title: An exploratory study of the relation of population density and agricultural activity to hematologic malignancies in North Dakota.
abstract: BACKGROUND
  Established risk factors for hematologic cancers include exposure to ionizing radiation, organic solvents, and genetic mutation; however, the potential roles of environmental and sociological factors are not well explored. As North Dakota engages in significant agricultural activity, the present investigation seeks to determine whether an association exists between the incidence of hematologic cancers and either population density or agricultural occupation for residents of south central North Dakota.
  
  
  METHODS
  The present study is a retrospective analysis. Cases of hematologic malignancies and associated pre-malignant conditions were collected from the regional Central North Dakota Cancer Registry, and analysis of study-specific demographic factors was performed.
  
  
  RESULTS
  Significantly higher incidence of hematologic cancers and pre-malignant disorders was associated with residence in an "urban" county and rural city/town. Within the latter designation, there was a higher rate of self-reported agricultural occupation (40% vs 10%, P < 0.0001).
  
  
  CONCLUSIONS
  The increased incidence of hematologic cancer in low population density areas of south central North Dakota supports the need for more detailed prospective research centered on agricultural exposures.
authors.affiliation: University of North Dakota, School of Medicine and Health Sciences, Southwest Campus-Bismarck; c/o Bismarck Cancer Center, Bismarck, ND 58501, USA.
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Watkins
authors.forename: John M
authors.initials: JM
authors.lastname: Watkins
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000383:Agriculture; D016009:Chi-Square Distribution; D004781:Environmental Exposure; D005260:Female; D019337:Hematologic Neoplasms / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009658:North Dakota / Q000453:epidemiology; D011156:Population Density; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012424:Rural Population; D018709:Statistics, Nonparametric; D014505:Urban Population