employment states per cohort. Changes in state probabilities over time were also depicted. Mean differences between genders and educational levels, and corresponding 95% confidence intervals were based on 1000 bootstrap samples. RESULTS: Both genders spent most time in work; however, per cohort, women worked approximately one year less than men. As cohorts aged, main reasons for working years lost changed from education and economic inactivity to sickness absence and disability pensioning; this trend was stronger for women than men. Individuals with a low education spent fewer years in work and more years in sickness absence and disability pensioning than highly educated peers. This difference tended to be larger for women and older cohorts. CONCLUSIONS: Per cohort, women participated one year less in work than men and, depending on age, spent more time in education, economic inactivity, sickness absence, and disability pensioning. Stronger educational gradients were seen for work and health-related absences for older cohorts and women.

Socio-economic status and head and neck cancer incidence in the Nordic countries.

BACKGROUND: The impact of societal factors on the occurrence of head and neck cancers (HNCs) remains understudied, especially in the Nordic countries. METHODS: To quantify the association between socio-economic status (SES) and the occurrence of HNCs, this cohort study uses data from the Nordic Occupational Cancer project that combine occupational and cancer registry data from 1961 to 2005 of 14.9 million individuals aged between 30 and 64 years. Occupational categories were combined into seven socio-economic categories. Standardized incidence ratio (SIR) analyses were conducted with the cancer incidence rates for the entire national study populations used as reference rates. RESULTS: Altogether, 83 997 HNCs-72% in men and 28% in women-were recorded. Among men, a gradient of risk associated with SES was observed for cancers of the tongue, other oral cavity subsites, pharynx, oropharynx and larynx in groups with lower SES. Managers showed decreased SIRs of 0.50 to -0.90 also for cancers of the lip, tongue, other oral cavity subsites, oropharynx, nasopharynx, nose and larynx. In contrast, excess risks of tongue, other oral cavity subsites, pharyngeal, oropharyngeal and laryngeal cancers were observed among clerical (SIRs 1.05-1.16), skilled workers (1.04-1.14), unskilled workers (1.16-1.26) and economically inactive men (1.38-1.87). Among women, no risk gradient similar to that in men was revealed. CONCLUSIONS: The current study underscores the influence of SES on the incidence of HNCs and highlights the need for targeted interventions, including tobacco and alcohol control policies, and improved access to healthcare services, particularly for socio-economically disadvantaged populations.

Narrative review of occupational exposures and noncommunicable diseases.

OBJECTIVE: Within the scope of the Exposome Project for Health and Occupational Research on applying the exposome concept to working life health, we aimed to provide a broad overview of the status of knowledge on occupational exposures and associated health effects across multiple noncommunicable diseases (NCDs) to help inform research priorities. METHODS: We conducted a narrative review of occupational risk factors that can be considered to have "consistent evidence for an association," or where there is "limited/inadequate evidence for an association" for 6 NCD groups: nonmalignant respiratory diseases; neurodegenerative diseases; cardiovascular/metabolic diseases; mental disorders; musculoskeletal diseases; and cancer. The assessment was done in expert sessions, primarily based on systematic reviews, supplemented with narrative reviews, reports, and original studies. Subsequently, knowledge gaps were identified, e.g. based on missing information on exposure-response relationships, gender differences, critical time-windows, interactions, and inadequate study quality. RESULTS: We identified over 200 occupational exposures with consistent or limited/inadequate evidence for associations with one or more of 60+ NCDs. Various exposures were identified as possible risk factors for multiple outcomes. Examples are diesel engine exhaust and cadmium, with consistent evidence for lung cancer, but limited/inadequate evidence for other cancer sites, respiratory, neurodegenerative, and cardiovascular diseases. Other examples are physically heavy work, shift work, and decision latitude/job control. For associations with limited/inadequate evidence, new studies are needed to confirm the association. For risk factors with consistent evidence, improvements in study design, exposure assessment, and case definition could lead to a better understanding of the association and help inform health-based threshold levels. CONCLUSIONS: By providing an overview of knowledge gaps in the associations between occupational exposures and their health effects, our narrative review will help setting priorities in occupational health research. Future epidemiological studies should prioritize to include large sample sizes, assess exposures prior to disease onset, and quantify exposures. Potential sources of biases and confounding need to be identified and accounted for in both original studies and systematic reviews.