Neighbourhood effects on psychiatric disorders among Finnish adolescents: The moderating impact of family background.

We study whether childhood neighbourhood context affects mental health in adolescence in Finland. We also examine heterogeneous effects by family background. By exploiting register data for 1999-2018, we use sibling fixed effects models to gain more robust evidence on the existence of neighbourhood effects. We do not find evidence of an association between neighbourhood characteristics and psychiatric disorders within families. Differences in the effects by family background were not consistent, and variation was mainly found in random effects models. In general, observed family characteristics were strongly associated with psychiatric disorders. This means that interventions should be targeted to children at risk rather than certain neighbourhoods.

Unravelling the demographic dynamics of ethnic residential segregation.

Selective intraurban migration of ethnic groups is often assumed to be the main microlevel mechanism reproducing ethnic residential segregation. However, other demographic processes, such as natural change and international migration, also matter. This paper contributes to the literature by unravelling the impacts of different demographic processes to changes in ethnic segregation. It uses longitudinal individual-level register data on the complete population of the Helsinki region in Finland. We calculate observed changes in exposure indices, segregation indices in counterfactual scenarios, and decompositions of population changes. Results indicate that intraregional migration is the main process affecting segregation between Finnish-origin and non-Western-origin populations, but whereas migration of the former increases segregation, migration of the latter decreases it. International migration and natural change among the non-Western-origin population are the main processes increasing exposure of the non-Western-origin population to other members of the group. No indication is found of a general tendency to "self-segregate."

Workplace Measurements of Ultrafine Particles-A Literature Review.

Workers are exposed to ultrafine particles (UFP) in a number of occupations. In order to summarize the current knowledge regarding occupational exposure to UFP (excluding engineered nanoparticles), we gathered information on UFP concentrations from published research articles. The aim of our study was to create a basis for future epidemiological studies that treat UFP as an exposure factor. The literature search found 72 publications regarding UFP measurements in work environments. These articles covered 314 measurement results and tabled concentrations. Mean concentrations were compared to typical urban UFP concentration level, which was considered non-occupational background concentration. Mean concentrations higher than the typical urban UFP concentration were reported in 240 workplace measurements. The results showed that workers' exposure to UFP may be significantly higher than their non-occupational exposure to background concentration alone. Mean concentrations of over 100 times the typical urban UFP concentration were reported in welding and metal industry. However, according to the results of the review, measurements of the UFP in work environments are, to date, too limited and reported too heterogeneous to allow us to draw general conclusions about workers' exposure. Harmonization of measurement strategies is essential if we are to generate more reliable and comparable data in the future.

Testicular germ cell tumours and parental occupational exposure to pesticides: a register-based case-control study in the Nordic countries (NORD-TEST study).

OBJECTIVES: A potential impact of exposure to endocrine disruptors, including pesticides, during intrauterine life, has been hypothesised in testicular germ cell tumour (TGCT) aetiology, but exposure assessment is challenging. This large-scale registry-based case-control study aimed to investigate the association between parental occupational exposure to pesticides and TGCT risk in their sons. METHODS: Cases born in 1960 or onwards, aged between 14 and 49 years, and diagnosed between 1978 and 2013 in Denmark, Finland, Norway or Sweden, were identified from the respective nationwide cancer registries. Four controls per case were randomly selected from the general national populations, matched on year of birth. Information on parental occupation was collected through censuses or Pension Fund information and converted into a pesticide exposure index based on the Finnish National Job-Exposure Matrix. RESULTS: A total of 9569 cases and 32,028 controls were included. No overall associations were found for either maternal or paternal exposures and TGCT risk in their sons, with ORs of 0.83 (95% CI 0.56 to 1.23) and of 1.03 (0.92 to 1.14), respectively. Country-specific estimates and stratification by birth cohorts revealed some heterogeneity. Cryptorchidism, hypospadias and family history of testicular cancer were risk factors but adjustment did not change the main results. CONCLUSIONS: This is the largest study on prenatal exposure to pesticides and TGCT risk, overall providing no evidence of an association. Limitations to assess individual exposure in registry-based studies might have contributed to the null result.

A case control study investigating the effects of levels of physical activity at work as a risk factor for prostate cancer.

BACKGROUND: A potential risk factor for prostate cancer is occupational physical activity. The occupational aetiology of prostate cancer remains unclear. The purpose of this research was to examine associations between the level of exposure to various measures of physical activity at work and the risk of Prostate Cancer. METHODS: Using the Finnish Job Exposure Matrix and the occupational history of 1,436 cases and 1,349 matched controls from an Australian case control study; we investigated five related exposure variables considered to be risk factors by comparing odds ratios. RESULTS: Modestly increasing odds ratios were detected with increasing levels of workload but there was no difference in this trend between moderate and high grade tumours. In regard to occupational physical workload no statistically significant association was observed overall but an increasing trend with level of exposure was observed for high grade compared with moderate grade tumours. CONCLUSION: Both workload and physical workload merit further investigation, particularly for the latter in relation to grade of tumour.

Occupational asbestos exposure and risk of oral cavity and pharyngeal cancer in the prospective Netherlands Cohort Study.

OBJECTIVES: The evidence for an association between occupational asbestos exposure and pharyngeal cancer (PhC) is limited, while for oral cavity cancer (OCC) the literature is even sparser. We studied OCC and PhC risk both separately and combined (OCPC) in relation to occupational asbestos exposure, specifically addressing the influence of potential confounders, the existence of an exposure-response relation, and the presence of interaction between asbestos and smoking. METHODS: Using the prospective Netherlands Cohort Study (N=58 279 men, aged 55-69 years), we estimated asbestos exposure by linkage to a general population job-exposure matrix (DOMJEM) and a Finnish job exposure matrix (FINJEM). After 17.3 years of follow-up, 58 OCC and 53 PhC cases were available for analysis. RESULTS: No association between asbestos and risk of OCC was observed for either JEM. Hazard ratios (HR) of PhC and OCPC increased after adjusting for confounders, particularly alcohol consumption and socioeconomic status. For PhC, a multivariable-adjusted increased HR was observed for "ever" versus "never" exposed to asbestos [HR 2.20, 95% confidence interval (95% CI) 1.08-4.49] when using FINJEM, but a trend of increased risks with higher cumulative exposure could not be demonstrated for either JEM. Results for OCPC showed patterns similar to those observed for PhC. None of the cancers showed a significant interaction between asbestos and smoking. CONCLUSIONS: This prospective population-based study showed no convincing evidence of an association between asbestos and risk of OCC, PhC, and OCPC as an exposure-response relation was lacking, and results were not robust against the use of different JEM. However, the potentially increased HR of PhC and OCPC observed in this and previous studies warrant further research.

Occupational exposure to solvents and acute myeloid leukemia: a population-based, case-control study in four Nordic countries.

OBJECTIVE: The aim of the current study was to assess the relation between occupational exposure to solvents and the risk of acute myeloid leukemia (AML). METHODS: Altogether, this study comprises 15 332 incident cases of AML diagnosed in Finland, Norway, Sweden and Iceland from 1961-2005 and 76 660 controls matched by year of birth, sex, and country. Occupational records were linked with Nordic Occupational Cancer Study job exposure matrix (JEM) to estimate quantitative values for 26 occupational exposure factors. Hazard ratios (HR) with 95% confidence intervals (95% CI) were estimated by using conditional logistic regression models. RESULTS: We did not observe statistically significantly increased risk for exposure to any of the solvents. HR estimates for high levels of toluene (HR 1.35, 95% CI 0.74-2.46), aromatic hydrocarbon solvents (ARHC) (HR 1.18, 95% CI 0.76-1.86), and moderate-to-high levels of trichloroethylene were slightly but non-significantly elevated. We did not observe an association between benzene exposure and AML in this study. CONCLUSIONS: This study did not provide clear evidence for an association between occupational solvent exposure and AML. There was some indication for an excess risk in the groups of workers exposed to toluene, trichloroethylene and ARHC.

Occupational asbestos exposure and risk of esophageal, gastric and colorectal cancer in the prospective Netherlands Cohort Study.

The evidence for an association between occupational asbestos exposure and esophageal, gastric and colorectal cancer is limited. We studied this association specifically addressing risk differences between relatively low and high exposure, risk associated with cancer subtypes, the influence of potential confounders and the interaction between asbestos and smoking in relation to cancer risk. Using the Netherlands Cohort Study (n = 58,279 men, aged 55-69 years at baseline), asbestos exposure was estimated by linkage to a job-exposure matrix. After 17.3 years of follow-up, 187 esophageal, 486 gastric and 1,724 colorectal cancer cases were available for analysis. The models adjusted for age and family history of cancer showed that mainly (prolonged) exposure to high levels of asbestos was statistically significantly associated with risk of esophageal adenocarcinoma (EAC), total and distal colon cancer and rectal cancer. For overall gastric cancer and gastric non-cardia adenocarcinoma (GNCA), also exposure to lower levels of asbestos was associated. Additional adjustment for lifestyle confounders, especially smoking status, yielded non-significant associations with overall gastric cancer and GNCA in the multivariable-adjusted model, except for the prolonged highly exposed subjects (tertile 3 vs. never: HR 2.67, 95% CI: 1.11-6.44 and HR 3.35, 95% CI: 1.33-8.44, respectively). No statistically significant additive or multiplicative interaction between asbestos and smoking was observed for any of the studied cancers. This prospective population-based study showed that (prolonged) high asbestos exposure was associated with overall gastric cancer, EAC, GNCA, total and distal colon cancer and rectal cancer.

Tetrachloroethylene exposure and bladder cancer risk: a meta-analysis of dry-cleaning-worker studies.

BACKGROUND: In 2012, the International Agency for Research on Cancer classified tetrachloroethylene, used in the production of chemicals and the primary solvent used in dry cleaning, as "probably carcinogenic to humans" based on limited evidence of an increased risk of bladder cancer in dry cleaners. OBJECTIVES: We assessed the epidemiological evidence for the association between tetrachloroethylene exposure and bladder cancer from published studies estimating occupational exposure to tetrachloroethylene or in workers in the dry-cleaning industry. METHODS: Random-effects meta-analyses were carried out separately for occupational exposure to tetrachloroethylene and employment as a dry cleaner. We qualitatively summarized exposure-response data because of the limited number of studies available. RESULTS: The meta-relative risk (mRR) among tetrachloroethylene-exposed workers was 1.08 (95% CI: 0.82, 1.42; three studies; 463 exposed cases). For employment as a dry cleaner, the overall mRR was 1.47 (95% CI: 1.16, 1.85; seven studies; 139 exposed cases), and for smoking-adjusted studies, the mRR was 1.50 (95% CI: 0.80, 2.84; 4 case-control studies). CONCLUSIONS: Our meta-analysis demonstrates an increased risk of bladder cancer in dry cleaners, reported in both cohort and case-control studies, and some evidence for an exposure-response relationship. Although dry cleaners incur mixed exposures, tetrachloroethylene could be responsible for the excess risk of bladder cancer because it is the primary solvent used and it is the only chemical commonly used by dry cleaners that is currently identified as a potential bladder carcinogen. Relatively crude approaches in exposure assessment in the studies of "tetrachloroethylene-exposed workers" may have attenuated the relative risks.

Use of the Finnish Information System on Occupational Exposure (FINJEM) in epidemiologic, surveillance, and other applications.

This paper reviews the use of the Finnish Information System on Occupational Exposure (Finnish job-exposure matrix, FINJEM) in different applications in Finland and other countries. We describe and discuss studies on FINJEM and studies utilizing FINJEM in regard to the validity of exposure estimates, occupational epidemiology, hazard surveillance and prevention, the assessment of health risks and the burden of disease, the assessment of exposure trends and future hazards, and the construction of job-exposure matrices (JEMs) in countries other than Finland. FINJEM can be used as an exposure assessment tool in occupational epidemiology, particularly in large register-based studies. It also provides information for hazard surveillance at the national level. It is able to identify occupations with high average exposures to chemical agents and can therefore serve the priority setting of prevention. However, it has only limited use at the workplace level due to the variability of exposure between workplaces. The national estimates of exposure and their temporal trends may contribute to the assessment of both the recent and future burden of work-related health outcomes. FINJEM has also proved to be useful in the construction of other national JEMs, for example in the Nordic Occupational Cancer study in the Nordic countries. FINJEM is a quantitative JEM, which can serve many purposes and its comprehensive documentation also makes it potentially useful in countries other than Finland.

Occupational asbestos exposure and risk of pleural mesothelioma, lung cancer, and laryngeal cancer in the prospective Netherlands cohort study.

OBJECTIVE: To study the association between occupational asbestos exposure and pleural mesothelioma, lung cancer, and laryngeal cancer, specifically addressing risk associated with the lower end of the exposure distribution, risk of cancer subtypes, and the interaction between asbestos and smoking. METHODS: Using the Netherlands Cohort Study (n = 58,279 men, aged 55 to 69 years), asbestos exposure was estimated by linkage to job-exposure matrices. After 17.3 years of follow-up, 132 pleural mesothelioma, 2324 lung cancer, and 166 laryngeal cancer cases were available. RESULTS: The multivariable-adjusted model showed overall positive associations between all levels of asbestos exposure and mesothelioma, lung cancer, and laryngeal cancer. Lung adenocarcinoma and glottis cancer showed only a positive association after prolonged higher asbestos exposure (hazard ratio per 10 years increment, 1.43 [95% confidence interval, 1.06 to 1.93] and 1.95 [95% confidence interval, 1.36 to 2.80], respectively). There was no statistically significant interaction between asbestos and smoking. CONCLUSIONS: Asbestos levels encountered at the lower end of the exposure distribution may be associated with an increased risk of pleural mesothelioma, lung cancer, and laryngeal cancer.

Cholangiocarcinoma among workers in the printing industry: using the NOCCA database to elucidate the generalisability of a cluster report from Japan.

OBJECTIVES: A cluster of 11 cases of cholangiocarcinoma (CC) was observed in a small Japanese printing firm. To elucidate whether the identified cluster is indicative of an elevated risk of CC among workers in the printing industry at large, we explored the risk of cancer of the liver and CC among individuals employed in the printing industry in a large cohort set-up in four Nordic countries (Finland, Iceland, Norway and Sweden) over a period of 45 years. METHODS: The cohort was set-up by linking occupational information from censuses to national cancer registry data utilising personal identity codes in use in all Nordic countries. We calculated standardised incidence ratios (SIRs) for men and women working in the printing industry, and stratified by occupational category (typographers, printers, lithographers, bookbinders). RESULTS: Among men, we observed elevated SIRs for cancer of the liver (1.35, 95% CI 1.14 to 1.60; 142 cases), specifically intrahepatic CC (2.34, 95% CI 1.45 to 3.57; 21 cases). SIRs for liver cancer were especially elevated among printers and lithographers, and SIRs for intrahepatic CC among typographers and printers. SIRs for extrahepatic CC were not elevated. SIRs for women followed a similar pattern but the number of cases was low. CONCLUSIONS: Our study supports the notion that the finding of excess CC risk among workers in a small Japanese printing firm possibly extends beyond this specific firm and country. Further studies should focus on the specific exposures that occur in the printing industry.

A job-exposure matrix for research and surveillance of occupational health and safety in Spanish workers: MatEmESp.

BACKGROUND: In this study we describe a general-population job-exposure matrix (MatEmESp) for Spanish workers covering the period 1996-2005. METHODS: The Finnish job-exposure matrix (FINJEM) provided the default value estimates for occupational exposure to chemical, physical and biological agents. These estimates were adapted to Spanish working conditions by local experts. Spanish surveys were used to obtain exposure estimates for ergonomic and psychosocial risk factors. Employment and socio-demographic conditions for Spanish workers were obtained from the Spanish National Statistics Institute. RESULTS: MatEmESp provides a large amount of national and occupation-specific data on the major occupational exposures in Spain. As some examples, the data show that the most prevalent occupational hazards are repetitive movements and a lack of support from co-workers. In addition, 10% of the Spanish working population perform night shifts, and bricklayers and concrete workers are the job titles with the highest risk of exposure to quartz dust. CONCLUSIONS: MatEmESp can be a useful tool for research and surveillance, and can help set priorities for occupational illness and injury prevention in Spain.

Assessing occupational exposure to chemicals in an international epidemiological study of brain tumours.

The INTEROCC project is a multi-centre case-control study investigating the risk of developing brain cancer due to occupational chemical and electromagnetic field exposures. To estimate chemical exposures, the Finnish Job Exposure Matrix (FINJEM) was modified to improve its performance in the INTEROCC study and to address some of its limitations, resulting in the development of the INTEROCC JEM. An international team of occupational hygienists developed a crosswalk between the Finnish occupational codes used in FINJEM and the International Standard Classification of Occupations 1968 (ISCO68). For ISCO68 codes linked to multiple Finnish codes, weighted means of the exposure estimates were calculated. Similarly, multiple ISCO68 codes linked to a single Finnish code with evidence of heterogeneous exposure were refined. One of the key time periods in FINJEM (1960-1984) was split into two periods (1960-1974 and 1975-1984). Benzene exposure estimates in early periods were modified upwards. The internal consistency of hydrocarbon exposures and exposures to engine exhaust fumes was improved. Finally, exposure to polycyclic aromatic hydrocarbon and benzo(a)pyrene was modified to include the contribution from second-hand smoke. The crosswalk ensured that the FINJEM exposure estimates could be applied to the INTEROCC study subjects. The modifications generally resulted in an increased prevalence of exposure to chemical agents. This increased prevalence of exposure was not restricted to the lowest categories of cumulative exposure, but was seen across all levels for some agents. Although this work has produced a JEM with important improvements compared to FINJEM, further improvements are possible with the expansion of agents and additional external data.

Occupational exposure to trichloroethylene and perchloroethylene and the risk of lymphoma, liver, and kidney cancer in four Nordic countries.

OBJECTIVES: Trichloroethylene (TCE) and Perchloroethylene (PER) are two chlorinated solvents that are applied widely as degreasers of metal parts, and in dry cleaning and other applications. In 2012, the International Agency for Research on Cancer classified TCE as carcinogenic to humans and PER as probably carcinogenic to humans. We explored exposure-response relations for TCE and PER and non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), and cancers of the kidney and liver in the Nordic Occupational Cancer cohort. METHODS: The cohort was set up by linking occupational information from censuses to national cancer registry data using personal identity codes in use in all Nordic countries. Country, time period, and job-specific exposure estimates were generated for TCE, PER and potentially confounding occupational exposures with a job-exposure matrix. A conditional logistic regression was conducted for exposure groups as well as for continuous cumulative exposure. RESULTS: HRs for liver cancer, NHL and MM but not kidney cancer were slightly elevated in groups with high exposure to PER (compared to occupationally unexposed subjects). HRs for liver cancer and NHL also increased with increasing continuous exposure to PER. We did not observe evidence for an association between exposure to TCE and NHL, MM or liver and kidney cancer. CONCLUSIONS: Although this study was subject to limitations related to the low prevalence of exposure to PER and TCE in the Nordic population and a limited exposure assessment strategy, we observed some evidence indicative of an excess risk of cancer of the liver and NHL in subjects exposed to PER.

Trends of occupational exposure to chemical agents in Finland in 1950-2020.

INTRODUCTION: The aim of this study was to quantitatively estimate the long-term trends of occupational exposure to chemical agents in Finland for surveillance, prevention, and risk assessment purposes. METHODS: We studied trends by utilizing the Finnish job-exposure matrix (FINJEM), which includes occupation-specific estimates of the prevalence P (percent of employed) and average level L (agent-specific units) of inhalation exposure to chemical agents at different time periods. We used FINJEM data to calculate national estimates of the numbers of exposed workers (N exp), and the prevalence of and level of exposure to 41 chemical agents in 1950, 1970, 1990, and 2008. We also estimated the prevalence of employees exposed to levels exceeding 50% of the Finnish occupational exposure limit (OEL) (P high) and national occupational inhalation exposure (NOIE = N exp × L). Future exposures in 2020 were estimated according to the predicted change of the occupational structure of the labor force and the observed agent-specific exposure trends in 1990-2008. We estimated dermal exposure indirectly from the statistics of occupational skin diseases in 1975-2009. RESULTS: Inhalation exposure to most chemical agents had decreased. Using 1990 as the reference (100), the median values of P for 1950, 1970, 1990, 2008, and 2020 were 91, 149, 100, 58, and 41, respectively. The corresponding values were 218, 224, 100, 30, and 14 for P high, 151, 121, 100, 78, and 66 for L, and 119, 176, 100, 38, and 20 for NOIE. The trends varied considerably according to the agent. Exposure of, for example, asbestos, benzene, and benzo(a)pyrene substantially decreased. The annual incidence of occupational skin diseases due to chemical factors decreased from 6.9 per 10 000 employed in 1975-1979 to 4.6 per 10 000 in 2000-2009, suggesting a decrease in dermal exposure. CONCLUSIONS: Inhalation exposure to most chemical agents has decreased in Finland since 1970. High exposures and the average level of exposure started to decrease already in the 1950s. The declining incidence of occupational skin diseases suggests that dermal exposure has also diminished. However, high exposures still exist and cause a substantial amount of occupational diseases and symptoms. Chemical exposures and the related disease burden are expected to continue decreasing in the future. These results cannot be generalized to other countries, particularly if the development phase of technology and the occupational structure of the labor force differ significantly from those in Finland.

Occupational exposure to particles and incidence of stroke.

OBJECTIVES: This paper aims to investigate the relation between occupational exposure to particles, particle size, and the incidence of ischemic and hemorrhagic stroke. METHODS: The cohort included all manual workers identified from the Swedish National Census in 1980, who were alive as of 1 January 1987. First time events of ischemic or hemorrhagic stroke during the period 1987-2005 were identified through linkage to the Hospital Discharge Register and the National Cause of Death Register. A job-exposure matrix for exposure to small (<1 µm) and large (>1 µm) particles was developed and applied. Hazard ratios (HR) were estimated by Cox regression with adjustment for age, socioeconomic group, and residential area. RESULTS: Increased HR of ischemic stroke were found among both women and men occupationally exposed to small as well as large particles for ≥5 years. The risks were higher for workers exposed for ≥5 years compared to "ever exposed" participants indicating a dose-response relationship, but no trend with exposure intensity was observed. A tentative association between particle exposure and hemorrhagic stroke was also found. CONCLUSIONS: Occupational exposure to small and large particles was associated with increased risks of ischemic stroke. Further studies are needed to explore the relationships between exposure to different types of particles and various doses and the occurrence of stroke among women as well as men.

Development and validation of a job exposure matrix for physical risk factors in low back pain.

OBJECTIVES: The aim was to construct and validate a gender-specific job exposure matrix (JEM) for physical exposures to be used in epidemiological studies of low back pain (LBP). MATERIALS AND METHODS: We utilized two large Finnish population surveys, one to construct the JEM and another to test matrix validity. The exposure axis of the matrix included exposures relevant to LBP (heavy physical work, heavy lifting, awkward trunk posture and whole body vibration) and exposures that increase the biomechanical load on the low back (arm elevation) or those that in combination with other known risk factors could be related to LBP (kneeling or squatting). Job titles with similar work tasks and exposures were grouped. Exposure information was based on face-to-face interviews. Validity of the matrix was explored by comparing the JEM (group-based) binary measures with individual-based measures. The predictive validity of the matrix against LBP was evaluated by comparing the associations of the group-based (JEM) exposures with those of individual-based exposures. RESULTS: The matrix includes 348 job titles, representing 81% of all Finnish job titles in the early 2000s. The specificity of the constructed matrix was good, especially in women. The validity measured with kappa-statistic ranged from good to poor, being fair for most exposures. In men, all group-based (JEM) exposures were statistically significantly associated with one-month prevalence of LBP. In women, four out of six group-based exposures showed an association with LBP. CONCLUSIONS: The gender-specific JEM for physical exposures showed relatively high specificity without compromising sensitivity. The matrix can therefore be considered as a valid instrument for exposure assessment in large-scale epidemiological studies, when more precise but more labour-intensive methods are not feasible. Although the matrix was based on Finnish data we foresee that it could be applicable, with some modifications, in other countries with a similar level of technology.

Occupational exposure to wood dust and formaldehyde and risk of nasal, nasopharyngeal, and lung cancer among Finnish men.

Controversy exists over whether or not occupational inhalation exposure to wood dust and/or formaldehyde increases risk for respiratory cancers. The objective of this study was to examine the risk of nasal, nasopharyngeal, and lung cancer in relation to occupational exposure to wood dust and formaldehyde among Finnish men. The cohort of all Finnish men born between the years 1906 and 1945 and in employment during 1970 was followed up through the Finnish Cancer Registry for cases of cancers of the nose (n = 292), nasopharynx (n = 149), and lung (n = 30,137) during the period 1971-1995. The subjects' occupations, as recorded in the population census in 1970, were converted to estimates of exposure to wood dust, formaldehyde, asbestos, and silica dust through the Finnish job-exposure matrix. Cumulative exposure (CE) was calculated based on the prevalence, average level, and estimated duration of exposure. The relative risk (RR) estimates for the CE categories of wood dust and formaldehyde were defined by Poisson regression, with adjustments made for smoking, socioeconomic status, and exposure to asbestos and/or silica dust. Men exposed to wood dust had a significant excess risk of nasal cancer overall (RR, 1.59; 95% confidence interval [CI], 1.06-2.38), and specifically nasal squamous cell carcinoma (RR, 1.98; 95% CI, 1.19-3.31). Workers exposed to formaldehyde had an RR of 1.18 (95% CI, 1.12-1.25) for lung cancer. There was no indication that CE to wood dust or formaldehyde would increase the risk of nasopharyngeal cancer. Occupational exposure to wood dust appeared to increase the risk of nasal cancer but not of nasopharyngeal or lung cancer. The slight excess risk of lung cancer observed for exposure to formaldehyde may be the result of residual confounding from smoking. In summary, this study provides further evidence that exposure to wood dust in a variety of occupations may increase the risk of nasal cancer.