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Spatial Clustering of Scleroderma in Three Michigan Counties

     . Spatial Clustering of Scleroderma in Three Michigan Counties. “The Toledo Twins” Sharon HensleyAlford Sarah Ann Cleveland.      .  Background . The disease that “turns people to stone” Chronic, connective tissue disease

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Spatial Clustering of Scleroderma in Three Michigan Counties

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  1.       Spatial Clustering of Scleroderma in Three Michigan Counties “The Toledo Twins” Sharon HensleyAlford Sarah Ann Cleveland      

  2. Background The disease that “turns people to stone” • Chronic, connective tissue disease • Unknown cause • Collagen accumulation in some organs Classifications • Localized • Systemic

  3. Who has scleroderma • Approximately 150,000 people in the United States • 4 times more women than men

  4. Symptoms May Include • Raynaud’s Phenomenon • Swelling of hands and feet • Pain and stiffness of joints • Thickening of the skin • Kidney, heart, and lung involvement • Oral, facial, and dental problems

  5. Diagnosis • Difficult • Involvement of several specialists • May take months to years

  6. Rates in Study Area Prevalence • 242 cases per 1million adults Incidence • 19 new cases per 1 million adults per year Reference: Prevalence, incidence and survival rates of systemic sclerosis in the Detroit metropolitan area. Mayes et al.

  7. Age Distribution of Cases

  8. Sex Distribution • 134 Females • 37 Males • 3.62 times more females than males

  9. Etiologies • UNKNOWN • Possibilities include: • silica dust • vinyl chloride monomer • pet ownership • some solvents • appetite suppressants

  10. Significance To Explore... • Environmental associations • Spatial pattern  Disease process

  11. Disease Data Incidence data for 1989-1991 (N=171) Three counties: Macomb Oakland Wayne Population Data 1990 Census data Block and Tract divisions Materials

  12. Methods • Gathering population data • Finding census data • Extract pertinent information • Geocoding cases • ArcView Batch Match • Digitizing unmatched cases

  13.  Working with Unmatched Cases  • Verifying address: US Post: www.usps.gov • Using web map programs • Mapquest: www.mapquest.com • gives county lines • Vicinity: www.mablast.com • Digitizing

  14. Batch-Matched Addresses n=148 Digitized n=13 Non-matched n=18 Unable to Digitize n=5 Matching Rate 171 Original 5 Unmatchable Addresses n=166 161 Matched/166 Total 96% Matching Rate

  15. Statistical Analysis Null Hypothesis: No spatial clustering Alter. Hypothesis: Spatial clustering Test statistic: Ipop, Moran’s I Statistical Program: STAT!

  16. Assumption R Variance : 0.0000000 z-score : -0.3175953 Significance : 0.7507920 (2-tailed) Approximation Variance : 0.0000000 z-score : -0.3121641 Significance : 0.7549158 (2-tailed) Simulation Significance : 0.8800000 (2-tailed) STAT Output 4/13/1999 Results from Ipop test Number of runs : 99 Ipop calculations Areas (m) : 194 cases (n) : 30 Population (x) : 724110 Ipop : -0.0000099 Ipop' : -0.2377846 E[I] : -0.0000014 % within : 99.9752702 % among : 0.0247298 Macomb/Tracts

  17. STAT Output 4/14/1999 Results from Ipop test Number of runs : 99 Ipop calculations Areas (m) : 661 cases (n) : 30 Population (x) : 724112 Ipop : -0.0000208 Ipop' : -0.5008514 E[I] : -0.0000014 % within : 99.9957345 % among : 0.0042655 Assumption R Variance : 0.0000000 z-score : -0.3930764 Significance : 0.6942630 (2-tailed) Approximation Variance : 0.0000000 z-score : -0.3855452 Significance : 0.6998335 (2-tailed) Simulation Significance : 0.6400000 (2-tailed) Macomb/Block

  18. STAT Output 4/13/1999 Results from Ipop test Number of runs : 99 Ipop calculations Population (x) : 1101540 Ipop : 0.0000033 Ipop' : 0.0817093 E[I] : -0.0000009 % within : 99.8772695 % among : 0.1227305 Assumption R Variance : 0.0000000 z-score : 0.2045747 Significance : 0.8379044 (2-tailed) Approximation Variance : 0.0000000 z-score : 0.2022084 Significance : 0.8397538 (2-tailed) Simulation Significance : 0.5600000 (2-tailed) Oakland/Tracts

  19. Oakland/Blocks

  20. STAT Output 4/13/1999 Results from Ipop test Number of runs : 99 Ipop calculations Areas (m) : 632 cases (n) : 86 Population (x) : 2159815 Ipop : -0.0000062 Ipop' : -0.1565116 E[I] : -0.0000005 % within : 100.4700628 % among : -0.4700628 Assumption R Variance : 0.0000000 z-score : -0.3578355 Significance : 0.7204664 (2-tailed) Approximation Variance : 0.0000000 z-score : -0.3542334 Significance : 0.7231640 (2-tailed) Simulation Significance : 0.9200000 (2-tailed) Wayne/Tracts

  21. Wayne/Blocks

  22. Discussion Limitations of Analysis • Position uncertainty • Residential history • Reliability of census data Future Analysis • Stratification by age, sex, race • 3 county combination analysis • Space/Time Analysis

  23. Thank You First Honors: Andy Long Mark Wilson Dr. Mayes Geoff Jacquez

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