1. Aldo Aviña Environmental and Occupational Health
Spatio-Temporal Analysis of Lymphoid Leukemia Mortality in Children aged 0-4 in Texas Counties,
Aldo Aviña
Environmental and Occupational Health

2. Leukemia Affects blood and bone marrow Four most common types
Acute Myeloid Leukemia (AML)
Acute Lymphoblastic Leukemia (ALL)
Chronic Myeloid Leukemia (CML)
Chronic Lymphocytic Leukemia (CLL)

3. Leukemia Risk factors Environmental exposures Cancer treatment Smoking
Genetic abnormalities
Family history

4. Leukemia Most common cancer in children
ALL comprises 25% of malignancies that occur in people <20 years
Survivability has increased substantially over last several decades
5-year survival, >80% by year 2000
(Smith et al, 1999; Ries et al, 2002)

5. Leukemia 5-year survival, ALL, 1990-1999 84% White children
75% Black children
72% Hispanic children
(Kadan-Lottick et al, 2003)

6. Leukemia 5-year survival, ALL, 1990-1999 69% overall
34% <1 year old
76% 1-9 years old
52% years
(Kadan-Lottick et al, 2003)

7. Research Goal Exploratory research
Identify racial disparities in Leukemia mortality across space (Texas)
Explore how Leukemia mortality is heterogeneous in time and space (Texas)

8. Data VitalWeb Standard (http://www.ehdp.com/vitalweb/use1.htm)
Texas County Level ICD-10 Underlying Cause of Death
Lymphoid Leukemia ICD C91; Ages 0-4, by race.
TIGER/Line Shapefiles (
Population by county

9. Methods Spatial Scan Statistics Compares observed/expected
SaTScan (
Retrospective space-time analysis
Poisson distribution
Data stratified by race
Compares observed/expected
Inside and outside cluster region
(Jung, Kulldorf, & Richard, 2003; Kulldorf et al, 1998)

10. Methods
Map visualization
Esri’s ArcGIS

16. Most Likely Cluster Model Results for cluster Race Observed Expected
Obs/Exp
Relative Risk
White
119
184
0.65
0.63
Black 8 24
0.34
0.32
Hispanic
128 47
2.70
3.11

22. Discussion Why is RR of Hispanics 3.11?
Count data – Greatest population of Hispanics in Texas
Requires further investigation, different model
Explore environmental factors
Mortality rate within cluster for Whites comparatively low
Geography of demographics?

23. Conclusion Geography and temporality of Leukemia by race
Heterogeneous
Emphasizes role of geography for targeted prevention and control
Questions about place vulnerability
Industrial processes, ionizing radiation exposure
Targeted studies: What environmental factors associated

25. Literature Cited
Jung I, Kulldorff M, Richard OJ, A spatial scan statistic for multinomial data. Statistics in Medicine, epub ( Kadan-Lottick, NS, Ness, KK, Bhatia, S, Gurney, JG, Survival Variability by Race and Ethnicity in Childhood Acute Lymphoblastic Leukemia. Journal of the American Medical Association, 290(15), Kulldorff M, Athas W, Feuer E, Miller B, Key C, Evaluating cluster alarms: A space-time scan statistic and brain cancer in Los Alamos. American Journal of Public Health, 88, Ries LAG, Eisner MP, Kosary CL. et al. SEER Cancer Statistics Review, Bethesda, Md: National Cancer Institute; Available at: Smith MA, Ries LAG, Gurney JG, Ross JA. Leukemia. In: Ries LAG, Smith MA, Gurney JG, et al, eds. Cancer Incidence and Survival Among Children and Adolescents: United States SEER Program , National Cancer Institute, SEER Program. Bethesda, Md: National Institutes of Health; NIH Pub No Available at: