High risk occupations for non-Hodgkin’s lymphoma in New Zealand: case–control study
- A ’t Mannetje1,
- E Dryson1,2,
- C Walls1,2,
- D McLean1,
- F McKenzie1,
- M Maule3,
- S Cheng1,
- C Cunningham4,
- H Kromhout5,
- P Boffetta6,
- A Blair7,
- N Pearce1
- 1Centre for Public Health Research, Massey University, Wellington, New Zealand
- 2Occupational Medicine Specialists, Auckland, New Zealand
- 3Cancer Epidemiology Unit, CeRMS and CPO Piemonte, University of Turin, Italy
- 4Research Centre for Māori Health and Development, Massey University, Wellington, New Zealand
- 5Institute for Risk Assessment Sciences, University of Utrecht, The Netherlands
- 6International Agency for Research on Cancer, Lyon, France
- 7Occupational and Environmental Epidemiology Branch, National Cancer Institute, Washington, DC, USA
- Dr A ‘t Mannetje, Centre for Public Health Research, Massey University Wellington Campus, Private Box 756, Wellington;
- Accepted 2 November 2007
- Published Online First 21 November 2007
Objectives: Previous studies into occupational risk factors for non-Hodgkin’s lymphoma (NHL) in New Zealand have indicated that farmers and meat workers are at increased risk for these neoplasms. A new nationwide case–control study was conducted to assess whether previously observed associations persist and to identify other occupations that may contribute to the risk of NHL in the New Zealand population.
Methods: A total of 291 incident cases of NHL (age 25–70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face-to-face. The questionnaire collected demographic information and a full occupational history. The relative risk for NHL associated with ever being employed in particular occupations and industries was calculated by unconditional logistic regression adjusting for age, sex, smoking, ethnicity and socioeconomic status. Estimates were subsequently semi-Bayes adjusted to account for the large number of occupations and industries being considered.
Results: An elevated NHL risk was observed for field crop and vegetable growers (OR 2.74, 95% CI 1.04 to 7.25) and horticulture and fruit growing (OR 2.28, 95% CI 1.37 to 3.79), particularly for women (OR 3.44, 95% CI 0.62 to 18.9; OR 3.15, 95% CI 1.50 to 6.61). Sheep and dairy farming was not associated with an increased risk of NHL. Meat processors had an elevated risk (OR 1.97, 95% CI 0.97 to 3.97), as did heavy truck drivers (OR 1.98, 95% CI 0.92 to 4.24), workers employed in metal product manufacturing (OR 1.92, 95% CI 1.12 to 3.28) and cleaners (OR 2.11, 95% CI 1.21 to 3.65). After semi-Bayes adjustment the elevated risks for horticulture and fruit growing, metal product manufacturing and cleaners remained statistically significant, representing the most robust findings of this study.
Conclusions: This study has confirmed that crop farmers and meat workers remain high risk occupations for NHL in New Zealand, and has identified several other occupations and industries of high NHL risk that merit further study.
▸ Additional tables are published online only at http://oem.bmj.com/content/vol65/issue5
Competing interests: None.