1. Non-Hodgkin’s Lymphoma (NHL) and the Agricultural Environment Exploring Environmental Links to Disease: A Look at Parkinson’s Disease & Non-Hodgkin’s Lymphoma Sioux Falls, SD, December 5, 2003 Kenneth P. Cantor Occupational & Environmental Epidemiology Branch National Cancer Institute cantork@nih.gov

2.  Known knowns  Known unknowns  Unknown unknowns Donald Rumsfeld:

3. Temporal & Geographic Patterns of NHL

4. Non-Hodgkin's lymphoma mortality, 5-year rates whites (1950-94) and blacks (1970-94)

5. Trends in NHL mortality among US white males, within selected age groups, 1950-59 to 1990-98 Source: Mortality data provided by NCHS (http://www.cdc.gov/nchs)

6. NHL Incidence Rates (Age-Adjusted to World Standard) by Sex, 1993-97 and 1973-77 Source: Cancer Incidence in Five Continents, vols. IV and VIII and Nine SEER Registries Rates per 100,000 person-years 1993-97* 1973-77 U.S. SEER, Whites U.S. SEER, Blacks Varese, Italy Sweden Cali, Colombia Osaka, Japan Bombay, India

7. Non-Hodgkin lymphoma mortality rates for white males from 1970-94 by state economic area Mortality Rate: 7.03 (per 100,000) # Deaths: 171,267

8. Non-Hodgkin lymphoma mortality rates for white females from 1970-94 by state economic area Mortality Rate: 4.76 (per 100,000) # Deaths: 160,172

9. Multiple myeloma mortality, 5-year rates whites (1950-94) and blacks (1970-94)

10. NHL: known knowns  Increasing rates over the past 50 years  Risk varies by geographic area:  High in developed world. High in upper midwest & northeast US  Risk higher among males than females  Risk is related to immunedeficiency and/or immunostimulation (immunosuppressent drugs, HIV, autoimmune diseases, genetic conditions)  Risk elevated among certain occupational groups with common exposures: solvents, pesticides, some others

11. HIGH RISK OCCUPATIONS (from epidemiologic studies) Farmers Grain handlers Rubber industry workers Refinery workers Dry cleaning workers Aircraft maintenance workers

12. The Agricultural Environment: Pesticides

13. EVALUATION OF PESTICIDES FOR CARCINOGENICITY IN ANIMALS Of 45 Pesticides reviewed by the International Agency for Research on Cancer (IARC) for carcinogenicity:  11 (24%) had sufficient evidence  22 (49%) had limited evidence

14. ORGANIC PESTICIDES CAUSING CANCER IN ANIMALS ACCORDING TO IARC Pesticide Type Cancer AldrinILiver, thyroid AmitroleHLiver, thyroid ChlordaneILiver 2,4,6-TrichlorophenolHLiver DDTILiver, lung DiallateHLiver, lung, lymphoma DicolILiver DieldrinILiver Ethylene dibromideILiver, breast, lung MirexILiver, lymphoma ToxapheneILiver, thyroid I = insecticide; H = herbicide

15. PESTICIDES WITH LIMITED EVIDENCE FOR CARCINOGENICITY IN ANIMALS ACCORDING TO IARC AldrinChlordaneChlorabenzilate DicofolDieldrinHeptachlor CalciumMethyl ParathionTetrachlorvinphos arsenate LindaneCarbarylDiallate CopperSodiumChlorothalonil arsenate arsenate CaptanMonuronArsenic acid

16. Epidemiologic Designs to Study Pesticides: Case-Control Studies  Cases: Patients newly diagnosed with (NHL) in a specified geographic area and time period.  Controls: Healthy individuals matched on age group & sex to cases; Selected randomly from the general population of the study area.  Subjects interviewed directly or by telephone (all characteristics & exposures of interest).  Biologic and/or env’l samples often collected.  Non-Hodgkin’s Lymphoma, Leukemia, Multiple Myeloma, Soft Tissue Sarcoma, Breast, Ovary, Childhood Cancers, Brain, and a few others

17. ISSUES RAISED ABOUT EPIDEMIOLOGIC STUDIES OF PESTICIDES  Multiple and simultaneous exposures make it difficult to determine what occurred  Inaccuracies in reporting or  Case-bias in reporting  Confounding by other risk factors  Carcinogenic mechanisms for pesticides not well established

18. RISK OF NHL IN NEBRASKA 2,4-D USERS BY DAYS/YEAR OF APPLICATION (Zahm et al. Epidemiology (1990)) CASES/ODDS CONFIDENCE CONTROLS RATIO INTERVAL Non-farmer54/184 1.0 1-516/44 1.2 0.6-2.4 6-2012/25 1.6 0.7-3.6 21+ 3/4 3.3 0.5-22.1 P for trend: 0.051 DAYS/YEAR APPLIED

19. NHL AMONG MALE FARMERS FROM NEBRASKA WHO HANDLED 2,4-D, ADJUSTED FOR OTHER PESTICIDE USE DAYS PER YEAR OF USE EVER 1-5 6-20 20+ Unadjusted for other pest. 1.51.21.6 3.3 Adjusted for: Chlor. Hydrocarbons 1.51.31.5 2.4 Carbamates 1.41.41.7 2.0 Organophosphate 1.10.91.3 1.8 Metals 1.81.4 2.3 3.4 Other 1.71.2 2.0 3.1 Unknown class 1.81.5 2.1 3.8

20. RISK OF NHL IN NEBRASKA 2,4-D USERS BY TIMING OF CHANGING TO CLEAN CLOTHES AFTER HANDLING PESTICIDES (Zahm et al. Epidemiology (1990)) CASES/ODDS CONFIDENCE CONTROLS RATIO INTERVAL RIGHT AWAY 6/19 1.1 0.4-3.1 AT END OF DAY 31/73 1.5 0.8-2.6 FOLLOWING DAY OR 6/4 4.7 1.1-21.5 LATER

21. RELATIVE RISKS FOR NON-HODGKIN’S LYMPHOMA MORTALITY BY HERBICIDE USE* IN A COHORT OF SASKATCHAWAN FARMERS (Wigle DT: J. Natl. Cancer Inst. 1990;82:575-582) Acres Sprayed (Farms <1000 Acres) 01-99100-249250+ Relative Risk1.01.31.92.2 95% CI0.7 - 2.41.2 - 3.31.0-4.6 *75-90% of all herbicides used were 2,4-D BUT OTHER STUDIES, INCLUDING SOME OF OUR OWN, DO NOT SUPPORT AN ASSOCIATION

22. RISK OF CANINE MALIGNANT LYMPHOMA BY DOG OWNER’S USE OF 2,4-D (Hayes et al. JNCI (1991)) APPLICATIONS CASES/ODDS PER YEAR CONTROLS RATIO None or dog not in yard 300/641 1.0 1 20/34 1.3 2 28/47 1.3 3 11/17 1.3 4+ 17/17 2.0 p for trend: 0.02

23. NHL and Organophosphate Pesticides (Waddell et al., 2001) Summary from published paper: “Although we found associations [with] several groups and specific organophosphate pesticides, larger risks from proxy respondents complicate interpretation. Associations, however, between … use of diazinon and NHL … among subjects providing direct interviews are not easily discounted.”

24. RISK OF NHL IN 4 STATES AND USE OF DIAZINON (Waddell et al. Ca Causes Ctl 2001) CASES/ODDS CONFIDENCE CONTROLS RATIO INTERVAL STATE IA22/331.10.6-2.1 KS1/113.00.7-230 MN19/261.30.4-4.0 NE16/271.40.7-2.9 # YRS USED <1020/400.90.5-1.7 10-1910/111.80.7-4.4 20+1/11.90.1-32 DAYS/YR USED <56/111.30.5-3.9 5+6/62.40.7-8.0

25. CHROMOSOME BREAKS AMONG APPLICATORS EXPOSED TO HERBICIDES, INSECTICIDES, OR FUMIGANTS (Garry et al. Ca.Epi.Biomark.Prev.(1996)) Chromosome site Non-Exp. Herb. Ins. Fum. (33) (20) (18) (23) 14q32(oncogene) 005*6* 18q21(oncogene)07*02 A ‘translocation’ involving chromosomes 14 & 18 is common in certain types of NHL.

26. t(14;18) chromosomal translocation & NHL  In a study of NHL, excess risk was found for several pesticides (dieldrin, toxaphene, lindane, atrazine) among patients with t(14;18), but not among t(14;18) negative patients. (Schroeder et al. Epidemiology (2001) 12:701-9)

27. FACTORS THAT SUPPORT A CAUSAL INFERENCE FROM EPIDEMIOLOGIC STUDIES  A strong association  Dose-response relationship  Can not be explained by other exposures  Similar findings in different populations under various conditions  Concordance of evidence within a study  Experimental support / finding makes biologic & mechanistic sense

28. SOME PESTICIDES LINKED WITH NHL IN ONE OR MORE STUDIES Pesticide Study Location Aldrin Duffie (2001)Canada (6 Provinces) Atrazine DeRoos (2003)IA/MN/KS/NE Chlordane Cantor (1992)IA/MN Carbaryl““ DDT Duffie (1992)Canada “ Cantor (1992)IA/MN Diazinon Waddell (2001) IA/MN/KS/NE “ Duffie (2001)Canada Dicamba““ Lindane““ Malathion ““ “ Cantor (1992)IA/MN 2,4-D Zahm (1986)Kansas “ Duffie (2001) Canada “ (?) Wigle (1990) Saskatchawan

29. SUMMARY  Pesticides can be studied epidemiologically.  Experimental and epidemiologic data indicate that pesticides may pose a risk of non- Hodgkin’s lymphoma and other cancers.  The evidence to date points to some specific pesticides, but uncertainties remain.  Exposure assessment is crucial

30. Agricultural Health Study (NCI/NIEHS/EPA) A cohort study [www.aghealth.org]

31. Epidemiologic Designs to Study Pesticides: Cohort Studies  Subjects enter the cohort & are followed over time for disease occurrence. Individual information is recorded at entry & often at later intervals.  Farmers & Other Agricultural Applicators, Commercial Applicators, Pesticide Manufacturers, Grain Workers, Forest Workers

32. Phase III Agricultural Health Study-Timeline Phase I Phase IV Phase V and Beyond Phase II Build the Cohort Exposure Assessment & Community Support Validate Exposure Disease Mechanism Passive Follow-up Cancer Etiology 199319972004200820122020

33. Agricultural Health Study Objectives  Create a prospective cohort of farmers and their spouses to evaluate health issues for a rural population.  Collect exposure information prior to onset of cancer (pesticides, other farm & occ’l exposures, diet, smoking, family medical history, other).  Update information every five years.  Collect biologic material for gene and gene- environment analyses.  Monitor a sample of farm families for pesticide exposures. Occupational & Env’l Epidemiology Branch National Cancer Institute

34. Agricultural Health Study Design & Status  Prospective cohort study of three groups (89,658 persons)  private pesticide applicators (52,395)  spouses of pesticide applicators (32,347)  commercial pesticide applicators (4,916)  Questionnaires completed at enrollment and subsequently [www.aghealth.org]  Cohort is linked annually to the National Death Index and state Cancer Registries  97% of applicators personally apply pesticides; 50% of spouses also apply. Occupational & Env’l Epidemiology Branch National Cancer Institute

35. Agricultural Health Study: HIGH USE PESTICIDES IN IOWA (1993 or 1994) Pesticide Type % Using last year 2,4-DH 35.3 GlyphosphateH33.6 ImazethapyrH32.1 AtrazineH29.9 DicambaH22.4 MetolachlorH19.6 TrifluralinH18.6 ChlorpyrifosI13.6 CyanazineH13.0 TerbufosI13.0 AlachlorH 9.9 Permethrin (Animal)I 5.4 H=Herbicide; I=Insecticide I = insecticide; H = herbicide

36. Expected Cancer Incidence (2006) in Agricultural Health Study Cohort  All cancers 4,500  Prostate 1,600  Digestive system 900  Respiratory system 610  Urinary system 273  Melanoma 220  Non-Hodgkin’s lymphoma 168  Leukemia 134  Buccal cavity 120  Ovarian 85  Thyroid and other endocrine 85  Brain and CNS 84  Multiple myeloma 76  Hodgkin’s lymphoma 40 2006: approximately 1 million person-years of follow-up

37. Cancer Cohort Analysis: Prostate CA (1 st to be evaluated)  Evaluate all pesticides  Dose-response analyses  Controlled for age, family history, smoking, other occupational exposures  Look for consistency (state, license type)  Sufficient numbers for cancer of focus

38. Relative Risk (95 % CI) for Methyl Bromide and Incident Prostate Cancer Reference group (No exposure) Exposure Group (cumulative exposure score) Linear trend (p value) I 1/3 II 1/3 III 1/6 IV 1/12 V 1/12 Odds ratio (95%CI) 1.0 1.0 (0.7- 1.6) 0.8 (0.5- 1.3) 0.7 (0.4- 1.3) 2.7 (1.2- 6.3) 3.5 (1.4- 8.8) 0.008 Exposed cases 48223221165 Logistic regression adjusted for: Age, family history of prostate cancer Alavanja MCR, et al. Prostate Cancer incidence in the AHS Cohort. American Journal of Epidemiology 1993; 157:800-814.

39. Plan For Cancer Etiology: Near Future(2004-2005)  Pesticide cohort analyses Alachlor Carbofuran Atrazine Carbaryl Chlorpyrifos Triazine herbicides Glyphosate 2,4D Pendimetalin Chlorinated pesticides  Cancer cohort analysis Prostate Melanoma Breast Ovarian Lung Multiple myeloma Colon Leukemia NHL

40. The Agricultural Environment: Nitrate in Drinking Water

41. NITRATE IN DRINKING WATER: REASONS FOR CONCERN  Levels are high and increasing in ground water of many agricultural regions.  Nitrate nitrite in the saliva.  Nitrite interacts with secondary amines & amides to form N-nitroso compounds (Vitamin C inhibits formation).  Most N-nitroso compounds are carcinogens in animal tests.

43. RISK OF NHL IN NEBRASKA AND NITRATE IN PUBLIC WATER SUPPLIES NITRATE ODDS CONFIDENCE LEVEL RATIO INTERVAL (mg/L) <1.61.0referent 1.6-<2.0 1.40.8-2.5 2.0-<4.01.50.7-3.0 4.0+ 2.01.1-3.6 Ward et al. Epidemiology 1996; 7: 465-71.

44. NITRATE IN DRINKING WATER: LIMITED FINDINGS NHL: 1 OF 2 STUDIES POSITIVE. OTHER STUDY IN LOWER EXPOSURE AREA. BLADDER CANCER: 2 STUDIES FROM SAME REGION (IOWA) ARE CONFLICTING. COLON CANCER: OVERALL, NO EXCESS RISK. HIGH RISK IN SUBGROUP WITH HIGH NITRATE & LOW VITAMIN C CONSUMPTION. PANCREAS CANCER: NO ASSOCIATION FOUND.