Introduction Bladder cancer risk is suggested to vary between occupational categories. We assessed the occupational variation in incidence of bladder cancer and relationship with chemical solvent exposures in the Nordic countries.

Methods The study is based on Nordic Occupational Cancer Study (NOCCA). Data consist of 14.9 million individuals of age 30 to 64 years from the Nordic countries who participated in one or more population censuses since 1960 and were followed up for 45 years. During the follow-up 148,669 cases of bladder cancer were detected. Standardised incidence ratio with 95% of confidence interval (CI) was used to describe the variation in bladder cancer risk in comparison to the national average. Quantitative estimates of solvents exposure for 113,343 bladder cancer cases and 566,715 population controls were assigned using Nordic job exposure matrix. Hazard ratios (HR) and 95% CI: for each solvent was estimated using conditional logistic regression.

Results Highest statistically significant risks were observed among tobacco workers (SIR 1.57, 95% CI: 1.24–1.96), chimney sweeps (1.48, 1.21–1.80), waiters (1.43, 1.33–1.53), hairdressers, seamen, printers, plumbers. Significant decreased risks were observed among farmers (0.70, 0.68–0.71) and forestry workers (0.74, 0.70–0.78). Significantly increasing trends in SIR over the years were observed among drivers and launderers. The occupational risk associated with the chemical solvent at highest exposure levels (>90th percentile of the exposed persons) were aliphatic and alicyclic hydrocarbon solvent (HR 1.08, 95% CI: 1.00–1.23), benzene (1.16, 1.04–1.31), toluene (1.20, 1.00–1.38) and trichloroethylene (1.23, 1.12–1.40).

Conclusion Occupation is evidently associated with bladder cancer risk. Part of that variation appears to be attributable to solvent exposures.